Imported from libpng-1.2.37beta03.tar
diff --git a/ANNOUNCE b/ANNOUNCE
index f291edc..f103018 100644
--- a/ANNOUNCE
+++ b/ANNOUNCE
@@ -1,5 +1,5 @@
 
-Libpng 1.2.37rc01 - May 19, 2009
+Libpng 1.2.37beta03 - May 20, 2009
 
 This is not intended to be a public release.  It will be replaced
 within a few weeks by a public version or by another test version.
@@ -9,37 +9,37 @@
 Source files with LF line endings (for Unix/Linux) and with a
 "configure" script
 
-   libpng-1.2.37rc01.tar.gz
-   libpng-1.2.37rc01.tar.lzma
+   libpng-1.2.37beta03.tar.gz
+   libpng-1.2.37beta03.tar.lzma
      (Get the lzma codec from <http://tukaani.org/lzma>).
-   libpng-1.2.37rc01.tar.bz2
+   libpng-1.2.37beta03.tar.bz2
 
 Source files with LF line endings (for Unix/Linux) without the
 "configure" script
 
-   libpng-1.2.37rc01-no-config.tar.gz
-   libpng-1.2.37rc01-no-config.tar.lzma
-   libpng-1.2.37rc01-no-config.tar.bz2
+   libpng-1.2.37beta03-no-config.tar.gz
+   libpng-1.2.37beta03-no-config.tar.lzma
+   libpng-1.2.37beta03-no-config.tar.bz2
 
 Source files with CRLF line endings (for Windows), without the
 "configure" script
 
-   lp1237r01.zip
-   lp1237r01.7z
-   lp1237r01.tar.bz2
+   lp1237b03.zip
+   lp1237b03.7z
+   lp1237b03.tar.bz2
 
 Project files
 
-   libpng-1.2.37rc01-project-netware.zip
-   libpng-1.2.37rc01-project-wince.zip
+   libpng-1.2.37beta03-project-netware.zip
+   libpng-1.2.37beta03-project-wince.zip
 
 Other information:
 
-   libpng-1.2.37rc01-README.txt
-   libpng-1.2.37rc01-KNOWNBUGS.txt
-   libpng-1.2.37rc01-LICENSE.txt
-   libpng-1.2.37rc01-Y2K-compliance.txt
-   libpng-1.2.37rc01-[previous version]-diff.txt
+   libpng-1.2.37beta03-README.txt
+   libpng-1.2.37beta03-KNOWNBUGS.txt
+   libpng-1.2.37beta03-LICENSE.txt
+   libpng-1.2.37beta03-Y2K-compliance.txt
+   libpng-1.2.37beta03-[previous version]-diff.txt
 
 Changes since the last public release (1.2.36):
 
@@ -59,7 +59,11 @@
   Added contrib/pngminim/preader to demonstrate building minimal progressive
     decoder, based on contrib/gregbook with embedded libpng and zlib.
 
-version 1.2.37rc01 [May 19, 2009]
+version 1.2.37beta03 [May 20, 2009]
+  In contrib/pngminim/*, renamed "makefile.std" to "makefile", since there
+    is only one makefile in those directories, and revised the README files
+    accordingly.
+  Reformated sources in libpng style (3-space indentation, comment format)
 
 Send comments/corrections/commendations to png-mng-implement at lists.sf.net
 
diff --git a/CHANGES b/CHANGES
index 8d7a3b3..8ec3e1a 100644
--- a/CHANGES
+++ b/CHANGES
@@ -2384,7 +2384,12 @@
   Added contrib/pngminim/preader to demonstrate building minimal progressive
     decoder, based on contrib/gregbook with embedded libpng and zlib.
 
-version 1.2.37rc01 [May 19, 2009]
+version 1.2.37beta03 [May 20, 2009]
+  In contrib/pngminim/*, renamed "makefile.std" to "makefile", since there
+    is only one makefile in those directories, and revised the README files
+    accordingly.
+  Reformated sources in libpng style (3-space indentation, comment format)
+  
 
 Send comments/corrections/commendations to png-mng-implement at lists.sf.net
 (subscription required; visit
diff --git a/INSTALL b/INSTALL
index 2382756..7565b29 100644
--- a/INSTALL
+++ b/INSTALL
@@ -1,5 +1,5 @@
 
-Installing libpng version 1.2.37rc01 - May 19, 2009
+Installing libpng version 1.2.37beta03 - May 20, 2009
 
 On Unix/Linux and similar systems, you can simply type
 
@@ -44,7 +44,7 @@
 correspond to the version of zlib that's installed.
 
 You can rename the directories that you downloaded (they
-might be called "libpng-1.2.37rc01" or "lpng109" and "zlib-1.2.1"
+might be called "libpng-1.2.37beta03" or "lpng109" and "zlib-1.2.1"
 or "zlib121") so that you have directories called "zlib" and "libpng".
 
 Your directory structure should look like this:
@@ -101,9 +101,9 @@
  CMakeLists.txt    =>  "cmake" script
  makefile.std      =>  Generic UNIX makefile (cc, creates static libpng.a)
  makefile.elf      =>  Linux/ELF makefile symbol versioning,
-                       gcc, creates libpng12.so.0.1.2.37rc01)
+                       gcc, creates libpng12.so.0.1.2.37beta03)
  makefile.linux    =>  Linux/ELF makefile
-                       (gcc, creates libpng12.so.0.1.2.37rc01)
+                       (gcc, creates libpng12.so.0.1.2.37beta03)
  makefile.gcc      =>  Generic makefile (gcc, creates static libpng.a)
  makefile.knr      =>  Archaic UNIX Makefile that converts files with
                        ansi2knr (Requires ansi2knr.c from
@@ -125,14 +125,14 @@
  makefile.openbsd  =>  OpenBSD makefile
  makefile.sgi      =>  Silicon Graphics IRIX makefile (cc, creates static lib)
  makefile.sggcc    =>  Silicon Graphics (gcc,
-                       creates libpng12.so.0.1.2.37rc01)
+                       creates libpng12.so.0.1.2.37beta03)
  makefile.sunos    =>  Sun makefile
  makefile.solaris  =>  Solaris 2.X makefile (gcc,
-                       creates libpng12.so.0.1.2.37rc01)
+                       creates libpng12.so.0.1.2.37beta03)
  makefile.solaris-x86 =>  Solaris/intelMMX 2.X makefile (gcc,
-                       creates libpng12.so.0.1.2.37rc01)
+                       creates libpng12.so.0.1.2.37beta03)
  makefile.so9      =>  Solaris 9 makefile (gcc,
-                       creates libpng12.so.0.1.2.37rc01)
+                       creates libpng12.so.0.1.2.37beta03)
  makefile.32sunu   =>  Sun Ultra 32-bit makefile
  makefile.64sunu   =>  Sun Ultra 64-bit makefile
  makefile.sco      =>  For SCO OSr5  ELF and Unixware 7 with Native cc
diff --git a/KNOWNBUG b/KNOWNBUG
index 8c9dd4c..dce6f12 100644
--- a/KNOWNBUG
+++ b/KNOWNBUG
@@ -1,5 +1,5 @@
 
-Known bugs in libpng version 1.2.37rc01
+Known bugs in libpng version 1.2.37beta03
 
 1. February 23, 2006: The custom makefiles don't build libpng with -lz.
 
diff --git a/LICENSE b/LICENSE
index 093fd1d..449e438 100644
--- a/LICENSE
+++ b/LICENSE
@@ -8,7 +8,7 @@
 If you modify libpng you may insert additional notices immediately following
 this sentence.
 
-libpng versions 1.2.6, August 15, 2004, through 1.2.37rc01, May 19, 2009, are
+libpng versions 1.2.6, August 15, 2004, through 1.2.37beta03, May 20, 2009, are
 Copyright (c) 2004, 2006-2009 Glenn Randers-Pehrson, and are
 distributed according to the same disclaimer and license as libpng-1.2.5
 with the following individual added to the list of Contributing Authors
@@ -106,4 +106,4 @@
 
 Glenn Randers-Pehrson
 glennrp at users.sourceforge.net
-May 19, 2009
+May 20, 2009
diff --git a/Makefile.am b/Makefile.am
index d2ba6b3..3703539 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -86,7 +86,7 @@
 	${srcdir}/contrib/pngsuite/* \
 	${srcdir}/contrib/visupng/* \
 	$(TESTS) \
-	example.c libpng-1.2.37rc01.txt pngvcrd.c 
+	example.c libpng-1.2.37beta03.txt pngvcrd.c 
 
 CLEANFILES= pngout.png libpng12.pc libpng12-config libpng.vers \
 libpng.sym
diff --git a/Makefile.in b/Makefile.in
index ad6ef51..06d04e7 100644
--- a/Makefile.in
+++ b/Makefile.in
@@ -333,7 +333,7 @@
 	${srcdir}/contrib/pngsuite/* \
 	${srcdir}/contrib/visupng/* \
 	$(TESTS) \
-	example.c libpng-1.2.37rc01.txt pngvcrd.c 
+	example.c libpng-1.2.37beta03.txt pngvcrd.c 
 
 CLEANFILES = pngout.png libpng12.pc libpng12-config libpng.vers \
 libpng.sym
diff --git a/README b/README
index 5495bd5..65cd5aa 100644
--- a/README
+++ b/README
@@ -1,4 +1,4 @@
-README for libpng version 1.2.37rc01 - May 19, 2009 (shared library 12.0)
+README for libpng version 1.2.37beta03 - May 20, 2009 (shared library 12.0)
 See the note about version numbers near the top of png.h
 
 See INSTALL for instructions on how to install libpng.
@@ -194,11 +194,11 @@
        descrip.mms      =>  VMS makefile for MMS or MMK
        makefile.std     =>  Generic UNIX makefile (cc, creates static libpng.a)
        makefile.elf     =>  Linux/ELF makefile symbol versioning,
-                            gcc, creates libpng12.so.0.1.2.37rc01)
+                            gcc, creates libpng12.so.0.1.2.37beta03)
        makefile.linux   =>  Linux/ELF makefile
-                            (gcc, creates libpng12.so.0.1.2.37rc01)
+                            (gcc, creates libpng12.so.0.1.2.37beta03)
        makefile.gcmmx   =>  Linux/ELF makefile
-                            (gcc, creates libpng12.so.0.1.2.37rc01,
+                            (gcc, creates libpng12.so.0.1.2.37beta03,
                             uses assembler code tuned for Intel MMX platform)
        makefile.gcc     =>  Generic makefile (gcc, creates static libpng.a)
        makefile.knr     =>  Archaic UNIX Makefile that converts files with
@@ -220,12 +220,12 @@
        makefile.openbsd =>  OpenBSD makefile
        makefile.sgi     =>  Silicon Graphics IRIX (cc, creates static lib)
        makefile.sggcc   =>  Silicon Graphics
-                            (gcc, creates libpng12.so.0.1.2.37rc01)
+                            (gcc, creates libpng12.so.0.1.2.37beta03)
        makefile.sunos   =>  Sun makefile
        makefile.solaris =>  Solaris 2.X makefile
-                            (gcc, creates libpng12.so.0.1.2.37rc01)
+                            (gcc, creates libpng12.so.0.1.2.37beta03)
        makefile.so9     =>  Solaris 9 makefile
-                            (gcc, creates libpng12.so.0.1.2.37rc01)
+                            (gcc, creates libpng12.so.0.1.2.37beta03)
        makefile.32sunu  =>  Sun Ultra 32-bit makefile
        makefile.64sunu  =>  Sun Ultra 64-bit makefile
        makefile.sco     =>  For SCO OSr5  ELF and Unixware 7 with Native cc
diff --git a/Y2KINFO b/Y2KINFO
index 5177d7c..12fa40e 100644
--- a/Y2KINFO
+++ b/Y2KINFO
@@ -1,13 +1,13 @@
    Y2K compliance in libpng:
    =========================
 
-      May 19, 2009
+      May 20, 2009
 
       Since the PNG Development group is an ad-hoc body, we can't make
       an official declaration.
 
       This is your unofficial assurance that libpng from version 0.71 and
-      upward through 1.2.37rc01 are Y2K compliant.  It is my belief that earlier
+      upward through 1.2.37beta03 are Y2K compliant.  It is my belief that earlier
       versions were also Y2K compliant.
 
       Libpng only has three year fields.  One is a 2-byte unsigned integer
diff --git a/configure b/configure
index 9fb9079..9017065 100755
--- a/configure
+++ b/configure
Binary files differ
diff --git a/configure.ac b/configure.ac
index 55b20c0..57f659d 100644
--- a/configure.ac
+++ b/configure.ac
@@ -18,12 +18,12 @@
 
 dnl Version number stuff here:
 
-AC_INIT([libpng], [1.2.37rc01], [png-mng-implement@lists.sourceforge.net])
+AC_INIT([libpng], [1.2.37beta03], [png-mng-implement@lists.sourceforge.net])
 AM_INIT_AUTOMAKE
 dnl stop configure from automagically running automake
 AM_MAINTAINER_MODE
 
-PNGLIB_VERSION=1.2.37rc01
+PNGLIB_VERSION=1.2.37beta03
 PNGLIB_MAJOR=1
 PNGLIB_MINOR=2
 PNGLIB_RELEASE=37
diff --git a/contrib/pngminim/decoder/README b/contrib/pngminim/decoder/README
index 981b60b..a656e0b 100644
--- a/contrib/pngminim/decoder/README
+++ b/contrib/pngminim/decoder/README
@@ -1,7 +1,9 @@
 This demonstrates the use of PNG_USER_CONFIG and pngusr.h
 
-To build a minimal read-only decoder, run
+To build a minimal read-only decoder with embedded libpng and zlib, run
 
     gather.sh  # to collect needed files from pngminus, libpng, and zlib
     make
- 
+
+If you prefer to use the shared libraries, go to contrib/pngminus
+and build the png2pnm application there. 
diff --git a/contrib/pngminim/encoder/README b/contrib/pngminim/encoder/README
index 3a44f13..2285544 100644
--- a/contrib/pngminim/encoder/README
+++ b/contrib/pngminim/encoder/README
@@ -1,7 +1,9 @@
 This demonstrates the use of PNG_USER_CONFIG and pngusr.h
 
-To build a minimal write-only encoder, run
+To build a minimal write-only decoder with embedded libpng and zlib, run
 
     gather.sh  # to collect needed files from pngminus, libpng, and zlib
     make
  
+If you prefer to use the shared libraries, go to contrib/pngminus
+and build the pnm2png application there. 
diff --git a/contrib/pngminim/preader/README b/contrib/pngminim/preader/README
index 33239dd..377d641 100644
--- a/contrib/pngminim/preader/README
+++ b/contrib/pngminim/preader/README
@@ -1,6 +1,7 @@
 This demonstrates the use of PNG_USER_CONFIG and pngusr.h
 
-To build a minimal read-only progressive decoder with X display, run
+To build a minimal read-only progressive decoder embedded libpng and
+zlib and with your system's X library, run
 
     gather.sh # to collect needed files from gregbook, libpng, and zlib
 
@@ -9,3 +10,5 @@
     
     make
  
+If you prefer to use the shared libraries, go to contrib/gregbook
+and build the rpng2-x application there. 
diff --git a/example.c b/example.c
index 72d0646..4075438 100644
--- a/example.c
+++ b/example.c
@@ -2,7 +2,7 @@
 #if 0 /* in case someone actually tries to compile this */
 
 /* example.c - an example of using libpng
- * Last changed in libpng 1.2.37 [May 19, 2009]
+ * Last changed in libpng 1.2.37 [May 20, 2009]
  * This file has been placed in the public domain by the authors.
  * Maintained 1998-2009 Glenn Randers-Pehrson
  * Maintained 1996, 1997 Andreas Dilger)
@@ -93,13 +93,13 @@
       return (ERROR);
 
 #else no_open_file /* prototype 2 */
-void read_png(FILE *fp, unsigned int sig_read)  /* file is already open */
+void read_png(FILE *fp, unsigned int sig_read)  /* File is already open */
 {
    png_structp png_ptr;
    png_infop info_ptr;
    png_uint_32 width, height;
    int bit_depth, color_type, interlace_type;
-#endif no_open_file /* only use one prototype! */
+#endif no_open_file /* Only use one prototype! */
 
    /* Create and initialize the png_struct with the desired error handler
     * functions.  If you want to use the default stderr and longjump method,
@@ -177,11 +177,11 @@
    png_get_IHDR(png_ptr, info_ptr, &width, &height, &bit_depth, &color_type,
        &interlace_type, int_p_NULL, int_p_NULL);
 
-/* Set up the data transformations you want.  Note that these are all
- * optional.  Only call them if you want/need them.  Many of the
- * transformations only work on specific types of images, and many
- * are mutually exclusive.
- */
+   /* Set up the data transformations you want.  Note that these are all
+    * optional.  Only call them if you want/need them.  Many of the
+    * transformations only work on specific types of images, and many
+    * are mutually exclusive.
+    */
 
    /* Tell libpng to strip 16 bit/color files down to 8 bits/color */
    png_set_strip_16(png_ptr);
@@ -230,9 +230,9 @@
       png_set_background(png_ptr, &my_background,
                          PNG_BACKGROUND_GAMMA_SCREEN, 0, 1.0);
 
-   /* Some suggestions as to how to get a screen gamma value */
-
-   /* Note that screen gamma is the display_exponent, which includes
+   /* Some suggestions as to how to get a screen gamma value
+    *
+    * Note that screen gamma is the display_exponent, which includes
     * the CRT_exponent and any correction for viewing conditions
     */
    if (/* We have a user-defined screen gamma value */)
@@ -280,7 +280,7 @@
       png_colorp palette;
 
       /* This reduces the image to the application supplied palette */
-      if (/* we have our own palette */)
+      if (/* We have our own palette */)
       {
          /* An array of colors to which the image should be dithered */
          png_color std_color_cube[MAX_SCREEN_COLORS];
@@ -377,13 +377,13 @@
 #else no_sparkle /* Read the image using the "rectangle" effect */
          png_read_rows(png_ptr, png_bytepp_NULL, &row_pointers[y],
             number_of_rows);
-#endif no_sparkle /* use only one of these two methods */
+#endif no_sparkle /* Use only one of these two methods */
       }
 
-      /* if you want to display the image after every pass, do so here */
-#endif no_single /* use only one of these two methods */
+      /* If you want to display the image after every pass, do so here */
+#endif no_single /* Use only one of these two methods */
    }
-#endif no_entire /* use only one of these two methods */
+#endif no_entire /* Use only one of these two methods */
 
    /* Read rest of file, and get additional chunks in info_ptr - REQUIRED */
    png_read_end(png_ptr, info_ptr);
@@ -397,7 +397,7 @@
    /* Close the file */
    fclose(fp);
 
-   /* that's it */
+   /* That's it */
    return (OK);
 }
 
@@ -480,34 +480,35 @@
 
 info_callback(png_structp png_ptr, png_infop info)
 {
-/* Do any setup here, including setting any of the transformations
- * mentioned in the Reading PNG files section.  For now, you _must_
- * call either png_start_read_image() or png_read_update_info()
- * after all the transformations are set (even if you don't set
- * any).  You may start getting rows before png_process_data()
- * returns, so this is your last chance to prepare for that.
- */
+   /* Do any setup here, including setting any of the transformations
+    * mentioned in the Reading PNG files section.  For now, you _must_
+    * call either png_start_read_image() or png_read_update_info()
+    * after all the transformations are set (even if you don't set
+    * any).  You may start getting rows before png_process_data()
+    * returns, so this is your last chance to prepare for that.
+    */
 }
 
 row_callback(png_structp png_ptr, png_bytep new_row,
    png_uint_32 row_num, int pass)
 {
-/*
- * This function is called for every row in the image.  If the
- * image is interlaced, and you turned on the interlace handler,
- * this function will be called for every row in every pass.
- *
- * In this function you will receive a pointer to new row data from
- * libpng called new_row that is to replace a corresponding row (of
- * the same data format) in a buffer allocated by your application.
- *
- * The new row data pointer "new_row" may be NULL, indicating there is
- * no new data to be replaced (in cases of interlace loading).
- *
- * If new_row is not NULL then you need to call
- * png_progressive_combine_row() to replace the corresponding row as
- * shown below:
- */
+   /*
+    * This function is called for every row in the image.  If the
+    * image is interlaced, and you turned on the interlace handler,
+    * this function will be called for every row in every pass.
+    *
+    * In this function you will receive a pointer to new row data from
+    * libpng called new_row that is to replace a corresponding row (of
+    * the same data format) in a buffer allocated by your application.
+    *
+    * The new row data pointer "new_row" may be NULL, indicating there is
+    * no new data to be replaced (in cases of interlace loading).
+    *
+    * If new_row is not NULL then you need to call
+    * png_progressive_combine_row() to replace the corresponding row as
+    * shown below:
+    */
+
    /* Check if row_num is in bounds. */
    if ((row_num >= 0) && (row_num < height))
    {
@@ -522,41 +523,41 @@
      if ((old_row != NULL) && (new_row != NULL))
      png_progressive_combine_row(png_ptr, old_row, new_row);
    }
-/*
- * The rows and passes are called in order, so you don't really
- * need the row_num and pass, but I'm supplying them because it
- * may make your life easier.
- *
- * For the non-NULL rows of interlaced images, you must call
- * png_progressive_combine_row() passing in the new row and the
- * old row, as demonstrated above.  You can call this function for
- * NULL rows (it will just return) and for non-interlaced images
- * (it just does the png_memcpy for you) if it will make the code
- * easier.  Thus, you can just do this for all cases:
- */
+   /*
+    * The rows and passes are called in order, so you don't really
+    * need the row_num and pass, but I'm supplying them because it
+    * may make your life easier.
+    *
+    * For the non-NULL rows of interlaced images, you must call
+    * png_progressive_combine_row() passing in the new row and the
+    * old row, as demonstrated above.  You can call this function for
+    * NULL rows (it will just return) and for non-interlaced images
+    * (it just does the png_memcpy for you) if it will make the code
+    * easier.  Thus, you can just do this for all cases:
+    */
 
    png_progressive_combine_row(png_ptr, old_row, new_row);
 
-/* where old_row is what was displayed for previous rows.  Note
- * that the first pass (pass == 0 really) will completely cover
- * the old row, so the rows do not have to be initialized.  After
- * the first pass (and only for interlaced images), you will have
- * to pass the current row as new_row, and the function will combine
- * the old row and the new row.
- */
+   /* where old_row is what was displayed for previous rows.  Note
+    * that the first pass (pass == 0 really) will completely cover
+    * the old row, so the rows do not have to be initialized.  After
+    * the first pass (and only for interlaced images), you will have
+    * to pass the current row as new_row, and the function will combine
+    * the old row and the new row.
+    */
 }
 
 end_callback(png_structp png_ptr, png_infop info)
 {
-/* This function is called when the whole image has been read,
- * including any chunks after the image (up to and including
- * the IEND).  You will usually have the same info chunk as you
- * had in the header, although some data may have been added
- * to the comments and time fields.
- *
- * Most people won't do much here, perhaps setting a flag that
- * marks the image as finished.
- */
+   /* This function is called when the whole image has been read,
+    * including any chunks after the image (up to and including
+    * the IEND).  You will usually have the same info chunk as you
+    * had in the header, although some data may have been added
+    * to the comments and time fields.
+    *
+    * Most people won't do much here, perhaps setting a flag that
+    * marks the image as finished.
+    */
 }
 
 /* Write a png file */
@@ -608,6 +609,7 @@
    }
 
    /* One of the following I/O initialization functions is REQUIRED */
+
 #ifdef streams /* I/O initialization method 1 */
    /* Set up the output control if you are using standard C streams */
    png_init_io(png_ptr, fp);
@@ -619,7 +621,7 @@
    png_set_write_fn(png_ptr, (void *)user_io_ptr, user_write_fn,
       user_IO_flush_function);
    /* where user_io_ptr is a structure you want available to the callbacks */
-#endif no_streams /* only use one initialization method */
+#endif no_streams /* Only use one initialization method */
 
 #ifdef hilevel
    /* This is the easy way.  Use it if you already have all the
@@ -771,7 +773,7 @@
 #ifdef entire /* Write out the entire image data in one call */
    png_write_image(png_ptr, row_pointers);
 
-   /* the other way to write the image - deal with interlacing */
+   /* The other way to write the image - deal with interlacing */
 
 #else no_entire /* Write out the image data by one or more scanlines */
 
diff --git a/libpng-1.2.37rc01.txt b/libpng-1.2.37beta03.txt
similarity index 99%
rename from libpng-1.2.37rc01.txt
rename to libpng-1.2.37beta03.txt
index 8826ec7..43d6a3e 100644
--- a/libpng-1.2.37rc01.txt
+++ b/libpng-1.2.37beta03.txt
@@ -1,6 +1,6 @@
 libpng.txt - A description on how to use and modify libpng
 
- libpng version 1.2.37rc01 - May 19, 2009
+ libpng version 1.2.37beta03 - May 20, 2009
  Updated and distributed by Glenn Randers-Pehrson
  <glennrp at users.sourceforge.net>
  Copyright (c) 1998-2009 Glenn Randers-Pehrson
@@ -9,7 +9,7 @@
 
  Based on:
 
- libpng versions 0.97, January 1998, through 1.2.37rc01 - May 19, 2009
+ libpng versions 0.97, January 1998, through 1.2.37beta03 - May 20, 2009
  Updated and distributed by Glenn Randers-Pehrson
  Copyright (c) 1998-2009 Glenn Randers-Pehrson
 
@@ -2947,13 +2947,13 @@
 IX.  (Omitted)
 X. Y2K Compliance in libpng
 
-May 19, 2009
+May 20, 2009
 
 Since the PNG Development group is an ad-hoc body, we can't make
 an official declaration.
 
 This is your unofficial assurance that libpng from version 0.71 and
-upward through 1.2.37rc01 are Y2K compliant.  It is my belief that earlier
+upward through 1.2.37beta03 are Y2K compliant.  It is my belief that earlier
 versions were also Y2K compliant.
 
 Libpng only has three year fields.  One is a 2-byte unsigned integer that
diff --git a/libpng.3 b/libpng.3
index 8e45c64..2e0f19c 100644
--- a/libpng.3
+++ b/libpng.3
@@ -1,6 +1,6 @@
-.TH LIBPNG 3 "May 19, 2009"
+.TH LIBPNG 3 "May 20, 2009"
 .SH NAME
-libpng \- Portable Network Graphics (PNG) Reference Library 1.2.37rc01
+libpng \- Portable Network Graphics (PNG) Reference Library 1.2.37beta03
 .SH SYNOPSIS
 \fI\fB
 
@@ -821,7 +821,7 @@
 .SH LIBPNG.TXT
 libpng.txt - A description on how to use and modify libpng
 
- libpng version 1.2.37rc01 - May 19, 2009
+ libpng version 1.2.37beta03 - May 20, 2009
  Updated and distributed by Glenn Randers-Pehrson
  <glennrp at users.sourceforge.net>
  Copyright (c) 1998-2009 Glenn Randers-Pehrson
@@ -830,7 +830,7 @@
 
  Based on:
 
- libpng versions 0.97, January 1998, through 1.2.37rc01 - May 19, 2009
+ libpng versions 0.97, January 1998, through 1.2.37beta03 - May 20, 2009
  Updated and distributed by Glenn Randers-Pehrson
  Copyright (c) 1998-2009 Glenn Randers-Pehrson
 
@@ -3768,13 +3768,13 @@
 .SH IX.  (Omitted)
 .SH X. Y2K Compliance in libpng
 
-May 19, 2009
+May 20, 2009
 
 Since the PNG Development group is an ad-hoc body, we can't make
 an official declaration.
 
 This is your unofficial assurance that libpng from version 0.71 and
-upward through 1.2.37rc01 are Y2K compliant.  It is my belief that earlier
+upward through 1.2.37beta03 are Y2K compliant.  It is my belief that earlier
 versions were also Y2K compliant.
 
 Libpng only has three year fields.  One is a 2-byte unsigned integer that
@@ -4040,7 +4040,7 @@
  1.2.36rc01          13    10236  12.so.0.36[.0]
  1.0.44              10    10044  10.so.0.44[.0]
  1.2.36              13    10236  12.so.0.36[.0]
- 1.2.37rc01          13    10237  12.so.0.37[.0]
+ 1.2.37beta01-03     13    10237  12.so.0.37[.0]
 
 Henceforth the source version will match the shared-library minor
 and patch numbers; the shared-library major version number will be
@@ -4096,7 +4096,7 @@
 
 Thanks to Frank J. T. Wojcik for helping with the documentation.
 
-Libpng version 1.2.37rc01 - May 19, 2009:
+Libpng version 1.2.37beta03 - May 20, 2009:
 Initially created in 1995 by Guy Eric Schalnat, then of Group 42, Inc.
 Currently maintained by Glenn Randers-Pehrson (glennrp at users.sourceforge.net).
 
@@ -4117,7 +4117,7 @@
 If you modify libpng you may insert additional notices immediately following
 this sentence.
 
-libpng versions 1.2.6, August 15, 2004, through 1.2.37rc01, May 19, 2009, are
+libpng versions 1.2.6, August 15, 2004, through 1.2.37beta03, May 20, 2009, are
 Copyright (c) 2004,2006-2008 Glenn Randers-Pehrson, and are
 distributed according to the same disclaimer and license as libpng-1.2.5
 with the following individual added to the list of Contributing Authors
@@ -4216,7 +4216,7 @@
 
 Glenn Randers-Pehrson
 glennrp at users.sourceforge.net
-May 19, 2009
+May 20, 2009
 
 .\" end of man page
 
diff --git a/libpngpf.3 b/libpngpf.3
index fcbb4be..30b99db 100644
--- a/libpngpf.3
+++ b/libpngpf.3
@@ -1,6 +1,6 @@
-.TH LIBPNGPF 3 "May 19, 2009"
+.TH LIBPNGPF 3 "May 20, 2009"
 .SH NAME
-libpng \- Portable Network Graphics (PNG) Reference Library 1.2.37rc01
+libpng \- Portable Network Graphics (PNG) Reference Library 1.2.37beta03
 (private functions)
 .SH SYNOPSIS
 \fB#include <png.h>\fP
diff --git a/png.5 b/png.5
index 853dfa6..eea7f69 100644
--- a/png.5
+++ b/png.5
@@ -1,4 +1,4 @@
-.TH PNG 5 "May 19, 2009"
+.TH PNG 5 "May 20, 2009"
 .SH NAME
 png \- Portable Network Graphics (PNG) format
 .SH DESCRIPTION
diff --git a/png.c b/png.c
index 6ee1685..40cd28c 100644
--- a/png.c
+++ b/png.c
@@ -1,9 +1,9 @@
 
 /* png.c - location for general purpose libpng functions
  *
- * Last changed in libpng 1.2.34 [December 18, 2008]
+ * Last changed in libpng 1.2.37 [May 20, 2009]
  * For conditions of distribution and use, see copyright notice in png.h
- * Copyright (c) 1998-2008 Glenn Randers-Pehrson
+ * Copyright (c) 1998-2009 Glenn Randers-Pehrson
  * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
  * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
  */
@@ -13,7 +13,7 @@
 #include "png.h"
 
 /* Generate a compiler error if there is an old png.h in the search path. */
-typedef version_1_2_37rc01 Your_png_h_is_not_version_1_2_37rc01;
+typedef version_1_2_37beta03 Your_png_h_is_not_version_1_2_37beta03;
 
 /* Version information for C files.  This had better match the version
  * string defined in png.h.  */
@@ -53,18 +53,18 @@
 PNG_zTXt;
 
 #ifdef PNG_READ_SUPPORTED
-/* arrays to facilitate easy interlacing - use pass (0 - 6) as index */
+/* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */
 
-/* start of interlace block */
+/* Start of interlace block */
 PNG_CONST int FARDATA png_pass_start[] = {0, 4, 0, 2, 0, 1, 0};
 
-/* offset to next interlace block */
+/* Offset to next interlace block */
 PNG_CONST int FARDATA png_pass_inc[] = {8, 8, 4, 4, 2, 2, 1};
 
-/* start of interlace block in the y direction */
+/* Start of interlace block in the y direction */
 PNG_CONST int FARDATA png_pass_ystart[] = {0, 0, 4, 0, 2, 0, 1};
 
-/* offset to next interlace block in the y direction */
+/* Offset to next interlace block in the y direction */
 PNG_CONST int FARDATA png_pass_yinc[] = {8, 8, 8, 4, 4, 2, 2};
 
 /* Height of interlace block.  This is not currently used - if you need
@@ -92,7 +92,8 @@
 void PNGAPI
 png_set_sig_bytes(png_structp png_ptr, int num_bytes)
 {
-   if (png_ptr == NULL) return;
+   if (png_ptr == NULL)
+      return;
    png_debug(1, "in png_set_sig_bytes");
    if (num_bytes > 8)
       png_error(png_ptr, "Too many bytes for PNG signature.");
@@ -153,7 +154,8 @@
    png_uint_32 save_flags=p->flags;
    png_uint_32 num_bytes;
 
-   if (png_ptr == NULL) return (NULL);
+   if (png_ptr == NULL)
+      return (NULL);
    if (items > PNG_UINT_32_MAX/size)
    {
      png_warning (p, "Potential overflow in png_zalloc()");
@@ -183,7 +185,7 @@
    return ((voidpf)ptr);
 }
 
-/* function to free memory for zlib */
+/* Function to free memory for zlib */
 #ifdef PNG_1_0_X
 void PNGAPI
 #else
@@ -241,7 +243,8 @@
    png_infop info_ptr;
 
    png_debug(1, "in png_create_info_struct");
-   if (png_ptr == NULL) return (NULL);
+   if (png_ptr == NULL)
+      return (NULL);
 #ifdef PNG_USER_MEM_SUPPORTED
    info_ptr = (png_infop)png_create_struct_2(PNG_STRUCT_INFO,
       png_ptr->malloc_fn, png_ptr->mem_ptr);
@@ -263,7 +266,8 @@
 png_destroy_info_struct(png_structp png_ptr, png_infopp info_ptr_ptr)
 {
    png_infop info_ptr = NULL;
-   if (png_ptr == NULL) return;
+   if (png_ptr == NULL)
+      return;
 
    png_debug(1, "in png_destroy_info_struct");
    if (info_ptr_ptr != NULL)
@@ -302,18 +306,19 @@
 {
    png_infop info_ptr = *ptr_ptr;
 
-   if (info_ptr == NULL) return;
+   if (info_ptr == NULL)
+      return;
 
    png_debug(1, "in png_info_init_3");
 
    if (png_sizeof(png_info) > png_info_struct_size)
-     {
-       png_destroy_struct(info_ptr);
-       info_ptr = (png_infop)png_create_struct(PNG_STRUCT_INFO);
-       *ptr_ptr = info_ptr;
-     }
+   {
+      png_destroy_struct(info_ptr);
+      info_ptr = (png_infop)png_create_struct(PNG_STRUCT_INFO);
+      *ptr_ptr = info_ptr;
+   }
 
-   /* set everything to 0 */
+   /* Set everything to 0 */
    png_memset(info_ptr, 0, png_sizeof(png_info));
 }
 
@@ -344,245 +349,245 @@
       return;
 
 #if defined(PNG_TEXT_SUPPORTED)
-/* free text item num or (if num == -1) all text items */
+   /* Free text item num or (if num == -1) all text items */
 #ifdef PNG_FREE_ME_SUPPORTED
-if ((mask & PNG_FREE_TEXT) & info_ptr->free_me)
+   if ((mask & PNG_FREE_TEXT) & info_ptr->free_me)
 #else
-if (mask & PNG_FREE_TEXT)
+   if (mask & PNG_FREE_TEXT)
 #endif
-{
-   if (num != -1)
    {
-     if (info_ptr->text && info_ptr->text[num].key)
-     {
-         png_free(png_ptr, info_ptr->text[num].key);
-         info_ptr->text[num].key = NULL;
-     }
+      if (num != -1)
+      {
+         if (info_ptr->text && info_ptr->text[num].key)
+         {
+            png_free(png_ptr, info_ptr->text[num].key);
+            info_ptr->text[num].key = NULL;
+         }
+      }
+      else
+      {
+         int i;
+         for (i = 0; i < info_ptr->num_text; i++)
+             png_free_data(png_ptr, info_ptr, PNG_FREE_TEXT, i);
+         png_free(png_ptr, info_ptr->text);
+         info_ptr->text = NULL;
+         info_ptr->num_text=0;
+      }
    }
-   else
-   {
-       int i;
-       for (i = 0; i < info_ptr->num_text; i++)
-           png_free_data(png_ptr, info_ptr, PNG_FREE_TEXT, i);
-       png_free(png_ptr, info_ptr->text);
-       info_ptr->text = NULL;
-       info_ptr->num_text=0;
-   }
-}
 #endif
 
 #if defined(PNG_tRNS_SUPPORTED)
-/* free any tRNS entry */
+   /* Free any tRNS entry */
 #ifdef PNG_FREE_ME_SUPPORTED
-if ((mask & PNG_FREE_TRNS) & info_ptr->free_me)
+   if ((mask & PNG_FREE_TRNS) & info_ptr->free_me)
 #else
-if ((mask & PNG_FREE_TRNS) && (png_ptr->flags & PNG_FLAG_FREE_TRNS))
+   if ((mask & PNG_FREE_TRNS) && (png_ptr->flags & PNG_FLAG_FREE_TRNS))
 #endif
-{
-    png_free(png_ptr, info_ptr->trans);
-    info_ptr->trans = NULL;
-    info_ptr->valid &= ~PNG_INFO_tRNS;
+   {
+      png_free(png_ptr, info_ptr->trans);
+      info_ptr->trans = NULL;
+      info_ptr->valid &= ~PNG_INFO_tRNS;
 #ifndef PNG_FREE_ME_SUPPORTED
-    png_ptr->flags &= ~PNG_FLAG_FREE_TRNS;
+      png_ptr->flags &= ~PNG_FLAG_FREE_TRNS;
 #endif
-}
+   }
 #endif
 
 #if defined(PNG_sCAL_SUPPORTED)
-/* free any sCAL entry */
+   /* Free any sCAL entry */
 #ifdef PNG_FREE_ME_SUPPORTED
-if ((mask & PNG_FREE_SCAL) & info_ptr->free_me)
+   if ((mask & PNG_FREE_SCAL) & info_ptr->free_me)
 #else
-if (mask & PNG_FREE_SCAL)
+   if (mask & PNG_FREE_SCAL)
 #endif
-{
+   {
 #if defined(PNG_FIXED_POINT_SUPPORTED) && !defined(PNG_FLOATING_POINT_SUPPORTED)
-    png_free(png_ptr, info_ptr->scal_s_width);
-    png_free(png_ptr, info_ptr->scal_s_height);
-    info_ptr->scal_s_width = NULL;
-    info_ptr->scal_s_height = NULL;
+      png_free(png_ptr, info_ptr->scal_s_width);
+      png_free(png_ptr, info_ptr->scal_s_height);
+      info_ptr->scal_s_width = NULL;
+      info_ptr->scal_s_height = NULL;
 #endif
-    info_ptr->valid &= ~PNG_INFO_sCAL;
-}
+      info_ptr->valid &= ~PNG_INFO_sCAL;
+   }
 #endif
 
 #if defined(PNG_pCAL_SUPPORTED)
-/* free any pCAL entry */
+   /* Free any pCAL entry */
 #ifdef PNG_FREE_ME_SUPPORTED
-if ((mask & PNG_FREE_PCAL) & info_ptr->free_me)
+   if ((mask & PNG_FREE_PCAL) & info_ptr->free_me)
 #else
-if (mask & PNG_FREE_PCAL)
+   if (mask & PNG_FREE_PCAL)
 #endif
-{
-    png_free(png_ptr, info_ptr->pcal_purpose);
-    png_free(png_ptr, info_ptr->pcal_units);
-    info_ptr->pcal_purpose = NULL;
-    info_ptr->pcal_units = NULL;
-    if (info_ptr->pcal_params != NULL)
-    {
-        int i;
-        for (i = 0; i < (int)info_ptr->pcal_nparams; i++)
-        {
-          png_free(png_ptr, info_ptr->pcal_params[i]);
-          info_ptr->pcal_params[i]=NULL;
-        }
-        png_free(png_ptr, info_ptr->pcal_params);
-        info_ptr->pcal_params = NULL;
-    }
-    info_ptr->valid &= ~PNG_INFO_pCAL;
-}
+   {
+      png_free(png_ptr, info_ptr->pcal_purpose);
+      png_free(png_ptr, info_ptr->pcal_units);
+      info_ptr->pcal_purpose = NULL;
+      info_ptr->pcal_units = NULL;
+      if (info_ptr->pcal_params != NULL)
+         {
+            int i;
+            for (i = 0; i < (int)info_ptr->pcal_nparams; i++)
+            {
+               png_free(png_ptr, info_ptr->pcal_params[i]);
+               info_ptr->pcal_params[i]=NULL;
+            }
+            png_free(png_ptr, info_ptr->pcal_params);
+            info_ptr->pcal_params = NULL;
+         }
+      info_ptr->valid &= ~PNG_INFO_pCAL;
+   }
 #endif
 
 #if defined(PNG_iCCP_SUPPORTED)
-/* free any iCCP entry */
+   /* Free any iCCP entry */
 #ifdef PNG_FREE_ME_SUPPORTED
-if ((mask & PNG_FREE_ICCP) & info_ptr->free_me)
+   if ((mask & PNG_FREE_ICCP) & info_ptr->free_me)
 #else
-if (mask & PNG_FREE_ICCP)
+   if (mask & PNG_FREE_ICCP)
 #endif
-{
-    png_free(png_ptr, info_ptr->iccp_name);
-    png_free(png_ptr, info_ptr->iccp_profile);
-    info_ptr->iccp_name = NULL;
-    info_ptr->iccp_profile = NULL;
-    info_ptr->valid &= ~PNG_INFO_iCCP;
-}
+   {
+      png_free(png_ptr, info_ptr->iccp_name);
+      png_free(png_ptr, info_ptr->iccp_profile);
+      info_ptr->iccp_name = NULL;
+      info_ptr->iccp_profile = NULL;
+      info_ptr->valid &= ~PNG_INFO_iCCP;
+   }
 #endif
 
 #if defined(PNG_sPLT_SUPPORTED)
-/* free a given sPLT entry, or (if num == -1) all sPLT entries */
+   /* Free a given sPLT entry, or (if num == -1) all sPLT entries */
 #ifdef PNG_FREE_ME_SUPPORTED
-if ((mask & PNG_FREE_SPLT) & info_ptr->free_me)
+   if ((mask & PNG_FREE_SPLT) & info_ptr->free_me)
 #else
-if (mask & PNG_FREE_SPLT)
+   if (mask & PNG_FREE_SPLT)
 #endif
-{
-   if (num != -1)
    {
-      if (info_ptr->splt_palettes)
+      if (num != -1)
       {
-          png_free(png_ptr, info_ptr->splt_palettes[num].name);
-          png_free(png_ptr, info_ptr->splt_palettes[num].entries);
-          info_ptr->splt_palettes[num].name = NULL;
-          info_ptr->splt_palettes[num].entries = NULL;
+         if (info_ptr->splt_palettes)
+         {
+            png_free(png_ptr, info_ptr->splt_palettes[num].name);
+            png_free(png_ptr, info_ptr->splt_palettes[num].entries);
+            info_ptr->splt_palettes[num].name = NULL;
+            info_ptr->splt_palettes[num].entries = NULL;
+         }
+      }
+      else
+      {
+         if (info_ptr->splt_palettes_num)
+         {
+            int i;
+            for (i = 0; i < (int)info_ptr->splt_palettes_num; i++)
+               png_free_data(png_ptr, info_ptr, PNG_FREE_SPLT, i);
+
+            png_free(png_ptr, info_ptr->splt_palettes);
+            info_ptr->splt_palettes = NULL;
+            info_ptr->splt_palettes_num = 0;
+         }
+         info_ptr->valid &= ~PNG_INFO_sPLT;
       }
    }
-   else
-   {
-       if (info_ptr->splt_palettes_num)
-       {
-         int i;
-         for (i = 0; i < (int)info_ptr->splt_palettes_num; i++)
-            png_free_data(png_ptr, info_ptr, PNG_FREE_SPLT, i);
-
-         png_free(png_ptr, info_ptr->splt_palettes);
-         info_ptr->splt_palettes = NULL;
-         info_ptr->splt_palettes_num = 0;
-       }
-       info_ptr->valid &= ~PNG_INFO_sPLT;
-   }
-}
 #endif
 
 #if defined(PNG_UNKNOWN_CHUNKS_SUPPORTED)
-  if (png_ptr->unknown_chunk.data)
-  {
-    png_free(png_ptr, png_ptr->unknown_chunk.data);
-    png_ptr->unknown_chunk.data = NULL;
-  }
+   if (png_ptr->unknown_chunk.data)
+   {
+      png_free(png_ptr, png_ptr->unknown_chunk.data);
+      png_ptr->unknown_chunk.data = NULL;
+   }
 
