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[master] Trivial revision of documentation.

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Glenn Randers-Pehrson 2010-04-16 10:04:53 -05:00
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37
libpng-1.4.2rc02.txt
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@ -1,6 +1,6 @@
libpng.txt - A description on how to use and modify libpng libpng.txt - A description on how to use and modify libpng
libpng version 1.4.2rc02 - April 16, 2010 libpng version 1.4.2rc03 - April 16, 2010
Updated and distributed by Glenn Randers-Pehrson Updated and distributed by Glenn Randers-Pehrson
<glennrp at users.sourceforge.net> <glennrp at users.sourceforge.net>
Copyright (c) 1998-2009 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: Based on:
libpng versions 0.97, January 1998, through 1.4.2rc02 - April 16, 2010 libpng versions 0.97, January 1998, through 1.4.2rc03 - April 16, 2010
Updated and distributed by Glenn Randers-Pehrson Updated and distributed by Glenn Randers-Pehrson
Copyright (c) 1998-2009 Glenn Randers-Pehrson Copyright (c) 1998-2009 Glenn Randers-Pehrson
@ -241,9 +241,13 @@ free any memory.
} }
If you would rather avoid the complexity of setjmp/longjmp issues, If you would rather avoid the complexity of setjmp/longjmp issues,
you can compile libpng with PNG_SETJMP_NOT_SUPPORTED, in which case you can compile libpng with PNG_NO_SETJMP, in which case
errors will result in a call to PNG_ABORT() which defaults to abort(). errors will result in a call to PNG_ABORT() which defaults to abort().
You can #define PNG_ABORT() to a function that does something
more useful than abort(), as long as your function does not
return.
Now you need to set up the input code. The default for libpng is to Now you need to set up the input code. The default for libpng is to
use the C function fread(). If you use this, you will need to pass a use the C function fread(). If you use this, you will need to pass a
valid FILE * in the function png_init_io(). Be sure that the file is valid FILE * in the function png_init_io(). Be sure that the file is
@ -899,7 +903,7 @@ things.
As of libpng version 1.2.9, png_set_expand_gray_1_2_4_to_8() was As of libpng version 1.2.9, png_set_expand_gray_1_2_4_to_8() was
added. It expands the sample depth without changing tRNS to alpha. added. It expands the sample depth without changing tRNS to alpha.
As of libpng version 1.4.2rc02, not all possible expansions are supported. As of libpng version 1.4.2rc03, not all possible expansions are supported.
In the following table, the 01 means grayscale with depth<8, 31 means In the following table, the 01 means grayscale with depth<8, 31 means
indexed with depth<8, other numerals represent the color type, "T" means indexed with depth<8, other numerals represent the color type, "T" means
@ -1722,9 +1726,13 @@ section below for more information on the libpng error handling.
return; return;
If you would rather avoid the complexity of setjmp/longjmp issues, If you would rather avoid the complexity of setjmp/longjmp issues,
you can compile libpng with PNG_SETJMP_NOT_SUPPORTED, in which case you can compile libpng with PNG_NO_SETJMP, in which case
errors will result in a call to PNG_ABORT() which defaults to abort(). errors will result in a call to PNG_ABORT() which defaults to abort().
You can #define PNG_ABORT() to a function that does something
more useful than abort(), as long as your function does not
return.
Now you need to set up the output code. The default for libpng is to Now you need to set up the output code. The default for libpng is to
use the C function fwrite(). If you use this, you will need to pass a use the C function fwrite(). If you use this, you will need to pass a
valid FILE * in the function png_init_io(). Be sure that the file is valid FILE * in the function png_init_io(). Be sure that the file is
@ -2585,8 +2593,9 @@ Error handling in libpng is done through png_error() and png_warning().
Errors handled through png_error() are fatal, meaning that png_error() Errors handled through png_error() are fatal, meaning that png_error()
should never return to its caller. Currently, this is handled via should never return to its caller. Currently, this is handled via
setjmp() and longjmp() (unless you have compiled libpng with setjmp() and longjmp() (unless you have compiled libpng with
PNG_SETJMP_NOT_SUPPORTED, in which case it is handled via PNG_ABORT()), 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 On non-fatal errors, png_warning() is called
to print a warning message, and then control returns to the calling code. to print a warning message, and then control returns to the calling code.
@ -3217,12 +3226,12 @@ the statement that follows the comment:
/* Single-line comment */ /* Single-line comment */
statement; statement;
/* Multiple-line /* This is a multiple-line
* comment * comment.
