src/apps/mplayerc/libpng.c

   1 /*
   2  *      Copyright (C) 2003-2006 Gabest
   3  *      http://www.gabest.org
   4  *
   5  *  This Program is free software; you can redistribute it and/or modify
   6  *  it under the terms of the GNU General Public License as published by
   7  *  the Free Software Foundation; either version 2, or (at your option)
   8  *  any later version.
   9  *
  10  *  This Program is distributed in the hope that it will be useful,
  11  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  13  *  GNU General Public License for more details.
  14  *
  15  *  You should have received a copy of the GNU General Public License
  16  *  along with GNU Make; see the file COPYING.  If not, write to
  17  *  the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
  18  *  http://www.gnu.org/copyleft/gpl.html
  19  *
  20  */
  21
  22 #include <stdio.h>
  23 #include <malloc.h>
  24 #include "libpng.h"
  25 #include "..\..\libpng\png.h"
  26
  27 static void read_data_fn(png_structp png_ptr, png_bytep data, png_size_t length)
  28 {
  29         struct png_t* png = (struct png_t*)png_get_progressive_ptr(png_ptr);
  30         if(png->pos + length > png->size) png_error(png_ptr, "Read Error");
  31         memcpy(data, &png->data[png->pos], length);
  32         png->pos += length;
  33 }
  34
  35 unsigned char* DecompressPNG(struct png_t* png, int* w, int* h)
  36 {
  37     png_structp png_ptr;
  38         png_infop info_ptr;
  39         png_infop end_info;
  40
  41         unsigned char* pic;
  42         unsigned char* row;
  43         unsigned int x, y, c;
  44
  45         if(png_sig_cmp(png->data, 0, 8) != 0)
  46                 return NULL;
  47
  48         png->pos = 8;
  49
  50     png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING, NULL, NULL, NULL);
  51                 // (png_voidp)user_error_ptr, user_error_fn, user_warning_fn);
  52     if(!png_ptr)
  53                 return NULL;
  54
  55     png_set_read_fn(png_ptr, (png_voidp)png, read_data_fn);
  56
  57     info_ptr = png_create_info_struct(png_ptr);
  58     if(!info_ptr)
  59     {
  60         png_destroy_read_struct(&png_ptr, (png_infopp)NULL, (png_infopp)NULL);
  61         return NULL;
  62     }
  63
  64     end_info = png_create_info_struct(png_ptr);
  65     if(!end_info)
  66     {
  67         png_destroy_read_struct(&png_ptr, &info_ptr, (png_infopp)NULL);
  68         return NULL;
  69     }
  70
  71     if(setjmp(png_jmpbuf(png_ptr)))
  72     {
  73         png_destroy_read_struct(&png_ptr, &info_ptr, &end_info);
  74         return NULL;
  75     }
  76
  77         png_set_sig_bytes(png_ptr, 8);
  78
  79         png_read_png(
  80                 png_ptr, info_ptr,
  81                 PNG_TRANSFORM_STRIP_16 |
  82                 PNG_TRANSFORM_STRIP_ALPHA |
  83                 PNG_TRANSFORM_PACKING |
  84                 PNG_TRANSFORM_EXPAND |
  85                 PNG_TRANSFORM_BGR,
  86                 NULL);
  87
  88         if(png_get_channels(png_ptr, info_ptr) != 3)
  89         {
  90         png_destroy_read_struct(&png_ptr, &info_ptr, &end_info);
  91                 return NULL;
  92         }
  93
  94         pic = calloc(info_ptr->width * info_ptr->height, 4);
  95
  96         *w = info_ptr->width;
  97         *h = info_ptr->height;
  98
  99         for(y = 0; y < info_ptr->height; y++)
 100         {
 101                 row = &pic[y * info_ptr->width * 4];
 102
 103                 for(x = 0; x < info_ptr->width*3; row += 4)
 104                 {
 105                         for(c = 0; c < 3; c++)
 106                         {
 107                                 row[c] = info_ptr->row_pointers[y][x++];
 108                         }
 109                 }
 110         }
 111
 112     png_destroy_read_struct(&png_ptr, &info_ptr, &end_info);
 113
 114         return pic;
 115 }