 #ifdef PNG_FREE_ME_SUPPORTED
-if ((mask & PNG_FREE_UNKN) & info_ptr->free_me)
+   if ((mask & PNG_FREE_UNKN) & info_ptr->free_me)
 #else
-if (mask & PNG_FREE_UNKN)
+   if (mask & PNG_FREE_UNKN)
 #endif
-{
-   if (num != -1)
    {
-       if (info_ptr->unknown_chunks)
-       {
-          png_free(png_ptr, info_ptr->unknown_chunks[num].data);
-          info_ptr->unknown_chunks[num].data = NULL;
-       }
-   }
-   else
-   {
-       int i;
+      if (num != -1)
+      {
+          if (info_ptr->unknown_chunks)
+          {
+             png_free(png_ptr, info_ptr->unknown_chunks[num].data);
+             info_ptr->unknown_chunks[num].data = NULL;
+          }
+      }
+      else
+      {
+         int i;
 
-       if (info_ptr->unknown_chunks_num)
-       {
-         for (i = 0; i < (int)info_ptr->unknown_chunks_num; i++)
-            png_free_data(png_ptr, info_ptr, PNG_FREE_UNKN, i);
+         if (info_ptr->unknown_chunks_num)
+         {
+            for (i = 0; i < (int)info_ptr->unknown_chunks_num; i++)
+               png_free_data(png_ptr, info_ptr, PNG_FREE_UNKN, i);
 
-         png_free(png_ptr, info_ptr->unknown_chunks);
-         info_ptr->unknown_chunks = NULL;
-         info_ptr->unknown_chunks_num = 0;
-       }
+            png_free(png_ptr, info_ptr->unknown_chunks);
+            info_ptr->unknown_chunks = NULL;
+            info_ptr->unknown_chunks_num = 0;
+         }
+      }
    }
-}
 #endif
 
 #if defined(PNG_hIST_SUPPORTED)
-/* free any hIST entry */
+   /* Free any hIST entry */
 #ifdef PNG_FREE_ME_SUPPORTED
-if ((mask & PNG_FREE_HIST)  & info_ptr->free_me)
+   if ((mask & PNG_FREE_HIST)  & info_ptr->free_me)
 #else
-if ((mask & PNG_FREE_HIST) && (png_ptr->flags & PNG_FLAG_FREE_HIST))
+   if ((mask & PNG_FREE_HIST) && (png_ptr->flags & PNG_FLAG_FREE_HIST))
 #endif
-{
-    png_free(png_ptr, info_ptr->hist);
-    info_ptr->hist = NULL;
-    info_ptr->valid &= ~PNG_INFO_hIST;
+   {
+      png_free(png_ptr, info_ptr->hist);
+      info_ptr->hist = NULL;
+      info_ptr->valid &= ~PNG_INFO_hIST;
 #ifndef PNG_FREE_ME_SUPPORTED
-    png_ptr->flags &= ~PNG_FLAG_FREE_HIST;
+      png_ptr->flags &= ~PNG_FLAG_FREE_HIST;
 #endif
-}
+   }
 #endif
 
-/* free any PLTE entry that was internally allocated */
+   /* Free any PLTE entry that was internally allocated */
 #ifdef PNG_FREE_ME_SUPPORTED
-if ((mask & PNG_FREE_PLTE) & info_ptr->free_me)
+   if ((mask & PNG_FREE_PLTE) & info_ptr->free_me)
 #else
-if ((mask & PNG_FREE_PLTE) && (png_ptr->flags & PNG_FLAG_FREE_PLTE))
+   if ((mask & PNG_FREE_PLTE) && (png_ptr->flags & PNG_FLAG_FREE_PLTE))
 #endif
-{
-    png_zfree(png_ptr, info_ptr->palette);
-    info_ptr->palette = NULL;
-    info_ptr->valid &= ~PNG_INFO_PLTE;
+   {
+      png_zfree(png_ptr, info_ptr->palette);
+      info_ptr->palette = NULL;
+      info_ptr->valid &= ~PNG_INFO_PLTE;
 #ifndef PNG_FREE_ME_SUPPORTED
-    png_ptr->flags &= ~PNG_FLAG_FREE_PLTE;
+      png_ptr->flags &= ~PNG_FLAG_FREE_PLTE;
 #endif
-    info_ptr->num_palette = 0;
-}
+      info_ptr->num_palette = 0;
+   }
 
 #if defined(PNG_INFO_IMAGE_SUPPORTED)
-/* free any image bits attached to the info structure */
+   /* Free any image bits attached to the info structure */
 #ifdef PNG_FREE_ME_SUPPORTED
-if ((mask & PNG_FREE_ROWS) & info_ptr->free_me)
+   if ((mask & PNG_FREE_ROWS) & info_ptr->free_me)
 #else
-if (mask & PNG_FREE_ROWS)
+   if (mask & PNG_FREE_ROWS)
 #endif
-{
-    if (info_ptr->row_pointers)
-    {
-       int row;
-       for (row = 0; row < (int)info_ptr->height; row++)
-       {
-          png_free(png_ptr, info_ptr->row_pointers[row]);
-          info_ptr->row_pointers[row]=NULL;
-       }
-       png_free(png_ptr, info_ptr->row_pointers);
-       info_ptr->row_pointers=NULL;
-    }
-    info_ptr->valid &= ~PNG_INFO_IDAT;
-}
+   {
+      if (info_ptr->row_pointers)
+      {
+         int row;
+         for (row = 0; row < (int)info_ptr->height; row++)
+         {
+            png_free(png_ptr, info_ptr->row_pointers[row]);
+            info_ptr->row_pointers[row]=NULL;
+         }
+         png_free(png_ptr, info_ptr->row_pointers);
+         info_ptr->row_pointers=NULL;
+      }
+      info_ptr->valid &= ~PNG_INFO_IDAT;
+   }
 #endif
 
 #ifdef PNG_FREE_ME_SUPPORTED
    if (num == -1)
-     info_ptr->free_me &= ~mask;
+      info_ptr->free_me &= ~mask;
    else
-     info_ptr->free_me &= ~(mask & ~PNG_FREE_MUL);
+      info_ptr->free_me &= ~(mask & ~PNG_FREE_MUL);
 #endif
 }
 
@@ -600,9 +605,9 @@
 #if defined(PNG_UNKNOWN_CHUNKS_SUPPORTED)
    if (png_ptr->num_chunk_list)
    {
-       png_free(png_ptr, png_ptr->chunk_list);
-       png_ptr->chunk_list=NULL;
-       png_ptr->num_chunk_list = 0;
+      png_free(png_ptr, png_ptr->chunk_list);
+      png_ptr->chunk_list=NULL;
+      png_ptr->num_chunk_list = 0;
    }
 #endif
 
@@ -617,7 +622,8 @@
 png_voidp PNGAPI
 png_get_io_ptr(png_structp png_ptr)
 {
-   if (png_ptr == NULL) return (NULL);
+   if (png_ptr == NULL)
+      return (NULL);
    return (png_ptr->io_ptr);
 }
 
@@ -633,7 +639,8 @@
 png_init_io(png_structp png_ptr, png_FILE_p fp)
 {
    png_debug(1, "in png_init_io");
-   if (png_ptr == NULL) return;
+   if (png_ptr == NULL)
+      return;
    png_ptr->io_ptr = (png_voidp)fp;
 }
 #endif
@@ -649,7 +656,8 @@
         {"Jan", "Feb", "Mar", "Apr", "May", "Jun",
          "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"};
 
-   if (png_ptr == NULL) return (NULL);
+   if (png_ptr == NULL)
+      return (NULL);
    if (png_ptr->time_buffer == NULL)
    {
       png_ptr->time_buffer = (png_charp)png_malloc(png_ptr, (png_uint_32)(29*
@@ -693,9 +701,9 @@
 png_charp PNGAPI
 png_get_copyright(png_structp png_ptr)
 {
-   png_ptr = png_ptr;  /* silence compiler warning about unused png_ptr */
-   return ((png_charp) "\n libpng version 1.2.37rc01 - May 19, 2009\n\
-   Copyright (c) 1998-2008 Glenn Randers-Pehrson\n\
+   png_ptr = png_ptr;  /* Silence compiler warning about unused png_ptr */
+   return ((png_charp) "\n libpng version 1.2.37beta03 - May 20, 2009\n\
+   Copyright (c) 1998-2009 Glenn Randers-Pehrson\n\
    Copyright (c) 1996-1997 Andreas Dilger\n\
    Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc.\n");
 }
@@ -712,7 +720,7 @@
 png_get_libpng_ver(png_structp png_ptr)
 {
    /* Version of *.c files used when building libpng */
-   png_ptr = png_ptr;  /* silence compiler warning about unused png_ptr */
+   png_ptr = png_ptr;  /* Silence compiler warning about unused png_ptr */
    return ((png_charp) PNG_LIBPNG_VER_STRING);
 }
 
@@ -720,7 +728,7 @@
 png_get_header_ver(png_structp png_ptr)
 {
    /* Version of *.h files used when building libpng */
-   png_ptr = png_ptr;  /* silence compiler warning about unused png_ptr */
+   png_ptr = png_ptr;  /* Silence compiler warning about unused png_ptr */
    return ((png_charp) PNG_LIBPNG_VER_STRING);
 }
 
@@ -728,7 +736,7 @@
 png_get_header_version(png_structp png_ptr)
 {
    /* Returns longer string containing both version and date */
-   png_ptr = png_ptr;  /* silence compiler warning about unused png_ptr */
+   png_ptr = png_ptr;  /* Silence compiler warning about unused png_ptr */
    return ((png_charp) PNG_HEADER_VERSION_STRING
 #ifndef PNG_READ_SUPPORTED
    "     (NO READ SUPPORT)"
@@ -741,7 +749,7 @@
 int PNGAPI
 png_handle_as_unknown(png_structp png_ptr, png_bytep chunk_name)
 {
-   /* check chunk_name and return "keep" value if it's on the list, else 0 */
+   /* Check chunk_name and return "keep" value if it's on the list, else 0 */
    int i;
    png_bytep p;
    if (png_ptr == NULL || chunk_name == NULL || png_ptr->num_chunk_list<=0)
@@ -758,7 +766,8 @@
 int PNGAPI
 png_reset_zstream(png_structp png_ptr)
 {
-   if (png_ptr == NULL) return Z_STREAM_ERROR;
+   if (png_ptr == NULL)
+      return Z_STREAM_ERROR;
    return (inflateReset(&png_ptr->zstream));
 }
 #endif /* defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED) */
@@ -774,11 +783,11 @@
 
 #if defined(PNG_READ_SUPPORTED) && defined(PNG_ASSEMBLER_CODE_SUPPORTED)
 #if !defined(PNG_1_0_X)
-/* this function was added to libpng 1.2.0 */
+/* This function was added to libpng 1.2.0 */
 int PNGAPI
 png_mmx_support(void)
 {
-   /* obsolete, to be removed from libpng-1.4.0 */
+   /* Obsolete, to be removed from libpng-1.4.0 */
     return -1;
 }
 #endif /* PNG_1_0_X */
@@ -791,9 +800,9 @@
 png_size_t PNGAPI
 png_convert_size(size_t size)
 {
-  if (size > (png_size_t)-1)
-     PNG_ABORT();  /* We haven't got access to png_ptr, so no png_error() */
-  return ((png_size_t)size);
+   if (size > (png_size_t)-1)
+      PNG_ABORT();  /* We haven't got access to png_ptr, so no png_error() */
+   return ((png_size_t)size);
 }
 #endif /* PNG_SIZE_T */
 
@@ -802,43 +811,44 @@
 #if !defined(PNG_NO_CHECK_cHRM)
 
 /*
- Multiply two 32-bit numbers, V1 and V2, using 32-bit
- arithmetic, to produce a 64 bit result in the HI/LO words.
-
-          A B
-        x C D
-       ------
-      AD || BD
-AC || CB || 0
-
- where A and B are the high and low 16-bit words of V1,
- C and D are the 16-bit words of V2, AD is the product of
- A and D, and X || Y is (X << 16) + Y.
+ *    Multiply two 32-bit numbers, V1 and V2, using 32-bit
+ *    arithmetic, to produce a 64 bit result in the HI/LO words.
+ *
+ *                  A B
+ *                x C D
+ *               ------
+ *              AD || BD
+ *        AC || CB || 0
+ *
+ *    where A and B are the high and low 16-bit words of V1,
+ *    C and D are the 16-bit words of V2, AD is the product of
+ *    A and D, and X || Y is (X << 16) + Y.
 */
 
 void png_64bit_product (long v1, long v2, unsigned long *hi_product,
    unsigned long *lo_product)
 {
- int a, b, c, d;
- long lo, hi, x, y;
+   int a, b, c, d;
+   long lo, hi, x, y;
 
- a = (v1 >> 16) & 0xffff;
- b = v1 & 0xffff;
- c = (v2 >> 16) & 0xffff;
- d = v2 & 0xffff;
+   a = (v1 >> 16) & 0xffff;
+   b = v1 & 0xffff;
+   c = (v2 >> 16) & 0xffff;
+   d = v2 & 0xffff;
 
- lo = b * d;                   /* BD */
- x = a * d + c * b;            /* AD + CB */
- y = ((lo >> 16) & 0xffff) + x;
+   lo = b * d;                   /* BD */
+   x = a * d + c * b;            /* AD + CB */
+   y = ((lo >> 16) & 0xffff) + x;
 
- lo = (lo & 0xffff) | ((y & 0xffff) << 16);
- hi = (y >> 16) & 0xffff;
+   lo = (lo & 0xffff) | ((y & 0xffff) << 16);
+   hi = (y >> 16) & 0xffff;
 
- hi += a * c;                  /* AC */
+   hi += a * c;                  /* AC */
 
- *hi_product = (unsigned long)hi;
- *lo_product = (unsigned long)lo;
+   *hi_product = (unsigned long)hi;
+   *lo_product = (unsigned long)lo;
 }
+
 int /* private */
 png_check_cHRM_fixed(png_structp png_ptr,
    png_fixed_point white_x, png_fixed_point white_y, png_fixed_point red_x,
diff --git a/png.h b/png.h
index 918fba8..03bda7a 100644
--- a/png.h
+++ b/png.h
@@ -1,6 +1,6 @@
 /* png.h - header file for PNG reference library
  *
- * libpng version 1.2.37beta03 - May 19, 2009
+ * libpng version 1.2.37beta03 - May 20, 2009
  * Copyright (c) 1998-2009 Glenn Randers-Pehrson
  * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
  * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
@@ -8,7 +8,7 @@
  * Authors and maintainers:
  *  libpng versions 0.71, May 1995, through 0.88, January 1996: Guy Schalnat
  *  libpng versions 0.89c, June 1996, through 0.96, May 1997: Andreas Dilger
- *  libpng versions 0.97, January 1998, through 1.2.37beta03 - May 19, 2009: Glenn
+ *  libpng versions 0.97, January 1998, through 1.2.37beta03 - May 20, 2009: Glenn
  *  See also "Contributing Authors", below.
  *
  * Note about libpng version numbers:
@@ -169,65 +169,64 @@
  *    1.0.30                  10    10030  10.so.0.30[.0]
  *    1.2.22                  13    10222  12.so.0.22[.0]
  *    1.2.23beta01-05         13    10223  12.so.0.23[.0]
- *    1.2.23beta03              13    10223  12.so.0.23[.0]
+ *    1.2.23rc01              13    10223  12.so.0.23[.0]
  *    1.2.23                  13    10223  12.so.0.23[.0]
  *    1.2.24beta01-02         13    10224  12.so.0.24[.0]
- *    1.2.24beta03              13    10224  12.so.0.24[.0]
+ *    1.2.24rc01              13    10224  12.so.0.24[.0]
  *    1.2.24                  13    10224  12.so.0.24[.0]
  *    1.2.25beta01-06         13    10225  12.so.0.25[.0]
- *    1.2.25beta03-02           13    10225  12.so.0.25[.0]
+ *    1.2.25rc01-02           13    10225  12.so.0.25[.0]
  *    1.0.31                  10    10031  10.so.0.31[.0]
  *    1.2.25                  13    10225  12.so.0.25[.0]
  *    1.2.26beta01-06         13    10226  12.so.0.26[.0]
- *    1.2.26beta03              13    10226  12.so.0.26[.0]
+ *    1.2.26rc01              13    10226  12.so.0.26[.0]
  *    1.2.26                  13    10226  12.so.0.26[.0]
  *    1.0.32                  10    10032  10.so.0.32[.0]
  *    1.2.27beta01-06         13    10227  12.so.0.27[.0]
- *    1.2.27beta03              13    10227  12.so.0.27[.0]
+ *    1.2.27rc01              13    10227  12.so.0.27[.0]
  *    1.0.33                  10    10033  10.so.0.33[.0]
  *    1.2.27                  13    10227  12.so.0.27[.0]
  *    1.0.34                  10    10034  10.so.0.34[.0]
  *    1.2.28                  13    10228  12.so.0.28[.0]
  *    1.2.29beta01-03         13    10229  12.so.0.29[.0]
- *    1.2.29beta03              13    10229  12.so.0.29[.0]
+ *    1.2.29rc01              13    10229  12.so.0.29[.0]
  *    1.0.35                  10    10035  10.so.0.35[.0]
  *    1.2.29                  13    10229  12.so.0.29[.0]
  *    1.0.37                  10    10037  10.so.0.37[.0]
  *    1.2.30beta01-04         13    10230  12.so.0.30[.0]
- *    1.0.38beta03-08           10    10038  10.so.0.38[.0]
- *    1.2.30beta03-08           13    10230  12.so.0.30[.0]
+ *    1.0.38rc01-08           10    10038  10.so.0.38[.0]
+ *    1.2.30rc01-08           13    10230  12.so.0.30[.0]
  *    1.0.38                  10    10038  10.so.0.38[.0]
  *    1.2.30                  13    10230  12.so.0.30[.0]
- *    1.0.39beta03-03           10    10039  10.so.0.39[.0]
- *    1.2.31beta03-03           13    10231  12.so.0.31[.0]
+ *    1.0.39rc01-03           10    10039  10.so.0.39[.0]
+ *    1.2.31rc01-03           13    10231  12.so.0.31[.0]
  *    1.0.39                  10    10039  10.so.0.39[.0]
  *    1.2.31                  13    10231  12.so.0.31[.0]
  *    1.2.32beta01-02         13    10232  12.so.0.32[.0]
- *    1.0.40beta03              10    10040  10.so.0.40[.0]
- *    1.2.32beta03              13    10232  12.so.0.32[.0]
+ *    1.0.40rc01              10    10040  10.so.0.40[.0]
+ *    1.2.32rc01              13    10232  12.so.0.32[.0]
  *    1.0.40                  10    10040  10.so.0.40[.0]
  *    1.2.32                  13    10232  12.so.0.32[.0]
  *    1.2.33beta01-02         13    10233  12.so.0.33[.0]
- *    1.2.33beta03-02           13    10233  12.so.0.33[.0]
- *    1.0.41beta03              10    10041  10.so.0.41[.0]
+ *    1.2.33rc01-02           13    10233  12.so.0.33[.0]
+ *    1.0.41rc01              10    10041  10.so.0.41[.0]
  *    1.2.33                  13    10233  12.so.0.33[.0]
  *    1.0.41                  10    10041  10.so.0.41[.0]
  *    1.2.34beta01-07         13    10234  12.so.0.34[.0]
- *    1.0.42beta03              10    10042  10.so.0.42[.0]
- *    1.2.34beta03              13    10234  12.so.0.34[.0]
+ *    1.0.42rc01              10    10042  10.so.0.42[.0]
+ *    1.2.34rc01              13    10234  12.so.0.34[.0]
  *    1.0.42                  10    10042  10.so.0.42[.0]
  *    1.2.34                  13    10234  12.so.0.34[.0]
  *    1.2.35beta01-03         13    10235  12.so.0.35[.0]
- *    1.0.43beta03-02           10    10043  10.so.0.43[.0]
- *    1.2.35beta03-02           13    10235  12.so.0.35[.0]
+ *    1.0.43rc01-02           10    10043  10.so.0.43[.0]
+ *    1.2.35rc01-02           13    10235  12.so.0.35[.0]
  *    1.0.43                  10    10043  10.so.0.43[.0]
  *    1.2.35                  13    10235  12.so.0.35[.0]
  *    1.2.36beta01-05         13    10236  12.so.0.36[.0]
- *    1.2.36beta03              13    10236  12.so.0.36[.0]
+ *    1.2.36rc01              13    10236  12.so.0.36[.0]
  *    1.0.44                  10    10044  10.so.0.44[.0]
  *    1.2.36                  13    10236  12.so.0.36[.0]
  *    1.2.37beta01-03         13    10237  12.so.0.37[.0]
- *    1.2.37beta03              13    10237  12.so.0.37[.0]
  *
  *    Henceforth the source version will match the shared-library major
  *    and minor numbers; the shared-library major version number will be
@@ -257,7 +256,7 @@
  * If you modify libpng you may insert additional notices immediately following
  * this sentence.
  *
- * libpng versions 1.2.6, August 15, 2004, through 1.2.37beta03, May 19, 2009, are
+ * libpng versions 1.2.6, August 15, 2004, through 1.2.37beta03, May 20, 2009, are
  * Copyright (c) 2004, 2006-2009 Glenn Randers-Pehrson, and are
  * distributed according to the same disclaimer and license as libpng-1.2.5
  * with the following individual added to the list of Contributing Authors:
@@ -369,7 +368,7 @@
  * Y2K compliance in libpng:
  * =========================
  *
- *    May 19, 2009
+ *    May 20, 2009
  *
  *    Since the PNG Development group is an ad-hoc body, we can't make
  *    an official declaration.
@@ -433,7 +432,7 @@
 /* Version information for png.h - this should match the version in png.c */
 #define PNG_LIBPNG_VER_STRING "1.2.37beta03"
 #define PNG_HEADER_VERSION_STRING \
-   " libpng version 1.2.37beta03 - May 19, 2009\n"
+   " libpng version 1.2.37beta03 - May 20, 2009\n"
 
 #define PNG_LIBPNG_VER_SONUM   0
 #define PNG_LIBPNG_VER_DLLNUM  13
@@ -445,7 +444,7 @@
 /* This should match the numeric part of the final component of
  * PNG_LIBPNG_VER_STRING, omitting any leading zero: */
 
-#define PNG_LIBPNG_VER_BUILD  01
+#define PNG_LIBPNG_VER_BUILD  03
 
 /* Release Status */
 #define PNG_LIBPNG_BUILD_ALPHA    1
@@ -462,7 +461,7 @@
 #define PNG_LIBPNG_BUILD_SPECIAL 32 /* Cannot be OR'ed with
                                        PNG_LIBPNG_BUILD_PRIVATE */
 
-#define PNG_LIBPNG_BUILD_BASE_TYPE PNG_LIBPNG_BUILD_RC
+#define PNG_LIBPNG_BUILD_BASE_TYPE PNG_LIBPNG_BUILD_BETA
 
 /* Careful here.  At one time, Guy wanted to use 082, but that would be octal.
  * We must not include leading zeros.
diff --git a/pngconf.h b/pngconf.h
index 3900a2f..532e6ca 100644
--- a/pngconf.h
+++ b/pngconf.h
@@ -1,7 +1,7 @@
 
 /* pngconf.h - machine configurable file for libpng
  *
- * libpng version 1.2.37rc01 - May 19, 2009
+ * libpng version 1.2.37beta03 - May 20, 2009
  * For conditions of distribution and use, see copyright notice in png.h
  * Copyright (c) 1998-2009 Glenn Randers-Pehrson
  * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
diff --git a/pngerror.c b/pngerror.c
index b85ee11..dea9c36 100644
--- a/pngerror.c
+++ b/pngerror.c
@@ -1,7 +1,7 @@
 
 /* pngerror.c - stub functions for i/o and memory allocation
  *
- * Last changed in libpng 1.2.36 [May 7, 2009]
+ * Last changed in libpng 1.2.37 [May 20, 2009]
  * For conditions of distribution and use, see copyright notice in png.h
  * Copyright (c) 1998-2009 Glenn Randers-Pehrson
  * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
@@ -234,9 +234,11 @@
        fprintf(stderr, PNG_STRING_NEWLINE);
      }
      else
+     {
        fprintf(stderr, "libpng error: %s, offset=%d",
           error_message, offset);
        fprintf(stderr, PNG_STRING_NEWLINE);
+     }
    }
    else
 #endif
@@ -263,7 +265,7 @@
    PNG_ABORT();
 #endif
 #ifdef PNG_NO_CONSOLE_IO
-   error_message = error_message; /* make compiler happy */
+   error_message = error_message; /* Make compiler happy */
 #endif
 }
 
@@ -309,9 +311,9 @@
      fprintf(stderr, PNG_STRING_NEWLINE);
    }
 #else
-   warning_message = warning_message; /* make compiler happy */
+   warning_message = warning_message; /* Make compiler happy */
 #endif
-   png_ptr = png_ptr; /* make compiler happy */
+   png_ptr = png_ptr; /* Make compiler happy */
 }
 #endif /* PNG_NO_WARNINGS */
 
diff --git a/pngget.c b/pngget.c
index 3b2b646..b300d6a 100644
--- a/pngget.c
+++ b/pngget.c
@@ -1,9 +1,9 @@
 
 /* pngget.c - retrieval of values from info struct
  *
- * Last changed in libpng 1.2.30 [August 15, 2008]
+ * Last changed in libpng 1.2.37 [May 20, 2009]
  * For conditions of distribution and use, see copyright notice in png.h
- * Copyright (c) 1998-2008 Glenn Randers-Pehrson
+ * Copyright (c) 1998-2009 Glenn Randers-Pehrson
  * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
  * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
  */
@@ -17,6 +17,7 @@
 {
    if (png_ptr != NULL && info_ptr != NULL)
       return(info_ptr->valid & flag);
+
    else
       return(0);
 }
@@ -26,6 +27,7 @@
 {
    if (png_ptr != NULL && info_ptr != NULL)
       return(info_ptr->rowbytes);
+
    else
       return(0);
 }
@@ -36,20 +38,20 @@
 {
    if (png_ptr != NULL && info_ptr != NULL)
       return(info_ptr->row_pointers);
+
    else
       return(0);
 }
 #endif
 
 #ifdef PNG_EASY_ACCESS_SUPPORTED
-/* easy access to info, added in libpng-0.99 */
+/* Easy access to info, added in libpng-0.99 */
 png_uint_32 PNGAPI
 png_get_image_width(png_structp png_ptr, png_infop info_ptr)
 {
    if (png_ptr != NULL && info_ptr != NULL)
-   {
       return info_ptr->width;
-   }
+
    return (0);
 }
 
@@ -57,9 +59,8 @@
 png_get_image_height(png_structp png_ptr, png_infop info_ptr)
 {
    if (png_ptr != NULL && info_ptr != NULL)
-   {
       return info_ptr->height;
-   }
+
    return (0);
 }
 
@@ -67,9 +68,8 @@
 png_get_bit_depth(png_structp png_ptr, png_infop info_ptr)
 {
    if (png_ptr != NULL && info_ptr != NULL)
-   {
       return info_ptr->bit_depth;
-   }
+
    return (0);
 }
 
@@ -77,9 +77,8 @@
 png_get_color_type(png_structp png_ptr, png_infop info_ptr)
 {
    if (png_ptr != NULL && info_ptr != NULL)
-   {
       return info_ptr->color_type;
-   }
+
    return (0);
 }
 
@@ -87,9 +86,8 @@
 png_get_filter_type(png_structp png_ptr, png_infop info_ptr)
 {
    if (png_ptr != NULL && info_ptr != NULL)
-   {
       return info_ptr->filter_type;
-   }
+
    return (0);
 }
 
@@ -97,9 +95,8 @@
 png_get_interlace_type(png_structp png_ptr, png_infop info_ptr)
 {
    if (png_ptr != NULL && info_ptr != NULL)
-   {
       return info_ptr->interlace_type;
-   }
+
    return (0);
 }
 
@@ -107,9 +104,8 @@
 png_get_compression_type(png_structp png_ptr, png_infop info_ptr)
 {
    if (png_ptr != NULL && info_ptr != NULL)
-   {
       return info_ptr->compression_type;
-   }
+
    return (0);
 }
 
@@ -121,8 +117,10 @@
    if (info_ptr->valid & PNG_INFO_pHYs)
    {
       png_debug1(1, "in %s retrieval function", "png_get_x_pixels_per_meter");
+
       if (info_ptr->phys_unit_type != PNG_RESOLUTION_METER)
           return (0);
+
       else return (info_ptr->x_pixels_per_unit);
    }
 #else
@@ -139,8 +137,10 @@
    if (info_ptr->valid & PNG_INFO_pHYs)
    {
       png_debug1(1, "in %s retrieval function", "png_get_y_pixels_per_meter");
+
       if (info_ptr->phys_unit_type != PNG_RESOLUTION_METER)
           return (0);
+
       else return (info_ptr->y_pixels_per_unit);
    }
 #else
@@ -157,9 +157,11 @@
    if (info_ptr->valid & PNG_INFO_pHYs)
    {
       png_debug1(1, "in %s retrieval function", "png_get_pixels_per_meter");
+
       if (info_ptr->phys_unit_type != PNG_RESOLUTION_METER ||
          info_ptr->x_pixels_per_unit != info_ptr->y_pixels_per_unit)
           return (0);
+
       else return (info_ptr->x_pixels_per_unit);
    }
 #else
@@ -174,6 +176,7 @@
    {
    if (png_ptr != NULL && info_ptr != NULL)
 #if defined(PNG_pHYs_SUPPORTED)
+
    if (info_ptr->valid & PNG_INFO_pHYs)
    {
       png_debug1(1, "in %s retrieval function", "png_get_aspect_ratio");
@@ -184,7 +187,7 @@
             /(float)info_ptr->x_pixels_per_unit));
    }
 #else
-   return (0.0);
+      return (0.0);
 #endif
    return ((float)0.0);
 }
@@ -195,15 +198,18 @@
 {
    if (png_ptr != NULL && info_ptr != NULL)
 #if defined(PNG_oFFs_SUPPORTED)
+
    if (info_ptr->valid & PNG_INFO_oFFs)
    {
       png_debug1(1, "in %s retrieval function", "png_get_x_offset_microns");
+
       if (info_ptr->offset_unit_type != PNG_OFFSET_MICROMETER)
           return (0);
+
       else return (info_ptr->x_offset);
    }
 #else
-   return (0);
+      return (0);
 #endif
    return (0);
 }
@@ -212,12 +218,15 @@
 png_get_y_offset_microns(png_structp png_ptr, png_infop info_ptr)
 {
    if (png_ptr != NULL && info_ptr != NULL)
+
 #if defined(PNG_oFFs_SUPPORTED)
    if (info_ptr->valid & PNG_INFO_oFFs)
    {
       png_debug1(1, "in %s retrieval function", "png_get_y_offset_microns");
+
       if (info_ptr->offset_unit_type != PNG_OFFSET_MICROMETER)
           return (0);
+
       else return (info_ptr->y_offset);
    }
 #else
@@ -230,12 +239,15 @@
 png_get_x_offset_pixels(png_structp png_ptr, png_infop info_ptr)
 {
    if (png_ptr != NULL && info_ptr != NULL)
+
 #if defined(PNG_oFFs_SUPPORTED)
    if (info_ptr->valid & PNG_INFO_oFFs)
    {
       png_debug1(1, "in %s retrieval function", "png_get_x_offset_microns");
+
       if (info_ptr->offset_unit_type != PNG_OFFSET_PIXEL)
           return (0);
+
       else return (info_ptr->x_offset);
    }
 #else
@@ -248,12 +260,15 @@
 png_get_y_offset_pixels(png_structp png_ptr, png_infop info_ptr)
 {
    if (png_ptr != NULL && info_ptr != NULL)
+
 #if defined(PNG_oFFs_SUPPORTED)
    if (info_ptr->valid & PNG_INFO_oFFs)
    {
       png_debug1(1, "in %s retrieval function", "png_get_y_offset_microns");
+
       if (info_ptr->offset_unit_type != PNG_OFFSET_PIXEL)
           return (0);
+
       else return (info_ptr->y_offset);
    }
 #else
@@ -495,8 +510,9 @@
       png_debug1(1, "in %s retrieval function", "iCCP");
       *name = info_ptr->iccp_name;
       *profile = info_ptr->iccp_profile;
-      /* compression_type is a dummy so the API won't have to change
-         if we introduce multiple compression types later. */
+      /* Compression_type is a dummy so the API won't have to change
+       * if we introduce multiple compression types later.
+       */
       *proflen = (int)info_ptr->iccp_proflen;
       *compression_type = (int)info_ptr->iccp_compression;
       return (PNG_INFO_iCCP);
@@ -549,22 +565,29 @@
       *height = info_ptr->height;
       *bit_depth = info_ptr->bit_depth;
       if (info_ptr->bit_depth < 1 || info_ptr->bit_depth > 16)
-        png_error(png_ptr, "Invalid bit depth");
+         png_error(png_ptr, "Invalid bit depth");
+
       *color_type = info_ptr->color_type;
+
       if (info_ptr->color_type > 6)
-        png_error(png_ptr, "Invalid color type");
+         png_error(png_ptr, "Invalid color type");
+
       if (compression_type != NULL)
          *compression_type = info_ptr->compression_type;
+
       if (filter_type != NULL)
          *filter_type = info_ptr->filter_type;
+
       if (interlace_type != NULL)
          *interlace_type = info_ptr->interlace_type;
 
-      /* check for potential overflow of rowbytes */
+      /* Check for potential overflow of rowbytes */
       if (*width == 0 || *width > PNG_UINT_31_MAX)
         png_error(png_ptr, "Invalid image width");
+
       if (*height == 0 || *height > PNG_UINT_31_MAX)
         png_error(png_ptr, "Invalid image height");
+
       if (info_ptr->width > (PNG_UINT_32_MAX
                  >> 3)      /* 8-byte RGBA pixels */
                  - 64       /* bigrowbuf hack */
@@ -575,6 +598,7 @@
          png_warning(png_ptr,
             "Width too large for libpng to process image data.");
       }
+
       return (1);
    }
    return (0);
@@ -605,8 +629,8 @@
    png_charp *units, png_charpp *params)
 {
    if (png_ptr != NULL && info_ptr != NULL && (info_ptr->valid & PNG_INFO_pCAL)
-      && purpose != NULL && X0 != NULL && X1 != NULL && type != NULL &&
-      nparams != NULL && units != NULL && params != NULL)
+       && purpose != NULL && X0 != NULL && X1 != NULL && type != NULL &&
+       nparams != NULL && units != NULL && params != NULL)
    {
       png_debug1(1, "in %s retrieval function", "pCAL");
       *purpose = info_ptr->pcal_purpose;
@@ -629,7 +653,7 @@
              int *unit, double *width, double *height)
 {
     if (png_ptr != NULL && info_ptr != NULL &&
-       (info_ptr->valid & PNG_INFO_sCAL))
+        (info_ptr->valid & PNG_INFO_sCAL))
     {
         *unit = info_ptr->scal_unit;
         *width = info_ptr->scal_pixel_width;
@@ -645,7 +669,7 @@
              int *unit, png_charpp width, png_charpp height)
 {
     if (png_ptr != NULL && info_ptr != NULL &&
-       (info_ptr->valid & PNG_INFO_sCAL))
+        (info_ptr->valid & PNG_INFO_sCAL))
     {
         *unit = info_ptr->scal_unit;
         *width = info_ptr->scal_s_width;
@@ -669,16 +693,19 @@
       (info_ptr->valid & PNG_INFO_pHYs))
    {
       png_debug1(1, "in %s retrieval function", "pHYs");
+
       if (res_x != NULL)
       {
          *res_x = info_ptr->x_pixels_per_unit;
          retval |= PNG_INFO_pHYs;
       }
+
       if (res_y != NULL)
       {
          *res_y = info_ptr->y_pixels_per_unit;
          retval |= PNG_INFO_pHYs;
       }
+
       if (unit_type != NULL)
       {
          *unit_type = (int)info_ptr->phys_unit_type;
@@ -730,10 +757,13 @@
       png_debug1(1, "in %s retrieval function",
          (png_ptr->chunk_name[0] == '\0' ? "text"
              : (png_const_charp)png_ptr->chunk_name));
+
       if (text_ptr != NULL)
          *text_ptr = info_ptr->text;
+
       if (num_text != NULL)
          *num_text = info_ptr->num_text;
+
       return ((png_uint_32)info_ptr->num_text);
    }
    if (num_text != NULL)
@@ -773,6 +803,7 @@
              *trans = info_ptr->trans;
              retval |= PNG_INFO_tRNS;
           }
+
           if (trans_values != NULL)
              *trans_values = &(info_ptr->trans_values);
       }
@@ -783,6 +814,7 @@
              *trans_values = &(info_ptr->trans_values);
              retval |= PNG_INFO_tRNS;
           }
+
           if (trans != NULL)
              *trans = NULL;
       }
@@ -836,47 +868,47 @@
 
 #ifdef PNG_ASSEMBLER_CODE_SUPPORTED
 #ifndef PNG_1_0_X
-/* this function was added to libpng 1.2.0 and should exist by default */
+/* This function was added to libpng 1.2.0 and should exist by default */
 png_uint_32 PNGAPI
 png_get_asm_flags (png_structp png_ptr)
 {
-    /* obsolete, to be removed from libpng-1.4.0 */
+    /* Obsolete, to be removed from libpng-1.4.0 */
     return (png_ptr? 0L: 0L);
 }
 
-/* this function was added to libpng 1.2.0 and should exist by default */
+/* This function was added to libpng 1.2.0 and should exist by default */
 png_uint_32 PNGAPI
 png_get_asm_flagmask (int flag_select)
 {
-    /* obsolete, to be removed from libpng-1.4.0 */
+    /* Obsolete, to be removed from libpng-1.4.0 */
     flag_select=flag_select;
     return 0L;
 }
 
     /* GRR:  could add this:   && defined(PNG_MMX_CODE_SUPPORTED) */
-/* this function was added to libpng 1.2.0 */
+/* This function was added to libpng 1.2.0 */
 png_uint_32 PNGAPI
 png_get_mmx_flagmask (int flag_select, int *compilerID)
 {
-    /* obsolete, to be removed from libpng-1.4.0 */
+    /* Obsolete, to be removed from libpng-1.4.0 */
     flag_select=flag_select;
     *compilerID = -1;   /* unknown (i.e., no asm/MMX code compiled) */
     return 0L;
 }
 
-/* this function was added to libpng 1.2.0 */
+/* This function was added to libpng 1.2.0 */
 png_byte PNGAPI
 png_get_mmx_bitdepth_threshold (png_structp png_ptr)
 {
-    /* obsolete, to be removed from libpng-1.4.0 */
+    /* Obsolete, to be removed from libpng-1.4.0 */
     return (png_ptr? 0: 0);
 }
 
-/* this function was added to libpng 1.2.0 */
+/* This function was added to libpng 1.2.0 */
 png_uint_32 PNGAPI
 png_get_mmx_rowbytes_threshold (png_structp png_ptr)
 {
-    /* obsolete, to be removed from libpng-1.4.0 */
+    /* Obsolete, to be removed from libpng-1.4.0 */
     return (png_ptr? 0L: 0L);
 }
 #endif /* ?PNG_1_0_X */
diff --git a/pngmem.c b/pngmem.c
index f3394d7..b30a1f0 100644
--- a/pngmem.c
+++ b/pngmem.c
@@ -1,9 +1,9 @@
 
 /* pngmem.c - stub functions for memory allocation
  *
- * Last changed in libpng 1.2.30 [August 15, 2008]
+ * Last changed in libpng 1.2.37 [May 20, 2009]
  * For conditions of distribution and use, see copyright notice in png.h
- * Copyright (c) 1998-2008 Glenn Randers-Pehrson
+ * Copyright (c) 1998-2009 Glenn Randers-Pehrson
  * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
  * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
  *
@@ -20,7 +20,7 @@
 
 /* Borland DOS special memory handler */
 #if defined(__TURBOC__) && !defined(_Windows) && !defined(__FLAT__)
-/* if you change this, be sure to change the one in png.h also */
+/* If you change this, be sure to change the one in png.h also */
 
 /* Allocate memory for a png_struct.  The malloc and memset can be replaced
    by a single call to calloc() if this is thought to improve performance. */
@@ -40,11 +40,11 @@
    png_voidp struct_ptr;
 
    if (type == PNG_STRUCT_INFO)
-     size = png_sizeof(png_info);
+      size = png_sizeof(png_info);
    else if (type == PNG_STRUCT_PNG)
-     size = png_sizeof(png_struct);
+      size = png_sizeof(png_struct);
    else
-     return (png_get_copyright(NULL));
+      return (png_get_copyright(NULL));
 
 #ifdef PNG_USER_MEM_SUPPORTED
    if (malloc_fn != NULL)
@@ -56,7 +56,7 @@
    }
    else
 #endif /* PNG_USER_MEM_SUPPORTED */
-      struct_ptr = (png_voidp)farmalloc(size);
+   struct_ptr = (png_voidp)farmalloc(size);
    if (struct_ptr != NULL)
       png_memset(struct_ptr, 0, size);
    return (struct_ptr);
@@ -122,9 +122,9 @@
 
 #ifdef PNG_USER_MEM_SUPPORTED
    if (png_ptr->malloc_fn != NULL)
-       ret = ((png_voidp)(*(png_ptr->malloc_fn))(png_ptr, (png_size_t)size));
+      ret = ((png_voidp)(*(png_ptr->malloc_fn))(png_ptr, (png_size_t)size));
    else
-       ret = (png_malloc_default(png_ptr, size));
+      ret = (png_malloc_default(png_ptr, size));
    if (ret == NULL && (png_ptr->flags&PNG_FLAG_MALLOC_NULL_MEM_OK) == 0)
        png_error(png_ptr, "Out of memory!");
    return (ret);
@@ -149,12 +149,12 @@
 #endif
 
    if (size != (size_t)size)
-     ret = NULL;
+      ret = NULL;
    else if (size == (png_uint_32)65536L)
    {
       if (png_ptr->offset_table == NULL)
       {
-         /* try to see if we need to do any of this fancy stuff */
+         /* Try to see if we need to do any of this fancy stuff */
          ret = farmalloc(size);
          if (ret == NULL || ((png_size_t)ret & 0xffff))
          {
@@ -269,10 +269,10 @@
    return (ret);
 }
 
-/* free a pointer allocated by png_malloc().  In the default
-   configuration, png_ptr is not used, but is passed in case it
-   is needed.  If ptr is NULL, return without taking any action. */
-
+/* Free a pointer allocated by png_malloc().  In the default
+ * configuration, png_ptr is not used, but is passed in case it
+ * is needed.  If ptr is NULL, return without taking any action.
+ */
 void PNGAPI
 png_free(png_structp png_ptr, png_voidp ptr)
 {
@@ -285,7 +285,8 @@
       (*(png_ptr->free_fn))(png_ptr, ptr);
       return;
    }
-   else png_free_default(png_ptr, ptr);
+   else
+      png_free_default(png_ptr, ptr);
 }
 
 void PNGAPI
@@ -293,7 +294,8 @@
 {
 #endif /* PNG_USER_MEM_SUPPORTED */
 
-   if (png_ptr == NULL || ptr == NULL) return;
+   if (png_ptr == NULL || ptr == NULL)
+      return;
 
    if (png_ptr->offset_table != NULL)
    {
@@ -420,10 +422,11 @@
 }
 
 /* Allocate memory.  For reasonable files, size should never exceed
-   64K.  However, zlib may allocate more then 64K if you don't tell
-   it not to.  See zconf.h and png.h for more information.  zlib does
-   need to allocate exactly 64K, so whatever you call here must
-   have the ability to do that. */
+ * 64K.  However, zlib may allocate more then 64K if you don't tell
+ * it not to.  See zconf.h and png.h for more information.  zlib does
+ * need to allocate exactly 64K, so whatever you call here must
+ * have the ability to do that.
+ */
 
 
 png_voidp PNGAPI
@@ -436,9 +439,9 @@
       return (NULL);
 
    if (png_ptr->malloc_fn != NULL)
-       ret = ((png_voidp)(*(png_ptr->malloc_fn))(png_ptr, (png_size_t)size));
+      ret = ((png_voidp)(*(png_ptr->malloc_fn))(png_ptr, (png_size_t)size));
    else
-       ret = (png_malloc_default(png_ptr, size));
+      ret = (png_malloc_default(png_ptr, size));
    if (ret == NULL && (png_ptr->flags&PNG_FLAG_MALLOC_NULL_MEM_OK) == 0)
        png_error(png_ptr, "Out of Memory!");
    return (ret);
@@ -465,23 +468,23 @@
    }
 #endif
 
- /* Check for overflow */
+   /* Check for overflow */
 #if defined(__TURBOC__) && !defined(__FLAT__)
- if (size != (unsigned long)size)
-   ret = NULL;
- else
-   ret = farmalloc(size);
+   if (size != (unsigned long)size)
+      ret = NULL;
+   else
+      ret = farmalloc(size);
 #else
 # if defined(_MSC_VER) && defined(MAXSEG_64K)
- if (size != (unsigned long)size)
-   ret = NULL;
- else
-   ret = halloc(size, 1);
+   if (size != (unsigned long)size)
+      ret = NULL;
+   else
+      ret = halloc(size, 1);
 # else
- if (size != (size_t)size)
-   ret = NULL;
- else
-   ret = malloc((size_t)size);
+   if (size != (size_t)size)
+      ret = NULL;
+   else
+      ret = malloc((size_t)size);
 # endif
 #endif
 
