refactor: Delete conditional compilation for libpng 1.6.0 or earlier
This is a cherry-pick of commit 5ff29c03bbe19992dcfe173a8db8528b4317ae4b
from branch 'libpng18'
diff --git a/contrib/libtests/pngimage.c b/contrib/libtests/pngimage.c
index 2e2dd08..af7cf56 100644
--- a/contrib/libtests/pngimage.c
+++ b/contrib/libtests/pngimage.c
@@ -1,6 +1,6 @@
/* pngimage.c
*
- * Copyright (c) 2021 Cosmin Truta
+ * Copyright (c) 2021-2025 Cosmin Truta
* Copyright (c) 2015,2016 John Cunningham Bowler
*
* This code is released under the libpng license.
@@ -39,7 +39,7 @@
/* 1.6.1 added support for the configure test harness, which uses 77 to indicate
* a skipped test, in earlier versions we need to succeed on a skipped test, so:
*/
-#if PNG_LIBPNG_VER >= 10601 && defined(HAVE_CONFIG_H)
+#if defined(HAVE_CONFIG_H)
# define SKIP 77
#else
# define SKIP 0
diff --git a/contrib/libtests/pngstest.c b/contrib/libtests/pngstest.c
index efdcdbf..ccdeab5 100644
--- a/contrib/libtests/pngstest.c
+++ b/contrib/libtests/pngstest.c
@@ -1,6 +1,6 @@
/* pngstest.c
*
- * Copyright (c) 2021 Cosmin Truta
+ * Copyright (c) 2021-2025 Cosmin Truta
* Copyright (c) 2013-2017 John Cunningham Bowler
*
* This code is released under the libpng license.
@@ -37,7 +37,7 @@
/* 1.6.1 added support for the configure test harness, which uses 77 to indicate
* a skipped test, in earlier versions we need to succeed on a skipped test, so:
*/
-#if PNG_LIBPNG_VER >= 10601 && defined(HAVE_CONFIG_H)
+#if defined(HAVE_CONFIG_H)
# define SKIP 77
#else
# define SKIP 0
diff --git a/contrib/libtests/pngunknown.c b/contrib/libtests/pngunknown.c
index 47a84d9..c39203f 100644
--- a/contrib/libtests/pngunknown.c
+++ b/contrib/libtests/pngunknown.c
@@ -1,6 +1,6 @@
/* pngunknown.c - test the read side unknown chunk handling
*
- * Copyright (c) 2021 Cosmin Truta
+ * Copyright (c) 2021-2025 Cosmin Truta
* Copyright (c) 2015,2017 Glenn Randers-Pehrson
* Written by John Cunningham Bowler
*
@@ -32,7 +32,7 @@
/* 1.6.1 added support for the configure test harness, which uses 77 to indicate
* a skipped test, in earlier versions we need to succeed on a skipped test, so:
*/
-#if PNG_LIBPNG_VER >= 10601 && defined(HAVE_CONFIG_H)
+#if defined(HAVE_CONFIG_H)
# define SKIP 77
#else
# define SKIP 0
@@ -54,48 +54,7 @@
#if defined(PNG_READ_USER_CHUNKS_SUPPORTED) ||\
defined(PNG_SAVE_UNKNOWN_CHUNKS_SUPPORTED)
-#if PNG_LIBPNG_VER < 10500
-/* This deliberately lacks the const. */
-typedef png_byte *png_const_bytep;
-/* This is copied from 1.5.1 png.h: */
-#define PNG_INTERLACE_ADAM7_PASSES 7
-#define PNG_PASS_START_ROW(pass) (((1U&~(pass))<<(3-((pass)>>1)))&7)
-#define PNG_PASS_START_COL(pass) (((1U& (pass))<<(3-(((pass)+1)>>1)))&7)
-#define PNG_PASS_ROW_SHIFT(pass) ((pass)>2?(8-(pass))>>1:3)
-#define PNG_PASS_COL_SHIFT(pass) ((pass)>1?(7-(pass))>>1:3)
-#define PNG_PASS_ROWS(height, pass) (((height)+(((1<<PNG_PASS_ROW_SHIFT(pass))\
- -1)-PNG_PASS_START_ROW(pass)))>>PNG_PASS_ROW_SHIFT(pass))
-#define PNG_PASS_COLS(width, pass) (((width)+(((1<<PNG_PASS_COL_SHIFT(pass))\
- -1)-PNG_PASS_START_COL(pass)))>>PNG_PASS_COL_SHIFT(pass))
-#define PNG_ROW_FROM_PASS_ROW(yIn, pass) \
- (((yIn)<<PNG_PASS_ROW_SHIFT(pass))+PNG_PASS_START_ROW(pass))
-#define PNG_COL_FROM_PASS_COL(xIn, pass) \
- (((xIn)<<PNG_PASS_COL_SHIFT(pass))+PNG_PASS_START_COL(pass))
-#define PNG_PASS_MASK(pass,off) ( \
- ((0x110145AFU>>(((7-(off))-(pass))<<2)) & 0xFU) | \
