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[libpng17] Merge recent changes to the manual and pngrutil.c from libpng-1.6.14beta04.

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Glenn Randers-Pehrson
2014-09-27 18:49:42 -05:00
parent 34e49ae1bc
commit 2799bf9a4f
4 changed files with 106 additions and 58 deletions
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47
libpng-manual.txt
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@@ -1,6 +1,6 @@
libpng-manual.txt - A description on how to use and modify libpng
libpng version 1.7.0beta36 - August 6, 2014
libpng version 1.7.0beta36 - September 27, 2014
Updated and distributed by Glenn Randers-Pehrson
<glennrp at users.sourceforge.net>
Copyright (c) 1998-2014 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 1.7.0beta36 - August 6, 2014
libpng versions 0.97, January 1998, through 1.7.0beta36 - September 27, 2014
Updated and distributed by Glenn Randers-Pehrson
Copyright (c) 1998-2014 Glenn Randers-Pehrson
@@ -5036,11 +5036,27 @@ Error detection in some chunks has improved; in particular the iCCP chunk
reader now does pretty complete validation of the basic format. Some bad
profiles that were previously accepted are now accepted with a warning or
rejected, depending upon the png_set_benign_errors() setting, in particular the
very old broken Microsoft/HP 3144-byte sRGB profile. The PNG spec requirement
that only grayscale profiles may appear in images with color type 0 or 4 and
that even if the image only contains gray pixels, only RGB profiles may appear
in images with color type 2, 3, or 6, is now enforced. The sRGB chunk
is allowed to appear in images with any color type.
very old broken Microsoft/HP 3144-byte sRGB profile. Starting with
libpng-1.6.11, recognizing and checking sRGB profiles can be avoided by
means of
#if defined(PNG_SKIP_sRGB_CHECK_PROFILE) && \
defined(PNG_SET_OPTION_SUPPORTED)
png_set_option(png_ptr, PNG_SKIP_sRGB_CHECK_PROFILE,
PNG_OPTION_ON);
#endif
It's not a good idea to do this if you are using the "simplified API",
which needs to be able to recognize an sRGB profile conveyed via the iCCP
chunk.
The PNG spec requirement that only grayscale profiles may appear in images
with color type 0 or 4 and that even if the image only contains gray pixels,
only RGB profiles may appear in images with color type 2, 3, or 6, is now
enforced. The sRGB chunk is allowed to appear in images with any color type
and is interpreted by libpng to convey a one-tracer-curve gray profile or a
three-tracer-curve RGB profile as appropriate.
Prior to libpng-1.6.0 a warning would be issued if the iTXt chunk contained
an empty language field or an empty translated keyword. Both of these
@@ -5239,12 +5255,15 @@ We mark all non-exported functions with "/* PRIVATE */"":
}
The prototypes for non-exported functions (except for those in
pngtest) appear in
pngpriv.h
above the comment that says
pngtest) appear in pngpriv.h above the comment that says
/* Maintainer: Put new private prototypes here ^ */
To avoid polluting the global namespace, the names of all exported
functions and variables begin with "png_", and all publicly visible C
preprocessor macros begin with "PNG". We request that applications that
use libpng *not* begin any of their own symbols with either of these strings.
We put a space after the "sizeof" operator and we omit the
optional parentheses around its argument when the argument
is an expression, not a type name, and we always enclose the
@@ -5256,10 +5275,8 @@ sizeof operator, with its argument, in parentheses:
Prior to libpng-1.6.0 we used a "png_sizeof()" macro, formatted as
though it were a function.
To avoid polluting the global namespace, the names of all exported
functions and variables begin with "png_", and all publicly visible C
preprocessor macros begin with "PNG". We request that applications that
use libpng *not* begin any of their own symbols with either of these strings.
Control keywords if, for, while, and switch are always followed by a space
to distinguish them from function calls, which have no trailing space.
We put a space after each comma and after each semicolon
in "for" statements, and we put spaces before and after each
@@ -5292,7 +5309,7 @@ Other rules can be inferred by inspecting the libpng source.
XVII. Y2K Compliance in libpng
August 6, 2014
September 27, 2014
Since the PNG Development group is an ad-hoc body, we can't make
an official declaration.