ungrib/src/ngl/g2/enc_png.c

   1 #include <stdio.h>
   2 #include <stdlib.h>
   3 #include <string.h>
   4 #ifdef USE_PNG
   5 #include <png.h>
   6 #endif /* USE_PNG */
   7
   8 #ifdef __64BIT__
   9   typedef int g2int;
  10 #else
  11   typedef long g2int;
  12 #endif
  13
  14 #if defined _UNDERSCORE
  15    #define enc_png enc_png_
  16 #elif defined _DOUBLEUNDERSCORE
  17    #define enc_png enc_png__
  18 #endif
  19
  20 #ifdef USE_PNG
  21 struct png_stream {
  22    unsigned char *stream_ptr;     /*  location to write PNG stream  */
  23    g2int stream_len;               /*  number of bytes written       */
  24 };
  25 typedef struct png_stream png_stream;
  26
  27 void user_write_data(png_structp ,png_bytep , png_uint_32 );
  28 void user_flush_data(png_structp );
  29
  30 void user_write_data(png_structp png_ptr,png_bytep data, png_uint_32 length)
  31 /*
  32         Custom write function used to that libpng will write
  33         to memory location instead of a file on disk
  34 */
  35 {
  36      unsigned char *ptr;
  37      g2int offset;
  38      png_stream *mem;
  39
  40      mem=(png_stream *)png_get_io_ptr(png_ptr);
  41      ptr=mem->stream_ptr;
  42      offset=mem->stream_len;
  43 /*     printf("SAGwr %ld %ld %x\n",offset,length,ptr);    */
  44      /*for (j=offset,k=0;k<length;j++,k++) ptr[j]=data[k];*/
  45      memcpy(ptr+offset,data,length);
  46      mem->stream_len += length;
  47 }
  48
  49
  50 void user_flush_data(png_structp png_ptr)
  51 /*
  52         Dummy Custom flush function
  53 */
  54 {
  55    int *do_nothing=NULL;
  56 }
  57 #endif /* USE_PNG */
  58
  59
  60 int enc_png(char *data,g2int *width,g2int *height,g2int *nbits,char *pngbuf)
  61 {
  62     g2int pnglen;
  63 #ifdef USE_PNG
  64     int color_type;
  65     g2int j,bytes,bit_depth;
  66     png_structp png_ptr;
  67     png_infop info_ptr;
  68 /*    png_bytep *row_pointers[*height]; */
  69     png_bytep **row_pointers;
  70     png_stream write_io_ptr;
  71
  72 /* create and initialize png_structs  */
  73
  74     png_ptr = png_create_write_struct(PNG_LIBPNG_VER_STRING, (png_voidp)NULL,
  75                                       NULL, NULL);
  76     if (!png_ptr)
  77        return (-1);
  78
  79     info_ptr = png_create_info_struct(png_ptr);
  80     if (!info_ptr)
  81     {
  82        png_destroy_write_struct(&png_ptr,(png_infopp)NULL);
  83        return (-2);
  84     }
  85
  86 /*     Set Error callback   */
  87
  88     if (setjmp(png_jmpbuf(png_ptr)))
  89     {
  90        png_destroy_write_struct(&png_ptr, &info_ptr);
  91        return (-3);
  92     }
  93
  94 /*    Initialize info for writing PNG stream to memory   */
  95
  96     write_io_ptr.stream_ptr=(png_voidp)pngbuf;
  97     write_io_ptr.stream_len=0;
  98
  99 /*    Set new custom write functions    */
 100
 101     png_set_write_fn(png_ptr,(voidp)&write_io_ptr,(png_rw_ptr)user_write_data,
 102                     (png_flush_ptr)user_flush_data);
 103 /*    png_init_io(png_ptr, fptr);   */
 104 /*    png_set_compression_level(png_ptr, Z_BEST_COMPRESSION);  */
 105
 106 /*     Set the image size, colortype, filter type, etc...      */
 107
 108 /*    printf("SAGTsettingIHDR %d %d %d\n",*width,*height,bit_depth); */
 109     bit_depth=*nbits;
 110     color_type=PNG_COLOR_TYPE_GRAY;
 111     if (*nbits == 24 ) {
 112         bit_depth=8;
 113         color_type=PNG_COLOR_TYPE_RGB;
 114     }
 115     else if (*nbits == 32 ) {
 116         bit_depth=8;
 117         color_type=PNG_COLOR_TYPE_RGB_ALPHA;
 118     }
 119     png_set_IHDR(png_ptr, info_ptr, *width, *height,
 120        bit_depth, color_type, PNG_INTERLACE_NONE,
 121        PNG_COMPRESSION_TYPE_DEFAULT, PNG_FILTER_TYPE_DEFAULT);
 122
 123 /*     Put image data into the PNG info structure    */
 124
 125     /*bytes=bit_depth/8;*/
 126     bytes=*nbits/8;
 127     row_pointers=malloc((*height)*sizeof(png_bytep));
 128     for (j=0;j<*height;j++) row_pointers[j]=(png_bytep *)(data+(j*(*width)*bytes));
 129     png_set_rows(png_ptr, info_ptr, (png_bytepp)row_pointers);
 130
 131 /*     Do the PNG encoding, and write out PNG stream  */
 132
 133     png_write_png(png_ptr, info_ptr, PNG_TRANSFORM_IDENTITY, NULL);
 134
 135 /*     Clean up   */
 136
 137     png_destroy_write_struct(&png_ptr, &info_ptr);
 138     free(row_pointers);
 139     pnglen=write_io_ptr.stream_len;
 140 #endif /* USE_PNG */
 141     return pnglen;
 142
 143 }
 144