- ((0x01145AF0U>>(((7-(off))-(pass))<<2)) & 0xF0U))
-#define PNG_ROW_IN_INTERLACE_PASS(y, pass) \
- ((PNG_PASS_MASK(pass,0) >> ((y)&7)) & 1)
-#define PNG_COL_IN_INTERLACE_PASS(x, pass) \
- ((PNG_PASS_MASK(pass,1) >> ((x)&7)) & 1)
-
-/* These are needed too for the default build: */
-#define PNG_WRITE_16BIT_SUPPORTED
-#define PNG_READ_16BIT_SUPPORTED
-
-/* This comes from pnglibconf.h after 1.5: */
-#define PNG_FP_1 100000
-#define PNG_GAMMA_THRESHOLD_FIXED\
- ((png_fixed_point)(PNG_GAMMA_THRESHOLD * PNG_FP_1))
-#endif
-
-#if PNG_LIBPNG_VER < 10600
- /* 1.6.0 constifies many APIs. The following exists to allow pngvalid to be
- * compiled against earlier versions.
- */
-# define png_const_structp png_structp
-#endif
#if PNG_LIBPNG_VER < 10700
/* Copied from libpng 1.7.0 png.h */
diff --git a/contrib/libtests/pngvalid.c b/contrib/libtests/pngvalid.c
index bddf321..64de171 100644
--- a/contrib/libtests/pngvalid.c
+++ b/contrib/libtests/pngvalid.c
@@ -1,6 +1,6 @@
/* pngvalid.c - validate libpng by constructing then reading png files.
*
- * Copyright (c) 2021 Cosmin Truta
+ * Copyright (c) 2021-2025 Cosmin Truta
* Copyright (c) 2014-2017 John Cunningham Bowler
*
* This code is released under the libpng license.
@@ -62,7 +62,7 @@
/* 1.6.1 added support for the configure test harness, which uses 77 to indicate
* a skipped test, in earlier versions we need to succeed on a skipped test, so:
*/
-#if PNG_LIBPNG_VER >= 10601 && defined(HAVE_CONFIG_H)
+#if defined(HAVE_CONFIG_H)
# define SKIP 77
#else
# define SKIP 0
@@ -76,48 +76,7 @@
(defined PNG_PROGRESSIVE_READ_SUPPORTED) &&\
(defined PNG_FIXED_POINT_SUPPORTED || defined PNG_FLOATING_POINT_SUPPORTED)
-#if PNG_LIBPNG_VER < 10500
-/* This deliberately lacks the const. */
-typedef png_byte *png_const_bytep;
-/* This is copied from 1.5.1 png.h: */
-#define PNG_INTERLACE_ADAM7_PASSES 7
-#define PNG_PASS_START_ROW(pass) (((1U&~(pass))<<(3-((pass)>>1)))&7)
-#define PNG_PASS_START_COL(pass) (((1U& (pass))<<(3-(((pass)+1)>>1)))&7)
-#define PNG_PASS_ROW_SHIFT(pass) ((pass)>2?(8-(pass))>>1:3)
-#define PNG_PASS_COL_SHIFT(pass) ((pass)>1?(7-(pass))>>1:3)
-#define PNG_PASS_ROWS(height, pass) (((height)+(((1<<PNG_PASS_ROW_SHIFT(pass))\
- -1)-PNG_PASS_START_ROW(pass)))>>PNG_PASS_ROW_SHIFT(pass))
-#define PNG_PASS_COLS(width, pass) (((width)+(((1<<PNG_PASS_COL_SHIFT(pass))\
- -1)-PNG_PASS_START_COL(pass)))>>PNG_PASS_COL_SHIFT(pass))
-#define PNG_ROW_FROM_PASS_ROW(yIn, pass) \
- (((yIn)<<PNG_PASS_ROW_SHIFT(pass))+PNG_PASS_START_ROW(pass))
-#define PNG_COL_FROM_PASS_COL(xIn, pass) \
- (((xIn)<<PNG_PASS_COL_SHIFT(pass))+PNG_PASS_START_COL(pass))
-#define PNG_PASS_MASK(pass,off) ( \
- ((0x110145AFU>>(((7-(off))-(pass))<<2)) & 0xFU) | \
- ((0x01145AF0U>>(((7-(off))-(pass))<<2)) & 0xF0U))
-#define PNG_ROW_IN_INTERLACE_PASS(y, pass) \
- ((PNG_PASS_MASK(pass,0) >> ((y)&7)) & 1)
-#define PNG_COL_IN_INTERLACE_PASS(x, pass) \
- ((PNG_PASS_MASK(pass,1) >> ((x)&7)) & 1)
-
-/* These are needed too for the default build: */
-#define PNG_WRITE_16BIT_SUPPORTED
-#define PNG_READ_16BIT_SUPPORTED
-
-/* This comes from pnglibconf.h after 1.5: */
-#define PNG_FP_1 100000
-#define PNG_GAMMA_THRESHOLD_FIXED\
- ((png_fixed_point)(PNG_GAMMA_THRESHOLD * PNG_FP_1))
-#endif
-
-#if PNG_LIBPNG_VER < 10600
- /* 1.6.0 constifies many APIs, the following exists to allow pngvalid to be
- * compiled against earlier versions.