*/ */
statement; statement;
Very short comments can be placed at the end of the statement Very short comments can be placed after the end of the statement
to which they pertain: to which they pertain:
statement; /* comment */ statement; /* comment */
@ -3269,9 +3278,9 @@ macros begin with "PNG_".
We put a space after each comma and after each semicolon We put a space after each comma and after each semicolon
in "for" statments, and we put spaces before and after each in "for" statments, and we put spaces before and after each
C binary operator and after "for" or "while". We don't C binary operator and after "for" or "while", and before
put a space between a typecast and the expression being "?". We don't put a space between a typecast and the expression
cast, nor do we put one between a function name and the being cast, nor do we put one between a function name and the
left parenthesis that follows it: left parenthesis that follows it:
for (i = 2; i > 0; --i) for (i = 2; i > 0; --i)
@ -3294,7 +3303,7 @@ Since the PNG Development group is an ad-hoc body, we can't make
an official declaration. an official declaration.
This is your unofficial assurance that libpng from version 0.71 and This is your unofficial assurance that libpng from version 0.71 and
upward through 1.4.2rc02 are Y2K compliant. It is my belief that earlier upward through 1.4.2rc03 are Y2K compliant. It is my belief that earlier
versions were also Y2K compliant. versions were also Y2K compliant.
Libpng only has three year fields. One is a 2-byte unsigned integer that Libpng only has three year fields. One is a 2-byte unsigned integer that

43
libpng.3
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@ -1,6 +1,6 @@
.TH LIBPNG 3 "April 16, 2010" .TH LIBPNG 3 "April 16, 2010"
.SH NAME .SH NAME
libpng \- Portable Network Graphics (PNG) Reference Library 1.4.2rc02 libpng \- Portable Network Graphics (PNG) Reference Library 1.4.2rc03
.SH SYNOPSIS .SH SYNOPSIS
\fI\fB \fI\fB
@ -785,7 +785,7 @@ Following is a copy of the libpng.txt file that accompanies libpng.
.SH LIBPNG.TXT .SH LIBPNG.TXT
libpng.txt - A description on how to use and modify libpng libpng.txt - A description on how to use and modify libpng
libpng version 1.4.2rc02 - April 16, 2010 libpng version 1.4.2rc03 - April 16, 2010
Updated and distributed by Glenn Randers-Pehrson Updated and distributed by Glenn Randers-Pehrson
<glennrp at users.sourceforge.net> <glennrp at users.sourceforge.net>
Copyright (c) 1998-2009 Glenn Randers-Pehrson Copyright (c) 1998-2009 Glenn Randers-Pehrson
@ -796,7 +796,7 @@ libpng.txt - A description on how to use and modify libpng
Based on: Based on:
libpng versions 0.97, January 1998, through 1.4.2rc02 - April 16, 2010 libpng versions 0.97, January 1998, through 1.4.2rc03 - April 16, 2010
Updated and distributed by Glenn Randers-Pehrson Updated and distributed by Glenn Randers-Pehrson
Copyright (c) 1998-2009 Glenn Randers-Pehrson Copyright (c) 1998-2009 Glenn Randers-Pehrson
@ -1026,9 +1026,13 @@ free any memory.
} }
If you would rather avoid the complexity of setjmp/longjmp issues, If you would rather avoid the complexity of setjmp/longjmp issues,
you can compile libpng with PNG_SETJMP_NOT_SUPPORTED, in which case you can compile libpng with PNG_NO_SETJMP, in which case
errors will result in a call to PNG_ABORT() which defaults to abort(). errors will result in a call to PNG_ABORT() which defaults to abort().
You can #define PNG_ABORT() to a function that does something
more useful than abort(), as long as your function does not
return.
Now you need to set up the input code. The default for libpng is to Now you need to set up the input code. The default for libpng is to
use the C function fread(). If you use this, you will need to pass a use the C function fread(). If you use this, you will need to pass a
valid FILE * in the function png_init_io(). Be sure that the file is valid FILE * in the function png_init_io(). Be sure that the file is
@ -1684,7 +1688,7 @@ things.
As of libpng version 1.2.9, png_set_expand_gray_1_2_4_to_8() was As of libpng version 1.2.9, png_set_expand_gray_1_2_4_to_8() was
added. It expands the sample depth without changing tRNS to alpha. added. It expands the sample depth without changing tRNS to alpha.
As of libpng version 1.4.2rc02, not all possible expansions are supported. As of libpng version 1.4.2rc03, not all possible expansions are supported.
