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<html><head><title>dlib C++ Library - pngwio.c</title></head><body bgcolor='white'><pre> |
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<font color='#009900'>/* pngwio.c - functions for data output |
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* |
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* Last changed in libpng 1.6.0 [February 14, 2013] |
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* Copyright (c) 1998-2013 Glenn Randers-Pehrson |
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* (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger) |
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* (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.) |
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* |
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* This code is released under the libpng license. |
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* For conditions of distribution and use, see the disclaimer |
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* and license in png.h |
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* |
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* This file provides a location for all output. Users who need |
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* special handling are expected to write functions that have the same |
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* arguments as these and perform similar functions, but that possibly |
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* use different output methods. Note that you shouldn't change these |
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* functions, but rather write replacement functions and then change |
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* them at run time with png_set_write_fn(...). |
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*/</font> |
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<font color='#0000FF'>#include</font> "<a style='text-decoration:none' href='pngpriv.h.html'>pngpriv.h</a>" |
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<font color='#0000FF'>#ifdef</font> PNG_WRITE_SUPPORTED |
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<font color='#009900'>/* Write the data to whatever output you are using. The default routine |
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* writes to a file pointer. Note that this routine sometimes gets called |
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* with very small lengths, so you should implement some kind of simple |
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* buffering if you are using unbuffered writes. This should never be asked |
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* to write more than 64K on a 16 bit machine. |
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*/</font> |
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<font color='#0000FF'><u>void</u></font> <font color='#009900'>/* PRIVATE */</font> |
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<b><a name='png_write_data'></a>png_write_data</b><font face='Lucida Console'>(</font>png_structrp png_ptr, png_const_bytep data, png_size_t length<font face='Lucida Console'>)</font> |
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<b>{</b> |
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<font color='#009900'>/* NOTE: write_data_fn must not change the buffer! */</font> |
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<font color='#0000FF'>if</font> <font face='Lucida Console'>(</font>png_ptr<font color='#5555FF'>-</font><font color='#5555FF'>></font>write_data_fn <font color='#5555FF'>!</font><font color='#5555FF'>=</font> NULL <font face='Lucida Console'>)</font> |
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<font face='Lucida Console'>(</font><font color='#5555FF'>*</font><font face='Lucida Console'>(</font>png_ptr<font color='#5555FF'>-</font><font color='#5555FF'>></font>write_data_fn<font face='Lucida Console'>)</font><font face='Lucida Console'>)</font><font face='Lucida Console'>(</font>png_ptr, <font color='#BB00BB'>png_constcast</font><font face='Lucida Console'>(</font>png_bytep,data<font face='Lucida Console'>)</font>, |
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length<font face='Lucida Console'>)</font>; |
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<font color='#0000FF'>else</font> |
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<font color='#BB00BB'>png_error</font><font face='Lucida Console'>(</font>png_ptr, "<font color='#CC0000'>Call to NULL write function</font>"<font face='Lucida Console'>)</font>; |
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<b>}</b> |
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<font color='#0000FF'>#ifdef</font> PNG_STDIO_SUPPORTED |
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<font color='#009900'>/* This is the function that does the actual writing of data. If you are |
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* not writing to a standard C stream, you should create a replacement |
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* write_data function and use it at run time with png_set_write_fn(), rather |
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* than changing the library. |
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*/</font> |
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<font color='#0000FF'><u>void</u></font> PNGCBAPI |
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<b><a name='png_default_write_data'></a>png_default_write_data</b><font face='Lucida Console'>(</font>png_structp png_ptr, png_bytep data, png_size_t length<font face='Lucida Console'>)</font> |
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<b>{</b> |
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png_size_t check; |
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<font color='#0000FF'>if</font> <font face='Lucida Console'>(</font>png_ptr <font color='#5555FF'>=</font><font color='#5555FF'>=</font> NULL<font face='Lucida Console'>)</font> |
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<font color='#0000FF'>return</font>; |