- */
-# define png_const_structp png_structp
-#endif
#ifndef RELEASE_BUILD
/* RELEASE_BUILD is true for releases and release candidates: */
@@ -647,34 +606,8 @@
static int
pixel_cmp(png_const_bytep pa, png_const_bytep pb, png_uint_32 bit_width)
{
-#if PNG_LIBPNG_VER < 10506
- if (memcmp(pa, pb, bit_width>>3) == 0)
- {
- png_uint_32 p;
-
- if ((bit_width & 7) == 0) return 0;
-
- /* Ok, any differences? */
- p = pa[bit_width >> 3];
- p ^= pb[bit_width >> 3];
-
- if (p == 0) return 0;
-
- /* There are, but they may not be significant, remove the bits
- * after the end (the low order bits in PNG.)
- */
- bit_width &= 7;
- p >>= 8-bit_width;
-
- if (p == 0) return 0;
- }
-#else
- /* From libpng-1.5.6 the overwrite should be fixed, so compare the trailing
- * bits too:
- */
if (memcmp(pa, pb, (bit_width+7)>>3) == 0)
return 0;
-#endif
/* Return the index of the changed byte. */
{
@@ -4851,9 +4784,7 @@
{
png_const_charp correct = "29 Aug 2079 13:53:60 +0000";
png_const_charp result;
-# if PNG_LIBPNG_VER >= 10600
- char timestring[29];
-# endif
+ char timestring[29];
png_structp pp;
png_time pt;
@@ -7484,22 +7415,7 @@
* 'scale' API (above) must be used.
*/
# ifdef PNG_READ_ACCURATE_SCALE_SUPPORTED
-# if PNG_LIBPNG_VER >= 10504
-# error PNG_READ_ACCURATE_SCALE should not be set
-# endif
-
- /* The strip 16 algorithm drops the low 8 bits rather than calculating
- * 1/257, so we need to adjust the permitted errors appropriately:
- * Notice that this is only relevant prior to the addition of the
- * png_set_scale_16 API in 1.5.4 (but 1.5.4+ always defines the above!)
- */
- {
- const double d = (255-128.5)/65535;
- that->rede += d;
- that->greene += d;
- that->bluee += d;
- that->alphae += d;
- }
+# error PNG_READ_ACCURATE_SCALE should not be set
# endif
}
@@ -9932,47 +9848,6 @@
* (chop) method of scaling was used.
*/
# ifndef PNG_READ_16_TO_8_ACCURATE_SCALE_SUPPORTED
-# if PNG_LIBPNG_VER < 10504
- /* This may be required for other components in the future,
- * but at present the presence of gamma correction effectively
- * prevents the errors in the component scaling (I don't quite
- * understand why, but since it's better this way I care not
- * to ask, JB 20110419.)