@@ -494,7 +497,8 @@
 }
 
 /* Free a pointer allocated by png_malloc().  If ptr is NULL, return
-   without taking any action. */
+ * without taking any action.
+ */
 void PNGAPI
 png_free(png_structp png_ptr, png_voidp ptr)
 {
@@ -507,7 +511,8 @@
       (*(png_ptr->free_fn))(png_ptr, ptr);
       return;
    }
-   else png_free_default(png_ptr, ptr);
+   else
+      png_free_default(png_ptr, ptr);
 }
 void PNGAPI
 png_free_default(png_structp png_ptr, png_voidp ptr)
@@ -543,7 +548,8 @@
 {
    png_voidp ptr;
    png_uint_32 save_flags;
-   if (png_ptr == NULL) return (NULL);
+   if (png_ptr == NULL)
+      return (NULL);
 
    save_flags = png_ptr->flags;
    png_ptr->flags|=PNG_FLAG_MALLOC_NULL_MEM_OK;
@@ -603,7 +609,8 @@
 png_voidp PNGAPI
 png_get_mem_ptr(png_structp png_ptr)
 {
-   if (png_ptr == NULL) return (NULL);
+   if (png_ptr == NULL)
+      return (NULL);
    return ((png_voidp)png_ptr->mem_ptr);
 }
 #endif /* PNG_USER_MEM_SUPPORTED */
diff --git a/pngpread.c b/pngpread.c
index 067eb63..a56ba96 100644
--- a/pngpread.c
+++ b/pngpread.c
@@ -1,7 +1,7 @@
 
 /* pngpread.c - read a png file in push mode
  *
- * Last changed in libpng 1.2.37 [May 19, 2009]
+ * Last changed in libpng 1.2.37 [May 20, 2009]
  * For conditions of distribution and use, see copyright notice in png.h
  * Copyright (c) 1998-2009 Glenn Randers-Pehrson
  * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
@@ -12,7 +12,7 @@
 #include "png.h"
 #ifdef PNG_PROGRESSIVE_READ_SUPPORTED
 
-/* push model modes */
+/* Push model modes */
 #define PNG_READ_SIG_MODE   0
 #define PNG_READ_CHUNK_MODE 1
 #define PNG_READ_IDAT_MODE  2
@@ -27,7 +27,9 @@
 png_process_data(png_structp png_ptr, png_infop info_ptr,
    png_bytep buffer, png_size_t buffer_size)
 {
-   if (png_ptr == NULL || info_ptr == NULL) return;
+   if (png_ptr == NULL || info_ptr == NULL)
+      return;
+
    png_push_restore_buffer(png_ptr, buffer, buffer_size);
 
    while (png_ptr->buffer_size)
@@ -42,7 +44,9 @@
 void /* PRIVATE */
 png_process_some_data(png_structp png_ptr, png_infop info_ptr)
 {
-   if (png_ptr == NULL) return;
+   if (png_ptr == NULL)
+      return;
+
    switch (png_ptr->process_mode)
    {
       case PNG_READ_SIG_MODE:
@@ -50,22 +54,26 @@
          png_push_read_sig(png_ptr, info_ptr);
          break;
       }
+
       case PNG_READ_CHUNK_MODE:
       {
          png_push_read_chunk(png_ptr, info_ptr);
          break;
       }
+
       case PNG_READ_IDAT_MODE:
       {
          png_push_read_IDAT(png_ptr);
          break;
       }
+
 #if defined(PNG_READ_tEXt_SUPPORTED)
       case PNG_READ_tEXt_MODE:
       {
          png_push_read_tEXt(png_ptr, info_ptr);
          break;
       }
+
 #endif
 #if defined(PNG_READ_zTXt_SUPPORTED)
       case PNG_READ_zTXt_MODE:
@@ -73,6 +81,7 @@
          png_push_read_zTXt(png_ptr, info_ptr);
          break;
       }
+
 #endif
 #if defined(PNG_READ_iTXt_SUPPORTED)
       case PNG_READ_iTXt_MODE:
@@ -80,12 +89,14 @@
          png_push_read_iTXt(png_ptr, info_ptr);
          break;
       }
+
 #endif
       case PNG_SKIP_MODE:
       {
          png_push_crc_finish(png_ptr);
          break;
       }
+
       default:
       {
          png_ptr->buffer_size = 0;
@@ -224,13 +235,16 @@
    {
       if (png_ptr->push_length != 13)
          png_error(png_ptr, "Invalid IHDR length");
+
       if (png_ptr->push_length + 4 > png_ptr->buffer_size)
       {
          png_push_save_buffer(png_ptr);
          return;
       }
+
       png_handle_IHDR(png_ptr, info_ptr, png_ptr->push_length);
    }
+
    else if (!png_memcmp(png_ptr->chunk_name, png_IEND, 4))
    {
       if (png_ptr->push_length + 4 > png_ptr->buffer_size)
@@ -238,11 +252,13 @@
          png_push_save_buffer(png_ptr);
          return;
       }
+
       png_handle_IEND(png_ptr, info_ptr, png_ptr->push_length);
 
       png_ptr->process_mode = PNG_READ_DONE_MODE;
       png_push_have_end(png_ptr, info_ptr);
    }
+
 #ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
    else if (png_handle_as_unknown(png_ptr, png_ptr->chunk_name))
    {
@@ -251,20 +267,26 @@
          png_push_save_buffer(png_ptr);
          return;
       }
+
       if (!png_memcmp(png_ptr->chunk_name, png_IDAT, 4))
          png_ptr->mode |= PNG_HAVE_IDAT;
+
       png_handle_unknown(png_ptr, info_ptr, png_ptr->push_length);
+
       if (!png_memcmp(png_ptr->chunk_name, png_PLTE, 4))
          png_ptr->mode |= PNG_HAVE_PLTE;
+
       else if (!png_memcmp(png_ptr->chunk_name, png_IDAT, 4))
       {
          if (!(png_ptr->mode & PNG_HAVE_IHDR))
             png_error(png_ptr, "Missing IHDR before IDAT");
+
          else if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE &&
                   !(png_ptr->mode & PNG_HAVE_PLTE))
             png_error(png_ptr, "Missing PLTE before IDAT");
       }
    }
+
 #endif
    else if (!png_memcmp(png_ptr->chunk_name, png_PLTE, 4))
    {
@@ -275,23 +297,26 @@
       }
       png_handle_PLTE(png_ptr, info_ptr, png_ptr->push_length);
    }
+
    else if (!png_memcmp(png_ptr->chunk_name, png_IDAT, 4))
    {
       /* If we reach an IDAT chunk, this means we have read all of the
        * header chunks, and we can start reading the image (or if this
        * is called after the image has been read - we have an error).
        */
-     if (!(png_ptr->mode & PNG_HAVE_IHDR))
-       png_error(png_ptr, "Missing IHDR before IDAT");
-     else if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE &&
-         !(png_ptr->mode & PNG_HAVE_PLTE))
-       png_error(png_ptr, "Missing PLTE before IDAT");
+
+      if (!(png_ptr->mode & PNG_HAVE_IHDR))
+         png_error(png_ptr, "Missing IHDR before IDAT");
+
+      else if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE &&
+          !(png_ptr->mode & PNG_HAVE_PLTE))
+         png_error(png_ptr, "Missing PLTE before IDAT");
 
       if (png_ptr->mode & PNG_HAVE_IDAT)
       {
          if (!(png_ptr->mode & PNG_HAVE_CHUNK_AFTER_IDAT))
-           if (png_ptr->push_length == 0)
-              return;
+            if (png_ptr->push_length == 0)
+               return;
 
          if (png_ptr->mode & PNG_AFTER_IDAT)
             png_error(png_ptr, "Too many IDAT's found");
@@ -305,6 +330,7 @@
       png_ptr->zstream.next_out = png_ptr->row_buf;
       return;
    }
+
 #if defined(PNG_READ_gAMA_SUPPORTED)
    else if (!png_memcmp(png_ptr->chunk_name, png_gAMA, 4))
    {
@@ -313,8 +339,10 @@
          png_push_save_buffer(png_ptr);
          return;
       }
+
       png_handle_gAMA(png_ptr, info_ptr, png_ptr->push_length);
    }
+
 #endif
 #if defined(PNG_READ_sBIT_SUPPORTED)
    else if (!png_memcmp(png_ptr->chunk_name, png_sBIT, 4))
@@ -324,8 +352,10 @@
          png_push_save_buffer(png_ptr);
          return;
       }
+
       png_handle_sBIT(png_ptr, info_ptr, png_ptr->push_length);
    }
+
 #endif
 #if defined(PNG_READ_cHRM_SUPPORTED)
    else if (!png_memcmp(png_ptr->chunk_name, png_cHRM, 4))
@@ -335,8 +365,10 @@
          png_push_save_buffer(png_ptr);
          return;
       }
+
       png_handle_cHRM(png_ptr, info_ptr, png_ptr->push_length);
    }
+
 #endif
 #if defined(PNG_READ_sRGB_SUPPORTED)
    else if (!png_memcmp(png_ptr->chunk_name, png_sRGB, 4))
@@ -346,8 +378,10 @@
          png_push_save_buffer(png_ptr);
          return;
       }
+
       png_handle_sRGB(png_ptr, info_ptr, png_ptr->push_length);
    }
+
 #endif
 #if defined(PNG_READ_iCCP_SUPPORTED)
    else if (!png_memcmp(png_ptr->chunk_name, png_iCCP, 4))
@@ -357,8 +391,10 @@
          png_push_save_buffer(png_ptr);
          return;
       }
+
       png_handle_iCCP(png_ptr, info_ptr, png_ptr->push_length);
    }
+
 #endif
 #if defined(PNG_READ_sPLT_SUPPORTED)
    else if (!png_memcmp(png_ptr->chunk_name, png_sPLT, 4))
@@ -368,8 +404,10 @@
          png_push_save_buffer(png_ptr);
          return;
       }
+
       png_handle_sPLT(png_ptr, info_ptr, png_ptr->push_length);
    }
+
 #endif
 #if defined(PNG_READ_tRNS_SUPPORTED)
    else if (!png_memcmp(png_ptr->chunk_name, png_tRNS, 4))
@@ -379,8 +417,10 @@
          png_push_save_buffer(png_ptr);
          return;
       }
+
       png_handle_tRNS(png_ptr, info_ptr, png_ptr->push_length);
    }
+
 #endif
 #if defined(PNG_READ_bKGD_SUPPORTED)
    else if (!png_memcmp(png_ptr->chunk_name, png_bKGD, 4))
@@ -390,8 +430,10 @@
          png_push_save_buffer(png_ptr);
          return;
       }
+
       png_handle_bKGD(png_ptr, info_ptr, png_ptr->push_length);
    }
+
 #endif
 #if defined(PNG_READ_hIST_SUPPORTED)
    else if (!png_memcmp(png_ptr->chunk_name, png_hIST, 4))
@@ -401,8 +443,10 @@
          png_push_save_buffer(png_ptr);
          return;
       }
+
       png_handle_hIST(png_ptr, info_ptr, png_ptr->push_length);
    }
+
 #endif
 #if defined(PNG_READ_pHYs_SUPPORTED)
    else if (!png_memcmp(png_ptr->chunk_name, png_pHYs, 4))
@@ -412,8 +456,10 @@
          png_push_save_buffer(png_ptr);
          return;
       }
+
       png_handle_pHYs(png_ptr, info_ptr, png_ptr->push_length);
    }
+
 #endif
 #if defined(PNG_READ_oFFs_SUPPORTED)
    else if (!png_memcmp(png_ptr->chunk_name, png_oFFs, 4))
@@ -423,9 +469,11 @@
          png_push_save_buffer(png_ptr);
          return;
       }
+
       png_handle_oFFs(png_ptr, info_ptr, png_ptr->push_length);
    }
 #endif
+
 #if defined(PNG_READ_pCAL_SUPPORTED)
    else if (!png_memcmp(png_ptr->chunk_name, png_pCAL, 4))
    {
@@ -434,8 +482,10 @@
          png_push_save_buffer(png_ptr);
          return;
       }
+
       png_handle_pCAL(png_ptr, info_ptr, png_ptr->push_length);
    }
+
 #endif
 #if defined(PNG_READ_sCAL_SUPPORTED)
    else if (!png_memcmp(png_ptr->chunk_name, png_sCAL, 4))
@@ -445,8 +495,10 @@
          png_push_save_buffer(png_ptr);
          return;
       }
+
       png_handle_sCAL(png_ptr, info_ptr, png_ptr->push_length);
    }
+
 #endif
 #if defined(PNG_READ_tIME_SUPPORTED)
    else if (!png_memcmp(png_ptr->chunk_name, png_tIME, 4))
@@ -456,8 +508,10 @@
          png_push_save_buffer(png_ptr);
          return;
       }
+
       png_handle_tIME(png_ptr, info_ptr, png_ptr->push_length);
    }
+
 #endif
 #if defined(PNG_READ_tEXt_SUPPORTED)
    else if (!png_memcmp(png_ptr->chunk_name, png_tEXt, 4))
@@ -467,8 +521,10 @@
          png_push_save_buffer(png_ptr);
          return;
       }
+
       png_push_handle_tEXt(png_ptr, info_ptr, png_ptr->push_length);
    }
+
 #endif
 #if defined(PNG_READ_zTXt_SUPPORTED)
    else if (!png_memcmp(png_ptr->chunk_name, png_zTXt, 4))
@@ -478,8 +534,10 @@
          png_push_save_buffer(png_ptr);
          return;
       }
+
       png_push_handle_zTXt(png_ptr, info_ptr, png_ptr->push_length);
    }
+
 #endif
 #if defined(PNG_READ_iTXt_SUPPORTED)
    else if (!png_memcmp(png_ptr->chunk_name, png_iTXt, 4))
@@ -489,8 +547,10 @@
          png_push_save_buffer(png_ptr);
          return;
       }
+
       png_push_handle_iTXt(png_ptr, info_ptr, png_ptr->push_length);
    }
+
 #endif
    else
    {
@@ -565,7 +625,9 @@
 {
    png_bytep ptr;
 
-   if (png_ptr == NULL) return;
+   if (png_ptr == NULL)
+      return;
+
    ptr = buffer;
    if (png_ptr->save_buffer_size)
    {
@@ -589,6 +651,7 @@
 
       if (length < png_ptr->current_buffer_size)
          save_size = length;
+
       else
          save_size = png_ptr->current_buffer_size;
 
@@ -629,6 +692,7 @@
       {
         png_error(png_ptr, "Potential overflow of save_buffer");
       }
+
       new_max = png_ptr->save_buffer_size + png_ptr->current_buffer_size + 256;
       old_buffer = png_ptr->save_buffer;
       png_ptr->save_buffer = (png_bytep)png_malloc(png_ptr,
@@ -697,7 +761,8 @@
       if (png_ptr->idat_size < (png_uint_32)png_ptr->save_buffer_size)
       {
          save_size = (png_size_t)png_ptr->idat_size;
-         /* check for overflow */
+
+         /* Check for overflow */
          if ((png_uint_32)save_size != png_ptr->idat_size)
             png_error(png_ptr, "save_size overflowed in pngpread");
       }
@@ -705,8 +770,10 @@
          save_size = png_ptr->save_buffer_size;
 
       png_calculate_crc(png_ptr, png_ptr->save_buffer_ptr, save_size);
+
       if (!(png_ptr->flags & PNG_FLAG_ZLIB_FINISHED))
          png_process_IDAT_data(png_ptr, png_ptr->save_buffer_ptr, save_size);
+
       png_ptr->idat_size -= save_size;
       png_ptr->buffer_size -= save_size;
       png_ptr->save_buffer_size -= save_size;
@@ -719,7 +786,8 @@
       if (png_ptr->idat_size < (png_uint_32)png_ptr->current_buffer_size)
       {
          save_size = (png_size_t)png_ptr->idat_size;
-         /* check for overflow */
+
+         /* Check for overflow */
          if ((png_uint_32)save_size != png_ptr->idat_size)
             png_error(png_ptr, "save_size overflowed in pngpread");
       }
@@ -769,6 +837,7 @@
          {
             if (png_ptr->zstream.avail_in)
                png_error(png_ptr, "Extra compressed data");
+
             if (!(png_ptr->zstream.avail_out))
             {
                png_push_process_row(png_ptr);
@@ -780,6 +849,7 @@
          }
          else if (ret == Z_BUF_ERROR)
             break;
+
          else
             png_error(png_ptr, "Decompression Error");
       }
@@ -801,6 +871,7 @@
          png_ptr->zstream.avail_out = (uInt)png_ptr->irowbytes;
          png_ptr->zstream.next_out = png_ptr->row_buf;
       }
+
       else
          break;
    }
@@ -829,7 +900,7 @@
       png_do_read_transformations(png_ptr);
 
 #if defined(PNG_READ_INTERLACING_SUPPORTED)
-   /* blow up interlaced rows to full size */
+   /* Blow up interlaced rows to full size */
    if (png_ptr->interlaced && (png_ptr->transformations & PNG_INTERLACE))
    {
       if (png_ptr->pass < 6)
@@ -847,9 +918,10 @@
             for (i = 0; i < 8 && png_ptr->pass == 0; i++)
             {
                png_push_have_row(png_ptr, png_ptr->row_buf + 1);
-               png_read_push_finish_row(png_ptr); /* updates png_ptr->pass */
+               png_read_push_finish_row(png_ptr); /* Updates png_ptr->pass */
             }
-            if (png_ptr->pass == 2) /* pass 1 might be empty */
+
+            if (png_ptr->pass == 2) /* Pass 1 might be empty */
             {
                for (i = 0; i < 4 && png_ptr->pass == 2; i++)
                {
@@ -857,6 +929,7 @@
                   png_read_push_finish_row(png_ptr);
                }
             }
+
             if (png_ptr->pass == 4 && png_ptr->height <= 4)
             {
                for (i = 0; i < 2 && png_ptr->pass == 4; i++)
@@ -865,13 +938,16 @@
                   png_read_push_finish_row(png_ptr);
                }
             }
+
             if (png_ptr->pass == 6 && png_ptr->height <= 4)
             {
                 png_push_have_row(png_ptr, png_bytep_NULL);
                 png_read_push_finish_row(png_ptr);
             }
+
             break;
          }
+
          case 1:
          {
             int i;
@@ -880,7 +956,8 @@
                png_push_have_row(png_ptr, png_ptr->row_buf + 1);
                png_read_push_finish_row(png_ptr);
             }
-            if (png_ptr->pass == 2) /* skip top 4 generated rows */
+
+            if (png_ptr->pass == 2) /* Skip top 4 generated rows */
             {
                for (i = 0; i < 4 && png_ptr->pass == 2; i++)
                {
@@ -888,22 +965,27 @@
                   png_read_push_finish_row(png_ptr);
                }
             }
+
             break;
          }
+
          case 2:
          {
             int i;
+
             for (i = 0; i < 4 && png_ptr->pass == 2; i++)
             {
                png_push_have_row(png_ptr, png_ptr->row_buf + 1);
                png_read_push_finish_row(png_ptr);
             }
+
             for (i = 0; i < 4 && png_ptr->pass == 2; i++)
             {
                png_push_have_row(png_ptr, png_bytep_NULL);
                png_read_push_finish_row(png_ptr);
             }
-            if (png_ptr->pass == 4) /* pass 3 might be empty */
+
+            if (png_ptr->pass == 4) /* Pass 3 might be empty */
             {
                for (i = 0; i < 2 && png_ptr->pass == 4; i++)
                {
@@ -911,17 +993,21 @@
                   png_read_push_finish_row(png_ptr);
                }
             }
+
             break;
          }
+
          case 3:
          {
             int i;
+
             for (i = 0; i < 4 && png_ptr->pass == 3; i++)
             {
                png_push_have_row(png_ptr, png_ptr->row_buf + 1);
                png_read_push_finish_row(png_ptr);
             }
-            if (png_ptr->pass == 4) /* skip top two generated rows */
+
+            if (png_ptr->pass == 4) /* Skip top two generated rows */
             {
                for (i = 0; i < 2 && png_ptr->pass == 4; i++)
                {
@@ -929,49 +1015,61 @@
                   png_read_push_finish_row(png_ptr);
                }
             }
+
             break;
          }
+
          case 4:
          {
             int i;
+
             for (i = 0; i < 2 && png_ptr->pass == 4; i++)
             {
                png_push_have_row(png_ptr, png_ptr->row_buf + 1);
                png_read_push_finish_row(png_ptr);
             }
+
             for (i = 0; i < 2 && png_ptr->pass == 4; i++)
             {
                png_push_have_row(png_ptr, png_bytep_NULL);
                png_read_push_finish_row(png_ptr);
             }
-            if (png_ptr->pass == 6) /* pass 5 might be empty */
+
+            if (png_ptr->pass == 6) /* Pass 5 might be empty */
             {
                png_push_have_row(png_ptr, png_bytep_NULL);
                png_read_push_finish_row(png_ptr);
             }
+
             break;
          }
+
          case 5:
          {
             int i;
+
             for (i = 0; i < 2 && png_ptr->pass == 5; i++)
             {
                png_push_have_row(png_ptr, png_ptr->row_buf + 1);
                png_read_push_finish_row(png_ptr);
             }
-            if (png_ptr->pass == 6) /* skip top generated row */
+
+            if (png_ptr->pass == 6) /* Skip top generated row */
             {
                png_push_have_row(png_ptr, png_bytep_NULL);
                png_read_push_finish_row(png_ptr);
             }
+
             break;
          }
          case 6:
          {
             png_push_have_row(png_ptr, png_ptr->row_buf + 1);
             png_read_push_finish_row(png_ptr);
+
             if (png_ptr->pass != 6)
                break;
+
             png_push_have_row(png_ptr, png_bytep_NULL);
             png_read_push_finish_row(png_ptr);
          }
@@ -989,18 +1087,18 @@
 png_read_push_finish_row(png_structp png_ptr)
 {
 #ifdef PNG_USE_LOCAL_ARRAYS
-   /* arrays to facilitate easy interlacing - use pass (0 - 6) as index */
+   /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */
 
-   /* start of interlace block */
+   /* Start of interlace block */
    PNG_CONST int FARDATA png_pass_start[] = {0, 4, 0, 2, 0, 1, 0};
 
-   /* offset to next interlace block */
+   /* Offset to next interlace block */
    PNG_CONST int FARDATA png_pass_inc[] = {8, 8, 4, 4, 2, 2, 1};
 
-   /* start of interlace block in the y direction */
+   /* Start of interlace block in the y direction */
    PNG_CONST int FARDATA png_pass_ystart[] = {0, 0, 4, 0, 2, 0, 1};
 
-   /* offset to next interlace block in the y direction */
+   /* Offset to next interlace block in the y direction */
    PNG_CONST int FARDATA png_pass_yinc[] = {8, 8, 8, 4, 4, 2, 2};
 
    /* Height of interlace block.  This is not currently used - if you need
@@ -1013,7 +1111,7 @@
    if (png_ptr->row_number < png_ptr->num_rows)
       return;
 
-#ifdef PNG_READ_INTERLACING_SUPPORTED
+#if defined(PNG_READ_INTERLACING_SUPPORTED)
    if (png_ptr->interlaced)
    {
       png_ptr->row_number = 0;
@@ -1029,6 +1127,7 @@
 
          if (png_ptr->pass > 7)
             png_ptr->pass--;
+
          if (png_ptr->pass >= 7)
             break;
 
@@ -1061,7 +1160,7 @@
    if (!(png_ptr->mode & PNG_HAVE_IHDR) || (png_ptr->mode & PNG_HAVE_IEND))
       {
          png_error(png_ptr, "Out of place tEXt");
-         info_ptr = info_ptr; /* to quiet some compiler warnings */
+         info_ptr = info_ptr; /* To quiet some compiler warnings */
       }
 
 #ifdef PNG_MAX_MALLOC_64K
@@ -1093,8 +1192,10 @@
 
       if (png_ptr->buffer_size < png_ptr->current_text_left)
          text_size = png_ptr->buffer_size;
+
       else
          text_size = png_ptr->current_text_left;
+
       png_crc_read(png_ptr, (png_bytep)png_ptr->current_text_ptr, text_size);
       png_ptr->current_text_left -= text_size;
       png_ptr->current_text_ptr += text_size;
@@ -1122,7 +1223,7 @@
       key = png_ptr->current_text;
 
       for (text = key; *text; text++)
-         /* empty loop */ ;
+         /* Empty loop */ ;
 
       if (text < key + png_ptr->current_text_size)
          text++;
@@ -1157,7 +1258,7 @@
    if (!(png_ptr->mode & PNG_HAVE_IHDR) || (png_ptr->mode & PNG_HAVE_IEND))
       {
          png_error(png_ptr, "Out of place zTXt");
-         info_ptr = info_ptr; /* to quiet some compiler warnings */
+         info_ptr = info_ptr; /* To quiet some compiler warnings */
       }
 
 #ifdef PNG_MAX_MALLOC_64K
@@ -1191,8 +1292,10 @@
 
       if (png_ptr->buffer_size < (png_uint_32)png_ptr->current_text_left)
          text_size = png_ptr->buffer_size;
+
       else
          text_size = png_ptr->current_text_left;
+
       png_crc_read(png_ptr, (png_bytep)png_ptr->current_text_ptr, text_size);
       png_ptr->current_text_left -= text_size;
       png_ptr->current_text_ptr += text_size;
@@ -1216,7 +1319,7 @@
       key = png_ptr->current_text;
 
       for (text = key; *text; text++)
-         /* empty loop */ ;
+         /* Empty loop */ ;
 
       /* zTXt can't have zero text */
       if (text >= key + png_ptr->current_text_size)
@@ -1228,7 +1331,7 @@
 
       text++;
 
-      if (*text != PNG_TEXT_COMPRESSION_zTXt) /* check compression byte */
+      if (*text != PNG_TEXT_COMPRESSION_zTXt) /* Check compression byte */
       {
          png_ptr->current_text = NULL;
          png_free(png_ptr, key);
@@ -1267,11 +1370,15 @@
                text = (png_charp)png_malloc(png_ptr,
                      (png_uint_32)(png_ptr->zbuf_size
                      - png_ptr->zstream.avail_out + key_size + 1));
+
                png_memcpy(text + key_size, png_ptr->zbuf,
                   png_ptr->zbuf_size - png_ptr->zstream.avail_out);
+
                png_memcpy(text, key, key_size);
+
                text_size = key_size + png_ptr->zbuf_size -
                   png_ptr->zstream.avail_out;
+
                *(text + text_size) = '\0';
             }
             else
@@ -1282,10 +1389,13 @@
                text = (png_charp)png_malloc(png_ptr, text_size +
                   (png_uint_32)(png_ptr->zbuf_size 
                   - png_ptr->zstream.avail_out + 1));
+
                png_memcpy(text, tmp, text_size);
                png_free(png_ptr, tmp);
+
                png_memcpy(text + text_size, png_ptr->zbuf,
                   png_ptr->zbuf_size - png_ptr->zstream.avail_out);
+
                text_size += png_ptr->zbuf_size - png_ptr->zstream.avail_out;
                *(text + text_size) = '\0';
             }
@@ -1349,7 +1459,7 @@
    if (!(png_ptr->mode & PNG_HAVE_IHDR) || (png_ptr->mode & PNG_HAVE_IEND))
       {
          png_error(png_ptr, "Out of place iTXt");
-         info_ptr = info_ptr; /* to quiet some compiler warnings */
+         info_ptr = info_ptr; /* To quiet some compiler warnings */
       }
 
 #ifdef PNG_MAX_MALLOC_64K
@@ -1382,8 +1492,10 @@
 
       if (png_ptr->buffer_size < png_ptr->current_text_left)
          text_size = png_ptr->buffer_size;
+
       else
          text_size = png_ptr->current_text_left;
+
       png_crc_read(png_ptr, (png_bytep)png_ptr->current_text_ptr, text_size);
       png_ptr->current_text_left -= text_size;
       png_ptr->current_text_ptr += text_size;
@@ -1414,23 +1526,25 @@
       key = png_ptr->current_text;
 
       for (lang = key; *lang; lang++)
-         /* empty loop */ ;
+         /* Empty loop */ ;
 
       if (lang < key + png_ptr->current_text_size - 3)
          lang++;
 
       comp_flag = *lang++;
-      lang++;     /* skip comp_type, always zero */
+      lang++;     /* Skip comp_type, always zero */
 
       for (lang_key = lang; *lang_key; lang_key++)
-         /* empty loop */ ;
-      lang_key++;        /* skip NUL separator */
+         /* Empty loop */ ;
+
+      lang_key++;        /* Skip NUL separator */
 
       text=lang_key;
+
       if (lang_key < key + png_ptr->current_text_size - 1)
       {
         for (; *text; text++)
-           /* empty loop */ ;
+           /* Empty loop */ ;
       }
 
       if (text < key + png_ptr->current_text_size)
@@ -1438,6 +1552,7 @@
 
       text_ptr = (png_textp)png_malloc(png_ptr,
          (png_uint_32)png_sizeof(png_text));
+
       text_ptr->compression = comp_flag + 2;
       text_ptr->key = key;
       text_ptr->lang = lang;
@@ -1479,7 +1594,7 @@
 #endif
          png_chunk_error(png_ptr, "unknown critical chunk");
 
-      info_ptr = info_ptr; /* to quiet some compiler warnings */
+      info_ptr = info_ptr; /* To quiet some compiler warnings */
    }
 
 #if defined(PNG_READ_UNKNOWN_CHUNKS_SUPPORTED)
@@ -1500,23 +1615,28 @@
         = '\0';
 
       png_ptr->unknown_chunk.size = (png_size_t)length;
+
       if (length == 0)
          png_ptr->unknown_chunk.data = NULL;
+
       else
       {
          png_ptr->unknown_chunk.data = (png_bytep)png_malloc(png_ptr,
        (png_uint_32)length);
          png_crc_read(png_ptr, (png_bytep)png_ptr->unknown_chunk.data, length);
       }
+
 #if defined(PNG_READ_USER_CHUNKS_SUPPORTED)
       if (png_ptr->read_user_chunk_fn != NULL)
       {
-         /* callback to user unknown chunk handler */
+         /* Callback to user unknown chunk handler */
          int ret;
          ret = (*(png_ptr->read_user_chunk_fn))
            (png_ptr, &png_ptr->unknown_chunk);
+
          if (ret < 0)
             png_chunk_error(png_ptr, "error in user chunk");
+
          if (ret == 0)
          {
             if (!(png_ptr->chunk_name[0] & 0x20))
@@ -1527,12 +1647,14 @@
                &png_ptr->unknown_chunk, 1);
          }
       }
+
       else
 #endif
         png_set_unknown_chunks(png_ptr, info_ptr, &png_ptr->unknown_chunk, 1);
       png_free(png_ptr, png_ptr->unknown_chunk.data);
       png_ptr->unknown_chunk.data = NULL;
    }
+
    else
 #endif
       skip=length;
@@ -1569,7 +1691,9 @@
    PNG_CONST int FARDATA png_pass_dsp_mask[7] =
       {0xff, 0x0f, 0xff, 0x33, 0xff, 0x55, 0xff};
 #endif
-   if (png_ptr == NULL) return;
+   if (png_ptr == NULL)
+      return;
+
    if (new_row != NULL)    /* new_row must == png_ptr->row_buf here. */
       png_combine_row(png_ptr, old_row, png_pass_dsp_mask[png_ptr->pass]);
 }
@@ -1579,7 +1703,9 @@
    png_progressive_info_ptr info_fn, png_progressive_row_ptr row_fn,
    png_progressive_end_ptr end_fn)
 {
-   if (png_ptr == NULL) return;
+   if (png_ptr == NULL)
+      return;
+
    png_ptr->info_fn = info_fn;
    png_ptr->row_fn = row_fn;
    png_ptr->end_fn = end_fn;
@@ -1590,7 +1716,9 @@
 png_voidp PNGAPI
 png_get_progressive_ptr(png_structp png_ptr)
 {
-   if (png_ptr == NULL) return (NULL);
+   if (png_ptr == NULL)
+      return (NULL);
+
    return png_ptr->io_ptr;
 }
 #endif /* PNG_PROGRESSIVE_READ_SUPPORTED */
diff --git a/pngread.c b/pngread.c
index 8e9c0cb..4ab5fa0 100644
--- a/pngread.c
+++ b/pngread.c
@@ -1,7 +1,7 @@
 
 /* pngread.c - read a PNG file
  *
- * Last changed in libpng 1.2.35 [February 14, 2009]
+ * Last changed in libpng 1.2.37 [May 20, 2009]
  * For conditions of distribution and use, see copyright notice in png.h
  * Copyright (c) 1998-2009 Glenn Randers-Pehrson
  * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
@@ -57,7 +57,7 @@
    if (png_ptr == NULL)
       return (NULL);
 
-   /* added at libpng-1.2.6 */
+   /* Added at libpng-1.2.6 */
 #ifdef PNG_SET_USER_LIMITS_SUPPORTED
    png_ptr->user_width_max=PNG_USER_WIDTH_MAX;
    png_ptr->user_height_max=PNG_USER_HEIGHT_MAX;
@@ -137,7 +137,7 @@
      }
    }
 
-   /* initialize zbuf - compression buffer */
+   /* Initialize zbuf - compression buffer */
    png_ptr->zbuf_size = PNG_ZBUF_SIZE;
    png_ptr->zbuf = (png_bytep)png_malloc(png_ptr,
      (png_uint_32)png_ptr->zbuf_size);
@@ -266,7 +266,7 @@
    png_debug(1, "in png_read_init_3");
 
 #ifdef PNG_SETJMP_SUPPORTED
-   /* save jump buffer and error functions */
+   /* Save jump buffer and error functions */
    png_memcpy(tmp_jmp, png_ptr->jmpbuf, png_sizeof(jmp_buf));
 #endif
 
@@ -277,21 +277,21 @@
       png_ptr = *ptr_ptr;
    }
 
-   /* reset all variables to 0 */
+   /* Reset all variables to 0 */
    png_memset(png_ptr, 0, png_sizeof(png_struct));
 
 #ifdef PNG_SETJMP_SUPPORTED
-   /* restore jump buffer */
+   /* Restore jump buffer */
    png_memcpy(png_ptr->jmpbuf, tmp_jmp, png_sizeof(jmp_buf));
 #endif
 
-   /* added at libpng-1.2.6 */
+   /* Added at libpng-1.2.6 */
 #ifdef PNG_SET_USER_LIMITS_SUPPORTED
    png_ptr->user_width_max=PNG_USER_WIDTH_MAX;
    png_ptr->user_height_max=PNG_USER_HEIGHT_MAX;
 #endif
 
-   /* initialize zbuf - compression buffer */
+   /* Initialize zbuf - compression buffer */
    png_ptr->zbuf_size = PNG_ZBUF_SIZE;
    png_ptr->zbuf = (png_bytep)png_malloc(png_ptr,
      (png_uint_32)png_ptr->zbuf_size);
@@ -326,7 +326,8 @@
 void PNGAPI
 png_read_info(png_structp png_ptr, png_infop info_ptr)
 {
-   if (png_ptr == NULL || info_ptr == NULL) return;
+   if (png_ptr == NULL || info_ptr == NULL)
+      return;
    png_debug(1, "in png_read_info");
    /* If we haven't checked all of the PNG signature bytes, do so now. */
    if (png_ptr->sig_bytes < 8)
@@ -529,12 +530,13 @@
 }
 #endif /* PNG_NO_SEQUENTIAL_READ_SUPPORTED */
 
-/* optional call to update the users info_ptr structure */
+/* Optional call to update the users info_ptr structure */
 void PNGAPI
 png_read_update_info(png_structp png_ptr, png_infop info_ptr)
 {
    png_debug(1, "in png_read_update_info");
-   if (png_ptr == NULL) return;
+   if (png_ptr == NULL)
+      return;
    if (!(png_ptr->flags & PNG_FLAG_ROW_INIT))
       png_read_start_row(png_ptr);
    else
@@ -553,7 +555,8 @@
 png_start_read_image(png_structp png_ptr)
 {
    png_debug(1, "in png_start_read_image");
-   if (png_ptr == NULL) return;
+   if (png_ptr == NULL)
+      return;
    if (!(png_ptr->flags & PNG_FLAG_ROW_INIT))
       png_read_start_row(png_ptr);
 }
@@ -570,14 +573,15 @@
    PNG_CONST int png_pass_mask[7] = {0x80, 0x08, 0x88, 0x22, 0xaa, 0x55, 0xff};
 #endif
    int ret;
-   if (png_ptr == NULL) return;
+   if (png_ptr == NULL)
+      return;
    png_debug2(1, "in png_read_row (row %lu, pass %d)",
       png_ptr->row_number, png_ptr->pass);
    if (!(png_ptr->flags & PNG_FLAG_ROW_INIT))
       png_read_start_row(png_ptr);
    if (png_ptr->row_number == 0 && png_ptr->pass == 0)
    {
-   /* check for transforms that have been set but were defined out */
+   /* Check for transforms that have been set but were defined out */
 #if defined(PNG_WRITE_INVERT_SUPPORTED) && !defined(PNG_READ_INVERT_SUPPORTED)
    if (png_ptr->transformations & PNG_INVERT_MONO)
       png_warning(png_ptr, "PNG_READ_INVERT_SUPPORTED is not defined.");
@@ -609,7 +613,7 @@
    }
 
 #if defined(PNG_READ_INTERLACING_SUPPORTED)
-   /* if interlaced and we do not need a new row, combine row and return */
+   /* If interlaced and we do not need a new row, combine row and return */
    if (png_ptr->interlaced && (png_ptr->transformations & PNG_INTERLACE))
    {
       switch (png_ptr->pass)
@@ -756,15 +760,15 @@
       png_do_read_transformations(png_ptr);
 
 #if defined(PNG_READ_INTERLACING_SUPPORTED)
-   /* blow up interlaced rows to full size */
+   /* Blow up interlaced rows to full size */
    if (png_ptr->interlaced &&
       (png_ptr->transformations & PNG_INTERLACE))
    {
       if (png_ptr->pass < 6)
-/*       old interface (pre-1.0.9):
-         png_do_read_interlace(&(png_ptr->row_info),
-            png_ptr->row_buf + 1, png_ptr->pass, png_ptr->transformations);
- */
+         /* Old interface (pre-1.0.9):
+          * png_do_read_interlace(&(png_ptr->row_info),
+          *    png_ptr->row_buf + 1, png_ptr->pass, png_ptr->transformations);
+          */
          png_do_read_interlace(png_ptr);
 
       if (dsp_row != NULL)
@@ -823,7 +827,8 @@
    png_bytepp dp;
 
    png_debug(1, "in png_read_rows");
-   if (png_ptr == NULL) return;
+   if (png_ptr == NULL)
+      return;
    rp = row;
    dp = display_row;
    if (rp != NULL && dp != NULL)
@@ -872,7 +877,8 @@
    png_bytepp rp;
 
    png_debug(1, "in png_read_image");
-   if (png_ptr == NULL) return;
+   if (png_ptr == NULL)
+      return;
 
 #ifdef PNG_READ_INTERLACING_SUPPORTED
    pass = png_set_interlace_handling(png_ptr);
@@ -908,7 +914,8 @@
 png_read_end(png_structp png_ptr, png_infop info_ptr)
 {
    png_debug(1, "in png_read_end");
-   if (png_ptr == NULL) return;
+   if (png_ptr == NULL)
+      return;
    png_crc_finish(png_ptr, 0); /* Finish off CRC from last IDAT chunk */
 
    do
@@ -1075,7 +1082,7 @@
 }
 #endif /* PNG_NO_SEQUENTIAL_READ_SUPPORTED */
 
-/* free all memory used by the read */
+/* Free all memory used by the read */
 void PNGAPI
 png_destroy_read_struct(png_structpp png_ptr_ptr, png_infopp info_ptr_ptr,
    png_infopp end_info_ptr_ptr)
@@ -1147,7 +1154,7 @@
    }
 }
 
-/* free all memory used by the read (old method) */
+/* Free all memory used by the read (old method) */
 void /* PRIVATE */
 png_read_destroy(png_structp png_ptr, png_infop info_ptr, png_infop end_info_ptr)
 {
@@ -1296,7 +1303,8 @@
 void PNGAPI
 png_set_read_status_fn(png_structp png_ptr, png_read_status_ptr read_row_fn)
 {
-   if (png_ptr == NULL) return;
+   if (png_ptr == NULL)
+      return;
    png_ptr->read_row_fn = read_row_fn;
 }
 
@@ -1310,9 +1318,10 @@
 {
    int row;
 
-   if (png_ptr == NULL) return;
+   if (png_ptr == NULL)
+      return;
 #if defined(PNG_READ_INVERT_ALPHA_SUPPORTED)
-   /* invert the alpha channel from opacity to transparency
+   /* Invert the alpha channel from opacity to transparency
     */
    if (transforms & PNG_TRANSFORM_INVERT_ALPHA)
        png_set_invert_alpha(png_ptr);
@@ -1328,10 +1337,10 @@
    /* -------------- image transformations start here ------------------- */
 
 #if defined(PNG_READ_16_TO_8_SUPPORTED)
-   /* tell libpng to strip 16 bit/color files down to 8 bits per color
+   /* Tell libpng to strip 16 bit/color files down to 8 bits per color.
     */
    if (transforms & PNG_TRANSFORM_STRIP_16)
-       png_set_strip_16(png_ptr);
+      png_set_strip_16(png_ptr);
 #endif
 
 #if defined(PNG_READ_STRIP_ALPHA_SUPPORTED)
@@ -1339,7 +1348,7 @@
     * the background (not recommended).
     */
    if (transforms & PNG_TRANSFORM_STRIP_ALPHA)
-       png_set_strip_alpha(png_ptr);
+      png_set_strip_alpha(png_ptr);
 #endif
 
 #if defined(PNG_READ_PACK_SUPPORTED) && !defined(PNG_READ_EXPAND_SUPPORTED)
@@ -1347,7 +1356,7 @@
     * byte into separate bytes (useful for paletted and grayscale images).
     */
    if (transforms & PNG_TRANSFORM_PACKING)
-       png_set_packing(png_ptr);
+      png_set_packing(png_ptr);
 #endif
 
 #if defined(PNG_READ_PACKSWAP_SUPPORTED)
@@ -1355,7 +1364,7 @@
     * (not useful if you are using png_set_packing).
     */
    if (transforms & PNG_TRANSFORM_PACKSWAP)
-       png_set_packswap(png_ptr);
+      png_set_packswap(png_ptr);
 #endif
 
 #if defined(PNG_READ_EXPAND_SUPPORTED)
@@ -1365,9 +1374,9 @@
     * channels so the data will be available as RGBA quartets.
     */
    if (transforms & PNG_TRANSFORM_EXPAND)
-       if ((png_ptr->bit_depth < 8) ||
-           (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE) ||
-           (png_get_valid(png_ptr, info_ptr, PNG_INFO_tRNS)))
+      if ((png_ptr->bit_depth < 8) ||
+          (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE) ||
+          (png_get_valid(png_ptr, info_ptr, PNG_INFO_tRNS)))
          png_set_expand(png_ptr);
 #endif
 
@@ -1375,10 +1384,10 @@
     */
 
 #if defined(PNG_READ_INVERT_SUPPORTED)
-   /* invert monochrome files to have 0 as white and 1 as black
+   /* Invert monochrome files to have 0 as white and 1 as black
     */
    if (transforms & PNG_TRANSFORM_INVERT_MONO)
-       png_set_invert_mono(png_ptr);
+      png_set_invert_mono(png_ptr);
 #endif
 
 #if defined(PNG_READ_SHIFT_SUPPORTED)
@@ -1397,24 +1406,24 @@
 #endif
 
 #if defined(PNG_READ_BGR_SUPPORTED)
-   /* flip the RGB pixels to BGR (or RGBA to BGRA)
+   /* Flip the RGB pixels to BGR (or RGBA to BGRA)
     */
    if (transforms & PNG_TRANSFORM_BGR)
-       png_set_bgr(png_ptr);
+      png_set_bgr(png_ptr);
 #endif
 
 #if defined(PNG_READ_SWAP_ALPHA_SUPPORTED)
-   /* swap the RGBA or GA data to ARGB or AG (or BGRA to ABGR)
+   /* Swap the RGBA or GA data to ARGB or AG (or BGRA to ABGR)
     */
    if (transforms & PNG_TRANSFORM_SWAP_ALPHA)
        png_set_swap_alpha(png_ptr);
 #endif
 
 #if defined(PNG_READ_SWAP_SUPPORTED)
-   /* swap bytes of 16 bit files to least significant byte first
+   /* Swap bytes of 16 bit files to least significant byte first
     */
    if (transforms & PNG_TRANSFORM_SWAP_ENDIAN)
-       png_set_swap(png_ptr);
+      png_set_swap(png_ptr);
 #endif
 
    /* We don't handle adding filler bytes */
@@ -1447,10 +1456,10 @@
    png_read_image(png_ptr, info_ptr->row_pointers);
    info_ptr->valid |= PNG_INFO_IDAT;
 
-   /* read rest of file, and get additional chunks in info_ptr - REQUIRED */
+   /* Read rest of file, and get additional chunks in info_ptr - REQUIRED */
    png_read_end(png_ptr, info_ptr);
 
