[devel] Updated commentary about the png_rgb_to_gray() default coefficients
diff --git a/ANNOUNCE b/ANNOUNCE
index 9b7e532..23a5afa 100644
--- a/ANNOUNCE
+++ b/ANNOUNCE
@@ -1,5 +1,5 @@
-Libpng 1.5.5beta04 - July 28, 2011
+Libpng 1.5.5beta04 - July 29, 2011
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.
@@ -40,8 +40,10 @@
changes to pngrutil.c to cast results where C++ expects it but C does not.
Minor editing of libpng.3 and libpng-manual.txt.
-Version 1.5.5beta04 [July 28, 2011]
+Version 1.5.5beta04 [July 29, 2011]
Revised CMakeLists.txt (Clifford Yapp)
+ Updated commentary about the png_rgb_to_gray() default coefficients
+ in the manual and in pngrtran.c
Send comments/corrections/commendations to png-mng-implement at lists.sf.net:
(subscription required; visit
diff --git a/CHANGES b/CHANGES
index b8fcfaa..a95d2da 100644
--- a/CHANGES
+++ b/CHANGES
@@ -3524,8 +3524,10 @@
changes to pngrutil.c to cast results where C++ expects it but C does not.
Minor editing of libpng.3 and libpng-manual.txt.
-Version 1.5.5beta04 [July 28, 2011]
+Version 1.5.5beta04 [July 29, 2011]
Revised CMakeLists.txt (Clifford Yapp)
+ Updated commentary about the png_rgb_to_gray() default coefficients
+ in the manual and in pngrtran.c
Send comments/corrections/commendations to png-mng-implement at lists.sf.net
(subscription required; visit
diff --git a/libpng-manual.txt b/libpng-manual.txt
index ced192d..fa04e66 100644
--- a/libpng-manual.txt
+++ b/libpng-manual.txt
@@ -1,6 +1,6 @@
libpng-manual.txt - A description on how to use and modify libpng
- libpng version 1.5.5beta04 - July 28, 2011
+ libpng version 1.5.5beta04 - July 29, 2011
Updated and distributed by Glenn Randers-Pehrson
<glennrp at users.sourceforge.net>
Copyright (c) 1998-2011 Glenn Randers-Pehrson
@@ -11,7 +11,7 @@
Based on:
- libpng versions 0.97, January 1998, through 1.5.5beta04 - July 28, 2011
+ libpng versions 0.97, January 1998, through 1.5.5beta04 - July 29, 2011
Updated and distributed by Glenn Randers-Pehrson
Copyright (c) 1998-2011 Glenn Randers-Pehrson
@@ -1677,8 +1677,17 @@
<http://www.poynton.com/notes/colour_and_gamma/ColorFAQ.html#RTFToC9>
+ Y = 0.2126 * R + 0.7152 * G + 0.0722 * B
+
+Previous versions of this document, 1998 through 2002, recommended a slightly
+different formula:
+
Y = 0.212671 * R + 0.715160 * G + 0.072169 * B
+Libpng uses an integer approximation:
+
+ Y = (6968 * R + 23434 * G + 2366 * B)/32768
+
The calculation is done in a linear colorspace, if the image gamma
can be determined.
@@ -4500,7 +4509,7 @@
XIV. Y2K Compliance in libpng
-July 28, 2011
+July 29, 2011
Since the PNG Development group is an ad-hoc body, we can't make
an official declaration.
diff --git a/libpng.3 b/libpng.3
index 9ebc328..5aecce8 100644
--- a/libpng.3
+++ b/libpng.3
@@ -1,4 +1,4 @@
-.TH LIBPNG 3 "July 28, 2011"
+.TH LIBPNG 3 "July 29, 2011"
.SH NAME
libpng \- Portable Network Graphics (PNG) Reference Library 1.5.5beta04
.SH SYNOPSIS
@@ -955,7 +955,7 @@
.SH LIBPNG.TXT
libpng-manual.txt - A description on how to use and modify libpng
- libpng version 1.5.5beta04 - July 28, 2011
+ libpng version 1.5.5beta04 - July 29, 2011
Updated and distributed by Glenn Randers-Pehrson
<glennrp at users.sourceforge.net>
Copyright (c) 1998-2011 Glenn Randers-Pehrson
@@ -966,7 +966,7 @@
Based on:
- libpng versions 0.97, January 1998, through 1.5.5beta04 - July 28, 2011
+ libpng versions 0.97, January 1998, through 1.5.5beta04 - July 29, 2011
Updated and distributed by Glenn Randers-Pehrson
Copyright (c) 1998-2011 Glenn Randers-Pehrson
@@ -2632,8 +2632,17 @@
<http://www.poynton.com/notes/colour_and_gamma/ColorFAQ.html#RTFToC9>
+ Y = 0.2126 * R + 0.7152 * G + 0.0722 * B
+
+Previous versions of this document, 1998 through 2002, recommended a slightly
+different formula:
+
Y = 0.212671 * R + 0.715160 * G + 0.072169 * B
+Libpng uses an integer approximation:
+
+ Y = (6968 * R + 23434 * G + 2366 * B)/32768
+
The calculation is done in a linear colorspace, if the image gamma
can be determined.
@@ -5456,7 +5465,7 @@
.SH XIV. Y2K Compliance in libpng
-July 28, 2011
+July 29, 2011
Since the PNG Development group is an ad-hoc body, we can't make
an official declaration.
@@ -5715,7 +5724,7 @@
Thanks to Frank J. T. Wojcik for helping with the documentation.
-Libpng version 1.5.5beta04 - July 28, 2011:
+Libpng version 1.5.5beta04 - July 29, 2011:
Initially created in 1995 by Guy Eric Schalnat, then of Group 42, Inc.
Currently maintained by Glenn Randers-Pehrson (glennrp at users.sourceforge.net).
@@ -5738,7 +5747,7 @@
This code is released under the libpng license.
-libpng versions 1.2.6, August 15, 2004, through 1.5.5beta04, July 28, 2011, are
+libpng versions 1.2.6, August 15, 2004, through 1.5.5beta04, July 29, 2011, are
Copyright (c) 2004,2006-2007 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
@@ -5837,7 +5846,7 @@
Glenn Randers-Pehrson
glennrp at users.sourceforge.net
-July 28, 2011
+July 29, 2011
.\" end of man page
