www.pudn.com > VCMPlayerClassic_Coder.rar > libpng.c

/*  
 *	Copyright (C) 2003-2006 Gabest 
 *	http://www.gabest.org 
 * 
 *  This Program is free software; you can redistribute it and/or modify 
 *  it under the terms of the GNU General Public License as published by 
 *  the Free Software Foundation; either version 2, or (at your option) 
 *  any later version. 
 *    
 *  This Program is distributed in the hope that it will be useful, 
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of 
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 
 *  GNU General Public License for more details. 
 *    
 *  You should have received a copy of the GNU General Public License 
 *  along with GNU Make; see the file COPYING.  If not, write to 
 *  the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.  
 *  http://www.gnu.org/copyleft/gpl.html 
 * 
 */ 
 
#include  
#include  
#include "libpng.h" 
#include "..\..\libpng\png.h" 
 
static void read_data_fn(png_structp png_ptr, png_bytep data, png_size_t length) 
{ 
	struct png_t* png = (struct png_t*)png_get_progressive_ptr(png_ptr); 
	if(png->pos + length > png->size) png_error(png_ptr, "Read Error"); 
	memcpy(data, &png->data[png->pos], length); 
	png->pos += length; 
} 
 
unsigned char* DecompressPNG(struct png_t* png, int* w, int* h) 
{ 
    png_structp png_ptr; 
	png_infop info_ptr; 
	png_infop end_info; 
 
	unsigned char* pic; 
	unsigned char* row; 
	unsigned int x, y, c; 
 
	if(png_sig_cmp(png->data, 0, 8) != 0) 
		return NULL;
 
	png->pos = 8; 
 
    png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING, NULL, NULL, NULL); 
		// (png_voidp)user_error_ptr, user_error_fn, user_warning_fn); 
    if(!png_ptr)  
		return NULL; 
 
    png_set_read_fn(png_ptr, (png_voidp)png, read_data_fn); 
 
    info_ptr = png_create_info_struct(png_ptr);
    if(!info_ptr)
    {
        png_destroy_read_struct(&png_ptr, (png_infopp)NULL, (png_infopp)NULL);
        return NULL;
    }
 
    end_info = png_create_info_struct(png_ptr);
    if(!end_info)
    {
        png_destroy_read_struct(&png_ptr, &info_ptr, (png_infopp)NULL);
        return NULL;
    }
 
    if(setjmp(png_jmpbuf(png_ptr)))
    {
        png_destroy_read_struct(&png_ptr, &info_ptr, &end_info);
        return NULL;
    }
 
	png_set_sig_bytes(png_ptr, 8); 
 
	png_read_png( 
		png_ptr, info_ptr,  
		PNG_TRANSFORM_STRIP_16 |  
		PNG_TRANSFORM_STRIP_ALPHA |  
		PNG_TRANSFORM_PACKING | 
		PNG_TRANSFORM_EXPAND | 
		PNG_TRANSFORM_BGR,  
		NULL); 
 
	if(png_get_channels(png_ptr, info_ptr) != 3)  
	{ 
        png_destroy_read_struct(&png_ptr, &info_ptr, &end_info);
		return NULL; 
	} 
 
	pic = calloc(info_ptr->width * info_ptr->height, 4); 
 
	*w = info_ptr->width; 
	*h = info_ptr->height; 
 
	for(y = 0; y < info_ptr->height; y++) 
	{ 
		row = &pic[y * info_ptr->width * 4]; 
 
		for(x = 0; x < info_ptr->width*3; row += 4) 
		{ 
			for(c = 0; c < 3; c++) 
			{ 
				row[c] = info_ptr->row_pointers[y][x++]; 
			} 
		} 
	} 
 
    png_destroy_read_struct(&png_ptr, &info_ptr, &end_info); 
 
	return pic; 
}