readpng.c

   1 #include <stdio.h>
   2 #include <string.h>
   3 #include <png.h>
   4 #include "readpng.h"
   5 #include "lprintf.h"
   6
   7 int readpng(void *dest, const char *fname, readpng_what what, int req_w, int req_h)
   8 {
   9         FILE *fp;
  10         png_structp png_ptr = NULL;
  11         png_infop info_ptr = NULL;
  12         png_bytepp row_ptr = NULL;
  13         int ret = -1;
  14
  15         if (dest == NULL || fname == NULL)
  16         {
  17                 return -1;
  18         }
  19
  20         fp = fopen(fname, "rb");
  21         if (fp == NULL)
  22         {
  23                 lprintf(__FILE__ ": failed to open: %s\n", fname);
  24                 return -1;
  25         }
  26
  27         png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING, NULL, NULL, NULL);
  28         if (!png_ptr)
  29         {
  30                 lprintf(__FILE__ ": png_create_read_struct() failed\n");
  31                 fclose(fp);
  32                 return -1;
  33         }
  34
  35         info_ptr = png_create_info_struct(png_ptr);
  36         if (!info_ptr)
  37         {
  38                 lprintf(__FILE__ ": png_create_info_struct() failed\n");
  39                 goto done;
  40         }
  41
  42         // Start reading
  43         png_init_io(png_ptr, fp);
  44         png_read_png(png_ptr, info_ptr, PNG_TRANSFORM_STRIP_16 | PNG_TRANSFORM_STRIP_ALPHA | PNG_TRANSFORM_PACKING, NULL);
  45         row_ptr = png_get_rows(png_ptr, info_ptr);
  46         if (row_ptr == NULL)
  47         {
  48                 lprintf(__FILE__ ": png_get_rows() failed\n");
  49                 goto done;
  50         }
  51
  52         // lprintf("%s: %ix%i @ %ibpp\n", fname, (int)info_ptr->width, (int)info_ptr->height, info_ptr->pixel_depth);
  53
  54         switch (what)
  55         {
  56                 case READPNG_BG:
  57                 {
  58                         int height, width, h;
  59                         unsigned short *dst = dest;
  60                         if (info_ptr->pixel_depth != 24)
  61                         {
  62                                 lprintf(__FILE__ ": bg image uses %ibpp, needed 24bpp\n", info_ptr->pixel_depth);
  63                                 break;
  64                         }
  65                         height = info_ptr->height;
  66                         if (height > req_h)
  67                                 height = req_h;
  68                         width = info_ptr->width;
  69                         if (width > req_w)
  70                                 width = req_w;
  71
  72                         for (h = 0; h < height; h++)
  73                         {
  74                                 unsigned char *src = row_ptr[h];
  75                                 int len = width;
  76                                 while (len--)
  77                                 {
  78 #ifdef PSP
  79                                         *dst++ = ((src[2]&0xf8)<<8) | ((src[1]&0xf8)<<3) | (src[0] >> 3); // BGR
  80 #else
  81                                         *dst++ = ((src[0]&0xf8)<<8) | ((src[1]&0xf8)<<3) | (src[2] >> 3); // RGB
  82 #endif
  83                                         src += 3;
  84                                 }
  85                                 dst += req_w - width;
  86                         }
  87                         break;
  88                 }
  89
  90                 case READPNG_FONT:
  91                 {
  92                         int x, y, x1, y1;
  93                         unsigned char *dst = dest;
  94                         if (info_ptr->width != req_w || info_ptr->height != req_h)
  95                         {
  96                                 lprintf(__FILE__ ": unexpected font image size %dx%d, needed %dx%d\n",
  97                                         (int)info_ptr->width, (int)info_ptr->height, req_w, req_h);
  98                                 break;
  99                         }
 100                         if (info_ptr->pixel_depth != 8)
 101                         {
 102                                 lprintf(__FILE__ ": font image uses %ibpp, needed 8bpp\n", info_ptr->pixel_depth);
 103                                 break;
 104                         }
 105                         for (y = 0; y < 16; y++)
 106                         {
 107                                 for (x = 0; x < 16; x++)
 108                                 {
 109                                         /* 16x16 grid of syms */
 110                                         int sym_w = req_w / 16;
 111                                         int sym_h = req_h / 16;
 112                                         for (y1 = 0; y1 < sym_h; y1++)
 113                                         {
 114                                                 unsigned char *src = row_ptr[y*sym_h + y1] + x*sym_w;
 115                                                 for (x1 = sym_w/2; x1 > 0; x1--, src+=2)
 116                                                         *dst++ = ((src[0]^0xff) & 0xf0) | ((src[1]^0xff) >> 4);
 117                                         }
 118                                 }
 119                         }
 120                         break;
 121                 }
 122
 123                 case READPNG_SELECTOR:
 124                 {
 125                         int x1, y1;
 126                         unsigned char *dst = dest;
 127                         if (info_ptr->width != req_w || info_ptr->height != req_h)
 128                         {
 129                                 lprintf(__FILE__ ": unexpected selector image size %ix%i, needed %dx%d\n",
 130                                         (int)info_ptr->width, (int)info_ptr->height, req_w, req_h);
 131                                 break;
 132                         }
 133                         if (info_ptr->pixel_depth != 8)
 134                         {
 135                                 lprintf(__FILE__ ": selector image uses %ibpp, needed 8bpp\n", info_ptr->pixel_depth);
 136                                 break;
 137                         }
 138                         for (y1 = 0; y1 < req_h; y1++)
 139                         {
 140                                 unsigned char *src = row_ptr[y1];
 141                                 for (x1 = req_w/2; x1 > 0; x1--, src+=2)
 142                                         *dst++ = ((src[0]^0xff) & 0xf0) | ((src[1]^0xff) >> 4);
 143                         }
 144                         break;
 145                 }
 146
 147                 case READPNG_24:
 148                 {
 149                         int height, width, h;
 150                         unsigned char *dst = dest;
 151                         if (info_ptr->pixel_depth != 24)
 152                         {
 153                                 lprintf(__FILE__ ": image uses %ibpp, needed 24bpp\n", info_ptr->pixel_depth);
 154                                 break;
 155                         }
 156                         height = info_ptr->height;
 157                         if (height > req_h)
 158                                 height = req_h;
 159                         width = info_ptr->width;
 160                         if (width > req_w)
 161                                 width = req_w;
 162
 163                         for (h = 0; h < height; h++)
 164                         {
 165                                 int len = width;
 166                                 unsigned char *src = row_ptr[h];
 167                                 dst += (req_w - width) * 3;
 168                                 for (len = width; len > 0; len--, dst+=3, src+=3)
 169                                         dst[0] = src[2], dst[1] = src[1], dst[2] = src[0];
 170                         }
 171                         break;
 172                 }
 173         }
 174
 175
 176         ret = 0;
 177 done:
 178         png_destroy_read_struct(&png_ptr, info_ptr ? &info_ptr : NULL, (png_infopp)NULL);
 179         fclose(fp);
 180         return ret;
 181 }
 182
 183