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[libpng17] Added information about setjmp/simplified API interaction in the

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manual page and INSTALL file. Added information about using
row_pointers with a single height*width*bpp allocated block
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Glenn Randers-Pehrson 2015-02-17 20:15:21 -06:00
parent 9c7aee825c
commit ed3543679a
4 changed files with 44 additions and 16 deletions
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7
ANNOUNCE
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@ -1,5 +1,5 @@
Libpng 1.7.0beta52 - February 17, 2015 Libpng 1.7.0beta52 - February 18, 2015
This is not intended to be a public release. It will be replaced 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. within a few weeks by a public version or by another test version.
@ -722,7 +722,10 @@ Version 1.7.0beta51 [February 17, 2015]
with a method that prevents overflow and does not increase cpu usage with a method that prevents overflow and does not increase cpu usage
significantly. significantly.
Version 1.7.0beta52 [February 17, 2015] Version 1.7.0beta52 [February 18, 2015]
Added information about setjmp/simplified API interaction in the
manual page and INSTALL file. Added information about using
row_pointers with a single height*width*bpp allocated block
Send comments/corrections/commendations to png-mng-implement at lists.sf.net Send comments/corrections/commendations to png-mng-implement at lists.sf.net
(subscription required; visit (subscription required; visit

9
INSTALL
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@ -17,7 +17,7 @@ VIII. Configuring libpng for 16-bit platforms
XII. Configuring for compiler xxx: XII. Configuring for compiler xxx:
XIII. Removing unwanted object code XIII. Removing unwanted object code
XIV. Changes to the build and configuration of libpng in libpng-1.5.x XIV. Changes to the build and configuration of libpng in libpng-1.5.x
XV. Configuring libpng for multiprocessing XV. Setjmp/longjmp issues
XVI. Other sources of information about libpng XVI. Other sources of information about libpng
I. Simple installation I. Simple installation
@ -362,7 +362,7 @@ $PREFIX/include directory). Do not edit pnglibconf.h after you have built
libpng, because than the settings would not accurately reflect the settings libpng, because than the settings would not accurately reflect the settings
that were used to build libpng. that were used to build libpng.
XV. Configuring libpng for multiprocessing XV. Setjmp/longjmp issues
Libpng uses setjmp()/longjmp() for error handling. Unfortunately setjmp() Libpng uses setjmp()/longjmp() for error handling. Unfortunately setjmp()
is known to be not thread-safe on some platforms and we don't know of is known to be not thread-safe on some platforms and we don't know of
@ -375,6 +375,11 @@ configure libpng with PNG_NO_SETJMP in your pngusr.dfa file, with
in your pnglibconf.h or pngusr.h. in your pnglibconf.h or pngusr.h.
Starting with libpng-1.6.0, the library included a "simplified API".
This requires setjmp/longjmp, so you must either build the library
with PNG_SETJMP_SUPPORTED defined, or with PNG_SIMPLIFIED_READ_SUPPORTED
and PNG_SIMPLIFIED_WRITE_SUPPORTED undefined.
XVI. Other sources of information about libpng: XVI. Other sources of information about libpng:
Further information can be found in the README and libpng-manual.txt Further information can be found in the README and libpng-manual.txt

18
libpng-manual.txt
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@ -1,6 +1,6 @@
libpng-manual.txt - A description on how to use and modify libpng libpng-manual.txt - A description on how to use and modify libpng
libpng version 1.7.0beta52 - February 17, 2015 libpng version 1.7.0beta52 - February 18, 2015
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) 1998-2015 Glenn Randers-Pehrson Copyright (c) 1998-2015 Glenn Randers-Pehrson
@ -11,7 +11,7 @@ libpng-manual.txt - A description on how to use and modify libpng
Based on: Based on:
libpng versions 0.97, January 1998, through 1.7.0beta52 - February 17, 2015 libpng versions 0.97, January 1998, through 1.7.0beta52 - February 18, 2015
Updated and distributed by Glenn Randers-Pehrson Updated and distributed by Glenn Randers-Pehrson
Copyright (c) 1998-2015 Glenn Randers-Pehrson Copyright (c) 1998-2015 Glenn Randers-Pehrson
@ -434,6 +434,10 @@ You can #define PNG_ABORT to a function or other C code that does something
more useful than abort(), as long as your function does not more useful than abort(), as long as your function does not
return. return.
If you do this, you cannot #define PNG_SIMPLIFIED_READ_SUPPORTED or
PNG_SIMPLIFIED_WRITE_SUPPORTED, because the simplified API requires
setjmp() support.
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
@ -1181,7 +1185,13 @@ row_pointers prior to calling png_read_png() with
png_set_rows(png_ptr, info_ptr, &row_pointers); png_set_rows(png_ptr, info_ptr, &row_pointers);
Alternatively you could allocate your image in one big block and define Alternatively you could allocate your image in one big block and define
row_pointers[i] to point into the proper places in your block. row_pointers[i] to point into the proper places in your block. Allocate
extra memory after the last row to leave working room for reading the
entire row if you are doing reductions such as 16-to-8 or rgb-to-gray.
In the worst case, reducing 16-bit RGBA to 8-bit gray, you'd need to
allocate seven extra rows worth of memory (you don't need extra memory
for any but the last row, because for other rows the working space just
overlaps the next row(s).
If you use png_set_rows(), the application is responsible for freeing If you use png_set_rows(), the application is responsible for freeing
row_pointers (and row_pointers[i], if they were separately allocated). row_pointers (and row_pointers[i], if they were separately allocated).
@ -5325,7 +5335,7 @@ Other rules can be inferred by inspecting the libpng source.
XVII. Y2K Compliance in libpng XVII. Y2K Compliance in libpng
February 17, 2015 February 18, 2015
Since the PNG Development group is an ad-hoc body, we can't make Since the PNG Development group is an ad-hoc body, we can't make
an official declaration. an official declaration.

