From 6098807252551c64e459e05638665827ff15b314 Mon Sep 17 00:00:00 2001 From: Glenn Randers-Pehrson Date: Tue, 13 Apr 2010 22:11:06 -0500 Subject: [PATCH] [devel] Document the fact that png_set_dither() is no longer supported. --- example.c | 4 +++- libpng-1.5.0beta17.txt | 13 +++++++++---- libpng.3 | 21 +++++++++++++-------- pngrtran.c | 2 +- 4 files changed, 26 insertions(+), 14 deletions(-) diff --git a/example.c b/example.c index 092a09f95..76d323f24 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 1.5.0 [April 1, 2010] + * Last changed in libpng 1.5.0 [April 14, 2010] * This file has been placed in the public domain by the authors. * Maintained 1998-2010 Glenn Randers-Pehrson * Maintained 1996, 1997 Andreas Dilger) @@ -271,6 +271,7 @@ void read_png(FILE *fp, unsigned int sig_read) /* File is already open */ png_set_gamma(png_ptr, screen_gamma, 0.45455); } +#ifdef PNG_READ_DITHER_SUPPORTED /* Dither RGB files down to 8 bit palette or reduce palettes * to the number of colors available on your screen. */ @@ -299,6 +300,7 @@ void read_png(FILE *fp, unsigned int sig_read) /* File is already open */ max_screen_colors, histogram, 0); } } +#endif /* PNG_READ_DITHER_SUPPORTED */ /* Invert monochrome files to have 0 as white and 1 as black */ png_set_invert_mono(png_ptr); diff --git a/libpng-1.5.0beta17.txt b/libpng-1.5.0beta17.txt index 7850b8afb..7963d8d25 100644 --- a/libpng-1.5.0beta17.txt +++ b/libpng-1.5.0beta17.txt @@ -1,6 +1,6 @@ libpng.txt - A description on how to use and modify libpng - libpng version 1.5.0beta17 - April 2, 2010 + libpng version 1.5.0beta17 - April 14, 2010 Updated and distributed by Glenn Randers-Pehrson Copyright (c) 1998-2009 Glenn Randers-Pehrson @@ -11,7 +11,7 @@ libpng.txt - A description on how to use and modify libpng Based on: - libpng versions 0.97, January 1998, through 1.5.0beta17 - April 2, 2010 + libpng versions 0.97, January 1998, through 1.5.0beta17 - April 14, 2010 Updated and distributed by Glenn Randers-Pehrson Copyright (c) 1998-2009 Glenn Randers-Pehrson @@ -2563,7 +2563,7 @@ Errors handled through png_error() are fatal, meaning that png_error() should never return to its caller. Currently, this is handled via setjmp() and longjmp() (unless you have compiled libpng with PNG_NO_SETJMP, in which case it is handled via PNG_ABORT()), -but you could change this to do things like exit() if you should wish. +but you could change this to do things like exit() if you should wish, as long as your function does not return. On non-fatal errors, png_warning() is called @@ -3118,6 +3118,11 @@ The png_zalloc() and png_zfree() functions are no longer exported. The png_zalloc() function no longer zeroes out the memory that it allocates. +Support for dithering was removed by default, because it has never +been well tested and doesn't work very well. The code has not +been removed, however, and can be enabled by building libpng with +PNG_READ_DITHER_SUPPORTED defined. + We removed the trailing '.' from the warning and error messages. X. Detecting libpng @@ -3258,7 +3263,7 @@ Other rules can be inferred by inspecting the libpng source. XIII. Y2K Compliance in libpng -April 2, 2010 +April 14, 2010 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 d37baddcc..36cf6258d 100644 --- a/libpng.3 +++ b/libpng.3 @@ -1,4 +1,4 @@ -.TH LIBPNG 3 "April 2, 2010" +.TH LIBPNG 3 "April 14, 2010" .SH NAME libpng \- Portable Network Graphics (PNG) Reference Library 1.5.0beta17 .SH SYNOPSIS @@ -789,7 +789,7 @@ Following is a copy of the libpng.txt file that accompanies libpng. .SH LIBPNG.TXT libpng.txt - A description on how to use and modify libpng - libpng version 1.5.0beta17 - April 2, 2010 + libpng version 1.5.0beta17 - April 14, 2010 Updated and distributed by Glenn Randers-Pehrson Copyright (c) 1998-2009 Glenn Randers-Pehrson @@ -800,7 +800,7 @@ libpng.txt - A description on how to use and modify libpng Based on: - libpng versions 0.97, January 1998, through 1.5.0beta17 - April 2, 2010 + libpng versions 0.97, January 1998, through 1.5.0beta17 - April 14, 2010 Updated and distributed by Glenn Randers-Pehrson Copyright (c) 1998-2009 Glenn Randers-Pehrson @@ -3352,7 +3352,7 @@ Errors handled through png_error() are fatal, meaning that png_error() should never return to its caller. Currently, this is handled via setjmp() and longjmp() (unless you have compiled libpng with PNG_NO_SETJMP, in which case it is handled via PNG_ABORT()), -but you could change this to do things like exit() if you should wish. +but you could change this to do things like exit() if you should wish, as long as your function does not return. On non-fatal errors, png_warning() is called @@ -3907,6 +3907,11 @@ The png_zalloc() and png_zfree() functions are no longer exported. The png_zalloc() function no longer zeroes out the memory that it allocates. +Support for dithering was removed by default, because it has never +been well tested and doesn't work very well. The code has not +been removed, however, and can be enabled by building libpng with +PNG_READ_DITHER_SUPPORTED defined. + We removed the trailing '.' from the warning and error messages. .SH X. Detecting libpng @@ -4047,7 +4052,7 @@ Other rules can be inferred by inspecting the libpng source. .SH XIII. Y2K Compliance in libpng -April 2, 2010 +April 14, 2010 Since the PNG Development group is an ad-hoc body, we can't make an official declaration. @@ -4287,7 +4292,7 @@ possible without all of you. Thanks to Frank J. T. Wojcik for helping with the documentation. -Libpng version 1.5.0beta17 - April 2, 2010: +Libpng version 1.5.0beta17 - April 14, 2010: Initially created in 1995 by Guy Eric Schalnat, then of Group 42, Inc. Currently maintained by Glenn Randers-Pehrson (glennrp at users.sourceforge.net). @@ -4310,7 +4315,7 @@ this sentence. This code is released under the libpng license. -libpng versions 1.2.6, August 15, 2004, through 1.5.0beta17, April 2, 2010, are +libpng versions 1.2.6, August 15, 2004, through 1.5.0beta17, April 14, 2010, 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 @@ -4409,7 +4414,7 @@ certification mark of the Open Source Initiative. Glenn Randers-Pehrson glennrp at users.sourceforge.net -April 2, 2010 +April 14, 2010 .\" end of man page diff --git a/pngrtran.c b/pngrtran.c index 38e158490..813394797 100644 --- a/pngrtran.c +++ b/pngrtran.c @@ -535,7 +535,7 @@ png_set_dither(png_structp png_ptr, png_colorp palette, png_free(png_ptr, distance); } } -#endif +#endif /* PNG_READ_DITHER_SUPPORTED */ #if defined(PNG_READ_GAMMA_SUPPORTED) && defined(PNG_FLOATING_POINT_SUPPORTED) /* Transform the image from the file_gamma to the screen_gamma. We