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check <font color='#5555FF'>=</font> <font color='#BB00BB'>fwrite</font><font face='Lucida Console'>(</font>data, <font color='#979000'>1</font>, length, <font face='Lucida Console'>(</font>png_FILE_p<font face='Lucida Console'>)</font><font face='Lucida Console'>(</font>png_ptr<font color='#5555FF'>-</font><font color='#5555FF'>></font>io_ptr<font face='Lucida Console'>)</font><font face='Lucida Console'>)</font>; |
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<font color='#0000FF'>if</font> <font face='Lucida Console'>(</font>check <font color='#5555FF'>!</font><font color='#5555FF'>=</font> length<font face='Lucida Console'>)</font> |
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<font color='#BB00BB'>png_error</font><font face='Lucida Console'>(</font>png_ptr, "<font color='#CC0000'>Write Error</font>"<font face='Lucida Console'>)</font>; |
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<b>}</b> |
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<font color='#0000FF'>#endif</font> |
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<font color='#009900'>/* This function is called to output any data pending writing (normally |
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* to disk). After png_flush is called, there should be no data pending |
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* writing in any buffers. |
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*/</font> |
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<font color='#0000FF'>#ifdef</font> PNG_WRITE_FLUSH_SUPPORTED |
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<font color='#0000FF'><u>void</u></font> <font color='#009900'>/* PRIVATE */</font> |
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<b><a name='png_flush'></a>png_flush</b><font face='Lucida Console'>(</font>png_structrp png_ptr<font face='Lucida Console'>)</font> |
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<b>{</b> |
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<font color='#0000FF'>if</font> <font face='Lucida Console'>(</font>png_ptr<font color='#5555FF'>-</font><font color='#5555FF'>></font>output_flush_fn <font color='#5555FF'>!</font><font color='#5555FF'>=</font> NULL<font face='Lucida Console'>)</font> |
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<font face='Lucida Console'>(</font><font color='#5555FF'>*</font><font face='Lucida Console'>(</font>png_ptr<font color='#5555FF'>-</font><font color='#5555FF'>></font>output_flush_fn<font face='Lucida Console'>)</font><font face='Lucida Console'>)</font><font face='Lucida Console'>(</font>png_ptr<font face='Lucida Console'>)</font>; |
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<b>}</b> |
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# ifdef PNG_STDIO_SUPPORTED |
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<font color='#0000FF'><u>void</u></font> PNGCBAPI |
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<b><a name='png_default_flush'></a>png_default_flush</b><font face='Lucida Console'>(</font>png_structp png_ptr<font face='Lucida Console'>)</font> |
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<b>{</b> |
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png_FILE_p io_ptr; |
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<font color='#0000FF'>if</font> <font face='Lucida Console'>(</font>png_ptr <font color='#5555FF'>=</font><font color='#5555FF'>=</font> NULL<font face='Lucida Console'>)</font> |
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<font color='#0000FF'>return</font>; |
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io_ptr <font color='#5555FF'>=</font> <font color='#BB00BB'>png_voidcast</font><font face='Lucida Console'>(</font>png_FILE_p, <font face='Lucida Console'>(</font>png_ptr<font color='#5555FF'>-</font><font color='#5555FF'>></font>io_ptr<font face='Lucida Console'>)</font><font face='Lucida Console'>)</font>; |
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<font color='#BB00BB'>fflush</font><font face='Lucida Console'>(</font>io_ptr<font face='Lucida Console'>)</font>; |
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<b>}</b> |
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# endif |
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<font color='#0000FF'>#endif</font> |
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<font color='#009900'>/* This function allows the application to supply new output functions for |
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* libpng if standard C streams aren't being used. |
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* |
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* This function takes as its arguments: |
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* png_ptr - pointer to a png output data structure |
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* io_ptr - pointer to user supplied structure containing info about |
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* the output functions. May be NULL. |
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* write_data_fn - pointer to a new output function that takes as its |
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* arguments a pointer to a png_struct, a pointer to |
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* data to be written, and a 32-bit unsigned int that is |
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* the number of bytes to be written. The new write |
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* function should call png_error(png_ptr, "Error msg") |
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* to exit and output any fatal error messages. May be |
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* NULL, in which case libpng's default function will |
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* be used. |
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* flush_data_fn - pointer to a new flush function that takes as its |
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* arguments a pointer to a png_struct. After a call to |
