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[devel] Added four new convenience functions (John Bowler)

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John Bowler
2011-01-22 18:29:24 -06:00
committed by Glenn Randers-Pehrson
parent 0a5c9c02fa
commit f19abd6725
3 changed files with 71 additions and 16 deletions
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73
libpng.3
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@@ -1,4 +1,4 @@
.TH LIBPNG 3 "January 22, 2011"
.TH LIBPNG 3 "January 23, 2011"
.SH NAME
libpng \- Portable Network Graphics (PNG) Reference Library 1.5.1beta08
.SH SYNOPSIS
@@ -154,6 +154,14 @@ libpng \- Portable Network Graphics (PNG) Reference Library 1.5.1beta08
\fI\fB
\fBpng_uint_32 png_get_current_row_number \fI(png_const_structp\fP\fB);\fP
\fI\fB
\fBpng_byte png_get_current_pass_number \fI(png_const_structp\fP\fB);\fP
\fI\fB
\fBpng_voidp png_get_error_ptr (png_const_structp \fIpng_ptr\fP\fB);\fP
\fI\fB
@@ -444,6 +452,14 @@ libpng \- Portable Network Graphics (PNG) Reference Library 1.5.1beta08
\fI\fB
\fBpng_size_t png_process_data_pause \fP\fI(png_structp\fP\fB, int \fIsave\fP\fB);\fP
\fI\fB
\fBpng_uint_32 png_process_data_skip \fI(png_structp\fP\fB);\fP
\fI\fB
\fBvoid png_progressive_combine_row (png_structp \fP\fIpng_ptr\fP\fB, png_bytep \fP\fIold_row\fP\fB, png_bytep \fInew_row\fP\fB);\fP
\fI\fB
@@ -903,7 +919,7 @@ 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 1.5.1beta08 - January 22, 2011
libpng version 1.5.1beta08 - January 23, 2011
Updated and distributed by Glenn Randers-Pehrson
<glennrp at users.sourceforge.net>
Copyright (c) 1998-2011 Glenn Randers-Pehrson
@@ -914,7 +930,7 @@ libpng-manual.txt - A description on how to use and modify libpng
Based on:
libpng versions 0.97, January 1998, through 1.5.1beta08 - January 22, 2011
libpng versions 0.97, January 1998, through 1.5.1beta08 - January 23, 2011
Updated and distributed by Glenn Randers-Pehrson
Copyright (c) 1998-2011 Glenn Randers-Pehrson
@@ -2418,7 +2434,20 @@ You must supply the function
row_info, png_bytep data)
See pngtest.c for a working example. Your function will be called
after all of the other transformations have been processed.
after all of the other transformations have been processed. Take care with
interlaced images if you do the interlace yourself - the width of the row is the
width in 'row_info', not the overall image width.
If supported libpng provides two information routines that you can use to find
where you are in processing the image:
png_get_current_pass_number(png_structp png_ptr);
png_get_current_row_number(png_structp png_ptr);
Don't try using these outside a transform callback - firstly they are only
supported if user transforms are supported, secondly they may well return
unexpected results unless the row is actually being processed at the moment they
are called.
You can also set up a pointer to a user structure for use by your
callback function, and you can inform libpng that your transform
@@ -2848,6 +2877,12 @@ png_infop info_ptr;
so there.
*/
png_process_data(png_ptr, info_ptr, buffer, length);
/* At this point you can call png_process_data_skip if
you want to handle data the library will skip yourself;
it simply returns the number of bytes to skip (and stops
libpng skipping that number of bytes on the next
png_process_data call).
return 0;
}
@@ -2871,6 +2906,16 @@ png_infop info_ptr;
This is where you turn on interlace handling,
assuming you don't want to do it yourself.
If you need to you can stop the processing of
your original input data at this point by calling
png_process_data_pause. This returns the number
of unprocessed bytes from the last png_process_data
call - it is up to you to ensure that the next call
sees these bytes again. If you don't want to bother
with this you can get libpng to cache the unread
bytes by setting the 'save' parameter (see png.h) but
then libpng will have to copy the data internally.
*/
}
@@ -2920,6 +2965,9 @@ png_infop info_ptr;
for interlaced images), you will have to pass
the current row, and the function will combine
the old row and the new row.
You can also call png_process_data_pause in this
callback - see above.
*/
}
@@ -3651,7 +3699,14 @@ You must supply the function
row_info, png_bytep data)
See pngtest.c for a working example. Your function will be called
before any of the other transformations are processed.
before any of the other transformations are processed. If supported
libpng also supplies an information routine that may be called from
your callback:
png_get_current_row_number(png_ptr);
This returns the current row passed to the transform. Even with interlaced
images the value returned is the row in the final output image.
You can also set up a pointer to a user structure for use by your
callback function.
@@ -4941,7 +4996,7 @@ Other rules can be inferred by inspecting the libpng source.
.SH XIV. Y2K Compliance in libpng
January 22, 2011
January 23, 2011
Since the PNG Development group is an ad-hoc body, we can't make
an official declaration.
@@ -5187,7 +5242,7 @@ possible without all of you.
Thanks to Frank J. T. Wojcik for helping with the documentation.
Libpng version 1.5.1beta08 - January 22, 2011:
Libpng version 1.5.1beta08 - January 23, 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).
@@ -5210,7 +5265,7 @@ this sentence.
This code is released under the libpng license.
libpng versions 1.2.6, August 15, 2004, through 1.5.1beta08, January 22, 2011, are
libpng versions 1.2.6, August 15, 2004, through 1.5.1beta08, January 23, 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
@@ -5309,7 +5364,7 @@ certification mark of the Open Source Initiative.
Glenn Randers-Pehrson
glennrp at users.sourceforge.net
January 22, 2011
January 23, 2011
.\" end of man page