src/gdpng.c

   1 /*****************************************************************************
   2  * RRDtool 1.2.12  Copyright by Tobi Oetiker, 1997-2005
   3  *****************************************************************************
   4  * gdpng.c  add PNG output routine to gd library
   5  *****************************************************************************/
   6
   7 #include <png.h>
   8 #include <gd.h>
   9 #include <stdlib.h>
  10
  11 typedef struct _jmpbuf_wrapper {
  12   jmp_buf jmpbuf;
  13 } jmpbuf_wrapper;
  14
  15 static jmpbuf_wrapper gdPngJmpbufStruct;
  16
  17 void gdImagePng(gdImagePtr im, FILE *out)
  18 {
  19     int i;
  20     png_colorp palette;
  21     png_structp png_write_ptr =
  22         png_create_write_struct(PNG_LIBPNG_VER_STRING,
  23                                 (png_voidp)NULL,
  24                                 /* we would need to point to error handlers
  25                                    here to do it properly */
  26                                 (png_error_ptr)NULL, (png_error_ptr)NULL);
  27     png_infop info_ptr = png_create_info_struct(png_write_ptr);
  28
  29     if (setjmp(gdPngJmpbufStruct.jmpbuf)) {
  30       png_destroy_write_struct(&png_write_ptr, &info_ptr);
  31       return;
  32     }
  33
  34     palette = (png_colorp)png_malloc (png_write_ptr,
  35                                       im->colorsTotal*sizeof(png_color));
  36     if (palette == NULL){
  37       png_destroy_write_struct(&png_write_ptr, &info_ptr);
  38       return;
  39     }
  40
  41
  42     png_init_io(png_write_ptr, out);
  43     png_set_write_status_fn(png_write_ptr, NULL);
  44     png_set_IHDR(png_write_ptr,info_ptr,
  45                  im->sx,im->sy,im->colorsTotal > 16 ? 8:4,
  46                  PNG_COLOR_TYPE_PALETTE,
  47                  im->interlace ? PNG_INTERLACE_ADAM7: PNG_INTERLACE_NONE ,
  48                  PNG_COMPRESSION_TYPE_DEFAULT, PNG_FILTER_TYPE_DEFAULT);
  49     for(i=0;i<im->colorsTotal;i++){
  50         palette[i].red = im->red[i];
  51         palette[i].green = im->green[i];
  52         palette[i].blue = im->blue[i];
  53     }
  54     png_set_PLTE(png_write_ptr, info_ptr, palette, im->colorsTotal);
  55
  56     /* choose between speed (1) and space (9) optimisation */
  57     /* we want to be fast ... */
  58     png_set_compression_level(png_write_ptr,1);
  59     png_set_filter(png_write_ptr,PNG_FILTER_TYPE_BASE,PNG_NO_FILTERS);
  60     /* store file info */
  61     png_write_info(png_write_ptr, info_ptr);
  62     png_set_packing(png_write_ptr);
  63     png_write_image(png_write_ptr, im->pixels);
  64     png_write_end(png_write_ptr, info_ptr);
  65     png_free(png_write_ptr, palette);
  66     png_destroy_write_struct(&png_write_ptr, &info_ptr);
  67 }
  68
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