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* the flush function, there should be no data in any buffers |
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* or pending transmission. If the output method doesn't do |
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* any buffering of output, a function prototype must still be |
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* supplied although it doesn't have to do anything. If |
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* PNG_WRITE_FLUSH_SUPPORTED is not defined at libpng compile |
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* time, output_flush_fn will be ignored, although it must be |
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* supplied for compatibility. May be NULL, in which case |
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* libpng's default function will be used, if |
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* PNG_WRITE_FLUSH_SUPPORTED is defined. This is not |
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* a good idea if io_ptr does not point to a standard |
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* *FILE structure. |
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*/</font> |
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<font color='#0000FF'><u>void</u></font> PNGAPI |
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<b><a name='png_set_write_fn'></a>png_set_write_fn</b><font face='Lucida Console'>(</font>png_structrp png_ptr, png_voidp io_ptr, |
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png_rw_ptr write_data_fn, png_flush_ptr output_flush_fn<font face='Lucida Console'>)</font> |
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<b>{</b> |
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<font color='#0000FF'>if</font> <font face='Lucida Console'>(</font>png_ptr <font color='#5555FF'>=</font><font color='#5555FF'>=</font> NULL<font face='Lucida Console'>)</font> |
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<font color='#0000FF'>return</font>; |
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png_ptr<font color='#5555FF'>-</font><font color='#5555FF'>></font>io_ptr <font color='#5555FF'>=</font> io_ptr; |
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<font color='#0000FF'>#ifdef</font> PNG_STDIO_SUPPORTED |
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<font color='#0000FF'>if</font> <font face='Lucida Console'>(</font>write_data_fn <font color='#5555FF'>!</font><font color='#5555FF'>=</font> NULL<font face='Lucida Console'>)</font> |
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png_ptr<font color='#5555FF'>-</font><font color='#5555FF'>></font>write_data_fn <font color='#5555FF'>=</font> write_data_fn; |
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<font color='#0000FF'>else</font> |
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png_ptr<font color='#5555FF'>-</font><font color='#5555FF'>></font>write_data_fn <font color='#5555FF'>=</font> png_default_write_data; |
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<font color='#0000FF'>#else</font> |
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png_ptr<font color='#5555FF'>-</font><font color='#5555FF'>></font>write_data_fn <font color='#5555FF'>=</font> write_data_fn; |
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<font color='#0000FF'>#endif</font> |
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<font color='#0000FF'>#ifdef</font> PNG_WRITE_FLUSH_SUPPORTED |
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# ifdef PNG_STDIO_SUPPORTED |
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<font color='#0000FF'>if</font> <font face='Lucida Console'>(</font>output_flush_fn <font color='#5555FF'>!</font><font color='#5555FF'>=</font> NULL<font face='Lucida Console'>)</font> |
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png_ptr<font color='#5555FF'>-</font><font color='#5555FF'>></font>output_flush_fn <font color='#5555FF'>=</font> output_flush_fn; |
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<font color='#0000FF'>else</font> |
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png_ptr<font color='#5555FF'>-</font><font color='#5555FF'>></font>output_flush_fn <font color='#5555FF'>=</font> png_default_flush; |
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# <font color='#0000FF'>else</font> |
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png_ptr<font color='#5555FF'>-</font><font color='#5555FF'>></font>output_flush_fn <font color='#5555FF'>=</font> output_flush_fn; |
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# endif |
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<font color='#0000FF'>#endif</font> <font color='#009900'>/* PNG_WRITE_FLUSH_SUPPORTED */</font> |
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<font color='#009900'>/* It is an error to read while writing a png file */</font> |
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<font color='#0000FF'>if</font> <font face='Lucida Console'>(</font>png_ptr<font color='#5555FF'>-</font><font color='#5555FF'>></font>read_data_fn <font color='#5555FF'>!</font><font color='#5555FF'>=</font> NULL<font face='Lucida Console'>)</font> |
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<b>{</b> |
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png_ptr<font color='#5555FF'>-</font><font color='#5555FF'>></font>read_data_fn <font color='#5555FF'>=</font> NULL; |
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<font color='#BB00BB'>png_warning</font><font face='Lucida Console'>(</font>png_ptr, |
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"<font color='#CC0000'>Can't set both read_data_fn and write_data_fn in the</font>" |
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"<font color='#CC0000'> same structure</font>"<font face='Lucida Console'>)</font>; |
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<b>}</b> |
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<b>}</b> |
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<font color='#0000FF'>#endif</font> <font color='#009900'>/* PNG_WRITE_SUPPORTED */</font> |
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</pre></body></html> |