- */
- if (pass == 0 && alpha < 0 && vi->scale16 && vi->sbit > 8 &&
- vi->sbit + vi->isbit_shift == 16)
- {
- tmp = ((id >> 8) - .5)/255;
-
- if (tmp > 0)
- {
- is_lo = ceil(outmax * tmp - vi->maxout_total);
- if (is_lo < 0) is_lo = 0;
- }
-
- else
- is_lo = 0;
-
- tmp = ((id >> 8) + .5)/255;
-
- if (tmp < 1)
- {
- is_hi = floor(outmax * tmp + vi->maxout_total);
- if (is_hi > outmax) is_hi = outmax;
- }
-
- else
- is_hi = outmax;
-
- if (!(od < is_lo || od > is_hi))
- {
- if (encoded_error < vi->outlog)
- return i;
-
- pass = "within 8 bit limits:\n";
- }
- }
-# endif
# endif
}
else /* !use_input_precision */
@@ -11755,9 +11630,9 @@
# ifdef PNG_WRITE_tRNS_SUPPORTED
pm.test_tRNS = 1;
# endif
- pm.test_lbg = PNG_LIBPNG_VER >= 10600;
+ pm.test_lbg = 1; /* PNG_LIBPNG_VER >= 10600 */
pm.test_lbg_gamma_threshold = 1;
- pm.test_lbg_gamma_transform = PNG_LIBPNG_VER >= 10600;
+ pm.test_lbg_gamma_transform = 1; /* PNG_LIBPNG_VER >= 10600 */
pm.test_lbg_gamma_sbit = 1;
pm.test_lbg_gamma_composition = PNG_LIBPNG_VER == 10700;
@@ -12213,7 +12088,7 @@
(pm.this.nerrors || (pm.this.treat_warnings_as_errors &&
pm.this.nwarnings)) ? "FAIL" : "PASS",
command,
-#if defined(PNG_FLOATING_ARITHMETIC_SUPPORTED) || PNG_LIBPNG_VER < 10500
+#if defined(PNG_FLOATING_ARITHMETIC_SUPPORTED)
"floating"
#else
"fixed"
diff --git a/libpng-manual.txt b/libpng-manual.txt
index 6c07e10..b390b79 100644
--- a/libpng-manual.txt
+++ b/libpng-manual.txt
@@ -3355,19 +3355,6 @@
/* Needed because miNE is not safe-to-copy */
png_set_keep_unknown_chunks(png, PNG_HANDLE_CHUNK_ALWAYS,
(png_bytep) "miNE", 1);
- # if PNG_LIBPNG_VER < 10600
- /* Deal with unknown chunk location bug in 1.5.x and earlier */
- png_set_unknown_chunk_location(png, info, 0, PNG_HAVE_IHDR);
- png_set_unknown_chunk_location(png, info, 1, PNG_AFTER_IDAT);
- # endif
- # if PNG_LIBPNG_VER < 10500
- /* PNG_AFTER_IDAT writes two copies of the chunk prior to libpng-1.5.0,
- * one before IDAT and another after IDAT, so don't use it; only use
- * PNG_HAVE_IHDR location. This call resets the location previously
- * set by assignment and png_set_unknown_chunk_location() for chunk 1.
- */
- png_set_unknown_chunk_location(png, info, 1, PNG_HAVE_IHDR);
- # endif
#endif
The high-level write interface
diff --git a/libpng.3 b/libpng.3
index 8980a25..2ee8fbc 100644
--- a/libpng.3
+++ b/libpng.3
@@ -1,6 +1,6 @@
-.TH LIBPNG 3 "July 1, 2025"
+.TH LIBPNG 3 "September 3, 2025"
.SH NAME
-libpng \- Portable Network Graphics (PNG) Reference Library 1.6.50
+libpng \- Portable Network Graphics (PNG) Reference Library 1.6.51.git
.SH SYNOPSIS
\fB#include <png.h>\fP
@@ -3874,19 +3874,6 @@
/* Needed because miNE is not safe-to-copy */
png_set_keep_unknown_chunks(png, PNG_HANDLE_CHUNK_ALWAYS,
(png_bytep) "miNE", 1);
- # if PNG_LIBPNG_VER < 10600
- /* Deal with unknown chunk location bug in 1.5.x and earlier */
- png_set_unknown_chunk_location(png, info, 0, PNG_HAVE_IHDR);
- png_set_unknown_chunk_location(png, info, 1, PNG_AFTER_IDAT);
- # endif
- # if PNG_LIBPNG_VER < 10500
- /* PNG_AFTER_IDAT writes two copies of the chunk prior to libpng-1.5.0,
- * one before IDAT and another after IDAT, so don't use it; only use
- * PNG_HAVE_IHDR location. This call resets the location previously
- * set by assignment and png_set_unknown_chunk_location() for chunk 1.
- */
- png_set_unknown_chunk_location(png, info, 1, PNG_HAVE_IHDR);
- # endif
#endif
.SS The high-level write interface