26
libpng.3
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@ -1,4 +1,4 @@
.TH LIBPNG 3 "February 17, 2015" .TH LIBPNG 3 "February 18, 2015"
.SH NAME .SH NAME
libpng \- Portable Network Graphics (PNG) Reference Library 1.7.0beta52 libpng \- Portable Network Graphics (PNG) Reference Library 1.7.0beta52
.SH SYNOPSIS .SH SYNOPSIS
@ -494,7 +494,7 @@ Following is a copy of the libpng-manual.txt file that accompanies libpng.
.SH LIBPNG.TXT .SH LIBPNG.TXT
libpng-manual.txt - A description on how to use and modify libpng libpng-manual.txt - A description on how to use and modify libpng
libpng version 1.7.0beta52 - February 17, 2015 libpng version 1.7.0beta52 - February 18, 2015
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) 1998-2015 Glenn Randers-Pehrson Copyright (c) 1998-2015 Glenn Randers-Pehrson
@ -505,7 +505,7 @@ libpng-manual.txt - A description on how to use and modify libpng
Based on: Based on:
libpng versions 0.97, January 1998, through 1.7.0beta52 - February 17, 2015 libpng versions 0.97, January 1998, through 1.7.0beta52 - February 18, 2015
Updated and distributed by Glenn Randers-Pehrson Updated and distributed by Glenn Randers-Pehrson
Copyright (c) 1998-2015 Glenn Randers-Pehrson Copyright (c) 1998-2015 Glenn Randers-Pehrson
@ -928,6 +928,10 @@ You can #define PNG_ABORT to a function or other C code that does something
more useful than abort(), as long as your function does not more useful than abort(), as long as your function does not
return. return.
If you do this, you cannot #define PNG_SIMPLIFIED_READ_SUPPORTED or
PNG_SIMPLIFIED_WRITE_SUPPORTED, because the simplified API requires
setjmp() support.
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
@ -1675,7 +1679,13 @@ row_pointers prior to calling png_read_png() with
png_set_rows(png_ptr, info_ptr, &row_pointers); png_set_rows(png_ptr, info_ptr, &row_pointers);
Alternatively you could allocate your image in one big block and define Alternatively you could allocate your image in one big block and define
row_pointers[i] to point into the proper places in your block. row_pointers[i] to point into the proper places in your block. Allocate
extra memory after the last row to leave working room for reading the
entire row if you are doing reductions such as 16-to-8 or rgb-to-gray.
In the worst case, reducing 16-bit RGBA to 8-bit gray, you'd need to
allocate seven extra rows worth of memory (you don't need extra memory
for any but the last row, because for other rows the working space just
overlaps the next row(s).
If you use png_set_rows(), the application is responsible for freeing If you use png_set_rows(), the application is responsible for freeing
row_pointers (and row_pointers[i], if they were separately allocated). row_pointers (and row_pointers[i], if they were separately allocated).
@ -5819,7 +5829,7 @@ Other rules can be inferred by inspecting the libpng source.
.SH XVII. Y2K Compliance in libpng .SH XVII. Y2K Compliance in libpng
February 17, 2015 February 18, 2015
Since the PNG Development group is an ad-hoc body, we can't make Since the PNG Development group is an ad-hoc body, we can't make
an official declaration. an official declaration.
@ -6089,7 +6099,7 @@ 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 1.7.0beta52 - February 17, 2015: Libpng version 1.7.0beta52 - February 18, 2015:
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).
@ -6112,7 +6122,7 @@ 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 1.7.0beta52, February 17, 2015, are libpng versions 1.2.6, August 15, 2004, through 1.7.0beta52, February 18, 2015, 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
@ -6211,7 +6221,7 @@ certification mark of the Open Source Initiative.
Glenn Randers-Pehrson Glenn Randers-Pehrson
glennrp at users.sourceforge.net glennrp at users.sourceforge.net
February 17, 2015 February 18, 2015
.\" end of man page .\" end of man page