-   transforms = transforms; /* quiet compiler warnings */
+   transforms = transforms; /* Quiet compiler warnings */
    params = params;
 
 }
diff --git a/pngrio.c b/pngrio.c
index d47d86d..642a416 100644
--- a/pngrio.c
+++ b/pngrio.c
@@ -1,7 +1,7 @@
 
 /* pngrio.c - functions for data input
  *
- * Last changed in libpng 1.2.36 [May 7, 2009]
+ * Last changed in libpng 1.2.37 [May 20, 2009]
  * For conditions of distribution and use, see copyright notice in png.h
  * Copyright (c) 1998-2009 Glenn Randers-Pehrson
  * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
@@ -20,10 +20,11 @@
 #if defined(PNG_READ_SUPPORTED)
 
 /* Read the data from whatever input you are using.  The default routine
-   reads from a file pointer.  Note that this routine sometimes gets called
-   with very small lengths, so you should implement some kind of simple
-   buffering if you are using unbuffered reads.  This should never be asked
-   to read more then 64K on a 16 bit machine. */
+ * reads from a file pointer.  Note that this routine sometimes gets called
+ * with very small lengths, so you should implement some kind of simple
+ * buffering if you are using unbuffered reads.  This should never be asked
+ * to read more then 64K on a 16 bit machine.
+ */
 void /* PRIVATE */
 png_read_data(png_structp png_ptr, png_bytep data, png_size_t length)
 {
@@ -36,16 +37,18 @@
 
 #if !defined(PNG_NO_STDIO)
 /* This is the function that does the actual reading of data.  If you are
-   not reading from a standard C stream, you should create a replacement
-   read_data function and use it at run time with png_set_read_fn(), rather
-   than changing the library. */
+ * not reading from a standard C stream, you should create a replacement
+ * read_data function and use it at run time with png_set_read_fn(), rather
+ * than changing the library.
+ */
 #ifndef USE_FAR_KEYWORD
 void PNGAPI
 png_default_read_data(png_structp png_ptr, png_bytep data, png_size_t length)
 {
    png_size_t check;
 
-   if (png_ptr == NULL) return;
+   if (png_ptr == NULL)
+      return;
    /* fread() returns 0 on error, so it is OK to store this in a png_size_t
     * instead of an int, which is what fread() actually returns.
     */
@@ -61,7 +64,7 @@
       png_error(png_ptr, "Read Error");
 }
 #else
-/* this is the model-independent version. Since the standard I/O library
+/* This is the model-independent version. Since the standard I/O library
    can't handle far buffers in the medium and small models, we have to copy
    the data.
 */
@@ -76,7 +79,8 @@
    png_byte *n_data;
    png_FILE_p io_ptr;
 
-   if (png_ptr == NULL) return;
+   if (png_ptr == NULL)
+      return;
    /* Check if data really is near. If so, use usual code. */
    n_data = (png_byte *)CVT_PTR_NOCHECK(data);
    io_ptr = (png_FILE_p)CVT_PTR(png_ptr->io_ptr);
@@ -121,25 +125,27 @@
 #endif
 
 /* This function allows the application to supply a new input function
-   for libpng if standard C streams aren't being used.
-
-   This function takes as its arguments:
-   png_ptr      - pointer to a png input data structure
-   io_ptr       - pointer to user supplied structure containing info about
-                  the input functions.  May be NULL.
-   read_data_fn - pointer to a new input function that takes as its
-                  arguments a pointer to a png_struct, a pointer to
-                  a location where input data can be stored, and a 32-bit
-                  unsigned int that is the number of bytes to be read.
-                  To exit and output any fatal error messages the new write
-                  function should call png_error(png_ptr, "Error msg").
-                  May be NULL, in which case libpng's default function will
-                  be used. */
+ * for libpng if standard C streams aren't being used.
+ *
+ * This function takes as its arguments:
+ * png_ptr      - pointer to a png input data structure
+ * io_ptr       - pointer to user supplied structure containing info about
+ *                the input functions.  May be NULL.
+ * read_data_fn - pointer to a new input function that takes as its
+ *                arguments a pointer to a png_struct, a pointer to
+ *                a location where input data can be stored, and a 32-bit
+ *                unsigned int that is the number of bytes to be read.
+ *                To exit and output any fatal error messages the new write
+ *                function should call png_error(png_ptr, "Error msg").
+ *                May be NULL, in which case libpng's default function will
+ *                be used.
+ */
 void PNGAPI
 png_set_read_fn(png_structp png_ptr, png_voidp io_ptr,
    png_rw_ptr read_data_fn)
 {
-   if (png_ptr == NULL) return;
+   if (png_ptr == NULL)
+      return;
    png_ptr->io_ptr = io_ptr;
 
 #if !defined(PNG_NO_STDIO)
diff --git a/pngrtran.c b/pngrtran.c
index d7dd8e7..c346ce7 100644
--- a/pngrtran.c
+++ b/pngrtran.c
@@ -1,7 +1,7 @@
 
 /* pngrtran.c - transforms the data in a row for PNG readers
  *
- * Last changed in libpng 1.2.35 [February 14, 2009]
+ * Last changed in libpng 1.2.37 [May 20, 2009]
  * For conditions of distribution and use, see copyright notice in png.h
  * Copyright (c) 1998-2009 Glenn Randers-Pehrson
  * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
@@ -23,24 +23,29 @@
 {
    png_debug(1, "in png_set_crc_action");
    /* Tell libpng how we react to CRC errors in critical chunks */
-   if (png_ptr == NULL) return;
+   if (png_ptr == NULL)
+      return;
    switch (crit_action)
    {
-      case PNG_CRC_NO_CHANGE:                        /* leave setting as is */
+      case PNG_CRC_NO_CHANGE:                        /* Leave setting as is */
          break;
-      case PNG_CRC_WARN_USE:                               /* warn/use data */
+
+      case PNG_CRC_WARN_USE:                               /* Warn/use data */
          png_ptr->flags &= ~PNG_FLAG_CRC_CRITICAL_MASK;
          png_ptr->flags |= PNG_FLAG_CRC_CRITICAL_USE;
          break;
-      case PNG_CRC_QUIET_USE:                             /* quiet/use data */
+
+      case PNG_CRC_QUIET_USE:                             /* Quiet/use data */
          png_ptr->flags &= ~PNG_FLAG_CRC_CRITICAL_MASK;
          png_ptr->flags |= PNG_FLAG_CRC_CRITICAL_USE |
                            PNG_FLAG_CRC_CRITICAL_IGNORE;
          break;
-      case PNG_CRC_WARN_DISCARD:    /* not a valid action for critical data */
+
+      case PNG_CRC_WARN_DISCARD:    /* Not a valid action for critical data */
          png_warning(png_ptr,
             "Can't discard critical data on CRC error.");
-      case PNG_CRC_ERROR_QUIT:                                /* error/quit */
+      case PNG_CRC_ERROR_QUIT:                                /* Error/quit */
+
       case PNG_CRC_DEFAULT:
       default:
          png_ptr->flags &= ~PNG_FLAG_CRC_CRITICAL_MASK;
@@ -49,22 +54,27 @@
 
    switch (ancil_action)
    {
-      case PNG_CRC_NO_CHANGE:                       /* leave setting as is */
+      case PNG_CRC_NO_CHANGE:                       /* Leave setting as is */
          break;
-      case PNG_CRC_WARN_USE:                              /* warn/use data */
+
+      case PNG_CRC_WARN_USE:                              /* Warn/use data */
          png_ptr->flags &= ~PNG_FLAG_CRC_ANCILLARY_MASK;
          png_ptr->flags |= PNG_FLAG_CRC_ANCILLARY_USE;
          break;
-      case PNG_CRC_QUIET_USE:                            /* quiet/use data */
+
+      case PNG_CRC_QUIET_USE:                            /* Quiet/use data */
          png_ptr->flags &= ~PNG_FLAG_CRC_ANCILLARY_MASK;
          png_ptr->flags |= PNG_FLAG_CRC_ANCILLARY_USE |
                            PNG_FLAG_CRC_ANCILLARY_NOWARN;
          break;
-      case PNG_CRC_ERROR_QUIT:                               /* error/quit */
+
+      case PNG_CRC_ERROR_QUIT:                               /* Error/quit */
          png_ptr->flags &= ~PNG_FLAG_CRC_ANCILLARY_MASK;
          png_ptr->flags |= PNG_FLAG_CRC_ANCILLARY_NOWARN;
          break;
-      case PNG_CRC_WARN_DISCARD:                      /* warn/discard data */
+
+      case PNG_CRC_WARN_DISCARD:                      /* Warn/discard data */
+
       case PNG_CRC_DEFAULT:
       default:
          png_ptr->flags &= ~PNG_FLAG_CRC_ANCILLARY_MASK;
@@ -74,14 +84,15 @@
 
 #if defined(PNG_READ_BACKGROUND_SUPPORTED) && \
     defined(PNG_FLOATING_POINT_SUPPORTED)
-/* handle alpha and tRNS via a background color */
+/* Handle alpha and tRNS via a background color */
 void PNGAPI
 png_set_background(png_structp png_ptr,
    png_color_16p background_color, int background_gamma_code,
    int need_expand, double background_gamma)
 {
    png_debug(1, "in png_set_background");
-   if (png_ptr == NULL) return;
+   if (png_ptr == NULL)
+      return;
    if (background_gamma_code == PNG_BACKGROUND_GAMMA_UNKNOWN)
    {
       png_warning(png_ptr, "Application must supply a known background gamma");
@@ -98,12 +109,13 @@
 #endif
 
 #if defined(PNG_READ_16_TO_8_SUPPORTED)
-/* strip 16 bit depth files to 8 bit depth */
+/* Strip 16 bit depth files to 8 bit depth */
 void PNGAPI
 png_set_strip_16(png_structp png_ptr)
 {
    png_debug(1, "in png_set_strip_16");
-   if (png_ptr == NULL) return;
+   if (png_ptr == NULL)
+      return;
    png_ptr->transformations |= PNG_16_TO_8;
 }
 #endif
@@ -113,7 +125,8 @@
 png_set_strip_alpha(png_structp png_ptr)
 {
    png_debug(1, "in png_set_strip_alpha");
-   if (png_ptr == NULL) return;
+   if (png_ptr == NULL)
+      return;
    png_ptr->flags |= PNG_FLAG_STRIP_ALPHA;
 }
 #endif
@@ -143,7 +156,8 @@
    int full_dither)
 {
    png_debug(1, "in png_set_dither");
-   if (png_ptr == NULL) return;
+   if (png_ptr == NULL)
+      return;
    png_ptr->transformations |= PNG_DITHER;
 
    if (!full_dither)
@@ -161,27 +175,29 @@
       if (histogram != NULL)
       {
          /* This is easy enough, just throw out the least used colors.
-            Perhaps not the best solution, but good enough. */
+          * Perhaps not the best solution, but good enough.
+          */
 
          int i;
 
-         /* initialize an array to sort colors */
+         /* Initialize an array to sort colors */
          png_ptr->dither_sort = (png_bytep)png_malloc(png_ptr,
             (png_uint_32)(num_palette * png_sizeof(png_byte)));
 
-         /* initialize the dither_sort array */
+         /* Initialize the dither_sort array */
          for (i = 0; i < num_palette; i++)
             png_ptr->dither_sort[i] = (png_byte)i;
 
          /* Find the least used palette entries by starting a
-            bubble sort, and running it until we have sorted
-            out enough colors.  Note that we don't care about
-            sorting all the colors, just finding which are
-            least used. */
+          * bubble sort, and running it until we have sorted
+          * out enough colors.  Note that we don't care about
+          * sorting all the colors, just finding which are
+          * least used.
+          */
 
          for (i = num_palette - 1; i >= maximum_colors; i--)
          {
-            int done; /* to stop early if the list is pre-sorted */
+            int done; /* To stop early if the list is pre-sorted */
             int j;
 
             done = 1;
@@ -202,13 +218,14 @@
                break;
          }
 
-         /* swap the palette around, and set up a table, if necessary */
+         /* Swap the palette around, and set up a table, if necessary */
          if (full_dither)
          {
             int j = num_palette;
 
-            /* put all the useful colors within the max, but don't
-               move the others */
+            /* Put all the useful colors within the max, but don't
+             * move the others.
+             */
             for (i = 0; i < maximum_colors; i++)
             {
                if ((int)png_ptr->dither_sort[i] >= maximum_colors)
@@ -224,11 +241,12 @@
          {
             int j = num_palette;
 
-            /* move all the used colors inside the max limit, and
-               develop a translation table */
+            /* Move all the used colors inside the max limit, and
+             * develop a translation table.
+             */
             for (i = 0; i < maximum_colors; i++)
             {
-               /* only move the colors we need to */
+               /* Only move the colors we need to */
                if ((int)png_ptr->dither_sort[i] >= maximum_colors)
                {
                   png_color tmp_color;
@@ -240,20 +258,20 @@
                   tmp_color = palette[j];
                   palette[j] = palette[i];
                   palette[i] = tmp_color;
-                  /* indicate where the color went */
+                  /* Indicate where the color went */
                   png_ptr->dither_index[j] = (png_byte)i;
                   png_ptr->dither_index[i] = (png_byte)j;
                }
             }
 
-            /* find closest color for those colors we are not using */
+            /* Find closest color for those colors we are not using */
             for (i = 0; i < num_palette; i++)
             {
                if ((int)png_ptr->dither_index[i] >= maximum_colors)
                {
                   int min_d, k, min_k, d_index;
 
-                  /* find the closest color to one we threw out */
+                  /* Find the closest color to one we threw out */
                   d_index = png_ptr->dither_index[i];
                   min_d = PNG_COLOR_DIST(palette[d_index], palette[0]);
                   for (k = 1, min_k = 0; k < maximum_colors; k++)
@@ -268,7 +286,7 @@
                         min_k = k;
                      }
                   }
-                  /* point to closest color */
+                  /* Point to closest color */
                   png_ptr->dither_index[i] = (png_byte)min_k;
                }
             }
@@ -279,13 +297,13 @@
       else
       {
          /* This is much harder to do simply (and quickly).  Perhaps
-            we need to go through a median cut routine, but those
-            don't always behave themselves with only a few colors
-            as input.  So we will just find the closest two colors,
-            and throw out one of them (chosen somewhat randomly).
-            [We don't understand this at all, so if someone wants to
-             work on improving it, be our guest - AED, GRP]
-            */
+          * we need to go through a median cut routine, but those
+          * don't always behave themselves with only a few colors
+          * as input.  So we will just find the closest two colors,
+          * and throw out one of them (chosen somewhat randomly).
+          * [We don't understand this at all, so if someone wants to
+          *  work on improving it, be our guest - AED, GRP]
+          */
          int i;
          int max_d;
          int num_new_palette;
@@ -294,13 +312,13 @@
 
          t = NULL;
 
-         /* initialize palette index arrays */
+         /* Initialize palette index arrays */
          png_ptr->index_to_palette = (png_bytep)png_malloc(png_ptr,
             (png_uint_32)(num_palette * png_sizeof(png_byte)));
          png_ptr->palette_to_index = (png_bytep)png_malloc(png_ptr,
             (png_uint_32)(num_palette * png_sizeof(png_byte)));
 
-         /* initialize the sort array */
+         /* Initialize the sort array */
          for (i = 0; i < num_palette; i++)
          {
             png_ptr->index_to_palette[i] = (png_byte)i;
@@ -313,14 +331,14 @@
 
          num_new_palette = num_palette;
 
-         /* initial wild guess at how far apart the farthest pixel
-            pair we will be eliminating will be.  Larger
-            numbers mean more areas will be allocated, Smaller
-            numbers run the risk of not saving enough data, and
-            having to do this all over again.
-
-            I have not done extensive checking on this number.
-            */
+         /* Initial wild guess at how far apart the farthest pixel
+          * pair we will be eliminating will be.  Larger
+          * numbers mean more areas will be allocated, Smaller
+          * numbers run the risk of not saving enough data, and
+          * having to do this all over again.
+          *
+          * I have not done extensive checking on this number.
+          */
          max_d = 96;
 
          while (num_new_palette > maximum_colors)
@@ -523,7 +541,8 @@
 png_set_gamma(png_structp png_ptr, double scrn_gamma, double file_gamma)
 {
    png_debug(1, "in png_set_gamma");
-   if (png_ptr == NULL) return;
+   if (png_ptr == NULL)
+      return;
    if ((fabs(scrn_gamma * file_gamma - 1.0) > PNG_GAMMA_THRESHOLD) ||
        (png_ptr->color_type & PNG_COLOR_MASK_ALPHA) ||
        (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE))
@@ -542,7 +561,8 @@
 png_set_expand(png_structp png_ptr)
 {
    png_debug(1, "in png_set_expand");
-   if (png_ptr == NULL) return;
+   if (png_ptr == NULL)
+      return;
    png_ptr->transformations |= (PNG_EXPAND | PNG_EXPAND_tRNS);
    png_ptr->flags &= ~PNG_FLAG_ROW_INIT;
 }
@@ -569,7 +589,8 @@
 png_set_palette_to_rgb(png_structp png_ptr)
 {
    png_debug(1, "in png_set_palette_to_rgb");
-   if (png_ptr == NULL) return;
+   if (png_ptr == NULL)
+      return;
    png_ptr->transformations |= (PNG_EXPAND | PNG_EXPAND_tRNS);
    png_ptr->flags &= ~PNG_FLAG_ROW_INIT;
 }
@@ -580,7 +601,8 @@
 png_set_expand_gray_1_2_4_to_8(png_structp png_ptr)
 {
    png_debug(1, "in png_set_expand_gray_1_2_4_to_8");
-   if (png_ptr == NULL) return;
+   if (png_ptr == NULL)
+      return;
    png_ptr->transformations |= PNG_EXPAND;
    png_ptr->flags &= ~PNG_FLAG_ROW_INIT;
 }
@@ -593,7 +615,8 @@
 png_set_gray_1_2_4_to_8(png_structp png_ptr)
 {
    png_debug(1, "in png_set_gray_1_2_4_to_8");
-   if (png_ptr == NULL) return;
+   if (png_ptr == NULL)
+      return;
    png_ptr->transformations |= (PNG_EXPAND | PNG_EXPAND_tRNS);
 }
 #endif
@@ -629,10 +652,11 @@
 png_set_rgb_to_gray(png_structp png_ptr, int error_action, double red,
    double green)
 {
-      int red_fixed = (int)((float)red*100000.0 + 0.5);
-      int green_fixed = (int)((float)green*100000.0 + 0.5);
-      if (png_ptr == NULL) return;
-      png_set_rgb_to_gray_fixed(png_ptr, error_action, red_fixed, green_fixed);
+   int red_fixed = (int)((float)red*100000.0 + 0.5);
+   int green_fixed = (int)((float)green*100000.0 + 0.5);
+   if (png_ptr == NULL)
+      return;
+   png_set_rgb_to_gray_fixed(png_ptr, error_action, red_fixed, green_fixed);
 }
 #endif
 
@@ -641,13 +665,16 @@
    png_fixed_point red, png_fixed_point green)
 {
    png_debug(1, "in png_set_rgb_to_gray");
-   if (png_ptr == NULL) return;
+   if (png_ptr == NULL)
+      return;
    switch(error_action)
    {
       case 1: png_ptr->transformations |= PNG_RGB_TO_GRAY;
               break;
+
       case 2: png_ptr->transformations |= PNG_RGB_TO_GRAY_WARN;
               break;
+
       case 3: png_ptr->transformations |= PNG_RGB_TO_GRAY_ERR;
    }
    if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
@@ -669,8 +696,8 @@
       }
       else if (red + green < 100000L)
       {
-        red_int = (png_uint_16)(((png_uint_32)red*32768L)/100000L);
-        green_int = (png_uint_16)(((png_uint_32)green*32768L)/100000L);
+         red_int = (png_uint_16)(((png_uint_32)red*32768L)/100000L);
+         green_int = (png_uint_16)(((png_uint_32)green*32768L)/100000L);
       }
       else
       {
@@ -694,7 +721,8 @@
    read_user_transform_fn)
 {
    png_debug(1, "in png_set_read_user_transform_fn");
-   if (png_ptr == NULL) return;
+   if (png_ptr == NULL)
+      return;
 #if defined(PNG_READ_USER_TRANSFORM_SUPPORTED)
    png_ptr->transformations |= PNG_USER_TRANSFORM;
    png_ptr->read_user_transform_fn = read_user_transform_fn;
@@ -727,8 +755,9 @@
 
 #if defined(PNG_READ_GRAY_TO_RGB_SUPPORTED)
    /* Detect gray background and attempt to enable optimization
-    * for gray --> RGB case */
-   /* Note:  if PNG_BACKGROUND_EXPAND is set and color_type is either RGB or
+    * for gray --> RGB case
+    *
+    * Note:  if PNG_BACKGROUND_EXPAND is set and color_type is either RGB or
     * RGB_ALPHA (in which case need_expand is superfluous anyway), the
     * background color might actually be gray yet not be flagged as such.
     * This is not a problem for the current code, which uses
@@ -755,7 +784,7 @@
    {
       if (!(color_type & PNG_COLOR_MASK_COLOR))  /* i.e., GRAY or GRAY_ALPHA */
       {
-         /* expand background and tRNS chunks */
+         /* Expand background and tRNS chunks */
          switch (png_ptr->bit_depth)
          {
             case 1:
@@ -769,6 +798,7 @@
                    = png_ptr->trans_values.blue = png_ptr->trans_values.gray;
                }
                break;
+
             case 2:
                png_ptr->background.gray *= (png_uint_16)0x55;
                png_ptr->background.red = png_ptr->background.green
@@ -780,6 +810,7 @@
                    = png_ptr->trans_values.blue = png_ptr->trans_values.gray;
                }
                break;
+
             case 4:
                png_ptr->background.gray *= (png_uint_16)0x11;
                png_ptr->background.red = png_ptr->background.green
@@ -791,7 +822,9 @@
                    = png_ptr->trans_values.blue = png_ptr->trans_values.gray;
                }
                break;
+
             case 8:
+
             case 16:
                png_ptr->background.red = png_ptr->background.green
                  = png_ptr->background.blue = png_ptr->background.gray;
@@ -814,8 +847,9 @@
            if (!(png_ptr->transformations & PNG_EXPAND_tRNS))
 #endif
            {
-           /* invert the alpha channel (in tRNS) unless the pixels are
-              going to be expanded, in which case leave it for later */
+           /* Invert the alpha channel (in tRNS) unless the pixels are
+            * going to be expanded, in which case leave it for later
+            */
               int i, istop;
               istop=(int)png_ptr->num_trans;
               for (i=0; i<istop; i++)
@@ -842,7 +876,7 @@
     for (i=0; i<png_ptr->num_trans; i++)
     {
       if (png_ptr->trans[i] != 0 && png_ptr->trans[i] != 0xff)
-        k=1; /* partial transparency is present */
+        k=1; /* Partial transparency is present */
     }
     if (k == 0)
       png_ptr->transformations &= ~PNG_GAMMA;
@@ -857,8 +891,7 @@
       {
          if (color_type == PNG_COLOR_TYPE_PALETTE)
          {
-           /* could skip if no transparency and
-           */
+           /* Could skip if no transparency */
             png_color back, back_1;
             png_colorp palette = png_ptr->palette;
             int num_palette = png_ptr->num_palette;
@@ -883,10 +916,12 @@
                      g = (png_ptr->screen_gamma);
                      gs = 1.0;
                      break;
+
                   case PNG_BACKGROUND_GAMMA_FILE:
                      g = 1.0 / (png_ptr->gamma);
                      gs = 1.0 / (png_ptr->gamma * png_ptr->screen_gamma);
                      break;
+
                   case PNG_BACKGROUND_GAMMA_UNIQUE:
                      g = 1.0 / (png_ptr->background_gamma);
                      gs = 1.0 / (png_ptr->background_gamma *
@@ -975,10 +1010,12 @@
                   g = (png_ptr->screen_gamma);
                   gs = 1.0;
                   break;
+
                case PNG_BACKGROUND_GAMMA_FILE:
                   g = 1.0 / (png_ptr->gamma);
                   gs = 1.0 / (png_ptr->gamma * png_ptr->screen_gamma);
                   break;
+
                case PNG_BACKGROUND_GAMMA_UNIQUE:
                   g = 1.0 / (png_ptr->background_gamma);
                   gs = 1.0 / (png_ptr->background_gamma *
@@ -1020,7 +1057,7 @@
          }
       }
       else
-      /* transformation does not include PNG_BACKGROUND */
+      /* Transformation does not include PNG_BACKGROUND */
 #endif /* PNG_READ_BACKGROUND_SUPPORTED */
       if (color_type == PNG_COLOR_TYPE_PALETTE)
       {
@@ -1192,8 +1229,8 @@
    if (png_ptr->transformations & PNG_DITHER)
    {
       if (((info_ptr->color_type == PNG_COLOR_TYPE_RGB) ||
-         (info_ptr->color_type == PNG_COLOR_TYPE_RGB_ALPHA)) &&
-         png_ptr->palette_lookup && info_ptr->bit_depth == 8)
+          (info_ptr->color_type == PNG_COLOR_TYPE_RGB_ALPHA)) &&
+          png_ptr->palette_lookup && info_ptr->bit_depth == 8)
       {
          info_ptr->color_type = PNG_COLOR_TYPE_PALETTE;
       }
@@ -1227,7 +1264,7 @@
        (info_ptr->color_type == PNG_COLOR_TYPE_GRAY)))
    {
       info_ptr->channels++;
-      /* if adding a true alpha channel not just filler */
+      /* If adding a true alpha channel not just filler */
 #if !defined(PNG_1_0_X)
       if (png_ptr->transformations & PNG_ADD_ALPHA)
         info_ptr->color_type |= PNG_COLOR_MASK_ALPHA;
@@ -1282,7 +1319,8 @@
    if (!(png_ptr->flags & PNG_FLAG_ROW_INIT))
       /* Application has failed to call either png_read_start_image()
        * or png_read_update_info() after setting transforms that expand
-       * pixels.  This check added to libpng-1.2.19 */
+       * pixels.  This check added to libpng-1.2.19
+       */
 #if (PNG_WARN_UNINITIALIZED_ROW==1)
       png_error(png_ptr, "Uninitialized row");
 #else
@@ -1335,39 +1373,41 @@
    }
 #endif
 
-/*
-From Andreas Dilger e-mail to png-implement, 26 March 1998:
-
-  In most cases, the "simple transparency" should be done prior to doing
-  gray-to-RGB, or you will have to test 3x as many bytes to check if a
-  pixel is transparent.  You would also need to make sure that the
-  transparency information is upgraded to RGB.
-
-  To summarize, the current flow is:
-  - Gray + simple transparency -> compare 1 or 2 gray bytes and composite
-                                  with background "in place" if transparent,
-                                  convert to RGB if necessary
-  - Gray + alpha -> composite with gray background and remove alpha bytes,
-                                  convert to RGB if necessary
-
-  To support RGB backgrounds for gray images we need:
-  - Gray + simple transparency -> convert to RGB + simple transparency, compare
-                                  3 or 6 bytes and composite with background
-                                  "in place" if transparent (3x compare/pixel
-                                  compared to doing composite with gray bkgrnd)
-  - Gray + alpha -> convert to RGB + alpha, composite with background and
-                                  remove alpha bytes (3x float operations/pixel
-                                  compared with composite on gray background)
-
-  Greg's change will do this.  The reason it wasn't done before is for
-  performance, as this increases the per-pixel operations.  If we would check
-  in advance if the background was gray or RGB, and position the gray-to-RGB
-  transform appropriately, then it would save a lot of work/time.
+/* From Andreas Dilger e-mail to png-implement, 26 March 1998:
+ * 
+ *   In most cases, the "simple transparency" should be done prior to doing
+ *   gray-to-RGB, or you will have to test 3x as many bytes to check if a
+ *   pixel is transparent.  You would also need to make sure that the
+ *   transparency information is upgraded to RGB.
+ * 
+ *   To summarize, the current flow is:
+ *   - Gray + simple transparency -> compare 1 or 2 gray bytes and composite
+ *                                   with background "in place" if transparent,
+ *                                   convert to RGB if necessary
+ *   - Gray + alpha -> composite with gray background and remove alpha bytes,
+ *                                   convert to RGB if necessary
+ *
+ *   To support RGB backgrounds for gray images we need:
+ *   - Gray + simple transparency -> convert to RGB + simple transparency,
+ *                                   compare 3 or 6 bytes and composite with
+ *                                   background "in place" if transparent
+ *                                   (3x compare/pixel compared to doing
+ *                                   composite with gray bkgrnd)
+ *   - Gray + alpha -> convert to RGB + alpha, composite with background and
+ *                                   remove alpha bytes (3x float
+ *                                   operations/pixel compared with composite
+ *                                   on gray background)
+ *
+ *  Greg's change will do this.  The reason it wasn't done before is for
+ *  performance, as this increases the per-pixel operations.  If we would check
+ *  in advance if the background was gray or RGB, and position the gray-to-RGB
+ *  transform appropriately, then it would save a lot of work/time.
  */
 
 #if defined(PNG_READ_GRAY_TO_RGB_SUPPORTED)
-   /* if gray -> RGB, do so now only if background is non-gray; else do later
-    * for performance reasons */
+   /* If gray -> RGB, do so now only if background is non-gray; else do later
+    * for performance reasons
+    */
    if ((png_ptr->transformations & PNG_GRAY_TO_RGB) &&
        !(png_ptr->mode & PNG_BACKGROUND_IS_GRAY))
       png_do_gray_to_rgb(&(png_ptr->row_info), png_ptr->row_buf + 1);
@@ -1392,14 +1432,14 @@
 #if defined(PNG_READ_GAMMA_SUPPORTED)
    if ((png_ptr->transformations & PNG_GAMMA) &&
 #if defined(PNG_READ_BACKGROUND_SUPPORTED)
-      !((png_ptr->transformations & PNG_BACKGROUND) &&
-      ((png_ptr->num_trans != 0) ||
-      (png_ptr->color_type & PNG_COLOR_MASK_ALPHA))) &&
+       !((png_ptr->transformations & PNG_BACKGROUND) &&
+       ((png_ptr->num_trans != 0) ||
+       (png_ptr->color_type & PNG_COLOR_MASK_ALPHA))) &&
 #endif
-      (png_ptr->color_type != PNG_COLOR_TYPE_PALETTE))
+       (png_ptr->color_type != PNG_COLOR_TYPE_PALETTE))
       png_do_gamma(&(png_ptr->row_info), png_ptr->row_buf + 1,
-         png_ptr->gamma_table, png_ptr->gamma_16_table,
-         png_ptr->gamma_shift);
+          png_ptr->gamma_table, png_ptr->gamma_16_table,
+          png_ptr->gamma_shift);
 #endif
 
 #if defined(PNG_READ_16_TO_8_SUPPORTED)
@@ -1444,7 +1484,7 @@
 #endif
 
 #if defined(PNG_READ_GRAY_TO_RGB_SUPPORTED)
-   /* if gray -> RGB, do so now only if we did not do so above */
+   /* If gray -> RGB, do so now only if we did not do so above */
    if ((png_ptr->transformations & PNG_GRAY_TO_RGB) &&
        (png_ptr->mode & PNG_BACKGROUND_IS_GRAY))
       png_do_gray_to_rgb(&(png_ptr->row_info), png_ptr->row_buf + 1);
@@ -1475,16 +1515,16 @@
    if (png_ptr->transformations & PNG_USER_TRANSFORM)
     {
       if (png_ptr->read_user_transform_fn != NULL)
-        (*(png_ptr->read_user_transform_fn)) /* user read transform function */
-          (png_ptr,                    /* png_ptr */
-           &(png_ptr->row_info),       /* row_info:     */
-             /*  png_uint_32 width;          width of row */
-             /*  png_uint_32 rowbytes;       number of bytes in row */
-             /*  png_byte color_type;        color type of pixels */
-             /*  png_byte bit_depth;         bit depth of samples */
-             /*  png_byte channels;          number of channels (1-4) */
-             /*  png_byte pixel_depth;       bits per pixel (depth*channels) */
-           png_ptr->row_buf + 1);      /* start of pixel data for row */
+         (*(png_ptr->read_user_transform_fn)) /* User read transform function */
+            (png_ptr,                    /* png_ptr */
+               &(png_ptr->row_info),     /* row_info: */
+               /*  png_uint_32 width;       width of row */
+               /*  png_uint_32 rowbytes;    number of bytes in row */
+               /*  png_byte color_type;     color type of pixels */
+               /*  png_byte bit_depth;      bit depth of samples */
+               /*  png_byte channels;       number of channels (1-4) */
+               /*  png_byte pixel_depth;    bits per pixel (depth*channels) */
+               png_ptr->row_buf + 1);    /* start of pixel data for row */
 #if defined(PNG_USER_TRANSFORM_PTR_SUPPORTED)
       if (png_ptr->user_transform_depth)
          png_ptr->row_info.bit_depth = png_ptr->user_transform_depth;
@@ -1542,6 +1582,7 @@
             }
             break;
          }
+
          case 2:
          {
 
@@ -1563,6 +1604,7 @@
             }
             break;
          }
+
          case 4:
          {
             png_bytep sp = row + (png_size_t)((row_width - 1) >> 1);
@@ -1654,6 +1696,7 @@
             }
             break;
          }
+
          case 4:
          {
             png_bytep bp = row;
@@ -1669,6 +1712,7 @@
             }
             break;
          }
+
          case 8:
          {
             png_bytep bp = row;
@@ -1681,6 +1725,7 @@
             }
             break;
          }
+
          case 16:
          {
             png_bytep bp = row;
@@ -1702,7 +1747,7 @@
 #endif
 
 #if defined(PNG_READ_16_TO_8_SUPPORTED)
-/* chop rows of bit depth 16 down to 8 */
+/* Chop rows of bit depth 16 down to 8 */
 void /* PRIVATE */
 png_do_chop(png_row_infop row_info, png_bytep row)
 {
@@ -1726,14 +1771,17 @@
        *
        * What the ideal calculation should be:
        *   *dp = (((((png_uint_32)(*sp) << 8) |
-       *          (png_uint_32)(*(sp + 1))) * 255 + 127) / (png_uint_32)65535L;
+       *          (png_uint_32)(*(sp + 1))) * 255 + 127)
+       *          / (png_uint_32)65535L;
        *
        * GRR: no, I think this is what it really should be:
        *   *dp = (((((png_uint_32)(*sp) << 8) |
-       *           (png_uint_32)(*(sp + 1))) + 128L) / (png_uint_32)257L;
+       *           (png_uint_32)(*(sp + 1))) + 128L)
+       *           / (png_uint_32)257L;
        *
        * GRR: here's the exact calculation with shifts:
-       *   temp = (((png_uint_32)(*sp) << 8) | (png_uint_32)(*(sp + 1))) + 128L;
+       *   temp = (((png_uint_32)(*sp) << 8) |
+       *           (png_uint_32)(*(sp + 1))) + 128L;
        *   *dp = (temp - (temp >> 8)) >> 8;
        *
        * Approximate calculation with shift/add instead of multiply/divide:
@@ -2123,7 +2171,7 @@
 #endif
 
 #if defined(PNG_READ_GRAY_TO_RGB_SUPPORTED)
-/* expand grayscale files to RGB, with or without alpha */
+/* Expand grayscale files to RGB, with or without alpha */
 void /* PRIVATE */
 png_do_gray_to_rgb(png_row_infop row_info, png_bytep row)
 {
@@ -2206,7 +2254,7 @@
 #endif
 
 #if defined(PNG_READ_RGB_TO_GRAY_SUPPORTED)
-/* reduce RGB files to grayscale, with or without alpha
+/* Reduce RGB files to grayscale, with or without alpha
  * using the equation given in Poynton's ColorFAQ at
  * <http://www.inforamp.net/~poynton/>  (THIS LINK IS DEAD June 2008)
  * New link:
@@ -2484,18 +2532,22 @@
          num_palette = 2;
          color_inc = 0xff;
          break;
+
       case 2:
          num_palette = 4;
          color_inc = 0x55;
          break;
+
       case 4:
          num_palette = 16;
          color_inc = 0x11;
          break;
+
       case 8:
          num_palette = 256;
          color_inc = 1;
          break;
+
       default:
          num_palette = 0;
          color_inc = 0;
@@ -2673,7 +2725,7 @@
             }
          }
       }
-      else /* assume grayscale palette (what else could it be?) */
+      else /* Assume grayscale palette (what else could it be?) */
       {
          int i;
 
@@ -2749,6 +2801,7 @@
                   }
                   break;
                }
+
                case 2:
                {
 #if defined(PNG_READ_GAMMA_SUPPORTED)
@@ -2805,6 +2858,7 @@
                   }
                   break;
                }
+
                case 4:
                {
 #if defined(PNG_READ_GAMMA_SUPPORTED)
@@ -2861,6 +2915,7 @@
                   }
                   break;
                }
+
                case 8:
                {
 #if defined(PNG_READ_GAMMA_SUPPORTED)
@@ -2893,6 +2948,7 @@
                   }
                   break;
                }
+
                case 16:
                {
 #if defined(PNG_READ_GAMMA_SUPPORTED)
@@ -2906,7 +2962,7 @@
                         v = (png_uint_16)(((*sp) << 8) + *(sp + 1));
                         if (v == trans_values->gray)
                         {
-                           /* background is already in screen gamma */
+                           /* Background is already in screen gamma */
                            *sp = (png_byte)((background->gray >> 8) & 0xff);
                            *(sp + 1) = (png_byte)(background->gray & 0xff);
                         }
@@ -2939,6 +2995,7 @@
             }
             break;
          }
+
          case PNG_COLOR_TYPE_RGB:
          {
             if (row_info->bit_depth == 8)
@@ -2996,7 +3053,7 @@
                      if (r == trans_values->red && g == trans_values->green &&
                         b == trans_values->blue)
                      {
-                        /* background is already in screen gamma */
+                        /* Background is already in screen gamma */
                         *sp = (png_byte)((background->red >> 8) & 0xff);
                         *(sp + 1) = (png_byte)(background->red & 0xff);
                         *(sp + 2) = (png_byte)((background->green >> 8) & 0xff);
@@ -3043,6 +3100,7 @@
             }
             break;
          }
+
          case PNG_COLOR_TYPE_GRAY_ALPHA:
          {
             if (row_info->bit_depth == 8)
@@ -3063,7 +3121,7 @@
                      }
                      else if (a == 0)
                      {
-                        /* background is already in screen gamma */
+                        /* Background is already in screen gamma */
                         *dp = (png_byte)background->gray;
                      }
                      else
@@ -3130,7 +3188,7 @@
                      else
 #endif
                      {
-                        /* background is already in screen gamma */
+                        /* Background is already in screen gamma */
                         *dp = (png_byte)((background->gray >> 8) & 0xff);
                         *(dp + 1) = (png_byte)(background->gray & 0xff);
                      }
@@ -3185,6 +3243,7 @@
             }
             break;
          }
+
          case PNG_COLOR_TYPE_RGB_ALPHA:
          {
             if (row_info->bit_depth == 8)
@@ -3207,7 +3266,7 @@
                      }
                      else if (a == 0)
                      {
-                        /* background is already in screen gamma */
+                        /* Background is already in screen gamma */
                         *dp = (png_byte)background->red;
                         *(dp + 1) = (png_byte)background->green;
                         *(dp + 2) = (png_byte)background->blue;
@@ -3288,7 +3347,7 @@
                      }
                      else if (a == 0)
                      {
-                        /* background is already in screen gamma */
+                        /* Background is already in screen gamma */
                         *dp = (png_byte)((background->red >> 8) & 0xff);
                         *(dp + 1) = (png_byte)(background->red & 0xff);
                         *(dp + 2) = (png_byte)((background->green >> 8) & 0xff);
@@ -3443,6 +3502,7 @@
             }
             break;
          }
+
          case PNG_COLOR_TYPE_RGB_ALPHA:
          {
             if (row_info->bit_depth == 8)
@@ -3480,6 +3540,7 @@
             }
             break;
          }
+
          case PNG_COLOR_TYPE_GRAY_ALPHA:
          {
             if (row_info->bit_depth == 8)
@@ -3504,6 +3565,7 @@
             }
             break;
          }
+
          case PNG_COLOR_TYPE_GRAY:
          {
             if (row_info->bit_depth == 2)
@@ -3524,6 +3586,7 @@
                   sp++;
                }
             }
+
             if (row_info->bit_depth == 4)
             {
                sp = row;
@@ -3537,6 +3600,7 @@
                   sp++;
                }
             }
+
             else if (row_info->bit_depth == 8)
             {
                sp = row;
@@ -3546,6 +3610,7 @@
                   sp++;
                }
             }
+
             else if (row_info->bit_depth == 16)
             {
                sp = row;
@@ -3611,6 +3676,7 @@
                }
                break;
             }
+
             case 2:
             {
                sp = row + (png_size_t)((row_width - 1) >> 2);
@@ -3632,6 +3698,7 @@
                }
                break;
             }
+
             case 4:
             {
                sp = row + (png_size_t)((row_width - 1) >> 1);
@@ -3696,6 +3763,7 @@
                   *dp-- = palette[*sp].red;
                   sp--;
                }
+
                row_info->bit_depth = 8;
                row_info->pixel_depth = 24;
                row_info->rowbytes = row_width * 3;
@@ -3757,6 +3825,7 @@
                   }
                   break;
                }
+
                case 2:
                {
                   gray = (png_uint_16)((gray&0x03)*0x55);
@@ -3780,6 +3849,7 @@
                   }
                   break;
                }
+
                case 4:
                {
                   gray = (png_uint_16)((gray&0x0f)*0x11);
@@ -3803,6 +3873,7 @@
                   break;
                }
             }
+
             row_info->bit_depth = 8;
             row_info->pixel_depth = 8;
             row_info->rowbytes = row_width;
@@ -3824,6 +3895,7 @@
                   *dp-- = *sp--;
                }
             }
+
             else if (row_info->bit_depth == 16)
             {
                png_byte gray_high = (gray >> 8) & 0xff;
@@ -3846,6 +3918,7 @@
                   *dp-- = *sp--;
                }
             }
+
             row_info->color_type = PNG_COLOR_TYPE_GRAY_ALPHA;
             row_info->channels = 2;
             row_info->pixel_depth = (png_byte)(row_info->bit_depth << 1);
@@ -3943,13 +4016,13 @@
             g = *sp++;
             b = *sp++;
 
-            /* this looks real messy, but the compiler will reduce
-               it down to a reasonable formula.  For example, with
-               5 bits per color, we get:
-               p = (((r >> 3) & 0x1f) << 10) |
-                  (((g >> 3) & 0x1f) << 5) |
-                  ((b >> 3) & 0x1f);
-               */
+            /* This looks real messy, but the compiler will reduce
+             * it down to a reasonable formula.  For example, with
+             * 5 bits per color, we get:
+             * p = (((r >> 3) & 0x1f) << 10) |
+             *    (((g >> 3) & 0x1f) << 5) |
+             *    ((b >> 3) & 0x1f);
+             */
             p = (((r >> (8 - PNG_DITHER_RED_BITS)) &
                ((1 << PNG_DITHER_RED_BITS) - 1)) <<
                (PNG_DITHER_GREEN_BITS + PNG_DITHER_BLUE_BITS)) |
@@ -4030,6 +4103,7 @@
 
      if (png_ptr->screen_gamma > .000001)
         g = 1.0 / (png_ptr->gamma * png_ptr->screen_gamma);
+
      else
         g = 1.0;
 
@@ -4064,8 +4138,9 @@
 
         if (png_ptr->screen_gamma > 0.000001)
            g = 1.0 / png_ptr->screen_gamma;
+
         else
-           g = png_ptr->gamma;   /* probably doing rgb_to_gray */
+           g = png_ptr->gamma;   /* Probably doing rgb_to_gray */
 
         for (i = 0; i < 256; i++)
         {
@@ -4086,8 +4161,10 @@
      if (png_ptr->color_type & PNG_COLOR_MASK_COLOR)
      {
         sig_bit = (int)png_ptr->sig_bit.red;
+
         if ((int)png_ptr->sig_bit.green > sig_bit)
            sig_bit = png_ptr->sig_bit.green;
+
         if ((int)png_ptr->sig_bit.blue > sig_bit)
            sig_bit = png_ptr->sig_bit.blue;
      }
@@ -4098,6 +4175,7 @@
 
      if (sig_bit > 0)
         shift = 16 - sig_bit;
+
      else
         shift = 0;
 
@@ -4109,6 +4187,7 @@
 
      if (shift > 8)
         shift = 8;
+
      if (shift < 0)
         shift = 0;
 
