src/gdpng.c

   1 /*****************************************************************************
   2  * RRDtool 1.2.23  Copyright by Tobi Oetiker, 1997-2007
   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(
  18     gdImagePtr im,
  19     FILE * out)
  20 {
  21     int       i;
  22     png_colorp palette;
  23     png_structp png_write_ptr = png_create_write_struct(PNG_LIBPNG_VER_STRING,
  24                                                         (png_voidp) NULL,
  25                                                         /* we would need to point to error handlers
  26                                                            here to do it properly */
  27                                                         (png_error_ptr) NULL,
  28                                                         (png_error_ptr) NULL);
  29     png_infop info_ptr = png_create_info_struct(png_write_ptr);
  30
  31     if (setjmp(gdPngJmpbufStruct.jmpbuf)) {
  32         png_destroy_write_struct(&png_write_ptr, &info_ptr);
  33         return;
  34     }
  35
  36     palette = (png_colorp) png_malloc(png_write_ptr,
  37                                       im->colorsTotal * sizeof(png_color));
  38     if (palette == NULL) {
  39         png_destroy_write_struct(&png_write_ptr, &info_ptr);
  40         return;
  41     }
  42
  43
  44     png_init_io(png_write_ptr, out);
  45     png_set_write_status_fn(png_write_ptr, NULL);
  46     png_set_IHDR(png_write_ptr, info_ptr,
  47                  im->sx, im->sy, im->colorsTotal > 16 ? 8 : 4,
  48                  PNG_COLOR_TYPE_PALETTE,
  49                  im->interlace ? PNG_INTERLACE_ADAM7 : PNG_INTERLACE_NONE,
  50                  PNG_COMPRESSION_TYPE_DEFAULT, PNG_FILTER_TYPE_DEFAULT);
  51     for (i = 0; i < im->colorsTotal; i++) {
  52         palette[i].red = im->red[i];
  53         palette[i].green = im->green[i];
  54         palette[i].blue = im->blue[i];
  55     }
  56     png_set_PLTE(png_write_ptr, info_ptr, palette, im->colorsTotal);
  57
  58     /* choose between speed (1) and space (9) optimisation */
  59     /* we want to be fast ... */
  60     png_set_compression_level(png_write_ptr, 1);
  61     png_set_filter(png_write_ptr, PNG_FILTER_TYPE_BASE, PNG_NO_FILTERS);
  62     /* store file info */
  63     png_write_info(png_write_ptr, info_ptr);
  64     png_set_packing(png_write_ptr);
  65     png_write_image(png_write_ptr, im->pixels);
  66     png_write_end(png_write_ptr, info_ptr);
  67     png_free(png_write_ptr, palette);
  68     png_destroy_write_struct(&png_write_ptr, &info_ptr);
  69 }