From 6c98897a64d5fd4357dd7aa3e1b9bb8a30f2a942 Mon Sep 17 00:00:00 2001 From: Glenn Randers-Pehrson Date: Fri, 29 Jul 2011 12:31:16 -0500 Subject: [PATCH] [devel] Updated commentary about the png_rgb_to_gray() default coefficients --- ANNOUNCE | 6 ++++-- CHANGES | 4 +++- libpng-manual.txt | 15 ++++++++++++--- libpng.3 | 23 ++++++++++++++++------- 4 files changed, 35 insertions(+), 13 deletions(-) diff --git a/ANNOUNCE b/ANNOUNCE index 9b7e532eb..23a5afafe 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 @@ Version 1.5.5beta03 [July 27, 2011] 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 b8fcfaad5..a95d2da52 100644 --- a/CHANGES +++ b/CHANGES @@ -3524,8 +3524,10 @@ Version 1.5.5beta03 [July 27, 2011] 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 ced192d4e..fa04e66fb 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 Copyright (c) 1998-2011 Glenn Randers-Pehrson @@ -11,7 +11,7 @@ libpng-manual.txt - A description on how to use and modify libpng 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 @@ space, as recommended in the Charles Poynton's Colour FAQ, + 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 @@ Other rules can be inferred by inspecting the libpng source. 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 9ebc328fd..5aecce807 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 @@ Following is a copy of the libpng-manual.txt file that accompanies libpng. .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 Copyright (c) 1998-2011 Glenn Randers-Pehrson @@ -966,7 +966,7 @@ libpng-manual.txt - A description on how to use and modify libpng 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 @@ space, as recommended in the Charles Poynton's Colour FAQ, + 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 @@ Other rules can be inferred by inspecting the libpng source. .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 @@ possible without all of you. 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 sentence. 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 @@ certification mark of the Open Source Initiative. Glenn Randers-Pehrson glennrp at users.sourceforge.net -July 28, 2011 +July 29, 2011 .\" end of man page