@@ -4166,6 +4245,7 @@
               (png_uint_32)(256 * png_sizeof(png_uint_16)));
 
            ig = (((png_uint_32)i * (png_uint_32)png_gamma_shift[shift]) >> 4);
+
            for (j = 0; j < 256; j++)
            {
               png_ptr->gamma_16_table[i][j] =
@@ -4203,8 +4283,9 @@
 
         if (png_ptr->screen_gamma > 0.000001)
            g = 1.0 / png_ptr->screen_gamma;
+
         else
-           g = png_ptr->gamma;   /* probably doing rgb_to_gray */
+           g = png_ptr->gamma;   /* Probably doing rgb_to_gray */
 
         png_ptr->gamma_16_from_1 = (png_uint_16pp)png_malloc(png_ptr,
            (png_uint_32)(num * png_sizeof(png_uint_16p)));
@@ -4218,6 +4299,7 @@
 
            ig = (((png_uint_32)i *
               (png_uint_32)png_gamma_shift[shift]) >> 4);
+
            for (j = 0; j < 256; j++)
            {
               png_ptr->gamma_16_from_1[i][j] =
@@ -4234,7 +4316,7 @@
 #endif
 
 #if defined(PNG_MNG_FEATURES_SUPPORTED)
-/* undoes intrapixel differencing  */
+/* Undoes intrapixel differencing  */
 void /* PRIVATE */
 png_do_read_intrapixel(png_row_infop row_info, png_bytep row)
 {
@@ -4254,8 +4336,10 @@
 
          if (row_info->color_type == PNG_COLOR_TYPE_RGB)
             bytes_per_pixel = 3;
+
          else if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
             bytes_per_pixel = 4;
+
          else
             return;
 
@@ -4272,8 +4356,10 @@
 
          if (row_info->color_type == PNG_COLOR_TYPE_RGB)
             bytes_per_pixel = 6;
+
          else if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
             bytes_per_pixel = 8;
+
          else
             return;
 
diff --git a/pngrutil.c b/pngrutil.c
index 1dc7317..daa5955 100644
--- a/pngrutil.c
+++ b/pngrutil.c
@@ -1,7 +1,7 @@
 
 /* pngrutil.c - utilities to read a PNG file
  *
- * Last changed in libpng 1.2.37 [May 19, 2009]
+ * Last changed in libpng 1.2.37 [May 20, 2009]
  * For conditions of distribution and use, see copyright notice in png.h
  * Copyright (c) 1998-2009 Glenn Randers-Pehrson
  * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
@@ -21,7 +21,7 @@
 
 #ifdef PNG_FLOATING_POINT_SUPPORTED
 #  if defined(WIN32_WCE_OLD)
-/* strtod() function is not supported on WindowsCE */
+/* The strtod() function is not supported on WindowsCE */
 __inline double png_strtod(png_structp png_ptr, PNG_CONST char *nptr, char **endptr)
 {
    double result = 0;
@@ -76,7 +76,8 @@
 
 /* Grab a signed 32-bit integer from a buffer in big-endian format.  The
  * data is stored in the PNG file in two's complement format, and it is
- * assumed that the machine format for signed integers is the same. */
+ * assumed that the machine format for signed integers is the same.
+ */
 png_int_32 PNGAPI
 png_get_int_32(png_bytep buf)
 {
@@ -108,21 +109,21 @@
    png_byte buf[8];
    png_uint_32 length;
 
-   /* read the length and the chunk name */
+   /* Read the length and the chunk name */
    png_read_data(png_ptr, buf, 8);
    length = png_get_uint_31(png_ptr, buf);
 
-   /* put the chunk name into png_ptr->chunk_name */
+   /* Put the chunk name into png_ptr->chunk_name */
    png_memcpy(png_ptr->chunk_name, buf + 4, 4);
 
    png_debug2(0, "Reading %s chunk, length = %lu",
       png_ptr->chunk_name, length);
 
-   /* reset the crc and run it over the chunk name */
+   /* Reset the crc and run it over the chunk name */
    png_reset_crc(png_ptr);
    png_calculate_crc(png_ptr, png_ptr->chunk_name, 4);
 
-   /* check to see if chunk name is valid */
+   /* Check to see if chunk name is valid */
    png_check_chunk_name(png_ptr, png_ptr->chunk_name);
 
    return length;
@@ -132,15 +133,17 @@
 void /* PRIVATE */
 png_crc_read(png_structp png_ptr, png_bytep buf, png_size_t length)
 {
-   if (png_ptr == NULL) return;
+   if (png_ptr == NULL)
+      return;
    png_read_data(png_ptr, buf, length);
    png_calculate_crc(png_ptr, buf, length);
 }
 
 /* Optionally skip data and then check the CRC.  Depending on whether we
-   are reading a ancillary or critical chunk, and how the program has set
-   things up, we may calculate the CRC on the data and print a message.
-   Returns '1' if there was a CRC error, '0' otherwise. */
+ * are reading a ancillary or critical chunk, and how the program has set
+ * things up, we may calculate the CRC on the data and print a message.
+ * Returns '1' if there was a CRC error, '0' otherwise.
+ */
 int /* PRIVATE */
 png_crc_finish(png_structp png_ptr, png_uint_32 skip)
 {
@@ -159,7 +162,7 @@
    if (png_crc_error(png_ptr))
    {
       if (((png_ptr->chunk_name[0] & 0x20) &&                /* Ancillary */
-           !(png_ptr->flags & PNG_FLAG_CRC_ANCILLARY_NOWARN)) ||
+          !(png_ptr->flags & PNG_FLAG_CRC_ANCILLARY_NOWARN)) ||
           (!(png_ptr->chunk_name[0] & 0x20) &&             /* Critical  */
           (png_ptr->flags & PNG_FLAG_CRC_CRITICAL_USE)))
       {
@@ -176,7 +179,8 @@
 }
 
 /* Compare the CRC stored in the PNG file with that calculated by libpng from
-   the data it has read thus far. */
+ * the data it has read thus far.
+ */
 int /* PRIVATE */
 png_crc_error(png_structp png_ptr)
 {
@@ -331,14 +335,17 @@
             png_snprintf(umsg, 52,
                 "Buffer error in compressed datastream in %s chunk",
                 png_ptr->chunk_name);
+
          else if (ret == Z_DATA_ERROR)
             png_snprintf(umsg, 52,
                 "Data error in compressed datastream in %s chunk",
                 png_ptr->chunk_name);
+
          else
             png_snprintf(umsg, 52,
                 "Incomplete compressed datastream in %s chunk",
                 png_ptr->chunk_name);
+
          png_warning(png_ptr, umsg);
 #else
          png_warning(png_ptr,
@@ -383,7 +390,7 @@
 }
 #endif
 
-/* read and check the IDHR chunk */
+/* Read and check the IDHR chunk */
 void /* PRIVATE */
 png_handle_IHDR(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
 {
@@ -397,7 +404,7 @@
    if (png_ptr->mode & PNG_HAVE_IHDR)
       png_error(png_ptr, "Out of place IHDR");
 
-   /* check the length */
+   /* Check the length */
    if (length != 13)
       png_error(png_ptr, "Invalid IHDR chunk");
 
@@ -414,7 +421,7 @@
    filter_type = buf[11];
    interlace_type = buf[12];
 
-   /* set internal variables */
+   /* Set internal variables */
    png_ptr->width = width;
    png_ptr->height = height;
    png_ptr->bit_depth = (png_byte)bit_depth;
@@ -425,25 +432,28 @@
 #endif
    png_ptr->compression_type = (png_byte)compression_type;
 
-   /* find number of channels */
+   /* Find number of channels */
    switch (png_ptr->color_type)
    {
       case PNG_COLOR_TYPE_GRAY:
       case PNG_COLOR_TYPE_PALETTE:
          png_ptr->channels = 1;
          break;
+
       case PNG_COLOR_TYPE_RGB:
          png_ptr->channels = 3;
          break;
+
       case PNG_COLOR_TYPE_GRAY_ALPHA:
          png_ptr->channels = 2;
          break;
+
       case PNG_COLOR_TYPE_RGB_ALPHA:
          png_ptr->channels = 4;
          break;
    }
 
-   /* set up other useful info */
+   /* Set up other useful info */
    png_ptr->pixel_depth = (png_byte)(png_ptr->bit_depth *
    png_ptr->channels);
    png_ptr->rowbytes = PNG_ROWBYTES(png_ptr->pixel_depth, png_ptr->width);
@@ -454,7 +464,7 @@
       color_type, interlace_type, compression_type, filter_type);
 }
 
-/* read and check the palette */
+/* Read and check the palette */
 void /* PRIVATE */
 png_handle_PLTE(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
 {
@@ -468,12 +478,14 @@
 
    if (!(png_ptr->mode & PNG_HAVE_IHDR))
       png_error(png_ptr, "Missing IHDR before PLTE");
+
    else if (png_ptr->mode & PNG_HAVE_IDAT)
    {
       png_warning(png_ptr, "Invalid PLTE after IDAT");
       png_crc_finish(png_ptr, length);
       return;
    }
+
    else if (png_ptr->mode & PNG_HAVE_PLTE)
       png_error(png_ptr, "Duplicate PLTE chunk");
 
@@ -502,6 +514,7 @@
          png_crc_finish(png_ptr, length);
          return;
       }
+
       else
       {
          png_error(png_ptr, "Invalid palette chunk");
@@ -526,7 +539,7 @@
       png_byte buf[3];
 
       png_crc_read(png_ptr, buf, 3);
-      /* don't depend upon png_color being any order */
+      /* Don't depend upon png_color being any order */
       palette[i].red = buf[0];
       palette[i].green = buf[1];
       palette[i].blue = buf[2];
@@ -534,9 +547,10 @@
 #endif
 
    /* If we actually NEED the PLTE chunk (ie for a paletted image), we do
-      whatever the normal CRC configuration tells us.  However, if we
-      have an RGB image, the PLTE can be considered ancillary, so
-      we will act as though it is. */
+    * whatever the normal CRC configuration tells us.  However, if we
+    * have an RGB image, the PLTE can be considered ancillary, so
+    * we will act as though it is.
+    */
 #if !defined(PNG_READ_OPT_PLTE_SUPPORTED)
    if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
 #endif
@@ -611,7 +625,7 @@
    }
    png_crc_finish(png_ptr, length);
 
-   info_ptr = info_ptr; /* quiet compiler warnings about unused info_ptr */
+   info_ptr = info_ptr; /* Quiet compiler warnings about unused info_ptr */
 }
 
 #if defined(PNG_READ_gAMA_SUPPORTED)
@@ -661,7 +675,7 @@
       return;
 
    igamma = (png_fixed_point)png_get_uint_32(buf);
-   /* check for zero gamma */
+   /* Check for zero gamma */
    if (igamma == 0)
       {
          png_warning(png_ptr,
@@ -925,7 +939,7 @@
       return;
 
    intent = buf[0];
-   /* check for bad intent */
+   /* Check for bad intent */
    if (intent >= PNG_sRGB_INTENT_LAST)
    {
       png_warning(png_ptr, "Unknown sRGB intent");
@@ -1040,12 +1054,13 @@
    png_ptr->chunkdata[slength] = 0x00;
 
    for (profile = png_ptr->chunkdata; *profile; profile++)
-      /* empty loop to find end of name */ ;
+      /* Empty loop to find end of name */ ;
 
    ++profile;
 
-   /* there should be at least one zero (the compression type byte)
-      following the separator, and we should be on it  */
+   /* There should be at least one zero (the compression type byte)
+    * following the separator, and we should be on it
+    */
    if ( profile >= png_ptr->chunkdata + slength - 1)
    {
       png_free(png_ptr, png_ptr->chunkdata);
@@ -1054,7 +1069,7 @@
       return;
    }
 
-   /* compression_type should always be zero */
+   /* Compression_type should always be zero */
    compression_type = *profile++;
    if (compression_type)
    {
@@ -1152,10 +1167,10 @@
    png_ptr->chunkdata[slength] = 0x00;
 
    for (entry_start = (png_bytep)png_ptr->chunkdata; *entry_start; entry_start++)
-      /* empty loop to find end of name */ ;
+      /* Empty loop to find end of name */ ;
    ++entry_start;
 
-   /* a sample depth should follow the separator, and we should be on it  */
+   /* A sample depth should follow the separator, and we should be on it  */
    if (entry_start > (png_bytep)png_ptr->chunkdata + slength - 2)
    {
       png_free(png_ptr, png_ptr->chunkdata);
@@ -1168,7 +1183,7 @@
    entry_size = (new_palette.depth == 8 ? 6 : 10);
    data_length = (slength - (entry_start - (png_bytep)png_ptr->chunkdata));
 
-   /* integrity-check the data length */
+   /* Integrity-check the data length */
    if (data_length % entry_size)
    {
       png_free(png_ptr, png_ptr->chunkdata);
@@ -1236,7 +1251,7 @@
    }
 #endif
 
-   /* discard all chunk data except the name and stash that */
+   /* Discard all chunk data except the name and stash that */
    new_palette.name = png_ptr->chunkdata;
 
    png_set_sPLT(png_ptr, info_ptr, &new_palette, 1);
@@ -1572,7 +1587,7 @@
 #endif
 
 #if defined(PNG_READ_pCAL_SUPPORTED)
-/* read the pCAL chunk (described in the PNG Extensions document) */
+/* Read the pCAL chunk (described in the PNG Extensions document) */
 void /* PRIVATE */
 png_handle_pCAL(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
 {
@@ -1619,11 +1634,11 @@
       return;
    }
 
-   png_ptr->chunkdata[slength] = 0x00; /* null terminate the last string */
+   png_ptr->chunkdata[slength] = 0x00; /* Null terminate the last string */
 
    png_debug(3, "Finding end of pCAL purpose string");
    for (buf = png_ptr->chunkdata; *buf; buf++)
-      /* empty loop */ ;
+      /* Empty loop */ ;
 
    endptr = png_ptr->chunkdata + slength;
 
@@ -1706,7 +1721,7 @@
 #endif
 
 #if defined(PNG_READ_sCAL_SUPPORTED)
-/* read the sCAL chunk */
+/* Read the sCAL chunk */
 void /* PRIVATE */
 png_handle_sCAL(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
 {
@@ -1756,9 +1771,9 @@
       return;
    }
 
-   png_ptr->chunkdata[slength] = 0x00; /* null terminate the last string */
+   png_ptr->chunkdata[slength] = 0x00; /* Null terminate the last string */
 
-   ep = png_ptr->chunkdata + 1;        /* skip unit byte */
+   ep = png_ptr->chunkdata + 1;        /* Skip unit byte */
 
 #ifdef PNG_FLOATING_POINT_SUPPORTED
    width = png_strtod(png_ptr, ep, &vp);
@@ -1780,7 +1795,7 @@
 #endif
 
    for (ep = png_ptr->chunkdata; *ep; ep++)
-      /* empty loop */ ;
+      /* Empty loop */ ;
    ep++;
 
    if (png_ptr->chunkdata + slength < ep)
@@ -1944,7 +1959,7 @@
    key[slength] = 0x00;
 
    for (text = key; *text; text++)
-      /* empty loop to find end of key */ ;
+      /* Empty loop to find end of key */ ;
 
    if (text != key + slength)
       text++;
@@ -1979,7 +1994,7 @@
 #endif
 
 #if defined(PNG_READ_zTXt_SUPPORTED)
-/* note: this does not correctly handle chunks that are > 64K under DOS */
+/* Note: this does not correctly handle chunks that are > 64K under DOS */
 void /* PRIVATE */
 png_handle_zTXt(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
 {
@@ -2028,7 +2043,7 @@
    png_ptr->chunkdata[slength] = 0x00;
 
    for (text = png_ptr->chunkdata; *text; text++)
-      /* empty loop */ ;
+      /* Empty loop */ ;
 
    /* zTXt must have some text after the chunkdataword */
    if (text >= png_ptr->chunkdata + slength - 2)
@@ -2046,7 +2061,7 @@
           png_warning(png_ptr, "Unknown compression type in zTXt chunk");
           comp_type = PNG_TEXT_COMPRESSION_zTXt;
        }
-       text++;        /* skip the compression_method byte */
+       text++;        /* Skip the compression_method byte */
    }
    prefix_len = text - png_ptr->chunkdata;
 
@@ -2083,7 +2098,7 @@
 #endif
 
 #if defined(PNG_READ_iTXt_SUPPORTED)
-/* note: this does not correctly handle chunks that are > 64K under DOS */
+/* Note: this does not correctly handle chunks that are > 64K under DOS */
 void /* PRIVATE */
 png_handle_iTXt(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
 {
@@ -2133,12 +2148,13 @@
    png_ptr->chunkdata[slength] = 0x00;
 
    for (lang = png_ptr->chunkdata; *lang; lang++)
-      /* empty loop */ ;
-   lang++;        /* skip NUL separator */
+      /* Empty loop */ ;
+   lang++;        /* Skip NUL separator */
 
    /* iTXt must have a language tag (possibly empty), two compression bytes,
-      translated keyword (possibly empty), and possibly some text after the
-      keyword */
+    * translated keyword (possibly empty), and possibly some text after the
+    * keyword
+    */
 
    if (lang >= png_ptr->chunkdata + slength - 3)
    {
@@ -2154,8 +2170,8 @@
    }
 
    for (lang_key = lang; *lang_key; lang_key++)
-      /* empty loop */ ;
-   lang_key++;        /* skip NUL separator */
+      /* Empty loop */ ;
+   lang_key++;        /* Skip NUL separator */
 
    if (lang_key >= png_ptr->chunkdata + slength)
    {
@@ -2166,8 +2182,8 @@
    }
 
    for (text = lang_key; *text; text++)
-      /* empty loop */ ;
-   text++;        /* skip NUL separator */
+      /* Empty loop */ ;
+   text++;        /* Skip NUL separator */
    if (text >= png_ptr->chunkdata + slength)
    {
       png_warning(png_ptr, "Malformed iTXt chunk");
@@ -2229,7 +2245,7 @@
 #ifdef PNG_USE_LOCAL_ARRAYS
       PNG_CONST PNG_IDAT;
 #endif
-      if (png_memcmp(png_ptr->chunk_name, png_IDAT, 4))  /* not an IDAT */
+      if (png_memcmp(png_ptr->chunk_name, png_IDAT, 4))  /* Not an IDAT */
          png_ptr->mode |= PNG_AFTER_IDAT;
    }
 
@@ -2273,7 +2289,7 @@
 #if defined(PNG_READ_USER_CHUNKS_SUPPORTED)
        if (png_ptr->read_user_chunk_fn != NULL)
        {
-          /* callback to user unknown chunk handler */
+          /* Callback to user unknown chunk handler */
           int ret;
           ret = (*(png_ptr->read_user_chunk_fn))
             (png_ptr, &png_ptr->unknown_chunk);
@@ -2302,7 +2318,7 @@
    png_crc_finish(png_ptr, skip);
 
 #if !defined(PNG_READ_USER_CHUNKS_SUPPORTED)
-   info_ptr = info_ptr; /* quiet compiler warnings about unused info_ptr */
+   info_ptr = info_ptr; /* Quiet compiler warnings about unused info_ptr */
 #endif
 }
 
@@ -2550,8 +2566,8 @@
    int pass = png_ptr->pass;
    png_uint_32 transformations = png_ptr->transformations;
 #ifdef PNG_USE_LOCAL_ARRAYS
-   /* arrays to facilitate easy interlacing - use pass (0 - 6) as index */
-   /* offset to next interlace block */
+   /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */
+   /* Offset to next interlace block */
    PNG_CONST int png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1};
 #endif
 
@@ -2759,7 +2775,7 @@
       row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth, final_width);
    }
 #if !defined(PNG_READ_PACKSWAP_SUPPORTED)
-   transformations = transformations; /* silence compiler warning */
+   transformations = transformations; /* Silence compiler warning */
 #endif
 }
 #endif /* PNG_READ_INTERLACING_SUPPORTED */
@@ -2843,7 +2859,7 @@
             rp++;
          }
 
-         for (i = 0; i < istop; i++)   /* use leftover rp,pp */
+         for (i = 0; i < istop; i++)   /* Use leftover rp,pp */
          {
             int a, b, c, pa, pb, pc, p;
 
@@ -2893,18 +2909,18 @@
 {
 #ifdef PNG_USE_LOCAL_ARRAYS
 #ifdef PNG_READ_INTERLACING_SUPPORTED
-   /* arrays to facilitate easy interlacing - use pass (0 - 6) as index */
+   /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */
 
-   /* start of interlace block */
+   /* Start of interlace block */
    PNG_CONST int png_pass_start[7] = {0, 4, 0, 2, 0, 1, 0};
 
-   /* offset to next interlace block */
+   /* Offset to next interlace block */
    PNG_CONST int png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1};
 
-   /* start of interlace block in the y direction */
+   /* Start of interlace block in the y direction */
    PNG_CONST int png_pass_ystart[7] = {0, 0, 4, 0, 2, 0, 1};
 
-   /* offset to next interlace block in the y direction */
+   /* Offset to next interlace block in the y direction */
    PNG_CONST int png_pass_yinc[7] = {8, 8, 8, 4, 4, 2, 2};
 #endif /* PNG_READ_INTERLACING_SUPPORTED */
 #endif
@@ -3026,18 +3042,18 @@
 {
 #ifdef PNG_USE_LOCAL_ARRAYS
 #ifdef PNG_READ_INTERLACING_SUPPORTED
-   /* arrays to facilitate easy interlacing - use pass (0 - 6) as index */
+   /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */
 
-   /* start of interlace block */
+   /* Start of interlace block */
    PNG_CONST int png_pass_start[7] = {0, 4, 0, 2, 0, 1, 0};
 
-   /* offset to next interlace block */
+   /* Offset to next interlace block */
    PNG_CONST int png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1};
 
-   /* start of interlace block in the y direction */
+   /* Start of interlace block in the y direction */
    PNG_CONST int png_pass_ystart[7] = {0, 0, 4, 0, 2, 0, 1};
 
-   /* offset to next interlace block in the y direction */
+   /* Offset to next interlace block in the y direction */
    PNG_CONST int png_pass_yinc[7] = {8, 8, 8, 4, 4, 2, 2};
 #endif
 #endif
@@ -3174,11 +3190,13 @@
      }
 #endif
 
-   /* align the width on the next larger 8 pixels.  Mainly used
-      for interlacing */
+   /* Align the width on the next larger 8 pixels.  Mainly used
+    * for interlacing
+    */
    row_bytes = ((png_ptr->width + 7) & ~((png_uint_32)7));
-   /* calculate the maximum bytes needed, adding a byte and a pixel
-      for safety's sake */
+   /* Calculate the maximum bytes needed, adding a byte and a pixel
+    * for safety's sake
+    */
    row_bytes = PNG_ROWBYTES(max_pixel_depth, row_bytes) +
       1 + ((max_pixel_depth + 7) >> 3);
 #ifdef PNG_MAX_MALLOC_64K
diff --git a/pngset.c b/pngset.c
index 9aa29f1..4387a13 100644
--- a/pngset.c
+++ b/pngset.c
@@ -1,7 +1,7 @@
 
 /* pngset.c - storage of image information into info struct
  *
- * Last changed in libpng 1.2.36 [May 7, 2009]
+ * Last changed in libpng 1.2.37 [May 20, 2009]
  * For conditions of distribution and use, see copyright notice in png.h
  * Copyright (c) 1998-2009 Glenn Randers-Pehrson
  * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
@@ -79,25 +79,25 @@
       white_x, white_y, red_x, red_y, green_x, green_y, blue_x, blue_y))
 #endif
    {
-     info_ptr->int_x_white = white_x;
-     info_ptr->int_y_white = white_y;
-     info_ptr->int_x_red   = red_x;
-     info_ptr->int_y_red   = red_y;
-     info_ptr->int_x_green = green_x;
-     info_ptr->int_y_green = green_y;
-     info_ptr->int_x_blue  = blue_x;
-     info_ptr->int_y_blue  = blue_y;
-#ifdef PNG_FLOATING_POINT_SUPPORTED
-     info_ptr->x_white = (float)(white_x/100000.);
-     info_ptr->y_white = (float)(white_y/100000.);
-     info_ptr->x_red   = (float)(  red_x/100000.);
-     info_ptr->y_red   = (float)(  red_y/100000.);
-     info_ptr->x_green = (float)(green_x/100000.);
-     info_ptr->y_green = (float)(green_y/100000.);
-     info_ptr->x_blue  = (float)( blue_x/100000.);
-     info_ptr->y_blue  = (float)( blue_y/100000.);
+      info_ptr->int_x_white = white_x;
+      info_ptr->int_y_white = white_y;
+      info_ptr->int_x_red   = red_x;
+      info_ptr->int_y_red   = red_y;
+      info_ptr->int_x_green = green_x;
+      info_ptr->int_y_green = green_y;
+      info_ptr->int_x_blue  = blue_x;
+      info_ptr->int_y_blue  = blue_y;
+#ifdef  PNG_FLOATING_POINT_SUPPORTED
+      info_ptr->x_white = (float)(white_x/100000.);
+      info_ptr->y_white = (float)(white_y/100000.);
+      info_ptr->x_red   = (float)(  red_x/100000.);
+      info_ptr->y_red   = (float)(  red_y/100000.);
+      info_ptr->x_green = (float)(green_x/100000.);
+      info_ptr->y_green = (float)(green_y/100000.);
+      info_ptr->x_blue  = (float)( blue_x/100000.);
+      info_ptr->y_blue  = (float)( blue_y/100000.);
 #endif
-     info_ptr->valid |= PNG_INFO_cHRM;
+      info_ptr->valid |= PNG_INFO_cHRM;
    }
 }
 #endif /* PNG_FIXED_POINT_SUPPORTED */
@@ -140,20 +140,20 @@
    if (png_ptr == NULL || info_ptr == NULL)
       return;
 
-   if (int_gamma > (png_fixed_point) PNG_UINT_31_MAX)
+   if (int_gamma > (png_fixed_point)PNG_UINT_31_MAX)
    {
-     png_warning(png_ptr, "Limiting gamma to 21474.83");
-     png_gamma=PNG_UINT_31_MAX;
+      png_warning(png_ptr, "Limiting gamma to 21474.83");
+      png_gamma=PNG_UINT_31_MAX;
    }
    else
    {
-     if (int_gamma < 0)
-     {
-       png_warning(png_ptr, "Setting negative gamma to zero");
-       png_gamma = 0;
-     }
-     else
-       png_gamma = int_gamma;
+      if (int_gamma < 0)
+      {
+         png_warning(png_ptr, "Setting negative gamma to zero");
+         png_gamma = 0;
+      }
+      else
+         png_gamma = int_gamma;
    }
 #ifdef PNG_FLOATING_POINT_SUPPORTED
    info_ptr->gamma = (float)(png_gamma/100000.);
@@ -179,26 +179,27 @@
    if (info_ptr->num_palette == 0 || info_ptr->num_palette
        > PNG_MAX_PALETTE_LENGTH)
    {
-       png_warning(png_ptr,
-          "Invalid palette size, hIST allocation skipped.");
-       return;
+      png_warning(png_ptr,
+         "Invalid palette size, hIST allocation skipped.");
+      return;
    }
 
 #ifdef PNG_FREE_ME_SUPPORTED
    png_free_data(png_ptr, info_ptr, PNG_FREE_HIST, 0);
 #endif
-   /* Changed from info->num_palette to PNG_MAX_PALETTE_LENGTH in version
-      1.2.1 */
+   /* Changed from info->num_palette to PNG_MAX_PALETTE_LENGTH in
+    * version 1.2.1
+    */
    png_ptr->hist = (png_uint_16p)png_malloc_warn(png_ptr,
       (png_uint_32)(PNG_MAX_PALETTE_LENGTH * png_sizeof(png_uint_16)));
    if (png_ptr->hist == NULL)
-     {
-       png_warning(png_ptr, "Insufficient memory for hIST chunk data.");
-       return;
-     }
+   {
+      png_warning(png_ptr, "Insufficient memory for hIST chunk data.");
+      return;
+   }
 
    for (i = 0; i < info_ptr->num_palette; i++)
-       png_ptr->hist[i] = hist[i];
+      png_ptr->hist[i] = hist[i];
    info_ptr->hist = png_ptr->hist;
    info_ptr->valid |= PNG_INFO_hIST;
 
@@ -220,7 +221,7 @@
    if (png_ptr == NULL || info_ptr == NULL)
       return;
 
-   /* check for width and height valid values */
+   /* Check for width and height valid values */
    if (width == 0 || height == 0)
       png_error(png_ptr, "Image width or height is zero in IHDR");
 #ifdef PNG_SET_USER_LIMITS_SUPPORTED
@@ -240,13 +241,13 @@
                  - 8)       /* extra max_pixel_depth pad */
       png_warning(png_ptr, "Width is too large for libpng to process pixels");
 
-   /* check other values */
+   /* Check other values */
    if (bit_depth != 1 && bit_depth != 2 && bit_depth != 4 &&
       bit_depth != 8 && bit_depth != 16)
       png_error(png_ptr, "Invalid bit depth in IHDR");
 
    if (color_type < 0 || color_type == 1 ||
-      color_type == 5 || color_type > 6)
+       color_type == 5 || color_type > 6)
       png_error(png_ptr, "Invalid color type in IHDR");
 
    if (((color_type == PNG_COLOR_TYPE_PALETTE) && bit_depth > 8) ||
@@ -276,9 +277,9 @@
    if (filter_type != PNG_FILTER_TYPE_BASE)
    {
      if (!((png_ptr->mng_features_permitted & PNG_FLAG_MNG_FILTER_64) &&
-        (filter_type == PNG_INTRAPIXEL_DIFFERENCING) &&
-        ((png_ptr->mode&PNG_HAVE_PNG_SIGNATURE) == 0) &&
-        (color_type == PNG_COLOR_TYPE_RGB ||
+         (filter_type == PNG_INTRAPIXEL_DIFFERENCING) &&
+         ((png_ptr->mode&PNG_HAVE_PNG_SIGNATURE) == 0) &&
+         (color_type == PNG_COLOR_TYPE_RGB ||
          color_type == PNG_COLOR_TYPE_RGB_ALPHA)))
         png_error(png_ptr, "Unknown filter method in IHDR");
      if (png_ptr->mode&PNG_HAVE_PNG_SIGNATURE)
@@ -306,7 +307,7 @@
       info_ptr->channels++;
    info_ptr->pixel_depth = (png_byte)(info_ptr->channels * info_ptr->bit_depth);
 
-   /* check for potential overflow */
+   /* Check for potential overflow */
    if (width > (PNG_UINT_32_MAX
                  >> 3)      /* 8-byte RGBA pixels */
                  - 64       /* bigrowbuf hack */
@@ -496,15 +497,15 @@
       return;
 
    if (num_palette < 0 || num_palette > PNG_MAX_PALETTE_LENGTH)
-     {
-       if (info_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
+   {
+      if (info_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
          png_error(png_ptr, "Invalid palette length");
-       else
-       {
+      else
+      {
          png_warning(png_ptr, "Invalid palette length");
          return;
-       }
-     }
+      }
+   }
 
    /*
     * It may not actually be necessary to set png_ptr->palette here;
@@ -516,8 +517,9 @@
 #endif
 
    /* Changed in libpng-1.2.1 to allocate PNG_MAX_PALETTE_LENGTH instead
-      of num_palette entries,
-      in case of an invalid PNG file that has too-large sample values. */
+    * of num_palette entries, in case of an invalid PNG file that has
+    * too-large sample values.
+    */
    png_ptr->palette = (png_colorp)png_malloc(png_ptr,
       PNG_MAX_PALETTE_LENGTH * png_sizeof(png_color));
    png_memset(png_ptr->palette, 0, PNG_MAX_PALETTE_LENGTH *
@@ -620,18 +622,18 @@
 
 #if !defined(PNG_NO_CHECK_cHRM)
    if (png_check_cHRM_fixed(png_ptr,
-      int_white_x, int_white_y, int_red_x, int_red_y, int_green_x,
-      int_green_y, int_blue_x, int_blue_y))
+       int_white_x, int_white_y, int_red_x, int_red_y, int_green_x,
+       int_green_y, int_blue_x, int_blue_y))
 #endif
    {
 #ifdef PNG_FIXED_POINT_SUPPORTED
-     png_set_cHRM_fixed(png_ptr, info_ptr,
-        int_white_x, int_white_y, int_red_x, int_red_y, int_green_x,
-        int_green_y, int_blue_x, int_blue_y);
+      png_set_cHRM_fixed(png_ptr, info_ptr,
+          int_white_x, int_white_y, int_red_x, int_red_y, int_green_x,
+          int_green_y, int_blue_x, int_blue_y);
 #endif
 #ifdef PNG_FLOATING_POINT_SUPPORTED
       png_set_cHRM(png_ptr, info_ptr,
-         white_x, white_y, red_x, red_y, green_x, green_y, blue_x, blue_y);
+          white_x, white_y, red_x, red_y, green_x, green_y, blue_x, blue_y);
 #endif
    }
 #endif /* cHRM */
@@ -689,17 +691,17 @@
 #if defined(PNG_TEXT_SUPPORTED)
 void PNGAPI
 png_set_text(png_structp png_ptr, png_infop info_ptr, png_textp text_ptr,
-   int num_text)
+             int num_text)
 {
    int ret;
    ret = png_set_text_2(png_ptr, info_ptr, text_ptr, num_text);
    if (ret)
-     png_error(png_ptr, "Insufficient memory to store text");
+      png_error(png_ptr, "Insufficient memory to store text");
 }
 
 int /* PRIVATE */
 png_set_text_2(png_structp png_ptr, png_infop info_ptr, png_textp text_ptr,
-   int num_text)
+               int num_text)
 {
    int i;
 
@@ -725,10 +727,10 @@
          info_ptr->text = (png_textp)png_malloc_warn(png_ptr,
             (png_uint_32)(info_ptr->max_text * png_sizeof(png_text)));
          if (info_ptr->text == NULL)
-           {
-             png_free(png_ptr, old_text);
-             return(1);
-           }
+         {
+            png_free(png_ptr, old_text);
+            return(1);
+         }
          png_memcpy(info_ptr->text, old_text, (png_size_t)(old_max *
             png_sizeof(png_text)));
          png_free(png_ptr, old_text);
@@ -740,7 +742,7 @@
          info_ptr->text = (png_textp)png_malloc_warn(png_ptr,
             (png_uint_32)(info_ptr->max_text * png_sizeof(png_text)));
          if (info_ptr->text == NULL)
-           return(1);
+            return(1);
 #ifdef PNG_FREE_ME_SUPPORTED
          info_ptr->free_me |= PNG_FREE_TEXT;
 #endif
@@ -761,26 +763,26 @@
 
       if (text_ptr[i].compression <= 0)
       {
-        lang_len = 0;
-        lang_key_len = 0;
+         lang_len = 0;
+         lang_key_len = 0;
       }
       else
 #ifdef PNG_iTXt_SUPPORTED
       {
-        /* set iTXt data */
-        if (text_ptr[i].lang != NULL)
-          lang_len = png_strlen(text_ptr[i].lang);
-        else
-          lang_len = 0;
-        if (text_ptr[i].lang_key != NULL)
-          lang_key_len = png_strlen(text_ptr[i].lang_key);
-        else
-          lang_key_len = 0;
+         /* Set iTXt data */
+         if (text_ptr[i].lang != NULL)
+            lang_len = png_strlen(text_ptr[i].lang);
+         else
+            lang_len = 0;
+         if (text_ptr[i].lang_key != NULL)
+            lang_key_len = png_strlen(text_ptr[i].lang_key);
+         else
+            lang_key_len = 0;
       }
 #else
       {
-        png_warning(png_ptr, "iTXt chunk not supported.");
-        continue;
+         png_warning(png_ptr, "iTXt chunk not supported.");
+         continue;
       }
 #endif
 
@@ -804,14 +806,13 @@
          (png_uint_32)
          (key_len + text_length + lang_len + lang_key_len + 4));
       if (textp->key == NULL)
-        return(1);
+         return(1);
       png_debug2(2, "Allocated %lu bytes at %x in png_set_text",
-         (png_uint_32)
-         (key_len + lang_len + lang_key_len + text_length + 4),
-         (int)textp->key);
+                 (png_uint_32)
+                 (key_len + lang_len + lang_key_len + text_length + 4),
+                 (int)textp->key);
 
-      png_memcpy(textp->key, text_ptr[i].key,
-         (png_size_t)(key_len));
+      png_memcpy(textp->key, text_ptr[i].key,(png_size_t)(key_len));
       *(textp->key + key_len) = '\0';
 #ifdef PNG_iTXt_SUPPORTED
       if (text_ptr[i].compression > 0)
@@ -898,7 +899,7 @@
        png_ptr->trans = info_ptr->trans = (png_bytep)png_malloc(png_ptr,
            (png_uint_32)PNG_MAX_PALETTE_LENGTH);
        if (num_trans > 0 && num_trans <= PNG_MAX_PALETTE_LENGTH)
-         png_memcpy(info_ptr->trans, trans, (png_size_t)num_trans);
+          png_memcpy(info_ptr->trans, trans, (png_size_t)num_trans);
    }
 
    if (trans_values != NULL)
@@ -910,12 +911,12 @@
           ((int)trans_values->red > sample_max ||
           (int)trans_values->green > sample_max ||
           (int)trans_values->blue > sample_max)))
-        png_warning(png_ptr,
-           "tRNS chunk has out-of-range samples for bit_depth");
+         png_warning(png_ptr,
+            "tRNS chunk has out-of-range samples for bit_depth");
       png_memcpy(&(info_ptr->trans_values), trans_values,
          png_sizeof(png_color_16));
       if (num_trans == 0)
-        num_trans = 1;
+         num_trans = 1;
    }
 
    info_ptr->num_trans = (png_uint_16)num_trans;
@@ -943,62 +944,62 @@
  *                   added.
  */
 {
-    png_sPLT_tp np;
-    int i;
+   png_sPLT_tp np;
+   int i;
 
-    if (png_ptr == NULL || info_ptr == NULL)
-       return;
-
-    np = (png_sPLT_tp)png_malloc_warn(png_ptr,
-        (info_ptr->splt_palettes_num + nentries) *
-        (png_uint_32)png_sizeof(png_sPLT_t));
-    if (np == NULL)
-    {
-      png_warning(png_ptr, "No memory for sPLT palettes.");
+   if (png_ptr == NULL || info_ptr == NULL)
       return;
-    }
 
-    png_memcpy(np, info_ptr->splt_palettes,
-           info_ptr->splt_palettes_num * png_sizeof(png_sPLT_t));
-    png_free(png_ptr, info_ptr->splt_palettes);
-    info_ptr->splt_palettes=NULL;
+   np = (png_sPLT_tp)png_malloc_warn(png_ptr,
+       (info_ptr->splt_palettes_num + nentries) *
+        (png_uint_32)png_sizeof(png_sPLT_t));
+   if (np == NULL)
+   {
+      png_warning(png_ptr, "No memory for sPLT palettes.");
+     return;
+   }
 
-    for (i = 0; i < nentries; i++)
-    {
-        png_sPLT_tp to = np + info_ptr->splt_palettes_num + i;
-        png_sPLT_tp from = entries + i;
-        png_uint_32 length;
+   png_memcpy(np, info_ptr->splt_palettes,
+          info_ptr->splt_palettes_num * png_sizeof(png_sPLT_t));
+   png_free(png_ptr, info_ptr->splt_palettes);
+   info_ptr->splt_palettes=NULL;
 
-        length = png_strlen(from->name) + 1;
+   for (i = 0; i < nentries; i++)
+   {
+      png_sPLT_tp to = np + info_ptr->splt_palettes_num + i;
+      png_sPLT_tp from = entries + i;
+      png_uint_32 length;
+
+      length = png_strlen(from->name) + 1;
         to->name = (png_charp)png_malloc_warn(png_ptr, length);
-        if (to->name == NULL)
-        {
-           png_warning(png_ptr,
-             "Out of memory while processing sPLT chunk");
-           continue;
-        }
-        png_memcpy(to->name, from->name, length);
-        to->entries = (png_sPLT_entryp)png_malloc_warn(png_ptr,
+      if (to->name == NULL)
+      {
+         png_warning(png_ptr,
+           "Out of memory while processing sPLT chunk");
+         continue;
+      }
+      png_memcpy(to->name, from->name, length);
+      to->entries = (png_sPLT_entryp)png_malloc_warn(png_ptr,
             (png_uint_32)(from->nentries * png_sizeof(png_sPLT_entry)));
-        if (to->entries == NULL)
-        {
-           png_warning(png_ptr,
-             "Out of memory while processing sPLT chunk");
-           png_free(png_ptr, to->name);
-           to->name = NULL;
-           continue;
-        }
-        png_memcpy(to->entries, from->entries,
-            from->nentries * png_sizeof(png_sPLT_entry));
-        to->nentries = from->nentries;
-        to->depth = from->depth;
-    }
+      if (to->entries == NULL)
+      {
+         png_warning(png_ptr,
+           "Out of memory while processing sPLT chunk");
+         png_free(png_ptr, to->name);
+         to->name = NULL;
+         continue;
+      }
+      png_memcpy(to->entries, from->entries,
+          from->nentries * png_sizeof(png_sPLT_entry));
+      to->nentries = from->nentries;
+      to->depth = from->depth;
+   }
 
-    info_ptr->splt_palettes = np;
-    info_ptr->splt_palettes_num += nentries;
-    info_ptr->valid |= PNG_INFO_sPLT;
+   info_ptr->splt_palettes = np;
+   info_ptr->splt_palettes_num += nentries;
+   info_ptr->valid |= PNG_INFO_sPLT;
 #ifdef PNG_FREE_ME_SUPPORTED
-    info_ptr->free_me |= PNG_FREE_SPLT;
+   info_ptr->free_me |= PNG_FREE_SPLT;
 #endif
 }
 #endif /* PNG_sPLT_SUPPORTED */
@@ -1008,61 +1009,61 @@
 png_set_unknown_chunks(png_structp png_ptr,
    png_infop info_ptr, png_unknown_chunkp unknowns, int num_unknowns)
 {
-    png_unknown_chunkp np;
-    int i;
+   png_unknown_chunkp np;
+   int i;
 
-    if (png_ptr == NULL || info_ptr == NULL || num_unknowns == 0)
-        return;
-
-    np = (png_unknown_chunkp)png_malloc_warn(png_ptr,
-        (png_uint_32)((info_ptr->unknown_chunks_num + num_unknowns) *
-        png_sizeof(png_unknown_chunk)));
-    if (np == NULL)
-    {
-       png_warning(png_ptr,
-          "Out of memory while processing unknown chunk.");
+   if (png_ptr == NULL || info_ptr == NULL || num_unknowns == 0)
        return;
-    }
 
-    png_memcpy(np, info_ptr->unknown_chunks,
-           info_ptr->unknown_chunks_num * png_sizeof(png_unknown_chunk));
-    png_free(png_ptr, info_ptr->unknown_chunks);
-    info_ptr->unknown_chunks=NULL;
+   np = (png_unknown_chunkp)png_malloc_warn(png_ptr,
+       (png_uint_32)((info_ptr->unknown_chunks_num + num_unknowns) *
+       png_sizeof(png_unknown_chunk)));
+   if (np == NULL)
+   {
+      png_warning(png_ptr,
+         "Out of memory while processing unknown chunk.");
+      return;
+   }
 
-    for (i = 0; i < num_unknowns; i++)
-    {
-       png_unknown_chunkp to = np + info_ptr->unknown_chunks_num + i;
-       png_unknown_chunkp from = unknowns + i;
+   png_memcpy(np, info_ptr->unknown_chunks,
+          info_ptr->unknown_chunks_num * png_sizeof(png_unknown_chunk));
+   png_free(png_ptr, info_ptr->unknown_chunks);
+   info_ptr->unknown_chunks=NULL;
 
-       png_memcpy((png_charp)to->name, 
-                  (png_charp)from->name, 
-                  png_sizeof(from->name));
-       to->name[png_sizeof(to->name)-1] = '\0';
-       to->size = from->size;
-       /* note our location in the read or write sequence */
-       to->location = (png_byte)(png_ptr->mode & 0xff);
+   for (i = 0; i < num_unknowns; i++)
+   {
+      png_unknown_chunkp to = np + info_ptr->unknown_chunks_num + i;
+      png_unknown_chunkp from = unknowns + i;
 
-       if (from->size == 0)
-          to->data=NULL;
-       else
-       {
-          to->data = (png_bytep)png_malloc_warn(png_ptr,
-            (png_uint_32)from->size);
-          if (to->data == NULL)
-          {
-             png_warning(png_ptr,
-              "Out of memory while processing unknown chunk.");
-             to->size = 0;
-          }
-          else
-             png_memcpy(to->data, from->data, from->size);
-       }
-    }
+      png_memcpy((png_charp)to->name, 
+                 (png_charp)from->name, 
+                 png_sizeof(from->name));
+      to->name[png_sizeof(to->name)-1] = '\0';
+      to->size = from->size;
+      /* Note our location in the read or write sequence */
+      to->location = (png_byte)(png_ptr->mode & 0xff);
 
