output.c

   1
   2 #include <stdint.h>
   3 #include <malloc.h>
   4 #include <png.h>
   5
   6 #include "common.h"
   7 #include "output.h"
   8
   9 typedef struct {
  10         FILE *fh;
  11         png_structp p_png;
  12         png_infop   p_info;
  13 } png_output_t;
  14
  15 int open_file_png(char *psz_filename, hnd_t *p_handle, int i_compression )
  16 {
  17         png_output_t *h = NULL;
  18         if( (h = calloc(1, sizeof(*h))) == NULL )
  19                 return -1;
  20
  21         if( !strcmp(psz_filename, "-") )
  22                 h->fh = stdout;
  23         else if( (h->fh = fopen(psz_filename, "wb")) == NULL )
  24         {
  25                 goto error;
  26         }
  27
  28         if( (h->p_png = png_create_write_struct( PNG_LIBPNG_VER_STRING, NULL, NULL, NULL )) == NULL )
  29         {
  30                 goto error;
  31         }
  32
  33         if( (h->p_info = png_create_info_struct(h->p_png)) == NULL )
  34         {
  35                 png_destroy_write_struct(&(h->p_png), (png_infopp)NULL);
  36                 goto error;
  37         }
  38
  39         png_init_io( h->p_png, h->fh );
  40
  41         png_set_compression_level( h->p_png, i_compression );
  42
  43         *p_handle = h;
  44
  45         return 0;
  46
  47 error:
  48         if( h->fh != NULL && h->fh != stdout )
  49                 fclose( h->fh );
  50         free(h);
  51
  52         return -1;
  53 }
  54
  55 int close_file_png( hnd_t handle )
  56 {
  57         int ret = 0;
  58         png_output_t *h = handle;
  59
  60         png_destroy_write_struct( &(h->p_png), &(h->p_info) );
  61
  62         if ((h->fh == NULL) || (h->fh == stdout))
  63                 return ret;
  64
  65         ret = fclose(h->fh);
  66
  67         free(h);
  68
  69         return ret;
  70 }