In the following table, the 01 means grayscale with depth<8, 31 means In the following table, the 01 means grayscale with depth<8, 31 means
indexed with depth<8, other numerals represent the color type, "T" means indexed with depth<8, other numerals represent the color type, "T" means
@ -2507,9 +2511,13 @@ section below for more information on the libpng error handling.
return; return;
If you would rather avoid the complexity of setjmp/longjmp issues, If you would rather avoid the complexity of setjmp/longjmp issues,
you can compile libpng with PNG_SETJMP_NOT_SUPPORTED, in which case you can compile libpng with PNG_NO_SETJMP, in which case
errors will result in a call to PNG_ABORT() which defaults to abort(). errors will result in a call to PNG_ABORT() which defaults to abort().
You can #define PNG_ABORT() to a function that does something
more useful than abort(), as long as your function does not
return.
Now you need to set up the output code. The default for libpng is to Now you need to set up the output code. The default for libpng is to
use the C function fwrite(). If you use this, you will need to pass a use the C function fwrite(). If you use this, you will need to pass a
valid FILE * in the function png_init_io(). Be sure that the file is valid FILE * in the function png_init_io(). Be sure that the file is
@ -3370,8 +3378,9 @@ Error handling in libpng is done through png_error() and png_warning().
Errors handled through png_error() are fatal, meaning that png_error() Errors handled through png_error() are fatal, meaning that png_error()
should never return to its caller. Currently, this is handled via should never return to its caller. Currently, this is handled via
setjmp() and longjmp() (unless you have compiled libpng with setjmp() and longjmp() (unless you have compiled libpng with
PNG_SETJMP_NOT_SUPPORTED, in which case it is handled via PNG_ABORT()), 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 On non-fatal errors, png_warning() is called
to print a warning message, and then control returns to the calling code. to print a warning message, and then control returns to the calling code.
@ -4002,12 +4011,12 @@ the statement that follows the comment:
/* Single-line comment */ /* Single-line comment */
statement; statement;
/* Multiple-line /* This is a multiple-line
* comment * comment.
*/ */
statement; statement;
Very short comments can be placed at the end of the statement Very short comments can be placed after the end of the statement
to which they pertain: to which they pertain:
statement; /* comment */ statement; /* comment */
@ -4054,9 +4063,9 @@ macros begin with "PNG_".
We put a space after each comma and after each semicolon We put a space after each comma and after each semicolon
in "for" statments, and we put spaces before and after each in "for" statments, and we put spaces before and after each
C binary operator and after "for" or "while". We don't C binary operator and after "for" or "while", and before
put a space between a typecast and the expression being "?". We don't put a space between a typecast and the expression
cast, nor do we put one between a function name and the being cast, nor do we put one between a function name and the
left parenthesis that follows it: left parenthesis that follows it:
for (i = 2; i > 0; --i) for (i = 2; i > 0; --i)
@ -4079,7 +4088,7 @@ Since the PNG Development group is an ad-hoc body, we can't make
an official declaration. an official declaration.
This is your unofficial assurance that libpng from version 0.71 and This is your unofficial assurance that libpng from version 0.71 and
upward through 1.4.2rc02 are Y2K compliant. It is my belief that earlier upward through 1.4.2rc03 are Y2K compliant. It is my belief that earlier
versions were also Y2K compliant. versions were also Y2K compliant.
Libpng only has three year fields. One is a 2-byte unsigned integer that Libpng only has three year fields. One is a 2-byte unsigned integer that
@ -4313,7 +4322,7 @@ possible without all of you.
Thanks to Frank J. T. Wojcik for helping with the documentation. Thanks to Frank J. T. Wojcik for helping with the documentation.
Libpng version 1.4.2rc02 - April 16, 2010: Libpng version 1.4.2rc03 - April 16, 2010:
Initially created in 1995 by Guy Eric Schalnat, then of Group 42, Inc. Initially created in 1995 by Guy Eric Schalnat, then of Group 42, Inc.
Currently maintained by Glenn Randers-Pehrson (glennrp at users.sourceforge.net). Currently maintained by Glenn Randers-Pehrson (glennrp at users.sourceforge.net).
@ -4336,7 +4345,7 @@ this sentence.
This code is released under the libpng license. This code is released under the libpng license.
libpng versions 1.2.6, August 15, 2004, through 1.4.2rc02, April 16, 2010, are libpng versions 1.2.6, August 15, 2004, through 1.4.2rc03, April 16, 2010, are
Copyright (c) 2004,2006-2007 Glenn Randers-Pehrson, and are Copyright (c) 2004,2006-2007 Glenn Randers-Pehrson, and are
distributed according to the same disclaimer and license as libpng-1.2.5 distributed according to the same disclaimer and license as libpng-1.2.5
with the following individual added to the list of Contributing Authors with the following individual added to the list of Contributing Authors