-    info_ptr->unknown_chunks = np;
-    info_ptr->unknown_chunks_num += num_unknowns;
+      if (from->size == 0)
+         to->data=NULL;
+      else
+      {
+         to->data = (png_bytep)png_malloc_warn(png_ptr,
+           (png_uint_32)from->size);
+         if (to->data == NULL)
+         {
+            png_warning(png_ptr,
+             "Out of memory while processing unknown chunk.");
+            to->size = 0;
+         }
+         else
+            png_memcpy(to->data, from->data, from->size);
+      }
+   }
+
+   info_ptr->unknown_chunks = np;
+   info_ptr->unknown_chunks_num += num_unknowns;
 #ifdef PNG_FREE_ME_SUPPORTED
-    info_ptr->free_me |= PNG_FREE_UNKN;
+   info_ptr->free_me |= PNG_FREE_UNKN;
 #endif
 }
 void PNGAPI
@@ -1111,44 +1112,44 @@
 png_set_keep_unknown_chunks(png_structp png_ptr, int keep, png_bytep
    chunk_list, int num_chunks)
 {
-    png_bytep new_list, p;
-    int i, old_num_chunks;
-    if (png_ptr == NULL)
-       return;
-    if (num_chunks == 0)
-    {
+   png_bytep new_list, p;
+   int i, old_num_chunks;
+   if (png_ptr == NULL)
+      return;
+   if (num_chunks == 0)
+   {
       if (keep == PNG_HANDLE_CHUNK_ALWAYS || keep == PNG_HANDLE_CHUNK_IF_SAFE)
-        png_ptr->flags |= PNG_FLAG_KEEP_UNKNOWN_CHUNKS;
+         png_ptr->flags |= PNG_FLAG_KEEP_UNKNOWN_CHUNKS;
       else
-        png_ptr->flags &= ~PNG_FLAG_KEEP_UNKNOWN_CHUNKS;
+         png_ptr->flags &= ~PNG_FLAG_KEEP_UNKNOWN_CHUNKS;
 
       if (keep == PNG_HANDLE_CHUNK_ALWAYS)
-        png_ptr->flags |= PNG_FLAG_KEEP_UNSAFE_CHUNKS;
+         png_ptr->flags |= PNG_FLAG_KEEP_UNSAFE_CHUNKS;
       else
-        png_ptr->flags &= ~PNG_FLAG_KEEP_UNSAFE_CHUNKS;
+         png_ptr->flags &= ~PNG_FLAG_KEEP_UNSAFE_CHUNKS;
       return;
-    }
-    if (chunk_list == NULL)
+   }
+   if (chunk_list == NULL)
       return;
-    old_num_chunks = png_ptr->num_chunk_list;
-    new_list=(png_bytep)png_malloc(png_ptr,
-       (png_uint_32)
-       (5*(num_chunks + old_num_chunks)));
-    if (png_ptr->chunk_list != NULL)
-    {
-       png_memcpy(new_list, png_ptr->chunk_list,
-          (png_size_t)(5*old_num_chunks));
-       png_free(png_ptr, png_ptr->chunk_list);
-       png_ptr->chunk_list=NULL;
-    }
-    png_memcpy(new_list + 5*old_num_chunks, chunk_list,
-       (png_size_t)(5*num_chunks));
-    for (p = new_list + 5*old_num_chunks + 4, i = 0; i<num_chunks; i++, p += 5)
-       *p=(png_byte)keep;
-    png_ptr->num_chunk_list = old_num_chunks + num_chunks;
-    png_ptr->chunk_list = new_list;
+   old_num_chunks = png_ptr->num_chunk_list;
+   new_list=(png_bytep)png_malloc(png_ptr,
+      (png_uint_32)
+      (5*(num_chunks + old_num_chunks)));
+   if (png_ptr->chunk_list != NULL)
+   {
+      png_memcpy(new_list, png_ptr->chunk_list,
+         (png_size_t)(5*old_num_chunks));
+      png_free(png_ptr, png_ptr->chunk_list);
+      png_ptr->chunk_list=NULL;
+   }
+   png_memcpy(new_list + 5*old_num_chunks, chunk_list,
+      (png_size_t)(5*num_chunks));
+   for (p = new_list + 5*old_num_chunks + 4, i = 0; i<num_chunks; i++, p += 5)
+      *p=(png_byte)keep;
+   png_ptr->num_chunk_list = old_num_chunks + num_chunks;
+   png_ptr->chunk_list = new_list;
 #ifdef PNG_FREE_ME_SUPPORTED
-    png_ptr->free_me |= PNG_FREE_LIST;
+   png_ptr->free_me |= PNG_FREE_LIST;
 #endif
 }
 #endif
@@ -1208,7 +1209,7 @@
 
 #ifndef PNG_1_0_X
 #ifdef PNG_ASSEMBLER_CODE_SUPPORTED
-/* function was added to libpng 1.2.0 and should always exist by default */
+/* Function was added to libpng 1.2.0 and should always exist by default */
 void PNGAPI
 png_set_asm_flags (png_structp png_ptr, png_uint_32 asm_flags)
 {
@@ -1218,7 +1219,7 @@
     asm_flags = asm_flags; /* Quiet the compiler */
 }
 
-/* this function was added to libpng 1.2.0 */
+/* This function was added to libpng 1.2.0 */
 void PNGAPI
 png_set_mmx_thresholds (png_structp png_ptr,
                         png_byte mmx_bitdepth_threshold,
@@ -1234,18 +1235,19 @@
 #endif /* ?PNG_ASSEMBLER_CODE_SUPPORTED */
 
 #ifdef PNG_SET_USER_LIMITS_SUPPORTED
-/* this function was added to libpng 1.2.6 */
+/* This function was added to libpng 1.2.6 */
 void PNGAPI
 png_set_user_limits (png_structp png_ptr, png_uint_32 user_width_max,
     png_uint_32 user_height_max)
 {
-    /* Images with dimensions larger than these limits will be
-     * rejected by png_set_IHDR().  To accept any PNG datastream
-     * regardless of dimensions, set both limits to 0x7ffffffL.
-     */
-    if (png_ptr == NULL) return;
-    png_ptr->user_width_max = user_width_max;
-    png_ptr->user_height_max = user_height_max;
+   /* Images with dimensions larger than these limits will be
+    * rejected by png_set_IHDR().  To accept any PNG datastream
+    * regardless of dimensions, set both limits to 0x7ffffffL.
+    */
+   if (png_ptr == NULL)
+      return;
+   png_ptr->user_width_max = user_width_max;
+   png_ptr->user_height_max = user_height_max;
 }
 #endif /* ?PNG_SET_USER_LIMITS_SUPPORTED */
 
diff --git a/pngtest.c b/pngtest.c
index 7689f14..8cbcca2 100644
--- a/pngtest.c
+++ b/pngtest.c
@@ -1,7 +1,7 @@
 
 /* pngtest.c - a simple test program to test libpng
  *
- * Last changed in libpng 1.2.36 [May 7, 2009]
+ * Last changed in libpng 1.2.37 [May 20, 2009]
  * For conditions of distribution and use, see copyright notice in png.h
  * Copyright (c) 1998-2009 Glenn Randers-Pehrson
  * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
@@ -65,7 +65,7 @@
 #endif
 
 #if !PNG_DEBUG
-#  define SINGLE_ROWBUF_ALLOC  /* makes buffer overruns easier to nail */
+#  define SINGLE_ROWBUF_ALLOC  /* Makes buffer overruns easier to nail */
 #endif
 
 /* Turn on CPU timing
@@ -95,9 +95,9 @@
 #include <mem.h>
 #endif
 
-/* defined so I can write to a file on gui/windowing platforms */
+/* Defined so I can write to a file on gui/windowing platforms */
 /*  #define STDERR stderr  */
-#define STDERR stdout   /* for DOS */
+#define STDERR stdout   /* For DOS */
 
 /* In case a system header (e.g., on AIX) defined jmpbuf */
 #ifdef jmpbuf
@@ -109,7 +109,7 @@
 #  define png_jmpbuf(png_ptr) png_ptr->jmpbuf
 #endif
 
-/* example of using row callbacks to make a simple progress meter */
+/* Example of using row callbacks to make a simple progress meter */
 static int status_pass = 1;
 static int status_dots_requested = 0;
 static int status_dots = 1;
@@ -125,20 +125,21 @@
 #endif
 read_row_callback(png_structp png_ptr, png_uint_32 row_number, int pass)
 {
-    if (png_ptr == NULL || row_number > PNG_UINT_31_MAX) return;
-    if (status_pass != pass)
-    {
-       fprintf(stdout, "\n Pass %d: ", pass);
-       status_pass = pass;
-       status_dots = 31;
-    }
-    status_dots--;
-    if (status_dots == 0)
-    {
-       fprintf(stdout, "\n         ");
-       status_dots=30;
-    }
-    fprintf(stdout, "r");
+   if (png_ptr == NULL || row_number > PNG_UINT_31_MAX)
+      return;
+   if (status_pass != pass)
+   {
+      fprintf(stdout, "\n Pass %d: ", pass);
+      status_pass = pass;
+      status_dots = 31;
+   }
+   status_dots--;
+   if (status_dots == 0)
+   {
+      fprintf(stdout, "\n         ");
+      status_dots=30;
+   }
+   fprintf(stdout, "r");
 }
 
 void
@@ -152,15 +153,17 @@
 #endif
 write_row_callback(png_structp png_ptr, png_uint_32 row_number, int pass)
 {
-    if (png_ptr == NULL || row_number > PNG_UINT_31_MAX || pass > 7) return;
-    fprintf(stdout, "w");
+   if (png_ptr == NULL || row_number > PNG_UINT_31_MAX || pass > 7)
+      return;
+   fprintf(stdout, "w");
 }
 
 
 #if defined(PNG_READ_USER_TRANSFORM_SUPPORTED)
 /* Example of using user transform callback (we don't transform anything,
-   but merely examine the row filters.  We set this to 256 rather than
-   5 in case illegal filter values are present.) */
+ * but merely examine the row filters.  We set this to 256 rather than
+ * 5 in case illegal filter values are present.)
+ */
 static png_uint_32 filters_used[256];
 void
 #ifdef PNG_1_0_X
@@ -173,14 +176,15 @@
 #endif
 count_filters(png_structp png_ptr, png_row_infop row_info, png_bytep data)
 {
-    if (png_ptr != NULL && row_info != NULL)
+   if (png_ptr != NULL && row_info != NULL)
       ++filters_used[*(data - 1)];
 }
 #endif
 
 #if defined(PNG_WRITE_USER_TRANSFORM_SUPPORTED)
-/* example of using user transform callback (we don't transform anything,
-   but merely count the zero samples) */
+/* Example of using user transform callback (we don't transform anything,
+ * but merely count the zero samples)
+ */
 
 static png_uint_32 zero_samples;
 
@@ -198,7 +202,7 @@
    png_bytep dp = data;
    if (png_ptr == NULL)return;
 
-   /* contents of row_info:
+   /* Contents of row_info:
     *  png_uint_32 width      width of row
     *  png_uint_32 rowbytes   number of bytes in row
     *  png_byte color_type    color type of pixels
@@ -207,8 +211,7 @@
     *  png_byte pixel_depth   bits per pixel (depth*channels)
     */
 
-
-    /* counts the number of zero samples (or zero pixels if color_type is 3 */
+    /* Counts the number of zero samples (or zero pixels if color_type is 3 */
 
     if (row_info->color_type == 0 || row_info->color_type == 3)
     {
@@ -218,7 +221,8 @@
        {
           if (row_info->bit_depth == 1)
           {
-             if (((*dp << pos++ ) & 0x80) == 0) zero_samples++;
+             if (((*dp << pos++ ) & 0x80) == 0)
+                zero_samples++;
              if (pos == 8)
              {
                 pos = 0;
@@ -227,7 +231,8 @@
           }
           if (row_info->bit_depth == 2)
           {
-             if (((*dp << (pos+=2)) & 0xc0) == 0) zero_samples++;
+             if (((*dp << (pos+=2)) & 0xc0) == 0)
+                zero_samples++;
              if (pos == 8)
              {
                 pos = 0;
@@ -236,7 +241,8 @@
           }
           if (row_info->bit_depth == 4)
           {
-             if (((*dp << (pos+=4)) & 0xf0) == 0) zero_samples++;
+             if (((*dp << (pos+=4)) & 0xf0) == 0)
+                zero_samples++;
              if (pos == 8)
              {
                 pos = 0;
@@ -244,7 +250,8 @@
              }
           }
           if (row_info->bit_depth == 8)
-             if (*dp++ == 0) zero_samples++;
+             if (*dp++ == 0)
+                zero_samples++;
           if (row_info->bit_depth == 16)
           {
              if ((*dp | *(dp+1)) == 0) zero_samples++;
@@ -252,7 +259,7 @@
           }
        }
     }
-    else /* other color types */
+    else /* Other color types */
     {
        png_uint_32 n, nstop;
        int channel;
@@ -264,7 +271,8 @@
           for (channel = 0; channel < color_channels; channel++)
           {
              if (row_info->bit_depth == 8)
-                if (*dp++ == 0) zero_samples++;
+                if (*dp++ == 0)
+                   zero_samples++;
              if (row_info->bit_depth == 16)
              {
                 if ((*dp | *(dp+1)) == 0) zero_samples++;
@@ -274,7 +282,8 @@
           if (row_info->color_type > 3)
           {
              dp++;
-             if (row_info->bit_depth == 16)dp++;
+             if (row_info->bit_depth == 16)
+                dp++;
           }
        }
     }
@@ -285,12 +294,13 @@
 
 #if defined(PNG_NO_STDIO)
 /* START of code to validate stdio-free compilation */
-/* These copies of the default read/write functions come from pngrio.c and */
-/* pngwio.c.  They allow "don't include stdio" testing of the library. */
-/* This is the function that does the actual reading of data.  If you are
-   not reading from a standard C stream, you should create a replacement
-   read_data function and use it at run time with png_set_read_fn(), rather
-   than changing the library. */
+/* These copies of the default read/write functions come from pngrio.c and
+ * pngwio.c.  They allow "don't include stdio" testing of the library.
+ * This is the function that does the actual reading of data.  If you are
+ * not reading from a standard C stream, you should create a replacement
+ * read_data function and use it at run time with png_set_read_fn(), rather
+ * than changing the library.
+ */
 
 #ifndef USE_FAR_KEYWORD
 static void
@@ -309,7 +319,7 @@
    }
 }
 #else
-/* this is the model-independent version. Since the standard I/O library
+/* This is the model-independent version. Since the standard I/O library
    can't handle far buffers in the medium and small models, we have to copy
    the data.
 */
@@ -341,7 +351,7 @@
       {
          read = MIN(NEAR_BUF_SIZE, remaining);
          READFILE(io_ptr, buf, 1, err);
-         png_memcpy(data, buf, read); /* copy far buffer to near buffer */
+         png_memcpy(data, buf, read); /* Copy far buffer to near buffer */
          if (err != read)
             break;
          else
@@ -352,9 +362,7 @@
       while (remaining != 0);
    }
    if (check != length)
-   {
       png_error(png_ptr, "read Error");
-   }
 }
 #endif /* USE_FAR_KEYWORD */
 
@@ -363,14 +371,15 @@
 pngtest_flush(png_structp png_ptr)
 {
    /* Do nothing; fflush() is said to be just a waste of energy. */
-   png_ptr = png_ptr;  /* stifle compiler warning */
+   png_ptr = png_ptr;  /* Stifle compiler warning */
 }
 #endif
 
 /* This is the function that does the actual writing of data.  If you are
-   not writing to a standard C stream, you should create a replacement
-   write_data function and use it at run time with png_set_write_fn(), rather
-   than changing the library. */
+ * not writing to a standard C stream, you should create a replacement
+ * write_data function and use it at run time with png_set_write_fn(), rather
+ * than changing the library.
+ */
 #ifndef USE_FAR_KEYWORD
 static void
 pngtest_write_data(png_structp png_ptr, png_bytep data, png_size_t length)
@@ -384,7 +393,7 @@
    }
 }
 #else
-/* this is the model-independent version. Since the standard I/O library
+/* This is the model-independent version. Since the standard I/O library
    can't handle far buffers in the medium and small models, we have to copy
    the data.
 */
@@ -415,7 +424,7 @@
       do
       {
          written = MIN(NEAR_BUF_SIZE, remaining);
-         png_memcpy(buf, data, written); /* copy far buffer to near buffer */
+         png_memcpy(buf, data, written); /* Copy far buffer to near buffer */
          WRITEFILE(io_ptr, buf, written, err);
          if (err != written)
             break;
@@ -457,7 +466,8 @@
 {
    pngtest_warning(png_ptr, message);
    /* We can return because png_error calls the default handler, which is
-    * actually OK in this case. */
+    * actually OK in this case.
+    */
 }
 #endif /* PNG_NO_STDIO */
 /* END of code to validate stdio-free compilation */
@@ -466,13 +476,14 @@
 #if defined(PNG_USER_MEM_SUPPORTED) && PNG_DEBUG
 
 /* Allocate memory.  For reasonable files, size should never exceed
-   64K.  However, zlib may allocate more then 64K if you don't tell
-   it not to.  See zconf.h and png.h for more information.  zlib does
-   need to allocate exactly 64K, so whatever you call here must
-   have the ability to do that.
-
-   This piece of code can be compiled to validate max 64K allocations
-   by setting MAXSEG_64K in zlib zconf.h *or* PNG_MAX_MALLOC_64K. */
+ * 64K.  However, zlib may allocate more then 64K if you don't tell
+ * it not to.  See zconf.h and png.h for more information.  zlib does
+ * need to allocate exactly 64K, so whatever you call here must
+ * have the ability to do that.
+ *
+ * This piece of code can be compiled to validate max 64K allocations
+ * by setting MAXSEG_64K in zlib zconf.h *or* PNG_MAX_MALLOC_64K.
+ */
 typedef struct memory_information
 {
    png_uint_32               size;
@@ -495,7 +506,8 @@
 {
 
    /* png_malloc has already tested for NULL; png_create_struct calls
-      png_debug_malloc directly, with png_ptr == NULL which is OK */
+    * png_debug_malloc directly, with png_ptr == NULL which is OK
+    */
 
    if (size == 0)
       return (NULL);
@@ -592,7 +604,7 @@
 /* Demonstration of user chunk support of the sTER and vpAg chunks */
 #if defined(PNG_UNKNOWN_CHUNKS_SUPPORTED)
 
-/* (sTER is a public chunk not yet understood by libpng.  vpAg is a private
+/* (sTER is a public chunk not yet known by libpng.  vpAg is a private
 chunk used in ImageMagick to store "virtual page" size).  */
 
 static png_uint_32 user_chunk_data[4];
@@ -606,50 +618,51 @@
 static int read_user_chunk_callback(png_struct *png_ptr,
    png_unknown_chunkp chunk)
 {
-  png_uint_32
-    *my_user_chunk_data;
+   png_uint_32
+     *my_user_chunk_data;
 
-  /* Return one of the following: */
-     /* return (-n);  chunk had an error */
-     /* return (0);  did not recognize */
-     /* return (n);  success */
+   /* Return one of the following:
+    *    return (-n);  chunk had an error
+    *    return (0);  did not recognize
+    *    return (n);  success
+    *
+    * The unknown chunk structure contains the chunk data:
+    * png_byte name[5];
+    * png_byte *data;
+    * png_size_t size;
+    *
+    * Note that libpng has already taken care of the CRC handling.
+    */
 
-  /* The unknown chunk structure contains the chunk data:
-   * png_byte name[5];
-   * png_byte *data;
-   * png_size_t size;
-   *
-   *  Note that libpng has already taken care of the CRC handling.
-   */
+   if (chunk->name[0] == 115 && chunk->name[1] ==  84 &&     /* s  T */
+       chunk->name[2] ==  69 && chunk->name[3] ==  82)       /* E  R */
+      {
+         /* Found sTER chunk */
+         if (chunk->size != 1)
+            return (-1); /* Error return */
+         if (chunk->data[0] != 0 && chunk->data[0] != 1)
+            return (-1);  /* Invalid mode */
+         my_user_chunk_data=(png_uint_32 *) png_get_user_chunk_ptr(png_ptr);
+         my_user_chunk_data[0]=chunk->data[0]+1;
+         return (1);
+      }
 
-  if (chunk->name[0] == 115 && chunk->name[1] ==  84 &&     /* s  T */
-      chunk->name[2] ==  69 && chunk->name[3] ==  82)       /* E  R */
-     {
-       /* Found sTER chunk */
-       if (chunk->size != 1)
-         return (-1); /* Error return */
-       if (chunk->data[0] != 0 && chunk->data[0] != 1)
-          return (-1);  /* Invalid mode */
-       my_user_chunk_data=(png_uint_32 *) png_get_user_chunk_ptr(png_ptr);
-       my_user_chunk_data[0]=chunk->data[0]+1;
-       return (1);
-     }
-  if (chunk->name[0] != 118 || chunk->name[1] != 112 ||    /* v  p */
-      chunk->name[2] !=  65 || chunk->name[3] != 103)      /* A  g */
-    return (0); /* Did not recognize */
+   if (chunk->name[0] != 118 || chunk->name[1] != 112 ||    /* v  p */
+       chunk->name[2] !=  65 || chunk->name[3] != 103)      /* A  g */
+      return (0); /* Did not recognize */
 
-  /* Found ImageMagick vpAg chunk */
+   /* Found ImageMagick vpAg chunk */
 
-  if (chunk->size != 9)
-    return (-1); /* Error return */
+   if (chunk->size != 9)
+      return (-1); /* Error return */
 
-  my_user_chunk_data=(png_uint_32 *) png_get_user_chunk_ptr(png_ptr);
+   my_user_chunk_data=(png_uint_32 *) png_get_user_chunk_ptr(png_ptr);
 
-  my_user_chunk_data[1]=png_get_uint_31(png_ptr, chunk->data);
-  my_user_chunk_data[2]=png_get_uint_31(png_ptr, chunk->data + 4);
-  my_user_chunk_data[3]=(png_uint_32)chunk->data[8];
+   my_user_chunk_data[1]=png_get_uint_31(png_ptr, chunk->data);
+   my_user_chunk_data[2]=png_get_uint_31(png_ptr, chunk->data + 4);
+   my_user_chunk_data[3]=(png_uint_32)chunk->data[8];
 
-  return (1);
+   return (1);
 
 }
 #endif
@@ -730,12 +743,12 @@
 #endif
 
 #if defined(PNG_UNKNOWN_CHUNKS_SUPPORTED)
-  user_chunk_data[0] = 0;
-  user_chunk_data[1] = 0;
-  user_chunk_data[2] = 0;
-  user_chunk_data[3] = 0;
-  png_set_read_user_chunk_fn(read_ptr, user_chunk_data,
-    read_user_chunk_callback);
+   user_chunk_data[0] = 0;
+   user_chunk_data[1] = 0;
+   user_chunk_data[2] = 0;
+   user_chunk_data[3] = 0;
+   png_set_read_user_chunk_fn(read_ptr, user_chunk_data,
+     read_user_chunk_callback);
 
 #endif
 #ifdef PNG_WRITE_SUPPORTED
@@ -844,10 +857,10 @@
 
 #if defined(PNG_READ_USER_TRANSFORM_SUPPORTED)
    {
-     int i;
-     for (i = 0; i<256; i++)
-        filters_used[i] = 0;
-     png_set_read_user_transform_fn(read_ptr, count_filters);
+      int i;
+      for (i = 0; i<256; i++)
+         filters_used[i] = 0;
+      png_set_read_user_transform_fn(read_ptr, count_filters);
    }
 #endif
 #if defined(PNG_WRITE_USER_TRANSFORM_SUPPORTED)
@@ -906,9 +919,7 @@
       png_fixed_point gamma;
 
       if (png_get_gAMA_fixed(read_ptr, read_info_ptr, &gamma))
-      {
          png_set_gAMA_fixed(write_ptr, write_info_ptr, gamma);
-      }
    }
 #endif
 #else /* Use floating point versions */
@@ -930,13 +941,11 @@
       double gamma;
 
       if (png_get_gAMA(read_ptr, read_info_ptr, &gamma))
-      {
          png_set_gAMA(write_ptr, write_info_ptr, gamma);
-      }
    }
 #endif
-#endif /* floating point */
-#endif /* fixed point */
+#endif /* Floating point */
+#endif /* Fixed point */
 #if defined(PNG_iCCP_SUPPORTED)
    {
       png_charp name;
@@ -957,9 +966,7 @@
       int intent;
 
       if (png_get_sRGB(read_ptr, read_info_ptr, &intent))
-      {
          png_set_sRGB(write_ptr, write_info_ptr, intent);
-      }
    }
 #endif
    {
@@ -967,9 +974,7 @@
       int num_palette;
 
       if (png_get_PLTE(read_ptr, read_info_ptr, &palette, &num_palette))
-      {
          png_set_PLTE(write_ptr, write_info_ptr, palette, num_palette);
-      }
    }
 #if defined(PNG_bKGD_SUPPORTED)
    {
@@ -986,9 +991,7 @@
       png_uint_16p hist;
 
       if (png_get_hIST(read_ptr, read_info_ptr, &hist))
-      {
          png_set_hIST(write_ptr, write_info_ptr, hist);
-      }
    }
 #endif
 #if defined(PNG_oFFs_SUPPORTED)
@@ -997,7 +1000,7 @@
       int unit_type;
 
       if (png_get_oFFs(read_ptr, read_info_ptr, &offset_x, &offset_y,
-         &unit_type))
+          &unit_type))
       {
          png_set_oFFs(write_ptr, write_info_ptr, offset_x, offset_y, unit_type);
       }
@@ -1024,9 +1027,7 @@
       int unit_type;
 
       if (png_get_pHYs(read_ptr, read_info_ptr, &res_x, &res_y, &unit_type))
-      {
          png_set_pHYs(write_ptr, write_info_ptr, res_x, res_y, unit_type);
-      }
    }
 #endif
 #if defined(PNG_sBIT_SUPPORTED)
@@ -1034,9 +1035,7 @@
       png_color_8p sig_bit;
 
       if (png_get_sBIT(read_ptr, read_info_ptr, &sig_bit))
-      {
          png_set_sBIT(write_ptr, write_info_ptr, sig_bit);
-      }
    }
 #endif
 #if defined(PNG_sCAL_SUPPORTED)
@@ -1086,9 +1085,10 @@
       {
          png_set_tIME(write_ptr, write_info_ptr, mod_time);
 #if defined(PNG_TIME_RFC1123_SUPPORTED)
-         /* we have to use png_memcpy instead of "=" because the string
-            pointed to by png_convert_to_rfc1123() gets free'ed before
-            we use it */
+         /* We have to use png_memcpy instead of "=" because the string
+          * pointed to by png_convert_to_rfc1123() gets free'ed before
+          * we use it.
+          */
          png_memcpy(tIME_string,
                     png_convert_to_rfc1123(read_ptr, mod_time),
                     png_sizeof(tIME_string));
@@ -1110,13 +1110,13 @@
          int sample_max = (1 << read_info_ptr->bit_depth);
          /* libpng doesn't reject a tRNS chunk with out-of-range samples */
          if (!((read_info_ptr->color_type == PNG_COLOR_TYPE_GRAY &&
-            (int)trans_values->gray > sample_max) ||
-            (read_info_ptr->color_type == PNG_COLOR_TYPE_RGB &&
-            ((int)trans_values->red > sample_max ||
-            (int)trans_values->green > sample_max ||
-            (int)trans_values->blue > sample_max))))
-           png_set_tRNS(write_ptr, write_info_ptr, trans, num_trans,
-              trans_values);
+             (int)trans_values->gray > sample_max) ||
+             (read_info_ptr->color_type == PNG_COLOR_TYPE_RGB &&
+             ((int)trans_values->red > sample_max ||
+             (int)trans_values->green > sample_max ||
+             (int)trans_values->blue > sample_max))))
+            png_set_tRNS(write_ptr, write_info_ptr, trans, num_trans,
+               trans_values);
       }
    }
 #endif
@@ -1130,9 +1130,10 @@
          png_size_t i;
          png_set_unknown_chunks(write_ptr, write_info_ptr, unknowns,
            num_unknowns);
-         /* copy the locations from the read_info_ptr.  The automatically
-            generated locations in write_info_ptr are wrong because we
-            haven't written anything yet */
+         /* Copy the locations from the read_info_ptr.  The automatically
+          * generated locations in write_info_ptr are wrong because we
+          * haven't written anything yet.
+          */
          for (i = 0; i < (png_size_t)num_unknowns; i++)
            png_set_unknown_chunk_location(write_ptr, write_info_ptr, i,
              unknowns[i].location);
@@ -1144,40 +1145,40 @@
    png_debug(0, "Writing info struct");
 
 /* If we wanted, we could write info in two steps:
-   png_write_info_before_PLTE(write_ptr, write_info_ptr);
+ * png_write_info_before_PLTE(write_ptr, write_info_ptr);
  */
    png_write_info(write_ptr, write_info_ptr);
 
 #if defined(PNG_UNKNOWN_CHUNKS_SUPPORTED)
    if (user_chunk_data[0] != 0)
    {
-     png_byte png_sTER[5] = {115,  84,  69,  82, '\0'};
+      png_byte png_sTER[5] = {115,  84,  69,  82, '\0'};
 
-     unsigned char
-       ster_chunk_data[1];
+      unsigned char
+        ster_chunk_data[1];
 
-     if (verbose)
-        fprintf(STDERR, "\n stereo mode = %lu\n",
-          (unsigned long)(user_chunk_data[0] - 1));
-     ster_chunk_data[0]=(unsigned char)(user_chunk_data[0] - 1);
-     png_write_chunk(write_ptr, png_sTER, ster_chunk_data, 1);
+      if (verbose)
+         fprintf(STDERR, "\n stereo mode = %lu\n",
+           (unsigned long)(user_chunk_data[0] - 1));
+      ster_chunk_data[0]=(unsigned char)(user_chunk_data[0] - 1);
+      png_write_chunk(write_ptr, png_sTER, ster_chunk_data, 1);
    }
    if (user_chunk_data[1] != 0 || user_chunk_data[2] != 0)
    {
-     png_byte png_vpAg[5] = {118, 112,  65, 103, '\0'};
+      png_byte png_vpAg[5] = {118, 112,  65, 103, '\0'};
 
-     unsigned char
-       vpag_chunk_data[9];
+      unsigned char
+        vpag_chunk_data[9];
 
-     if (verbose)
-        fprintf(STDERR, " vpAg = %lu x %lu, units = %lu\n",
-          (unsigned long)user_chunk_data[1],
-          (unsigned long)user_chunk_data[2],
-          (unsigned long)user_chunk_data[3]);
-     png_save_uint_32(vpag_chunk_data, user_chunk_data[1]);
-     png_save_uint_32(vpag_chunk_data + 4, user_chunk_data[2]);
-     vpag_chunk_data[8] = (unsigned char)(user_chunk_data[3] & 0xff);
-     png_write_chunk(write_ptr, png_vpAg, vpag_chunk_data, 9);
+      if (verbose)
+         fprintf(STDERR, " vpAg = %lu x %lu, units = %lu\n",
+           (unsigned long)user_chunk_data[1],
+           (unsigned long)user_chunk_data[2],
+           (unsigned long)user_chunk_data[3]);
+      png_save_uint_32(vpag_chunk_data, user_chunk_data[1]);
+      png_save_uint_32(vpag_chunk_data + 4, user_chunk_data[2]);
+      vpag_chunk_data[8] = (unsigned char)(user_chunk_data[3] & 0xff);
+      png_write_chunk(write_ptr, png_vpAg, vpag_chunk_data, 9);
    }
 
 #endif
@@ -1272,7 +1273,7 @@
       {
          png_set_tIME(write_ptr, write_end_info_ptr, mod_time);
 #if defined(PNG_TIME_RFC1123_SUPPORTED)
-         /* we have to use png_memcpy instead of "=" because the string
+         /* We have to use png_memcpy instead of "=" because the string
             pointed to by png_convert_to_rfc1123() gets free'ed before
             we use it */
          png_memcpy(tIME_string,
@@ -1295,9 +1296,10 @@
          png_size_t i;
          png_set_unknown_chunks(write_ptr, write_end_info_ptr, unknowns,
            num_unknowns);
-         /* copy the locations from the read_info_ptr.  The automatically
-            generated locations in write_end_info_ptr are wrong because we
-            haven't written the end_info yet */
+         /* Copy the locations from the read_info_ptr.  The automatically
+          * generated locations in write_end_info_ptr are wrong because we
+          * haven't written the end_info yet.
+          */
          for (i = 0; i < (png_size_t)num_unknowns; i++)
            png_set_unknown_chunk_location(write_ptr, write_end_info_ptr, i,
              unknowns[i].location);
@@ -1420,7 +1422,7 @@
    return (0);
 }
 
-/* input and output filenames */
+/* Input and output filenames */
 #ifdef RISCOS
 static PNG_CONST char *inname = "pngtest/png";
 static PNG_CONST char *outname = "pngout/png";
@@ -1449,9 +1451,10 @@
                     (long)png_sizeof(png_struct), (long)png_sizeof(png_info));
 
    /* Do some consistency checking on the memory allocation settings, I'm
-      not sure this matters, but it is nice to know, the first of these
-      tests should be impossible because of the way the macros are set
-      in pngconf.h */
+    * not sure this matters, but it is nice to know, the first of these
+    * tests should be impossible because of the way the macros are set
+    * in pngconf.h
+    */
 #if defined(MAXSEG_64K) && !defined(PNG_MAX_MALLOC_64K)
       fprintf(STDERR, " NOTE: Zlib compiled for max 64k, libpng not\n");
 #endif
@@ -1681,4 +1684,4 @@
 }
 
 /* Generate a compiler error if there is an old png.h in the search path. */
-typedef version_1_2_37rc01 your_png_h_is_not_version_1_2_37rc01;
+typedef version_1_2_37beta03 your_png_h_is_not_version_1_2_37beta03;
diff --git a/pngtrans.c b/pngtrans.c
index f92f4b0..f221f54 100644
--- a/pngtrans.c
+++ b/pngtrans.c
@@ -1,9 +1,9 @@
 
 /* pngtrans.c - transforms the data in a row (used by both readers and writers)
  *
- * Last changed in libpng 1.2.30 [August 15, 2008]
+ * Last changed in libpng 1.2.36 [May 14, 2009]
  * For conditions of distribution and use, see copyright notice in png.h
- * Copyright (c) 1998-2008 Glenn Randers-Pehrson
+ * Copyright (c) 1998-2009 Glenn Randers-Pehrson
  * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
  * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
  */
@@ -13,35 +13,38 @@
 #if defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED)
 
 #if defined(PNG_READ_BGR_SUPPORTED) || defined(PNG_WRITE_BGR_SUPPORTED)
-/* turn on BGR-to-RGB mapping */
+/* Turn on BGR-to-RGB mapping */
 void PNGAPI
 png_set_bgr(png_structp png_ptr)
 {
    png_debug(1, "in png_set_bgr");
-   if (png_ptr == NULL) return;
+   if (png_ptr == NULL)
+      return;
    png_ptr->transformations |= PNG_BGR;
 }
 #endif
 
 #if defined(PNG_READ_SWAP_SUPPORTED) || defined(PNG_WRITE_SWAP_SUPPORTED)
-/* turn on 16 bit byte swapping */
+/* Turn on 16 bit byte swapping */
 void PNGAPI
 png_set_swap(png_structp png_ptr)
 {
    png_debug(1, "in png_set_swap");
-   if (png_ptr == NULL) return;
+   if (png_ptr == NULL)
+      return;
    if (png_ptr->bit_depth == 16)
       png_ptr->transformations |= PNG_SWAP_BYTES;
 }
 #endif
 
 #if defined(PNG_READ_PACK_SUPPORTED) || defined(PNG_WRITE_PACK_SUPPORTED)
-/* turn on pixel packing */
+/* Turn on pixel packing */
 void PNGAPI
 png_set_packing(png_structp png_ptr)
 {
    png_debug(1, "in png_set_packing");
-   if (png_ptr == NULL) return;
+   if (png_ptr == NULL)
+      return;
    if (png_ptr->bit_depth < 8)
    {
       png_ptr->transformations |= PNG_PACK;
@@ -51,12 +54,13 @@
 #endif
 
 #if defined(PNG_READ_PACKSWAP_SUPPORTED)||defined(PNG_WRITE_PACKSWAP_SUPPORTED)
-/* turn on packed pixel swapping */
+/* Turn on packed pixel swapping */
 void PNGAPI
 png_set_packswap(png_structp png_ptr)
 {
    png_debug(1, "in png_set_packswap");
-   if (png_ptr == NULL) return;
+   if (png_ptr == NULL)
+      return;
    if (png_ptr->bit_depth < 8)
       png_ptr->transformations |= PNG_PACKSWAP;
 }
@@ -67,7 +71,8 @@
 png_set_shift(png_structp png_ptr, png_color_8p true_bits)
 {
    png_debug(1, "in png_set_shift");
-   if (png_ptr == NULL) return;
+   if (png_ptr == NULL)
+      return;
    png_ptr->transformations |= PNG_SHIFT;
    png_ptr->shift = *true_bits;
 }
@@ -99,7 +104,8 @@
 png_set_filler(png_structp png_ptr, png_uint_32 filler, int filler_loc)
 {
    png_debug(1, "in png_set_filler");
-   if (png_ptr == NULL) return;
+   if (png_ptr == NULL)
+      return;
    png_ptr->transformations |= PNG_FILLER;
    png_ptr->filler = (png_byte)filler;
    if (filler_loc == PNG_FILLER_AFTER)
@@ -132,7 +138,8 @@
 png_set_add_alpha(png_structp png_ptr, png_uint_32 filler, int filler_loc)
 {
    png_debug(1, "in png_set_add_alpha");
-   if (png_ptr == NULL) return;
+   if (png_ptr == NULL)
+      return;
    png_set_filler(png_ptr, filler, filler_loc);
    png_ptr->transformations |= PNG_ADD_ALPHA;
 }
@@ -146,7 +153,8 @@
 png_set_swap_alpha(png_structp png_ptr)
 {
    png_debug(1, "in png_set_swap_alpha");
-   if (png_ptr == NULL) return;
+   if (png_ptr == NULL)
+      return;
    png_ptr->transformations |= PNG_SWAP_ALPHA;
 }
 #endif
@@ -157,7 +165,8 @@
 png_set_invert_alpha(png_structp png_ptr)
 {
    png_debug(1, "in png_set_invert_alpha");
-   if (png_ptr == NULL) return;
+   if (png_ptr == NULL)
+      return;
    png_ptr->transformations |= PNG_INVERT_ALPHA;
 }
 #endif
@@ -167,11 +176,12 @@
 png_set_invert_mono(png_structp png_ptr)
 {
    png_debug(1, "in png_set_invert_mono");
-   if (png_ptr == NULL) return;
+   if (png_ptr == NULL)
+      return;
    png_ptr->transformations |= PNG_INVERT_MONO;
 }
 
-/* invert monochrome grayscale data */
+/* Invert monochrome grayscale data */
 void /* PRIVATE */
 png_do_invert(png_row_infop row_info, png_bytep row)
 {
@@ -226,7 +236,7 @@
 #endif
 
 #if defined(PNG_READ_SWAP_SUPPORTED) || defined(PNG_WRITE_SWAP_SUPPORTED)
-/* swaps byte order on 16 bit depth images */
+/* Swaps byte order on 16 bit depth images */
 void /* PRIVATE */
 png_do_swap(png_row_infop row_info, png_bytep row)
 {
@@ -357,7 +367,7 @@
    0x8F, 0x9F, 0xAF, 0xBF, 0xCF, 0xDF, 0xEF, 0xFF
 };
 
-/* swaps pixel packing order within bytes */
+/* Swaps pixel packing order within bytes */
 void /* PRIVATE */
 png_do_packswap(png_row_infop row_info, png_bytep row)
 {
@@ -389,7 +399,7 @@
 
 #if defined(PNG_WRITE_FILLER_SUPPORTED) || \
     defined(PNG_READ_STRIP_ALPHA_SUPPORTED)
-/* remove filler or alpha byte(s) */
+/* Remove filler or alpha byte(s) */
 void /* PRIVATE */
 png_do_strip_filler(png_row_infop row_info, png_bytep row, png_uint_32 flags)
 {
@@ -404,9 +414,9 @@
       png_uint_32 i;
 
       if ((row_info->color_type == PNG_COLOR_TYPE_RGB ||
-         (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA &&
-         (flags & PNG_FLAG_STRIP_ALPHA))) &&
-         row_info->channels == 4)
+          (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA &&
+          (flags & PNG_FLAG_STRIP_ALPHA))) &&
+          row_info->channels == 4)
       {
          if (row_info->bit_depth == 8)
          {
@@ -547,7 +557,7 @@
 #endif
 
 #if defined(PNG_READ_BGR_SUPPORTED) || defined(PNG_WRITE_BGR_SUPPORTED)
-/* swaps red and blue bytes within a pixel */
+/* Swaps red and blue bytes within a pixel */
 void /* PRIVATE */
 png_do_bgr(png_row_infop row_info, png_bytep row)
 {
@@ -631,7 +641,8 @@
    user_transform_ptr, int user_transform_depth, int user_transform_channels)
 {
    png_debug(1, "in png_set_user_transform_info");
-   if (png_ptr == NULL) return;
+   if (png_ptr == NULL)
+      return;
 #if defined(PNG_USER_TRANSFORM_PTR_SUPPORTED)
    png_ptr->user_transform_ptr = user_transform_ptr;
    png_ptr->user_transform_depth = (png_byte)user_transform_depth;
@@ -652,7 +663,8 @@
 png_voidp PNGAPI
 png_get_user_transform_ptr(png_structp png_ptr)
 {
-   if (png_ptr == NULL) return (NULL);
+   if (png_ptr == NULL)
+      return (NULL);
 #if defined(PNG_USER_TRANSFORM_PTR_SUPPORTED)
    return ((png_voidp)png_ptr->user_transform_ptr);
 #else
diff --git a/pngwio.c b/pngwio.c
index ab4dba2..fabfaff 100644
--- a/pngwio.c
+++ b/pngwio.c
@@ -1,7 +1,7 @@
 
 /* pngwio.c - functions for data output
  *
- * Last changed in libpng 1.2.36 [May 7, 2009]
+ * Last changed in libpng 1.2.37 [May 20, 2009]
  * For conditions of distribution and use, see copyright notice in png.h
  * Copyright (c) 1998-2009 Glenn Randers-Pehrson
  * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
@@ -20,10 +20,11 @@
 #ifdef PNG_WRITE_SUPPORTED
 
 /* Write the data to whatever output you are using.  The default routine
-   writes to a file pointer.  Note that this routine sometimes gets called
-   with very small lengths, so you should implement some kind of simple
-   buffering if you are using unbuffered writes.  This should never be asked
-   to write more than 64K on a 16 bit machine.  */
+ * writes to a file pointer.  Note that this routine sometimes gets called
+ * with very small lengths, so you should implement some kind of simple
+ * buffering if you are using unbuffered writes.  This should never be asked
+ * to write more than 64K on a 16 bit machine.
+ */
 
 void /* PRIVATE */
 png_write_data(png_structp png_ptr, png_bytep data, png_size_t length)
@@ -36,9 +37,10 @@
 
 #if !defined(PNG_NO_STDIO)
 /* This is the function that does the actual writing of data.  If you are
-   not writing to a standard C stream, you should create a replacement
-   write_data function and use it at run time with png_set_write_fn(), rather
-   than changing the library. */
+ * not writing to a standard C stream, you should create a replacement
+ * write_data function and use it at run time with png_set_write_fn(), rather
+ * than changing the library.
+ */
 #ifndef USE_FAR_KEYWORD
 void PNGAPI
 png_default_write_data(png_structp png_ptr, png_bytep data, png_size_t length)
@@ -56,10 +58,10 @@
       png_error(png_ptr, "Write Error");
 }
 #else
-/* this is the model-independent version. Since the standard I/O library
-   can't handle far buffers in the medium and small models, we have to copy
-   the data.
-*/
+/* This is the model-independent version. Since the standard I/O library
+ * can't handle far buffers in the medium and small models, we have to copy
+ * the data.
+ */
 
 #define NEAR_BUF_SIZE 1024
 #define MIN(a,b) (a <= b ? a : b)
@@ -93,7 +95,7 @@
       do
       {
          written = MIN(NEAR_BUF_SIZE, remaining);
-         png_memcpy(buf, data, written); /* copy far buffer to near buffer */
+         png_memcpy(buf, data, written); /* Copy far buffer to near buffer */
 #if defined(_WIN32_WCE)
          if ( !WriteFile(io_ptr, buf, written, &err, NULL) )
             err = 0;
@@ -102,8 +104,10 @@
 #endif
          if (err != written)
             break;
+
          else
             check += err;
+
          data += written;
          remaining -= written;
       }
@@ -117,8 +121,9 @@
 #endif
 
 /* This function is called to output any data pending writing (normally
-   to disk).  After png_flush is called, there should be no data pending
-   writing in any buffers. */
+ * to disk).  After png_flush is called, there should be no data pending
+ * writing in any buffers.
+ */
 #if defined(PNG_WRITE_FLUSH_SUPPORTED)
 void /* PRIVATE */
 png_flush(png_structp png_ptr)
@@ -134,7 +139,8 @@
 #if !defined(_WIN32_WCE)
    png_FILE_p io_ptr;
 #endif
-   if (png_ptr == NULL) return;
+   if (png_ptr == NULL)
+      return;
 #if !defined(_WIN32_WCE)
    io_ptr = (png_FILE_p)CVT_PTR((png_ptr->io_ptr));
    fflush(io_ptr);
@@ -144,43 +150,47 @@
 #endif
 
 /* This function allows the application to supply new output functions for
-   libpng if standard C streams aren't being used.
-
-   This function takes as its arguments:
-   png_ptr       - pointer to a png output data structure
-   io_ptr        - pointer to user supplied structure containing info about
-                   the output functions.  May be NULL.
-   write_data_fn - pointer to a new output function that takes as its
-                   arguments a pointer to a png_struct, a pointer to
-                   data to be written, and a 32-bit unsigned int that is
-                   the number of bytes to be written.  The new write
-                   function should call png_error(png_ptr, "Error msg")
-                   to exit and output any fatal error messages.  May be
-                   NULL, in which case libpng's default function will
-                   be used.
-   flush_data_fn - pointer to a new flush function that takes as its
-                   arguments a pointer to a png_struct.  After a call to
-                   the flush function, there should be no data in any buffers
-                   or pending transmission.  If the output method doesn't do
-                   any buffering of ouput, a function prototype must still be
-                   supplied although it doesn't have to do anything.  If
-                   PNG_WRITE_FLUSH_SUPPORTED is not defined at libpng compile
-                   time, output_flush_fn will be ignored, although it must be
-                   supplied for compatibility.  May be NULL, in which case
-                   libpng's default function will be used, if
-                   PNG_WRITE_FLUSH_SUPPORTED is defined.  This is not
-                   a good idea if io_ptr does not point to a standard
-                   *FILE structure. */
+ * libpng if standard C streams aren't being used.
+ *
+ * This function takes as its arguments:
+ * png_ptr       - pointer to a png output data structure
+ * io_ptr        - pointer to user supplied structure containing info about
+ *                 the output functions.  May be NULL.
+ * write_data_fn - pointer to a new output function that takes as its
+ *                 arguments a pointer to a png_struct, a pointer to
+ *                 data to be written, and a 32-bit unsigned int that is
+ *                 the number of bytes to be written.  The new write
+ *                 function should call png_error(png_ptr, "Error msg")
+ *                 to exit and output any fatal error messages.  May be
+ *                 NULL, in which case libpng's default function will
+ *                 be used.
+ * flush_data_fn - pointer to a new flush function that takes as its
+ *                 arguments a pointer to a png_struct.  After a call to
+ *                 the flush function, there should be no data in any buffers
+ *                 or pending transmission.  If the output method doesn't do
+ *                 any buffering of ouput, a function prototype must still be
+ *                 supplied although it doesn't have to do anything.  If
+ *                 PNG_WRITE_FLUSH_SUPPORTED is not defined at libpng compile
+ *                 time, output_flush_fn will be ignored, although it must be
+ *                 supplied for compatibility.  May be NULL, in which case
+ *                 libpng's default function will be used, if
+ *                 PNG_WRITE_FLUSH_SUPPORTED is defined.  This is not
+ *                 a good idea if io_ptr does not point to a standard
+ *                 *FILE structure.
+ */
 void PNGAPI
 png_set_write_fn(png_structp png_ptr, png_voidp io_ptr,
    png_rw_ptr write_data_fn, png_flush_ptr output_flush_fn)
 {
-   if (png_ptr == NULL) return;
+   if (png_ptr == NULL)
+      return;
+
    png_ptr->io_ptr = io_ptr;
 
 #if !defined(PNG_NO_STDIO)
    if (write_data_fn != NULL)
       png_ptr->write_data_fn = write_data_fn;
+
    else
       png_ptr->write_data_fn = png_default_write_data;
 #else
@@ -191,6 +201,7 @@
 #if !defined(PNG_NO_STDIO)
    if (output_flush_fn != NULL)
       png_ptr->output_flush_fn = output_flush_fn;
+
    else
       png_ptr->output_flush_fn = png_default_flush;
 #else
@@ -217,9 +228,11 @@
    void FAR *far_ptr;
    FP_OFF(near_ptr) = FP_OFF(ptr);
    far_ptr = (void FAR *)near_ptr;
+
    if (check != 0)
       if (FP_SEG(ptr) != FP_SEG(far_ptr))
          png_error(png_ptr, "segment lost in conversion");
+
    return(near_ptr);
 }
 #  else
@@ -229,9 +242,11 @@
    void FAR *far_ptr;
    near_ptr = (void FAR *)ptr;
    far_ptr = (void FAR *)near_ptr;
+
    if (check != 0)
       if (far_ptr != ptr)
          png_error(png_ptr, "segment lost in conversion");
+
    return(near_ptr);
 }
 #   endif
diff --git a/pngwrite.c b/pngwrite.c
index add8126..fe361cb 100644
--- a/pngwrite.c
+++ b/pngwrite.c
@@ -1,14 +1,14 @@
 
 /* pngwrite.c - general routines to write a PNG file
  *
- * Last changed in libpng 1.2.34 [December 18, 2008]
+ * Last changed in libpng 1.2.37 [May 20, 2009]
  * For conditions of distribution and use, see copyright notice in png.h
- * Copyright (c) 1998-2008 Glenn Randers-Pehrson
+ * Copyright (c) 1998-2009 Glenn Randers-Pehrson
  * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
  * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
  */
 
-/* get internal access to png.h */
+/* Get internal access to png.h */
 #define PNG_INTERNAL
 #include "png.h"
 #ifdef PNG_WRITE_SUPPORTED
@@ -30,7 +30,7 @@
       return;
    if (!(png_ptr->mode & PNG_WROTE_INFO_BEFORE_PLTE))
    {
-   png_write_sig(png_ptr); /* write PNG signature */
+   png_write_sig(png_ptr); /* Write PNG signature */
 #if defined(PNG_MNG_FEATURES_SUPPORTED)
    if ((png_ptr->mode&PNG_HAVE_PNG_SIGNATURE)&&(png_ptr->mng_features_permitted))
    {
@@ -38,7 +38,7 @@
       png_ptr->mng_features_permitted=0;
    }
 #endif
-   /* write IHDR information. */
+   /* Write IHDR information. */
    png_write_IHDR(png_ptr, info_ptr->width, info_ptr->height,
       info_ptr->bit_depth, info_ptr->color_type, info_ptr->compression_type,
       info_ptr->filter_type,
@@ -47,8 +47,9 @@
 #else
       0);
 #endif
-   /* the rest of these check to see if the valid field has the appropriate
-      flag set, and if it does, writes the chunk. */
+   /* The rest of these check to see if the valid field has the appropriate
+    * flag set, and if it does, writes the chunk.
+    */
 #if defined(PNG_WRITE_gAMA_SUPPORTED)
    if (info_ptr->valid & PNG_INFO_gAMA)
    {
@@ -97,14 +98,14 @@
 #if defined(PNG_WRITE_UNKNOWN_CHUNKS_SUPPORTED)
    if (info_ptr->unknown_chunks_num)
    {
-       png_unknown_chunk *up;
+      png_unknown_chunk *up;
 
-       png_debug(5, "writing extra chunks");
+      png_debug(5, "writing extra chunks");
 
-       for (up = info_ptr->unknown_chunks;
-            up < info_ptr->unknown_chunks + info_ptr->unknown_chunks_num;
-            up++)
-       {
+      for (up = info_ptr->unknown_chunks;
+           up < info_ptr->unknown_chunks + info_ptr->unknown_chunks_num;
+           up++)
+      {
          int keep=png_handle_as_unknown(png_ptr, up->name);
          if (keep != PNG_HANDLE_CHUNK_NEVER &&
             up->location && !(up->location & PNG_HAVE_PLTE) &&
@@ -116,7 +117,7 @@
                png_warning(png_ptr, "Writing zero-length unknown chunk");
             png_write_chunk(png_ptr, up->name, up->data, up->size);
          }
-       }
+      }
    }
 #endif
       png_ptr->mode |= PNG_WROTE_INFO_BEFORE_PLTE;
@@ -145,20 +146,20 @@
 
 #if defined(PNG_WRITE_tRNS_SUPPORTED)
    if (info_ptr->valid & PNG_INFO_tRNS)
-      {
+   {
 #if defined(PNG_WRITE_INVERT_ALPHA_SUPPORTED)
-         /* invert the alpha channel (in tRNS) */
-         if ((png_ptr->transformations & PNG_INVERT_ALPHA) &&
-            info_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
-         {
-            int j;
-            for (j=0; j<(int)info_ptr->num_trans; j++)
-               info_ptr->trans[j] = (png_byte)(255 - info_ptr->trans[j]);
-         }
+      /* Invert the alpha channel (in tRNS) */
+      if ((png_ptr->transformations & PNG_INVERT_ALPHA) &&
+         info_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
+      {
+         int j;
+         for (j=0; j<(int)info_ptr->num_trans; j++)
+            info_ptr->trans[j] = (png_byte)(255 - info_ptr->trans[j]);
+      }
 #endif
       png_write_tRNS(png_ptr, info_ptr->trans, &(info_ptr->trans_values),
          info_ptr->num_trans, info_ptr->color_type);
-      }
+   }
 #endif
 #if defined(PNG_WRITE_bKGD_SUPPORTED)
    if (info_ptr->valid & PNG_INFO_bKGD)
@@ -202,30 +203,33 @@
    if (info_ptr->valid & PNG_INFO_pHYs)
       png_write_pHYs(png_ptr, info_ptr->x_pixels_per_unit,
          info_ptr->y_pixels_per_unit, info_ptr->phys_unit_type);
-#endif
+#endif /* pHYs */
+
 #if defined(PNG_WRITE_tIME_SUPPORTED)
    if (info_ptr->valid & PNG_INFO_tIME)
    {
       png_write_tIME(png_ptr, &(info_ptr->mod_time));
       png_ptr->mode |= PNG_WROTE_tIME;
    }
-#endif
+#endif /* tIME */
+
 #if defined(PNG_WRITE_sPLT_SUPPORTED)
    if (info_ptr->valid & PNG_INFO_sPLT)
      for (i = 0; i < (int)info_ptr->splt_palettes_num; i++)
        png_write_sPLT(png_ptr, info_ptr->splt_palettes + i);
-#endif
+#endif /* sPLT */
+
 #if defined(PNG_WRITE_TEXT_SUPPORTED)
    /* Check to see if we need to write text chunks */
    for (i = 0; i < info_ptr->num_text; i++)
    {
       png_debug2(2, "Writing header text chunk %d, type %d", i,
          info_ptr->text[i].compression);
-      /* an internationalized chunk? */
+      /* An internationalized chunk? */
       if (info_ptr->text[i].compression > 0)
       {
 #if defined(PNG_WRITE_iTXt_SUPPORTED)
-          /* write international chunk */
+          /* Write international chunk */
           png_write_iTXt(png_ptr,
                          info_ptr->text[i].compression,
                          info_ptr->text[i].key,
@@ -242,7 +246,7 @@
       else if (info_ptr->text[i].compression == PNG_TEXT_COMPRESSION_zTXt)
       {
 #if defined(PNG_WRITE_zTXt_SUPPORTED)
-         /* write compressed chunk */
+         /* Write compressed chunk */
          png_write_zTXt(png_ptr, info_ptr->text[i].key,
             info_ptr->text[i].text, 0,
             info_ptr->text[i].compression);
@@ -255,18 +259,20 @@
       else if (info_ptr->text[i].compression == PNG_TEXT_COMPRESSION_NONE)
       {
 #if defined(PNG_WRITE_tEXt_SUPPORTED)
-         /* write uncompressed chunk */
+         /* Write uncompressed chunk */
          png_write_tEXt(png_ptr, info_ptr->text[i].key,
                          info_ptr->text[i].text,
                          0);
-#else
-         png_warning(png_ptr, "Unable to write uncompressed text");
-#endif
          /* Mark this chunk as written */
          info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_NONE_WR;
+#else
+         /* Can't get here */
+         png_warning(png_ptr, "Unable to write uncompressed text");
+#endif
       }
    }
-#endif
+#endif /* tEXt */
+
 #if defined(PNG_WRITE_UNKNOWN_CHUNKS_SUPPORTED)
    if (info_ptr->unknown_chunks_num)
    {
@@ -306,29 +312,29 @@
    if (!(png_ptr->mode & PNG_HAVE_IDAT))
       png_error(png_ptr, "No IDATs written into file");
 
-   /* see if user wants us to write information chunks */
+   /* See if user wants us to write information chunks */
    if (info_ptr != NULL)
    {
 #if defined(PNG_WRITE_TEXT_SUPPORTED)
-      int i; /* local index variable */
+      int i; /* Local index variable */
 #endif
 #if defined(PNG_WRITE_tIME_SUPPORTED)
-      /* check to see if user has supplied a time chunk */
+      /* Check to see if user has supplied a time chunk */
       if ((info_ptr->valid & PNG_INFO_tIME) &&
          !(png_ptr->mode & PNG_WROTE_tIME))
          png_write_tIME(png_ptr, &(info_ptr->mod_time));
 #endif
 #if defined(PNG_WRITE_TEXT_SUPPORTED)
-      /* loop through comment chunks */
+      /* Loop through comment chunks */
       for (i = 0; i < info_ptr->num_text; i++)
       {
          png_debug2(2, "Writing trailer text chunk %d, type %d", i,
             info_ptr->text[i].compression);
-         /* an internationalized chunk? */
+         /* An internationalized chunk? */
          if (info_ptr->text[i].compression > 0)
          {
 #if defined(PNG_WRITE_iTXt_SUPPORTED)
-             /* write international chunk */
+             /* Write international chunk */
              png_write_iTXt(png_ptr,
                          info_ptr->text[i].compression,
                          info_ptr->text[i].key,
@@ -344,7 +350,7 @@
          else if (info_ptr->text[i].compression >= PNG_TEXT_COMPRESSION_zTXt)
          {
 #if defined(PNG_WRITE_zTXt_SUPPORTED)
-            /* write compressed chunk */
+            /* Write compressed chunk */
             png_write_zTXt(png_ptr, info_ptr->text[i].key,
                info_ptr->text[i].text, 0,
                info_ptr->text[i].compression);
@@ -357,7 +363,7 @@
          else if (info_ptr->text[i].compression == PNG_TEXT_COMPRESSION_NONE)
          {
 #if defined(PNG_WRITE_tEXt_SUPPORTED)
-            /* write uncompressed chunk */
+            /* Write uncompressed chunk */
             png_write_tEXt(png_ptr, info_ptr->text[i].key,
                info_ptr->text[i].text, 0);
 #else
@@ -395,7 +401,7 @@
 
    png_ptr->mode |= PNG_AFTER_IDAT;
 
-   /* write end of PNG file */
+   /* Write end of PNG file */
    png_write_IEND(png_ptr);
    /* This flush, added in libpng-1.0.8, removed from libpng-1.0.9beta03,
     * and restored again in libpng-1.2.30, may cause some applications that
@@ -475,7 +481,7 @@
    if (png_ptr == NULL)
       return (NULL);
 
-   /* added at libpng-1.2.6 */
+   /* Added at libpng-1.2.6 */
 #ifdef PNG_SET_USER_LIMITS_SUPPORTED
    png_ptr->user_width_max=PNG_USER_WIDTH_MAX;
    png_ptr->user_height_max=PNG_USER_HEIGHT_MAX;
@@ -546,7 +552,7 @@
      }
    }
 
-   /* initialize zbuf - compression buffer */
+   /* Initialize zbuf - compression buffer */
    png_ptr->zbuf_size = PNG_ZBUF_SIZE;
    png_ptr->zbuf = (png_bytep)png_malloc(png_ptr,
       (png_uint_32)png_ptr->zbuf_size);
@@ -640,7 +646,7 @@
 {
    png_structp png_ptr=*ptr_ptr;
 #ifdef PNG_SETJMP_SUPPORTED
-   jmp_buf tmp_jmp; /* to save current jump buffer */
+   jmp_buf tmp_jmp; /* To save current jump buffer */
 #endif
 
    int i = 0;
@@ -666,7 +672,7 @@
    png_debug(1, "in png_write_init_3");
 
 #ifdef PNG_SETJMP_SUPPORTED
-   /* save jump buffer and error functions */
+   /* Save jump buffer and error functions */
    png_memcpy(tmp_jmp, png_ptr->jmpbuf, png_sizeof(jmp_buf));
 #endif
 
@@ -677,24 +683,24 @@
        *ptr_ptr = png_ptr;
      }
 
-   /* reset all variables to 0 */
+   /* Reset all variables to 0 */
    png_memset(png_ptr, 0, png_sizeof(png_struct));
 
-   /* added at libpng-1.2.6 */
+   /* Added at libpng-1.2.6 */
 #ifdef PNG_SET_USER_LIMITS_SUPPORTED
    png_ptr->user_width_max=PNG_USER_WIDTH_MAX;
    png_ptr->user_height_max=PNG_USER_HEIGHT_MAX;
 #endif
 
 #ifdef PNG_SETJMP_SUPPORTED
-   /* restore jump buffer */
+   /* Restore jump buffer */
    png_memcpy(png_ptr->jmpbuf, tmp_jmp, png_sizeof(jmp_buf));
 #endif
 
    png_set_write_fn(png_ptr, png_voidp_NULL, png_rw_ptr_NULL,
       png_flush_ptr_NULL);
 
-   /* initialize zbuf - compression buffer */
+   /* Initialize zbuf - compression buffer */
    png_ptr->zbuf_size = PNG_ZBUF_SIZE;
    png_ptr->zbuf = (png_bytep)png_malloc(png_ptr,
       (png_uint_32)png_ptr->zbuf_size);
@@ -714,15 +720,15 @@
 png_write_rows(png_structp png_ptr, png_bytepp row,
    png_uint_32 num_rows)
 {
-   png_uint_32 i; /* row counter */
-   png_bytepp rp; /* row pointer */
+   png_uint_32 i; /* Row counter */
+   png_bytepp rp; /* Row pointer */
 
    png_debug(1, "in png_write_rows");
 
    if (png_ptr == NULL)
       return;
 
-   /* loop through the rows */
+   /* Loop through the rows */
    for (i = 0, rp = row; i < num_rows; i++, rp++)
    {
       png_write_row(png_ptr, *rp);
@@ -735,25 +741,26 @@
 void PNGAPI
 png_write_image(png_structp png_ptr, png_bytepp image)
 {
-   png_uint_32 i; /* row index */
-   int pass, num_pass; /* pass variables */
-   png_bytepp rp; /* points to current row */
+   png_uint_32 i; /* Row index */
+   int pass, num_pass; /* Pass variables */
+   png_bytepp rp; /* Points to current row */
 
    if (png_ptr == NULL)
       return;
 
    png_debug(1, "in png_write_image");
 #if defined(PNG_WRITE_INTERLACING_SUPPORTED)
-   /* intialize interlace handling.  If image is not interlaced,
-      this will set pass to 1 */
+   /* Initialize interlace handling.  If image is not interlaced,
+    * this will set pass to 1
+    */
    num_pass = png_set_interlace_handling(png_ptr);
 #else
    num_pass = 1;
 #endif
-   /* loop through passes */
+   /* Loop through passes */
    for (pass = 0; pass < num_pass; pass++)
    {
-      /* loop through image */
+      /* Loop through image */
       for (i = 0, rp = image; i < png_ptr->height; i++, rp++)
       {
          png_write_row(png_ptr, *rp);
@@ -761,7 +768,7 @@
    }
 }
 
-/* called by user to write a row of image data */
+/* Called by user to write a row of image data */
 void PNGAPI
 png_write_row(png_structp png_ptr, png_bytep row)
 {
@@ -770,49 +777,49 @@
    png_debug2(1, "in png_write_row (row %ld, pass %d)",
       png_ptr->row_number, png_ptr->pass);
 
-   /* initialize transformations and other stuff if first time */
+   /* Initialize transformations and other stuff if first time */
    if (png_ptr->row_number == 0 && png_ptr->pass == 0)
    {
-   /* make sure we wrote the header info */
-   if (!(png_ptr->mode & PNG_WROTE_INFO_BEFORE_PLTE))
-      png_error(png_ptr,
-         "png_write_info was never called before png_write_row.");
+      /* Make sure we wrote the header info */
+      if (!(png_ptr->mode & PNG_WROTE_INFO_BEFORE_PLTE))
+         png_error(png_ptr,
+            "png_write_info was never called before png_write_row.");
 
-   /* check for transforms that have been set but were defined out */
+      /* Check for transforms that have been set but were defined out */
 #if !defined(PNG_WRITE_INVERT_SUPPORTED) && defined(PNG_READ_INVERT_SUPPORTED)
-   if (png_ptr->transformations & PNG_INVERT_MONO)
-      png_warning(png_ptr, "PNG_WRITE_INVERT_SUPPORTED is not defined.");
+      if (png_ptr->transformations & PNG_INVERT_MONO)
+         png_warning(png_ptr, "PNG_WRITE_INVERT_SUPPORTED is not defined.");
 #endif
 #if !defined(PNG_WRITE_FILLER_SUPPORTED) && defined(PNG_READ_FILLER_SUPPORTED)
-   if (png_ptr->transformations & PNG_FILLER)
-      png_warning(png_ptr, "PNG_WRITE_FILLER_SUPPORTED is not defined.");
+      if (png_ptr->transformations & PNG_FILLER)
+         png_warning(png_ptr, "PNG_WRITE_FILLER_SUPPORTED is not defined.");
 #endif
 #if !defined(PNG_WRITE_PACKSWAP_SUPPORTED) && defined(PNG_READ_PACKSWAP_SUPPORTED)
-   if (png_ptr->transformations & PNG_PACKSWAP)
-      png_warning(png_ptr, "PNG_WRITE_PACKSWAP_SUPPORTED is not defined.");
+      if (png_ptr->transformations & PNG_PACKSWAP)
+         png_warning(png_ptr, "PNG_WRITE_PACKSWAP_SUPPORTED is not defined.");
 #endif
 #if !defined(PNG_WRITE_PACK_SUPPORTED) && defined(PNG_READ_PACK_SUPPORTED)
-   if (png_ptr->transformations & PNG_PACK)
-      png_warning(png_ptr, "PNG_WRITE_PACK_SUPPORTED is not defined.");
+      if (png_ptr->transformations & PNG_PACK)
+         png_warning(png_ptr, "PNG_WRITE_PACK_SUPPORTED is not defined.");
 #endif
 #if !defined(PNG_WRITE_SHIFT_SUPPORTED) && defined(PNG_READ_SHIFT_SUPPORTED)
-   if (png_ptr->transformations & PNG_SHIFT)
-      png_warning(png_ptr, "PNG_WRITE_SHIFT_SUPPORTED is not defined.");
+      if (png_ptr->transformations & PNG_SHIFT)
+         png_warning(png_ptr, "PNG_WRITE_SHIFT_SUPPORTED is not defined.");
 #endif
 #if !defined(PNG_WRITE_BGR_SUPPORTED) && defined(PNG_READ_BGR_SUPPORTED)
-   if (png_ptr->transformations & PNG_BGR)
-      png_warning(png_ptr, "PNG_WRITE_BGR_SUPPORTED is not defined.");
+      if (png_ptr->transformations & PNG_BGR)
+         png_warning(png_ptr, "PNG_WRITE_BGR_SUPPORTED is not defined.");
 #endif
 #if !defined(PNG_WRITE_SWAP_SUPPORTED) && defined(PNG_READ_SWAP_SUPPORTED)
-   if (png_ptr->transformations & PNG_SWAP_BYTES)
-      png_warning(png_ptr, "PNG_WRITE_SWAP_SUPPORTED is not defined.");
+      if (png_ptr->transformations & PNG_SWAP_BYTES)
+         png_warning(png_ptr, "PNG_WRITE_SWAP_SUPPORTED is not defined.");
 #endif
 
       png_write_start_row(png_ptr);
    }
 
 #if defined(PNG_WRITE_INTERLACING_SUPPORTED)
-   /* if interlaced and not interested in row, return */
+   /* If interlaced and not interested in row, return */
    if (png_ptr->interlaced && (png_ptr->transformations & PNG_INTERLACE))
    {
       switch (png_ptr->pass)
@@ -870,7 +877,7 @@
    }
 #endif
 
-   /* set up row info for transformations */
+   /* Set up row info for transformations */
    png_ptr->row_info.color_type = png_ptr->color_type;
    png_ptr->row_info.width = png_ptr->usr_width;
    png_ptr->row_info.channels = png_ptr->usr_channels;
@@ -893,13 +900,13 @@
       png_ptr->row_info.rowbytes);
 
 #if defined(PNG_WRITE_INTERLACING_SUPPORTED)
-   /* handle interlacing */
+   /* Handle interlacing */
    if (png_ptr->interlaced && png_ptr->pass < 6 &&
       (png_ptr->transformations & PNG_INTERLACE))
    {
       png_do_write_interlace(&(png_ptr->row_info),
          png_ptr->row_buf + 1, png_ptr->pass);
-      /* this should always get caught above, but still ... */
+      /* This should always get caught above, but still ... */
       if (!(png_ptr->row_info.width))
       {
          png_write_finish_row(png_ptr);
@@ -908,7 +915,7 @@
    }
 #endif
 
-   /* handle other transformations */
+   /* Handle other transformations */
    if (png_ptr->transformations)
       png_do_write_transformations(png_ptr);
 
@@ -948,7 +955,7 @@
    png_ptr->flush_dist = (nrows < 0 ? 0 : nrows);
 }
 
-/* flush the current output buffers now */
+/* Flush the current output buffers now */
 void PNGAPI
 png_write_flush(png_structp png_ptr)
 {
@@ -959,17 +966,17 @@
       return;
    /* We have already written out all of the data */
    if (png_ptr->row_number >= png_ptr->num_rows)
-     return;
+      return;
 
    do
    {
       int ret;
 
-      /* compress the data */
+      /* Compress the data */
       ret = deflate(&png_ptr->zstream, Z_SYNC_FLUSH);
       wrote_IDAT = 0;
 
-      /* check for compression errors */
+      /* Check for compression errors */
       if (ret != Z_OK)
       {
          if (png_ptr->zstream.msg != NULL)
@@ -980,7 +987,7 @@
 
       if (!(png_ptr->zstream.avail_out))
       {
-         /* write the IDAT and reset the zlib output buffer */
+         /* Write the IDAT and reset the zlib output buffer */
          png_write_IDAT(png_ptr, png_ptr->zbuf,
                         png_ptr->zbuf_size);
          png_ptr->zstream.next_out = png_ptr->zbuf;
@@ -992,7 +999,7 @@
    /* If there is any data left to be output, write it into a new IDAT */
    if (png_ptr->zbuf_size != png_ptr->zstream.avail_out)
    {
-      /* write the IDAT and reset the zlib output buffer */
+      /* Write the IDAT and reset the zlib output buffer */
       png_write_IDAT(png_ptr, png_ptr->zbuf,
                      png_ptr->zbuf_size - png_ptr->zstream.avail_out);
       png_ptr->zstream.next_out = png_ptr->zbuf;
@@ -1003,7 +1010,7 @@
 }
 #endif /* PNG_WRITE_FLUSH_SUPPORTED */
 
-/* free all memory used by the write */
+/* Free all memory used by the write */
 void PNGAPI
 png_destroy_write_struct(png_structpp png_ptr_ptr, png_infopp info_ptr_ptr)
 {
@@ -1079,7 +1086,7 @@
 png_write_destroy(png_structp png_ptr)
 {
 #ifdef PNG_SETJMP_SUPPORTED
-   jmp_buf tmp_jmp; /* save jump buffer */
+   jmp_buf tmp_jmp; /* Save jump buffer */
 #endif
    png_error_ptr error_fn;
    png_error_ptr warning_fn;
@@ -1089,10 +1096,10 @@
 #endif
 
    png_debug(1, "in png_write_destroy");
-   /* free any memory zlib uses */
+   /* Free any memory zlib uses */
    deflateEnd(&png_ptr->zstream);
 
-   /* free our memory.  png_free checks NULL for us. */
+   /* Free our memory.  png_free checks NULL for us. */
    png_free(png_ptr, png_ptr->zbuf);
    png_free(png_ptr, png_ptr->row_buf);
 #ifndef PNG_NO_WRITE_FILTER
@@ -1116,7 +1123,7 @@
 #endif
 
 #ifdef PNG_SETJMP_SUPPORTED
-   /* reset structure */
+   /* Reset structure */
    png_memcpy(tmp_jmp, png_ptr->jmpbuf, png_sizeof(jmp_buf));
 #endif
 
@@ -1419,7 +1426,7 @@
    else if (window_bits < 8)
       png_warning(png_ptr, "Only compression windows >= 256 supported by PNG");
 #ifndef WBITS_8_OK
-   /* avoid libpng bug with 256-byte windows */
+   /* Avoid libpng bug with 256-byte windows */
    if (window_bits == 8)
      {
        png_warning(png_ptr, "Compression window is being reset to 512");
@@ -1472,9 +1479,9 @@
    if (png_ptr == NULL || info_ptr == NULL)
       return;
 #if defined(PNG_WRITE_INVERT_ALPHA_SUPPORTED)
-   /* invert the alpha channel from opacity to transparency */
+   /* Invert the alpha channel from opacity to transparency */
    if (transforms & PNG_TRANSFORM_INVERT_ALPHA)
-       png_set_invert_alpha(png_ptr);
+      png_set_invert_alpha(png_ptr);
 #endif
 
    /* Write the file header information. */
@@ -1483,9 +1490,9 @@
    /* ------ these transformations don't touch the info structure ------- */
 
 #if defined(PNG_WRITE_INVERT_SUPPORTED)
-   /* invert monochrome pixels */
+   /* Invert monochrome pixels */
    if (transforms & PNG_TRANSFORM_INVERT_MONO)
-       png_set_invert_mono(png_ptr);
+      png_set_invert_mono(png_ptr);
 #endif
 
 #if defined(PNG_WRITE_SHIFT_SUPPORTED)
@@ -1494,57 +1501,57 @@
     */
    if ((transforms & PNG_TRANSFORM_SHIFT)
                && (info_ptr->valid & PNG_INFO_sBIT))
-       png_set_shift(png_ptr, &info_ptr->sig_bit);
+      png_set_shift(png_ptr, &info_ptr->sig_bit);
 #endif
 
 #if defined(PNG_WRITE_PACK_SUPPORTED)
-   /* pack pixels into bytes */
+   /* Pack pixels into bytes */
    if (transforms & PNG_TRANSFORM_PACKING)
        png_set_packing(png_ptr);
 #endif
 
 #if defined(PNG_WRITE_SWAP_ALPHA_SUPPORTED)
-   /* swap location of alpha bytes from ARGB to RGBA */
+   /* Swap location of alpha bytes from ARGB to RGBA */
    if (transforms & PNG_TRANSFORM_SWAP_ALPHA)
-       png_set_swap_alpha(png_ptr);
+      png_set_swap_alpha(png_ptr);
 #endif
 
 #if defined(PNG_WRITE_FILLER_SUPPORTED)
    /* Pack XRGB/RGBX/ARGB/RGBA into * RGB (4 channels -> 3 channels) */
-  if (transforms & PNG_TRANSFORM_STRIP_FILLER_AFTER)
+   if (transforms & PNG_TRANSFORM_STRIP_FILLER_AFTER)
       png_set_filler(png_ptr, 0, PNG_FILLER_AFTER);
-  else if (transforms & PNG_TRANSFORM_STRIP_FILLER_BEFORE)
+   else if (transforms & PNG_TRANSFORM_STRIP_FILLER_BEFORE)
       png_set_filler(png_ptr, 0, PNG_FILLER_BEFORE);
 #endif
 
 #if defined(PNG_WRITE_BGR_SUPPORTED)
-   /* flip BGR pixels to RGB */
+   /* Flip BGR pixels to RGB */
    if (transforms & PNG_TRANSFORM_BGR)
-       png_set_bgr(png_ptr);
+      png_set_bgr(png_ptr);
 #endif
 
 #if defined(PNG_WRITE_SWAP_SUPPORTED)
-   /* swap bytes of 16-bit files to most significant byte first */
+   /* Swap bytes of 16-bit files to most significant byte first */
    if (transforms & PNG_TRANSFORM_SWAP_ENDIAN)
-       png_set_swap(png_ptr);
+      png_set_swap(png_ptr);
 #endif
 
 #if defined(PNG_WRITE_PACKSWAP_SUPPORTED)
-   /* swap bits of 1, 2, 4 bit packed pixel formats */
+   /* Swap bits of 1, 2, 4 bit packed pixel formats */
    if (transforms & PNG_TRANSFORM_PACKSWAP)
-       png_set_packswap(png_ptr);
+      png_set_packswap(png_ptr);
 #endif
 
    /* ----------------------- end of transformations ------------------- */
 
-   /* write the bits */
+   /* Write the bits */
    if (info_ptr->valid & PNG_INFO_IDAT)
        png_write_image(png_ptr, info_ptr->row_pointers);
 
    /* It is REQUIRED to call this to finish writing the rest of the file */
    png_write_end(png_ptr, info_ptr);
 
-   transforms = transforms; /* quiet compiler warnings */
+   transforms = transforms; /* Quiet compiler warnings */
    params = params;
 }
 #endif
diff --git a/pngwtran.c b/pngwtran.c
index 398fc41..70d5f0a 100644
--- a/pngwtran.c
+++ b/pngwtran.c
@@ -1,9 +1,9 @@
 
 /* pngwtran.c - transforms the data in a row for PNG writers
  *
- * Last changed in libpng 1.2.9 April 14, 2006
+ * Last changed in libpng 1.2.37 [May 20, 2009]
  * For conditions of distribution and use, see copyright notice in png.h
- * Copyright (c) 1998-2006 Glenn Randers-Pehrson
+ * Copyright (c) 1998-2009 Glenn Randers-Pehrson
  * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
  * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
  */
@@ -26,7 +26,7 @@
 #if defined(PNG_WRITE_USER_TRANSFORM_SUPPORTED)
    if (png_ptr->transformations & PNG_USER_TRANSFORM)
       if (png_ptr->write_user_transform_fn != NULL)
-        (*(png_ptr->write_user_transform_fn)) /* user write transform function */
+        (*(png_ptr->write_user_transform_fn)) /* User write transform function */
           (png_ptr,                    /* png_ptr */
            &(png_ptr->row_info),       /* row_info:     */
              /*  png_uint_32 width;          width of row */
@@ -248,7 +248,7 @@
          channels++;
       }
 
-      /* with low row depths, could only be grayscale, so one channel */
+      /* With low row depths, could only be grayscale, so one channel */
       if (row_info->bit_depth < 8)
       {
          png_bytep bp = row;
@@ -439,7 +439,7 @@
             png_uint_32 row_width = row_info->width;
             for (i = 0, sp = dp = row; i < row_width; i++)
             {
-               /* does nothing
+               /* Does nothing
                *(dp++) = *(sp++);
                *(dp++) = *(sp++);
                *(dp++) = *(sp++);
@@ -457,7 +457,7 @@
 
             for (i = 0, sp = dp = row; i < row_width; i++)
             {
-               /* does nothing
+               /* Does nothing
                *(dp++) = *(sp++);
                *(dp++) = *(sp++);
                *(dp++) = *(sp++);
@@ -495,7 +495,7 @@
 
             for (i = 0, sp = dp = row; i < row_width; i++)
             {
-               /* does nothing
+               /* Does nothing
                *(dp++) = *(sp++);
                *(dp++) = *(sp++);
                */
@@ -510,7 +510,7 @@
 #endif
 
 #if defined(PNG_MNG_FEATURES_SUPPORTED)
-/* undoes intrapixel differencing  */
+/* Undoes intrapixel differencing  */
 void /* PRIVATE */
 png_do_write_intrapixel(png_row_infop row_info, png_bytep row)
 {
diff --git a/pngwutil.c b/pngwutil.c
index 3f55f57..efc812f 100644
--- a/pngwutil.c
+++ b/pngwutil.c
@@ -1,7 +1,7 @@
 
 /* pngwutil.c - utilities to write a PNG file
  *
- * Last changed in libpng 1.2.36 [May 7, 2009]
+ * Last changed in libpng 1.2.36 [May 20, 2009]
  * For conditions of distribution and use, see copyright notice in png.h
  * Copyright (c) 1998-2009 Glenn Randers-Pehrson
  * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
@@ -60,7 +60,7 @@
 {
    png_byte png_signature[8] = {137, 80, 78, 71, 13, 10, 26, 10};
 
-   /* write the rest of the 8 byte signature */
+   /* Write the rest of the 8 byte signature */
    png_write_data(png_ptr, &png_signature[png_ptr->sig_bytes],
       (png_size_t)(8 - png_ptr->sig_bytes));
    if (png_ptr->sig_bytes < 3)
@@ -80,7 +80,8 @@
 png_write_chunk(png_structp png_ptr, png_bytep chunk_name,
    png_bytep data, png_size_t length)
 {
-   if (png_ptr == NULL) return;
+   if (png_ptr == NULL)
+      return;
    png_write_chunk_start(png_ptr, chunk_name, (png_uint_32)length);
    png_write_chunk_data(png_ptr, data, (png_size_t)length);
    png_write_chunk_end(png_ptr);
@@ -98,15 +99,16 @@
 
    png_debug2(0, "Writing %s chunk, length = %lu", chunk_name,
       (unsigned long)length);
-   if (png_ptr == NULL) return;
+   if (png_ptr == NULL)
+      return;
 
-   /* write the length and the chunk name */
+   /* Write the length and the chunk name */
    png_save_uint_32(buf, length);
    png_memcpy(buf + 4, chunk_name, 4);
    png_write_data(png_ptr, buf, (png_size_t)8);
-   /* put the chunk name into png_ptr->chunk_name */
+   /* Put the chunk name into png_ptr->chunk_name */
    png_memcpy(png_ptr->chunk_name, chunk_name, 4);
-   /* reset the crc and run it over the chunk name */
+   /* Reset the crc and run it over the chunk name */
    png_reset_crc(png_ptr);
    png_calculate_crc(png_ptr, chunk_name, (png_size_t)4);
 }
@@ -119,12 +121,13 @@
 void PNGAPI
 png_write_chunk_data(png_structp png_ptr, png_bytep data, png_size_t length)
 {
-   /* write the data, and run the CRC over it */
-   if (png_ptr == NULL) return;
+   /* Write the data, and run the CRC over it */
+   if (png_ptr == NULL)
+      return;
    if (data != NULL && length > 0)
    {
       png_write_data(png_ptr, data, length);
-      /* update the CRC after writing the data,
+      /* Update the CRC after writing the data,
        * in case that the user I/O routine alters it.
        */
       png_calculate_crc(png_ptr, data, length);
@@ -139,15 +142,14 @@
 
    if (png_ptr == NULL) return;
 
-   /* write the crc in a single operation */
+   /* Write the crc in a single operation */
    png_save_uint_32(buf, png_ptr->crc);
 
    png_write_data(png_ptr, buf, (png_size_t)4);
 }
 
 #if defined(PNG_WRITE_TEXT_SUPPORTED) || defined(PNG_WRITE_iCCP_SUPPORTED)
-/*
- * This pair of functions encapsulates the operation of (a) compressing a
+/* This pair of functions encapsulates the operation of (a) compressing a
  * text string, and (b) issuing it later as a series of chunk data writes.
  * The compression_state structure is shared context for these functions
  * set up by the caller in order to make the whole mess thread-safe.
@@ -155,14 +157,14 @@
 
 typedef struct
 {
-    char *input;   /* the uncompressed input data */
-    int input_len;   /* its length */
-    int num_output_ptr; /* number of output pointers used */
-    int max_output_ptr; /* size of output_ptr */
-    png_charpp output_ptr; /* array of pointers to output */
+   char *input;   /* The uncompressed input data */
+   int input_len;   /* Its length */
+   int num_output_ptr; /* Number of output pointers used */
+   int max_output_ptr; /* Size of output_ptr */
+   png_charpp output_ptr; /* Array of pointers to output */
 } compression_state;
 
-/* compress given text into storage in the png_ptr structure */
+/* Compress given text into storage in the png_ptr structure */
 static int /* PRIVATE */
 png_text_compress(png_structp png_ptr,
         png_charp text, png_size_t text_len, int compression,
@@ -176,7 +178,7 @@
    comp->input = NULL;
    comp->input_len = 0;
 
-   /* we may just want to pass the text right through */
+   /* We may just want to pass the text right through */
    if (compression == PNG_TEXT_COMPRESSION_NONE)
    {
        comp->input = text;
@@ -210,29 +212,29 @@
     * wouldn't cause a failure, just a slowdown due to swapping).
     */
 
-   /* set up the compression buffers */
+   /* Set up the compression buffers */
    png_ptr->zstream.avail_in = (uInt)text_len;
    png_ptr->zstream.next_in = (Bytef *)text;
    png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;
    png_ptr->zstream.next_out = (Bytef *)png_ptr->zbuf;
 
-   /* this is the same compression loop as in png_write_row() */
+   /* This is the same compression loop as in png_write_row() */
    do
    {
-      /* compress the data */
+      /* Compress the data */
       ret = deflate(&png_ptr->zstream, Z_NO_FLUSH);
       if (ret != Z_OK)
       {
-         /* error */
+         /* Error */
          if (png_ptr->zstream.msg != NULL)
             png_error(png_ptr, png_ptr->zstream.msg);
          else
             png_error(png_ptr, "zlib error");
       }
-      /* check to see if we need more room */
+      /* Check to see if we need more room */
       if (!(png_ptr->zstream.avail_out))
       {
-         /* make sure the output array has room */
+         /* Make sure the output array has room */
          if (comp->num_output_ptr >= comp->max_output_ptr)
          {
             int old_max;
@@ -257,7 +259,7 @@
                   (comp->max_output_ptr * png_sizeof(png_charp)));
          }
 
-         /* save the data */
+         /* Save the data */
          comp->output_ptr[comp->num_output_ptr] =
             (png_charp)png_malloc(png_ptr,
             (png_uint_32)png_ptr->zbuf_size);
@@ -269,21 +271,21 @@
          png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;
          png_ptr->zstream.next_out = png_ptr->zbuf;
       }
-   /* continue until we don't have any more to compress */
+   /* Continue until we don't have any more to compress */
    } while (png_ptr->zstream.avail_in);
 
-   /* finish the compression */
+   /* Finish the compression */
    do
    {
-      /* tell zlib we are finished */
+      /* Tell zlib we are finished */
       ret = deflate(&png_ptr->zstream, Z_FINISH);
 
       if (ret == Z_OK)
       {
-         /* check to see if we need more room */
+         /* Check to see if we need more room */
          if (!(png_ptr->zstream.avail_out))
          {
-            /* check to make sure our output array has room */
+            /* Check to make sure our output array has room */
             if (comp->num_output_ptr >= comp->max_output_ptr)
             {
                int old_max;
@@ -309,7 +311,7 @@
                      png_sizeof(png_charp)));
             }
 
-            /* save off the data */
+            /* Save the data */
             comp->output_ptr[comp->num_output_ptr] =
                (png_charp)png_malloc(png_ptr,
                (png_uint_32)png_ptr->zbuf_size);
@@ -324,7 +326,7 @@
       }
       else if (ret != Z_STREAM_END)
       {
-         /* we got an error */
+         /* We got an error */
          if (png_ptr->zstream.msg != NULL)
             png_error(png_ptr, png_ptr->zstream.msg);
          else
@@ -332,7 +334,7 @@
       }
    } while (ret != Z_STREAM_END);
 
-   /* text length is number of buffers plus last buffer */
+   /* Text length is number of buffers plus last buffer */
    text_len = png_ptr->zbuf_size * comp->num_output_ptr;
    if (png_ptr->zstream.avail_out < png_ptr->zbuf_size)
       text_len += png_ptr->zbuf_size - (png_size_t)png_ptr->zstream.avail_out;
@@ -340,21 +342,21 @@
    return((int)text_len);
 }
 
-/* ship the compressed text out via chunk writes */
+/* Ship the compressed text out via chunk writes */
 static void /* PRIVATE */
 png_write_compressed_data_out(png_structp png_ptr, compression_state *comp)
 {
    int i;
 
-   /* handle the no-compression case */
+   /* Handle the no-compression case */
    if (comp->input)
    {
-       png_write_chunk_data(png_ptr, (png_bytep)comp->input,
+      png_write_chunk_data(png_ptr, (png_bytep)comp->input,
                             (png_size_t)comp->input_len);
-       return;
+      return;
    }
 
-   /* write saved output buffers, if any */
+   /* Write saved output buffers, if any */
    for (i = 0; i < comp->num_output_ptr; i++)
    {
       png_write_chunk_data(png_ptr, (png_bytep)comp->output_ptr[i],
@@ -365,12 +367,12 @@
    if (comp->max_output_ptr != 0)
       png_free(png_ptr, comp->output_ptr);
        comp->output_ptr=NULL;
-   /* write anything left in zbuf */
+   /* Write anything left in zbuf */
    if (png_ptr->zstream.avail_out < (png_uint_32)png_ptr->zbuf_size)
       png_write_chunk_data(png_ptr, png_ptr->zbuf,
          (png_size_t)(png_ptr->zbuf_size - png_ptr->zstream.avail_out));
 
-   /* reset zlib for another zTXt/iTXt or image data */
+   /* Reset zlib for another zTXt/iTXt or image data */
    deflateReset(&png_ptr->zstream);
    png_ptr->zstream.data_type = Z_BINARY;
 }
@@ -390,7 +392,7 @@
 #endif
    int ret;
 
-   png_byte buf[13]; /* buffer to store the IHDR info */
+   png_byte buf[13]; /* Buffer to store the IHDR info */
 
    png_debug(1, "in png_write_IHDR");
    /* Check that we have valid input data from the application info */
@@ -476,7 +478,7 @@
    interlace_type=PNG_INTERLACE_NONE;
 #endif
 
-   /* save off the relevent information */
+   /* Save the relevent information */
    png_ptr->bit_depth = (png_byte)bit_depth;
    png_ptr->color_type = (png_byte)color_type;
    png_ptr->interlaced = (png_byte)interlace_type;
@@ -489,12 +491,12 @@
 
    png_ptr->pixel_depth = (png_byte)(bit_depth * png_ptr->channels);
    png_ptr->rowbytes = PNG_ROWBYTES(png_ptr->pixel_depth, width);
-   /* set the usr info, so any transformations can modify it */
+   /* Set the usr info, so any transformations can modify it */
    png_ptr->usr_width = png_ptr->width;
    png_ptr->usr_bit_depth = png_ptr->bit_depth;
    png_ptr->usr_channels = png_ptr->channels;
 
-   /* pack the header information into the buffer */
+   /* Pack the header information into the buffer */
    png_save_uint_32(buf, width);
    png_save_uint_32(buf + 4, height);
    buf[8] = (png_byte)bit_depth;
@@ -503,10 +505,10 @@
    buf[11] = (png_byte)filter_type;
    buf[12] = (png_byte)interlace_type;
 
-   /* write the chunk */
+   /* Write the chunk */
    png_write_chunk(png_ptr, (png_bytep)png_IHDR, buf, (png_size_t)13);
 
-   /* initialize zlib with PNG info */
+   /* Initialize zlib with PNG info */
    png_ptr->zstream.zalloc = png_zalloc;
    png_ptr->zstream.zfree = png_zfree;
    png_ptr->zstream.opaque = (voidpf)png_ptr;
@@ -549,13 +551,13 @@
    png_ptr->zstream.next_out = png_ptr->zbuf;
    png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;
    /* libpng is not interested in zstream.data_type */
-   /* set it to a predefined value, to avoid its evaluation inside zlib */
+   /* Set it to a predefined value, to avoid its evaluation inside zlib */
    png_ptr->zstream.data_type = Z_BINARY;
 
    png_ptr->mode = PNG_HAVE_IHDR;
 }
 
-/* write the palette.  We are careful not to trust png_color to be in the
+/* Write the palette.  We are careful not to trust png_color to be in the
  * correct order for PNG, so people can redefine it to any convenient
  * structure.
  */
@@ -622,7 +624,7 @@
    png_ptr->mode |= PNG_HAVE_PLTE;
 }
 
-/* write an IDAT chunk */
+/* Write an IDAT chunk */
 void /* PRIVATE */
 png_write_IDAT(png_structp png_ptr, png_bytep data, png_size_t length)
 {
@@ -639,9 +641,11 @@
       unsigned int z_cmf = data[0];  /* zlib compression method and flags */
       if ((z_cmf & 0x0f) == 8 && (z_cmf & 0xf0) <= 0x70)
       {
-         /* Avoid memory underflows and multiplication overflows. */
-         /* The conditions below are practically always satisfied;
-            however, they still must be checked. */
+         /* Avoid memory underflows and multiplication overflows.
+          *
+          * The conditions below are practically always satisfied;
+          * however, they still must be checked.
+          */
          if (length >= 2 &&
              png_ptr->height < 16384 && png_ptr->width < 16384)
          {
@@ -674,7 +678,7 @@
    png_ptr->mode |= PNG_HAVE_IDAT;
 }
 
-/* write an IEND chunk */
+/* Write an IEND chunk */
 void /* PRIVATE */
 png_write_IEND(png_structp png_ptr)
 {
@@ -688,7 +692,7 @@
 }
 
 #if defined(PNG_WRITE_gAMA_SUPPORTED)
-/* write a gAMA chunk */
+/* Write a gAMA chunk */
 #ifdef PNG_FLOATING_POINT_SUPPORTED
 void /* PRIVATE */
 png_write_gAMA(png_structp png_ptr, double file_gamma)
@@ -724,7 +728,7 @@
 #endif
 
 #if defined(PNG_WRITE_sRGB_SUPPORTED)
-/* write a sRGB chunk */
+/* Write a sRGB chunk */
 void /* PRIVATE */
 png_write_sRGB(png_structp png_ptr, int srgb_intent)
 {
@@ -743,7 +747,7 @@
 #endif
 
 #if defined(PNG_WRITE_iCCP_SUPPORTED)
-/* write an iCCP chunk */
+/* Write an iCCP chunk */
 void /* PRIVATE */
 png_write_iCCP(png_structp png_ptr, png_charp name, int compression_type,
    png_charp profile, int profile_len)
@@ -800,7 +804,7 @@
       profile_len = png_text_compress(png_ptr, profile,
         (png_size_t)profile_len, PNG_COMPRESSION_TYPE_BASE, &comp);
 
-   /* make sure we include the NULL after the name and the compression type */
+   /* Make sure we include the NULL after the name and the compression type */
    png_write_chunk_start(png_ptr, (png_bytep)png_iCCP,
           (png_uint_32)(name_len + profile_len + 2));
    new_name[name_len + 1] = 0x00;
@@ -816,7 +820,7 @@
 #endif
 
 #if defined(PNG_WRITE_sPLT_SUPPORTED)
-/* write a sPLT chunk */
+/* Write a sPLT chunk */
 void /* PRIVATE */
 png_write_sPLT(png_structp png_ptr, png_sPLT_tp spalette)
 {
@@ -834,18 +838,17 @@
 #endif
 
    png_debug(1, "in png_write_sPLT");
-   if ((name_len = png_check_keyword(png_ptr,
-      spalette->name, &new_name))==0)
-     return;
+   if ((name_len = png_check_keyword(png_ptr,spalette->name, &new_name))==0)
+      return;
 
-   /* make sure we include the NULL after the name */
+   /* Make sure we include the NULL after the name */
    png_write_chunk_start(png_ptr, (png_bytep)png_sPLT,
      (png_uint_32)(name_len + 2 + palette_size));
    png_write_chunk_data(png_ptr, (png_bytep)new_name,
      (png_size_t)(name_len + 1));
    png_write_chunk_data(png_ptr, (png_bytep)&spalette->depth, (png_size_t)1);
 
-   /* loop through each palette entry, writing appropriately */
+   /* Loop through each palette entry, writing appropriately */
 #ifndef PNG_NO_POINTER_INDEXING
    for (ep = spalette->entries; ep<spalette->entries + spalette->nentries; ep++)
    {
@@ -897,7 +900,7 @@
 #endif
 
 #if defined(PNG_WRITE_sBIT_SUPPORTED)
-/* write the sBIT chunk */
+/* Write the sBIT chunk */
 void /* PRIVATE */
 png_write_sBIT(png_structp png_ptr, png_color_8p sbit, int color_type)
 {
@@ -908,7 +911,7 @@
    png_size_t size;
 
    png_debug(1, "in png_write_sBIT");
-   /* make sure we don't depend upon the order of PNG_COLOR_8 */
+   /* Make sure we don't depend upon the order of PNG_COLOR_8 */
    if (color_type & PNG_COLOR_MASK_COLOR)
    {
       png_byte maxbits;
@@ -953,7 +956,7 @@
 #endif
 
 #if defined(PNG_WRITE_cHRM_SUPPORTED)
-/* write the cHRM chunk */
+/* Write the cHRM chunk */
 #ifdef PNG_FLOATING_POINT_SUPPORTED
 void /* PRIVATE */
 png_write_cHRM(png_structp png_ptr, double white_x, double white_y,
@@ -984,21 +987,21 @@
       int_red_x, int_red_y, int_green_x, int_green_y, int_blue_x, int_blue_y))
 #endif
    {
-     /* each value is saved in 1/100,000ths */
-   
-     png_save_uint_32(buf, int_white_x);
-     png_save_uint_32(buf + 4, int_white_y);
+      /* Each value is saved in 1/100,000ths */
+    
+      png_save_uint_32(buf, int_white_x);
+      png_save_uint_32(buf + 4, int_white_y);
 
-     png_save_uint_32(buf + 8, int_red_x);
-     png_save_uint_32(buf + 12, int_red_y);
+      png_save_uint_32(buf + 8, int_red_x);
+      png_save_uint_32(buf + 12, int_red_y);
 
-     png_save_uint_32(buf + 16, int_green_x);
-     png_save_uint_32(buf + 20, int_green_y);
+      png_save_uint_32(buf + 16, int_green_x);
+      png_save_uint_32(buf + 20, int_green_y);
 
-     png_save_uint_32(buf + 24, int_blue_x);
-     png_save_uint_32(buf + 28, int_blue_y);
+      png_save_uint_32(buf + 24, int_blue_x);
+      png_save_uint_32(buf + 28, int_blue_y);
 
-     png_write_chunk(png_ptr, (png_bytep)png_cHRM, buf, (png_size_t)32);
+      png_write_chunk(png_ptr, (png_bytep)png_cHRM, buf, (png_size_t)32);
    }
 }
 #endif
@@ -1015,32 +1018,32 @@
    png_byte buf[32];
 
    png_debug(1, "in png_write_cHRM");
-   /* each value is saved in 1/100,000ths */
+   /* Each value is saved in 1/100,000ths */
 #if !defined(PNG_NO_CHECK_cHRM)
    if (png_check_cHRM_fixed(png_ptr, white_x, white_y, red_x, red_y,
       green_x, green_y, blue_x, blue_y))
 #endif
    {
-   png_save_uint_32(buf, (png_uint_32)white_x);
-   png_save_uint_32(buf + 4, (png_uint_32)white_y);
+      png_save_uint_32(buf, (png_uint_32)white_x);
+      png_save_uint_32(buf + 4, (png_uint_32)white_y);
 
-   png_save_uint_32(buf + 8, (png_uint_32)red_x);
-   png_save_uint_32(buf + 12, (png_uint_32)red_y);
+      png_save_uint_32(buf + 8, (png_uint_32)red_x);
+      png_save_uint_32(buf + 12, (png_uint_32)red_y);
 
-   png_save_uint_32(buf + 16, (png_uint_32)green_x);
-   png_save_uint_32(buf + 20, (png_uint_32)green_y);
+      png_save_uint_32(buf + 16, (png_uint_32)green_x);
+      png_save_uint_32(buf + 20, (png_uint_32)green_y);
 
-   png_save_uint_32(buf + 24, (png_uint_32)blue_x);
-   png_save_uint_32(buf + 28, (png_uint_32)blue_y);
+      png_save_uint_32(buf + 24, (png_uint_32)blue_x);
+      png_save_uint_32(buf + 28, (png_uint_32)blue_y);
 
-   png_write_chunk(png_ptr, (png_bytep)png_cHRM, buf, (png_size_t)32);
+      png_write_chunk(png_ptr, (png_bytep)png_cHRM, buf, (png_size_t)32);
    }
 }
 #endif
 #endif
 
 #if defined(PNG_WRITE_tRNS_SUPPORTED)
-/* write the tRNS chunk */
+/* Write the tRNS chunk */
 void /* PRIVATE */
 png_write_tRNS(png_structp png_ptr, png_bytep trans, png_color_16p tran,
    int num_trans, int color_type)
@@ -1058,13 +1061,13 @@
          png_warning(png_ptr, "Invalid number of transparent colors specified");
          return;
       }
-      /* write the chunk out as it is */
+      /* Write the chunk out as it is */
       png_write_chunk(png_ptr, (png_bytep)png_tRNS, trans,
         (png_size_t)num_trans);
    }
    else if (color_type == PNG_COLOR_TYPE_GRAY)
    {
-      /* one 16 bit value */
+      /* One 16 bit value */
       if (tran->gray >= (1 << png_ptr->bit_depth))
       {
          png_warning(png_ptr,
@@ -1076,7 +1079,7 @@
    }
    else if (color_type == PNG_COLOR_TYPE_RGB)
    {
-      /* three 16 bit values */
+      /* Three 16 bit values */
       png_save_uint_16(buf, tran->red);
       png_save_uint_16(buf + 2, tran->green);
       png_save_uint_16(buf + 4, tran->blue);
@@ -1096,7 +1099,7 @@
 #endif
 
 #if defined(PNG_WRITE_bKGD_SUPPORTED)
-/* write the background chunk */
+/* Write the background chunk */
 void /* PRIVATE */
 png_write_bKGD(png_structp png_ptr, png_color_16p back, int color_type)
 {
@@ -1149,7 +1152,7 @@
 #endif
 
 #if defined(PNG_WRITE_hIST_SUPPORTED)
-/* write the histogram */
+/* Write the histogram */
 void /* PRIVATE */
 png_write_hIST(png_structp png_ptr, png_uint_16p hist, int num_hist)
 {
@@ -1249,8 +1252,8 @@
 
       while (*kp == ' ')
       {
-        *(kp--) = '\0';
-        key_len--;
+         *(kp--) = '\0';
+         key_len--;
       }
    }
 
@@ -1262,8 +1265,8 @@
 
       while (*kp == ' ')
       {
-        kp++;
-        key_len--;
+         kp++;
+         key_len--;
       }
    }
 
@@ -1311,7 +1314,7 @@
 #endif
 
 #if defined(PNG_WRITE_tEXt_SUPPORTED)
-/* write a tEXt chunk */
+/* Write a tEXt chunk */
 void /* PRIVATE */
 png_write_tEXt(png_structp png_ptr, png_charp key, png_charp text,
    png_size_t text_len)
@@ -1331,7 +1334,7 @@
    else
       text_len = png_strlen(text);
 
-   /* make sure we include the 0 after the key */
+   /* Make sure we include the 0 after the key */
    png_write_chunk_start(png_ptr, (png_bytep)png_tEXt,
       (png_uint_32)(key_len + text_len + 1));
    /*
@@ -1351,7 +1354,7 @@
 #endif
 
 #if defined(PNG_WRITE_zTXt_SUPPORTED)
-/* write a compressed text chunk */
+/* Write a compressed text chunk */
 void /* PRIVATE */
 png_write_zTXt(png_structp png_ptr, png_charp key, png_charp text,
    png_size_t text_len, int compression)
@@ -1387,31 +1390,31 @@
 
    text_len = png_strlen(text);
 
-   /* compute the compressed data; do it now for the length */
+   /* Compute the compressed data; do it now for the length */
    text_len = png_text_compress(png_ptr, text, text_len, compression,
        &comp);
 
-   /* write start of chunk */
+   /* Write start of chunk */
    png_write_chunk_start(png_ptr, (png_bytep)png_zTXt,
      (png_uint_32)(key_len+text_len + 2));
-   /* write key */
+   /* Write key */
    png_write_chunk_data(png_ptr, (png_bytep)new_key,
      (png_size_t)(key_len + 1));
    png_free(png_ptr, new_key);
 
    buf[0] = (png_byte)compression;
-   /* write compression */
+   /* Write compression */
    png_write_chunk_data(png_ptr, (png_bytep)buf, (png_size_t)1);
-   /* write the compressed data */
+   /* Write the compressed data */
    png_write_compressed_data_out(png_ptr, &comp);
 
-   /* close the chunk */
+   /* Close the chunk */
    png_write_chunk_end(png_ptr);
 }
 #endif
 
 #if defined(PNG_WRITE_iTXt_SUPPORTED)
-/* write an iTXt chunk */
+/* Write an iTXt chunk */
 void /* PRIVATE */
 png_write_iTXt(png_structp png_ptr, int compression, png_charp key,
     png_charp lang, png_charp lang_key, png_charp text)
@@ -1443,21 +1446,21 @@
    }
 
    if (lang_key == NULL)
-     lang_key_len = 0;
+      lang_key_len = 0;
    else
-     lang_key_len = png_strlen(lang_key);
+      lang_key_len = png_strlen(lang_key);
 
    if (text == NULL)
       text_len = 0;
    else
-     text_len = png_strlen(text);
+      text_len = png_strlen(text);
 
-   /* compute the compressed data; do it now for the length */
+   /* Compute the compressed data; do it now for the length */
    text_len = png_text_compress(png_ptr, text, text_len, compression-2,
       &comp);
 
 
-   /* make sure we include the compression flag, the compression byte,
+   /* Make sure we include the compression flag, the compression byte,
     * and the NULs after the key, lang, and lang_key parts */
 
    png_write_chunk_start(png_ptr, (png_bytep)png_iTXt,
@@ -1468,8 +1471,7 @@
         + lang_key_len
         + text_len));
 
-   /*
-    * We leave it to the application to meet PNG-1.0 requirements on the
+   /* We leave it to the application to meet PNG-1.0 requirements on the
     * contents of the text.  PNG-1.0 through PNG-1.2 discourage the use of
     * any non-Latin-1 characters except for NEWLINE.  ISO PNG will forbid them.
     * The NUL character is forbidden by PNG-1.0 through PNG-1.2 and ISO PNG.
@@ -1477,13 +1479,13 @@
    png_write_chunk_data(png_ptr, (png_bytep)new_key,
      (png_size_t)(key_len + 1));
 
-   /* set the compression flag */
+   /* Set the compression flag */
    if (compression == PNG_ITXT_COMPRESSION_NONE || \
        compression == PNG_TEXT_COMPRESSION_NONE)
        cbuf[0] = 0;
    else /* compression == PNG_ITXT_COMPRESSION_zTXt */
        cbuf[0] = 1;
-   /* set the compression method */
+   /* Set the compression method */
    cbuf[1] = 0;
    png_write_chunk_data(png_ptr, cbuf, (png_size_t)2);
 
@@ -1501,7 +1503,7 @@
 #endif
 
 #if defined(PNG_WRITE_oFFs_SUPPORTED)
-/* write the oFFs chunk */
+/* Write the oFFs chunk */
 void /* PRIVATE */
 png_write_oFFs(png_structp png_ptr, png_int_32 x_offset, png_int_32 y_offset,
    int unit_type)
@@ -1523,7 +1525,7 @@
 }
 #endif
 #if defined(PNG_WRITE_pCAL_SUPPORTED)
-/* write the pCAL chunk (described in the PNG extensions document) */
+/* Write the pCAL chunk (described in the PNG extensions document) */
 void /* PRIVATE */
 png_write_pCAL(png_structp png_ptr, png_charp purpose, png_int_32 X0,
    png_int_32 X1, int type, int nparams, png_charp units, png_charpp params)
@@ -1585,7 +1587,7 @@
 #endif
 
 #if defined(PNG_WRITE_sCAL_SUPPORTED)
-/* write the sCAL chunk */
+/* Write the sCAL chunk */
 #if defined(PNG_FLOATING_POINT_SUPPORTED) && !defined(PNG_NO_STDIO)
 void /* PRIVATE */
 png_write_sCAL(png_structp png_ptr, int unit, double width, double height)
@@ -1648,8 +1650,8 @@
    }
 
    buf[0] = (png_byte)unit;
-   png_memcpy(buf + 1, width, wlen + 1);      /* append the '\0' here */
-   png_memcpy(buf + wlen + 2, height, hlen);  /* do NOT append the '\0' here */
+   png_memcpy(buf + 1, width, wlen + 1);      /* Append the '\0' here */
+   png_memcpy(buf + wlen + 2, height, hlen);  /* Do NOT append the '\0' here */
 
    png_debug1(3, "sCAL total length = %u", (unsigned int)total_len);
    png_write_chunk(png_ptr, (png_bytep)png_sCAL, buf, total_len);
@@ -1659,7 +1661,7 @@
 #endif
 
 #if defined(PNG_WRITE_pHYs_SUPPORTED)
-/* write the pHYs chunk */
+/* Write the pHYs chunk */
 void /* PRIVATE */
 png_write_pHYs(png_structp png_ptr, png_uint_32 x_pixels_per_unit,
    png_uint_32 y_pixels_per_unit,
@@ -1714,24 +1716,24 @@
 }
 #endif
 
-/* initializes the row writing capability of libpng */
+/* Initializes the row writing capability of libpng */
 void /* PRIVATE */
 png_write_start_row(png_structp png_ptr)
 {
 #ifdef PNG_WRITE_INTERLACING_SUPPORTED
 #ifdef PNG_USE_LOCAL_ARRAYS
-   /* arrays to facilitate easy interlacing - use pass (0 - 6) as index */
+   /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */
 
-   /* start of interlace block */
+   /* Start of interlace block */
    int png_pass_start[7] = {0, 4, 0, 2, 0, 1, 0};
 
-   /* offset to next interlace block */
+   /* Offset to next interlace block */
    int png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1};
 
-   /* start of interlace block in the y direction */
+   /* Start of interlace block in the y direction */
    int png_pass_ystart[7] = {0, 0, 4, 0, 2, 0, 1};
 
-   /* offset to next interlace block in the y direction */
+   /* Offset to next interlace block in the y direction */
    int png_pass_yinc[7] = {8, 8, 8, 4, 4, 2, 2};
 #endif
 #endif
@@ -1742,13 +1744,13 @@
    buf_size = (png_size_t)(PNG_ROWBYTES(
       png_ptr->usr_channels*png_ptr->usr_bit_depth, png_ptr->width) + 1);
 
-   /* set up row buffer */
+   /* Set up row buffer */
    png_ptr->row_buf = (png_bytep)png_malloc(png_ptr,
      (png_uint_32)buf_size);
    png_ptr->row_buf[0] = PNG_FILTER_VALUE_NONE;
 
 #ifndef PNG_NO_WRITE_FILTER
-   /* set up filtering buffer, if using this filter */
+   /* Set up filtering buffer, if using this filter */
    if (png_ptr->do_filter & PNG_FILTER_SUB)
    {
       png_ptr->sub_row = (png_bytep)png_malloc(png_ptr,
@@ -1759,7 +1761,7 @@
    /* We only need to keep the previous row if we are using one of these. */
    if (png_ptr->do_filter & (PNG_FILTER_AVG | PNG_FILTER_UP | PNG_FILTER_PAETH))
    {
-     /* set up previous row buffer */
+     /* Set up previous row buffer */
      png_ptr->prev_row = (png_bytep)png_malloc(png_ptr,
         (png_uint_32)buf_size);
      png_memset(png_ptr->prev_row, 0, buf_size);
@@ -1788,7 +1790,7 @@
 #endif /* PNG_NO_WRITE_FILTER */
 
 #ifdef PNG_WRITE_INTERLACING_SUPPORTED
-   /* if interlaced, we need to set up width and height of pass */
+   /* If interlaced, we need to set up width and height of pass */
    if (png_ptr->interlaced)
    {
       if (!(png_ptr->transformations & PNG_INTERLACE))
@@ -1820,18 +1822,18 @@
 {
 #ifdef PNG_WRITE_INTERLACING_SUPPORTED
 #ifdef PNG_USE_LOCAL_ARRAYS
-   /* arrays to facilitate easy interlacing - use pass (0 - 6) as index */
+   /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */
 
-   /* start of interlace block */
+   /* Start of interlace block */
    int png_pass_start[7] = {0, 4, 0, 2, 0, 1, 0};
 
-   /* offset to next interlace block */
+   /* Offset to next interlace block */
    int png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1};
 
-   /* start of interlace block in the y direction */
+   /* Start of interlace block in the y direction */
    int png_pass_ystart[7] = {0, 0, 4, 0, 2, 0, 1};
 
-   /* offset to next interlace block in the y direction */
+   /* Offset to next interlace block in the y direction */
    int png_pass_yinc[7] = {8, 8, 8, 4, 4, 2, 2};
 #endif
 #endif
@@ -1839,15 +1841,15 @@
    int ret;
 
    png_debug(1, "in png_write_finish_row");
-   /* next row */
+   /* Next row */
    png_ptr->row_number++;
 
-   /* see if we are done */
+   /* See if we are done */
    if (png_ptr->row_number < png_ptr->num_rows)
       return;
 
 #ifdef PNG_WRITE_INTERLACING_SUPPORTED
-   /* if interlaced, go to next pass */
+   /* If interlaced, go to next pass */
    if (png_ptr->interlaced)
    {
       png_ptr->row_number = 0;
@@ -1857,7 +1859,7 @@
       }
       else
       {
-         /* loop until we find a non-zero width or height pass */
+         /* Loop until we find a non-zero width or height pass */
          do
          {
             png_ptr->pass++;
@@ -1877,7 +1879,7 @@
 
       }
 
-      /* reset the row above the image for the next pass */
+      /* Reset the row above the image for the next pass */
       if (png_ptr->pass < 7)
       {
          if (png_ptr->prev_row != NULL)
@@ -1889,16 +1891,16 @@
    }
 #endif
 
-   /* if we get here, we've just written the last row, so we need
+   /* If we get here, we've just written the last row, so we need
       to flush the compressor */
    do
    {
-      /* tell the compressor we are done */
+      /* Tell the compressor we are done */
       ret = deflate(&png_ptr->zstream, Z_FINISH);
-      /* check for an error */
+      /* Check for an error */
       if (ret == Z_OK)
       {
-         /* check to see if we need more room */
+         /* Check to see if we need more room */
          if (!(png_ptr->zstream.avail_out))
          {
             png_write_IDAT(png_ptr, png_ptr->zbuf, png_ptr->zbuf_size);
@@ -1915,7 +1917,7 @@
       }
    } while (ret != Z_STREAM_END);
 
-   /* write any extra space */
+   /* Write any extra space */
    if (png_ptr->zstream.avail_out < png_ptr->zbuf_size)
    {
       png_write_IDAT(png_ptr, png_ptr->zbuf, png_ptr->zbuf_size -
@@ -1938,24 +1940,24 @@
 png_do_write_interlace(png_row_infop row_info, png_bytep row, int pass)
 {
 #ifdef PNG_USE_LOCAL_ARRAYS
-   /* arrays to facilitate easy interlacing - use pass (0 - 6) as index */
+   /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */
 
-   /* start of interlace block */
+   /* Start of interlace block */
    int png_pass_start[7] = {0, 4, 0, 2, 0, 1, 0};
 
-   /* offset to next interlace block */
+   /* Offset to next interlace block */
    int png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1};
 #endif
 
    png_debug(1, "in png_do_write_interlace");
-   /* we don't have to do anything on the last pass (6) */
+   /* We don't have to do anything on the last pass (6) */
 #if defined(PNG_USELESS_TESTS_SUPPORTED)
    if (row != NULL && row_info != NULL && pass < 6)
 #else
    if (pass < 6)
 #endif
    {
-      /* each pixel depth is handled separately */
+      /* Each pixel depth is handled separately */
       switch (row_info->pixel_depth)
       {
          case 1:
@@ -2066,27 +2068,27 @@
             png_uint_32 row_width = row_info->width;
             png_size_t pixel_bytes;
 
-            /* start at the beginning */
+            /* Start at the beginning */
             dp = row;
-            /* find out how many bytes each pixel takes up */
+            /* Find out how many bytes each pixel takes up */
             pixel_bytes = (row_info->pixel_depth >> 3);
-            /* loop through the row, only looking at the pixels that
+            /* Loop through the row, only looking at the pixels that
                matter */
             for (i = png_pass_start[pass]; i < row_width;
                i += png_pass_inc[pass])
             {
-               /* find out where the original pixel is */
+               /* Find out where the original pixel is */
                sp = row + (png_size_t)i * pixel_bytes;
-               /* move the pixel */
+               /* Move the pixel */
                if (dp != sp)
                   png_memcpy(dp, sp, pixel_bytes);
-               /* next pixel */
+               /* Next pixel */
                dp += pixel_bytes;
             }
             break;
          }
       }
-      /* set new row width */
+      /* Set new row width */
       row_info->width = (row_info->width +
          png_pass_inc[pass] - 1 -
          png_pass_start[pass]) /
@@ -2119,7 +2121,7 @@
 #endif
 
    png_debug(1, "in png_write_find_filter");
-   /* find out how many bytes offset each pixel is */
+   /* Find out how many bytes offset each pixel is */
    bpp = (row_info->pixel_depth + 7) >> 3;
 
    prev_row = png_ptr->prev_row;
@@ -2206,9 +2208,9 @@
       mins = sum;
    }
 
-   /* sub filter */
+   /* Sub filter */
    if (filter_to_do == PNG_FILTER_SUB)
-   /* it's the only filter so no testing is needed */
+   /* It's the only filter so no testing is needed */
    {
       png_bytep rp, lp, dp;
       png_uint_32 i;
@@ -2323,7 +2325,7 @@
       }
    }
 
-   /* up filter */
+   /* Up filter */
    if (filter_to_do == PNG_FILTER_UP)
    {
       png_bytep rp, dp, pp;
@@ -2426,7 +2428,7 @@
       }
    }
 
-   /* avg filter */
+   /* Avg filter */
    if (filter_to_do == PNG_FILTER_AVG)
    {
       png_bytep rp, dp, pp, lp;
@@ -2729,18 +2731,18 @@
 {
    png_debug(1, "in png_write_filtered_row");
    png_debug1(2, "filter = %d", filtered_row[0]);
-   /* set up the zlib input buffer */
+   /* Set up the zlib input buffer */
 
    png_ptr->zstream.next_in = filtered_row;
    png_ptr->zstream.avail_in = (uInt)png_ptr->row_info.rowbytes + 1;
-   /* repeat until we have compressed all the data */
+   /* Repeat until we have compressed all the data */
    do
    {
-      int ret; /* return of zlib */
+      int ret; /* Return of zlib */
 
-      /* compress the data */
+      /* Compress the data */
       ret = deflate(&png_ptr->zstream, Z_NO_FLUSH);
-      /* check for compression errors */
+      /* Check for compression errors */
       if (ret != Z_OK)
       {
          if (png_ptr->zstream.msg != NULL)
@@ -2749,18 +2751,18 @@
             png_error(png_ptr, "zlib error");
       }
 
-      /* see if it is time to write another IDAT */
+      /* See if it is time to write another IDAT */
       if (!(png_ptr->zstream.avail_out))
       {
-         /* write the IDAT and reset the zlib output buffer */
+         /* Write the IDAT and reset the zlib output buffer */
          png_write_IDAT(png_ptr, png_ptr->zbuf, png_ptr->zbuf_size);
          png_ptr->zstream.next_out = png_ptr->zbuf;
          png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;
       }
-   /* repeat until all data has been compressed */
+   /* Repeat until all data has been compressed */
    } while (png_ptr->zstream.avail_in);
 
-   /* swap the current and previous rows */
+   /* Swap the current and previous rows */
    if (png_ptr->prev_row != NULL)
    {
       png_bytep tptr;
@@ -2770,7 +2772,7 @@
       png_ptr->row_buf = tptr;
    }
 
-   /* finish row - updates counters and flushes zlib if last row */
+   /* Finish row - updates counters and flushes zlib if last row */
    png_write_finish_row(png_ptr);
 
 #if defined(PNG_WRITE_FLUSH_SUPPORTED)
diff --git a/scripts/CMakeLists.txt b/scripts/CMakeLists.txt
index 8967001..26433d3 100644
--- a/scripts/CMakeLists.txt
+++ b/scripts/CMakeLists.txt
@@ -169,7 +169,7 @@
 
 # SET UP LINKS
 set_target_properties(${PNG_LIB_NAME} PROPERTIES
-#    VERSION 0.${PNGLIB_RELEASE}.1.2.37rc01
+#    VERSION 0.${PNGLIB_RELEASE}.1.2.37beta03
      VERSION 0.${PNGLIB_RELEASE}.0
      SOVERSION 0
      CLEAN_DIRECT_OUTPUT 1)
diff --git a/scripts/libpng-config-head.in b/scripts/libpng-config-head.in
index 0a7569f..18eaf70 100755
--- a/scripts/libpng-config-head.in
+++ b/scripts/libpng-config-head.in
@@ -8,7 +8,7 @@
 
 # Modeled after libxml-config.
 
-version=1.2.37rc01
+version=1.2.37beta03
 prefix=""
 libdir=""
 libs=""
diff --git a/scripts/libpng.pc.in b/scripts/libpng.pc.in
index b7f0783..38e6cbc 100644
--- a/scripts/libpng.pc.in
+++ b/scripts/libpng.pc.in
@@ -5,6 +5,6 @@
 
 Name: libpng
 Description: Loads and saves PNG files
-Version: 1.2.37rc01
+Version: 1.2.37beta03
 Libs: -L${libdir} -lpng12
 Cflags: -I${includedir}
diff --git a/scripts/makefile.32sunu b/scripts/makefile.32sunu
index 5e467fa..1cd0931 100644
--- a/scripts/makefile.32sunu
+++ b/scripts/makefile.32sunu
@@ -8,7 +8,7 @@
 # Library name:
 LIBNAME=libpng12
 PNGMAJ = 0
-PNGMIN = 1.2.37rc01
+PNGMIN = 1.2.37beta03
 PNGVER = $(PNGMAJ).$(PNGMIN)
 
 # Shared library names:
diff --git a/scripts/makefile.64sunu b/scripts/makefile.64sunu
index f217619..91393cd 100644
--- a/scripts/makefile.64sunu
+++ b/scripts/makefile.64sunu
@@ -8,7 +8,7 @@
 # Library name:
 LIBNAME=libpng12
 PNGMAJ = 0
-PNGMIN = 1.2.37rc01
+PNGMIN = 1.2.37beta03
 PNGVER = $(PNGMAJ).$(PNGMIN)
 
 # Shared library names:
diff --git a/scripts/makefile.aix b/scripts/makefile.aix
index f6a342c..b42080c 100644
--- a/scripts/makefile.aix
+++ b/scripts/makefile.aix
@@ -20,7 +20,7 @@
 
 LIBNAME=libpng12
 PNGMAJ = 0
-PNGMIN = 1.2.37rc01
+PNGMIN = 1.2.37beta03
 PNGVER = $(PNGMAJ).$(PNGMIN)
 
 prefix=/usr/local
diff --git a/scripts/makefile.beos b/scripts/makefile.beos
index 2c066e4..d98eaeb 100644
--- a/scripts/makefile.beos
+++ b/scripts/makefile.beos
@@ -8,7 +8,7 @@
 # Library name:
 LIBNAME=libpng12
 PNGMAJ = 0
-PNGMIN = 1.2.37rc01
+PNGMIN = 1.2.37beta03
 PNGVER = $(PNGMAJ).$(PNGMIN)
 
 # Shared library names:
diff --git a/scripts/makefile.cygwin b/scripts/makefile.cygwin
index 7d48ac2..b1eb46f 100644
--- a/scripts/makefile.cygwin
+++ b/scripts/makefile.cygwin
@@ -74,7 +74,7 @@
 LIBNAME = libpng12
 PNGMAJ = 0
 CYGDLL = 12
-PNGMIN = 1.2.37rc01
+PNGMIN = 1.2.37beta03
 PNGVER = $(PNGMAJ).$(PNGMIN)
 
 SHAREDLIB=cygpng$(CYGDLL).dll
diff --git a/scripts/makefile.darwin b/scripts/makefile.darwin
index 064fe36..b32a972 100644
--- a/scripts/makefile.darwin
+++ b/scripts/makefile.darwin
@@ -19,7 +19,7 @@
 # Library name:
 LIBNAME = libpng12
 PNGMAJ = 12
-PNGMIN = 1.2.37rc01
+PNGMIN = 1.2.37beta03
 PNGVER = $(PNGMAJ).$(PNGMIN)
 
 # Shared library names:
diff --git a/scripts/makefile.dec b/scripts/makefile.dec
index 133add7..326178a 100644
--- a/scripts/makefile.dec
+++ b/scripts/makefile.dec
@@ -5,7 +5,7 @@
 
 # Library name:
 PNGMAJ = 0
-PNGMIN = 1.2.37rc01
+PNGMIN = 1.2.37beta03
 PNGVER = $(PNGMAJ).$(PNGMIN)
 LIBNAME = libpng12
 
diff --git a/scripts/makefile.elf b/scripts/makefile.elf
index ecd3631..5106e33 100644
--- a/scripts/makefile.elf
+++ b/scripts/makefile.elf
@@ -13,7 +13,7 @@
 # Library name:
 LIBNAME = libpng12
 PNGMAJ = 0
-PNGMIN = 1.2.37rc01
+PNGMIN = 1.2.37beta03
 PNGVER = $(PNGMAJ).$(PNGMIN)
 
 # Shared library names:
diff --git a/scripts/makefile.gcmmx b/scripts/makefile.gcmmx
index a1c6135..0f0e108 100644
--- a/scripts/makefile.gcmmx
+++ b/scripts/makefile.gcmmx
@@ -14,7 +14,7 @@
 # Library name:
 LIBNAME = libpng12
 PNGMAJ = 0
-PNGMIN = 1.2.37rc01
+PNGMIN = 1.2.37beta03
 PNGVER = $(PNGMAJ).$(PNGMIN)
 
 # Shared library names:
diff --git a/scripts/makefile.hp64 b/scripts/makefile.hp64
index 56f56d8..f38a9fe 100644
--- a/scripts/makefile.hp64
+++ b/scripts/makefile.hp64
@@ -18,7 +18,7 @@
 # Library name:
 LIBNAME = libpng12
 PNGMAJ = 0
-PNGMIN = 1.2.37rc01
+PNGMIN = 1.2.37beta03
 PNGVER = $(PNGMAJ).$(PNGMIN)
 
 # Shared library names:
diff --git a/scripts/makefile.hpgcc b/scripts/makefile.hpgcc
index cfb0416..42b0c9d 100644
--- a/scripts/makefile.hpgcc
+++ b/scripts/makefile.hpgcc
@@ -8,7 +8,7 @@
 # Library name:
 LIBNAME = libpng12
 PNGMAJ = 0
-PNGMIN = 1.2.37rc01
+PNGMIN = 1.2.37beta03
 PNGVER = $(PNGMAJ).$(PNGMIN)
 
 # Shared library names:
diff --git a/scripts/makefile.hpux b/scripts/makefile.hpux
index 705be7f..a1b2382 100644
--- a/scripts/makefile.hpux
+++ b/scripts/makefile.hpux
@@ -18,7 +18,7 @@
 # Library name:
 LIBNAME = libpng12
 PNGMAJ = 0
-PNGMIN = 1.2.37rc01
+PNGMIN = 1.2.37beta03
 PNGVER = $(PNGMAJ).$(PNGMIN)
 
 # Shared library names:
diff --git a/scripts/makefile.linux b/scripts/makefile.linux
index 28b4890..8ed3115 100644
--- a/scripts/makefile.linux
+++ b/scripts/makefile.linux
@@ -7,7 +7,7 @@
 # Library name:
 LIBNAME = libpng12
 PNGMAJ = 0
-PNGMIN = 1.2.37rc01
+PNGMIN = 1.2.37beta03
 PNGVER = $(PNGMAJ).$(PNGMIN)
 
 # Shared library names:
diff --git a/scripts/makefile.mingw b/scripts/makefile.mingw
index 2961be9..ff39b1a 100644
--- a/scripts/makefile.mingw
+++ b/scripts/makefile.mingw
@@ -74,7 +74,7 @@
 LIBNAME = libpng12
 PNGMAJ = 0
 MINGDLL = 12
-PNGMIN = 1.2.37rc01
+PNGMIN = 1.2.37beta03
 PNGVER = $(PNGMAJ).$(PNGMIN)
 
 SHAREDLIB=libpng$(MINGDLL).dll
diff --git a/scripts/makefile.ne12bsd b/scripts/makefile.ne12bsd
index d6fb7fd..10571aa 100644
--- a/scripts/makefile.ne12bsd
+++ b/scripts/makefile.ne12bsd
@@ -14,7 +14,7 @@
 
 LIB=	png12
 SHLIB_MAJOR=	0
-SHLIB_MINOR=	1.2.37rc01
+SHLIB_MINOR=	1.2.37beta03
 SRCS=	png.c pngset.c pngget.c pngrutil.c pngtrans.c pngwutil.c \
 	pngread.c pngrio.c pngwio.c pngwrite.c pngrtran.c \
 	pngwtran.c pngmem.c pngerror.c pngpread.c
diff --git a/scripts/makefile.netbsd b/scripts/makefile.netbsd
index a59b42f..0e87498 100644
--- a/scripts/makefile.netbsd
+++ b/scripts/makefile.netbsd
@@ -14,7 +14,7 @@
 
 LIB=	png
 SHLIB_MAJOR=	3
-SHLIB_MINOR=	1.2.37rc01
+SHLIB_MINOR=	1.2.37beta03
 SRCS=	png.c pngset.c pngget.c pngrutil.c pngtrans.c pngwutil.c \
 	pngread.c pngrio.c pngwio.c pngwrite.c pngrtran.c \
 	pngwtran.c pngmem.c pngerror.c pngpread.c
diff --git a/scripts/makefile.nommx b/scripts/makefile.nommx
index a787f4d..2ea3157 100644
--- a/scripts/makefile.nommx
+++ b/scripts/makefile.nommx
@@ -7,7 +7,7 @@
 # Library name:
 LIBNAME = libpng12
 PNGMAJ = 0
-PNGMIN = 1.2.37rc01
+PNGMIN = 1.2.37beta03
 PNGVER = $(PNGMAJ).$(PNGMIN)
 
 # Shared library names:
diff --git a/scripts/makefile.openbsd b/scripts/makefile.openbsd
index 28ca3ec..0a6ce06 100644
--- a/scripts/makefile.openbsd
+++ b/scripts/makefile.openbsd
@@ -8,7 +8,7 @@
 MANDIR= ${PREFIX}/man/cat
 
 SHLIB_MAJOR=	0
-SHLIB_MINOR=	1.2.37rc01
+SHLIB_MINOR=	1.2.37beta03
 
 LIB=	png
 SRCS=	png.c pngerror.c pngget.c pngmem.c pngpread.c \
diff --git a/scripts/makefile.sco b/scripts/makefile.sco
index 03b18db..d29ed5a 100644
--- a/scripts/makefile.sco
+++ b/scripts/makefile.sco
@@ -9,7 +9,7 @@
 # Library name:
 LIBNAME = libpng12
 PNGMAJ = 0
-PNGMIN = 1.2.37rc01
+PNGMIN = 1.2.37beta03
 PNGVER = $(PNGMAJ).$(PNGMIN)
 
 # Shared library names:
diff --git a/scripts/makefile.sggcc b/scripts/makefile.sggcc
index 60b4f3b..b9da566 100644
--- a/scripts/makefile.sggcc
+++ b/scripts/makefile.sggcc
@@ -6,7 +6,7 @@
 # Library name:
 LIBNAME=libpng12
 PNGMAJ = 0
-PNGMIN = 1.2.37rc01
+PNGMIN = 1.2.37beta03
 PNGVER = $(PNGMAJ).$(PNGMIN)
 
 # Shared library names:
diff --git a/scripts/makefile.sgi b/scripts/makefile.sgi
index f2db6c8..198a264 100644
--- a/scripts/makefile.sgi
+++ b/scripts/makefile.sgi
@@ -6,7 +6,7 @@
 # Library name:
 LIBNAME=libpng12
 PNGMAJ = 0
-PNGMIN = 1.2.37rc01
+PNGMIN = 1.2.37beta03
 PNGVER = $(PNGMAJ).$(PNGMIN)
 
 # Shared library names:
diff --git a/scripts/makefile.so9 b/scripts/makefile.so9
index 6ce3844..6d4b92f 100644
--- a/scripts/makefile.so9
+++ b/scripts/makefile.so9
@@ -8,7 +8,7 @@
 
 # Library name:
 PNGMAJ = 0
-PNGMIN = 1.2.37rc01
+PNGMIN = 1.2.37beta03
 PNGVER = $(PNGMAJ).$(PNGMIN)
 LIBNAME = libpng12
 
diff --git a/scripts/makefile.solaris b/scripts/makefile.solaris
index 0d244a4..f34380e 100644
--- a/scripts/makefile.solaris
+++ b/scripts/makefile.solaris
@@ -8,7 +8,7 @@
 # Library name:
 LIBNAME = libpng12
 PNGMAJ = 0
-PNGMIN = 1.2.37rc01
+PNGMIN = 1.2.37beta03
 PNGVER = $(PNGMAJ).$(PNGMIN)
 
 # Shared library names:
diff --git a/scripts/makefile.solaris-x86 b/scripts/makefile.solaris-x86
index 6ef7d4d..0b9dcd3 100644
--- a/scripts/makefile.solaris-x86
+++ b/scripts/makefile.solaris-x86
@@ -8,7 +8,7 @@
 # Library name:
 LIBNAME = libpng12
 PNGMAJ = 0
-PNGMIN = 1.2.37rc01
+PNGMIN = 1.2.37beta03
 PNGVER = $(PNGMAJ).$(PNGMIN)
 
 # Shared library names:
diff --git a/scripts/pngos2.def b/scripts/pngos2.def
index f5c818e..6f4bb33 100644
--- a/scripts/pngos2.def
+++ b/scripts/pngos2.def
@@ -2,7 +2,7 @@
 ; PNG.LIB module definition file for OS/2
 ;----------------------------------------
 
-; Version 1.2.37rc01
+; Version 1.2.37beta03
 
 LIBRARY		PNG
 DESCRIPTION	"PNG image compression library for OS/2"
diff --git a/scripts/pngw32.def b/scripts/pngw32.def
index b3484d9..a5f434f 100644
--- a/scripts/pngw32.def
+++ b/scripts/pngw32.def
@@ -5,7 +5,7 @@
 LIBRARY
 
 EXPORTS
-;Version 1.2.37rc01
+;Version 1.2.37beta03
   png_build_grayscale_palette  @1
   png_check_sig        @2
   png_chunk_error      @3