The Android Open Source Project | 8b23a6c | 2009-03-03 19:30:32 -0800 | [diff] [blame] | 1 | #include <stdio.h> |
| 2 | #include <stdlib.h> |
| 3 | |
| 4 | #include <png.h> |
| 5 | |
| 6 | #if 0 |
| 7 | #define LOG(x...) fprintf(stderr,"error: " x) |
| 8 | #else |
| 9 | #define LOG(x...) do {} while (0) |
| 10 | #endif |
| 11 | |
| 12 | void *loadpng(const char *fn, unsigned *_width, unsigned *_height) |
| 13 | { |
| 14 | FILE *fp = 0; |
| 15 | unsigned char header[8]; |
| 16 | unsigned char *data = 0; |
| 17 | unsigned char **rowptrs = 0; |
| 18 | png_structp p = 0; |
| 19 | png_infop pi = 0; |
| 20 | |
| 21 | png_uint_32 width, height; |
| 22 | int bitdepth, colortype, imethod, cmethod, fmethod, i; |
| 23 | |
| 24 | p = png_create_read_struct(PNG_LIBPNG_VER_STRING, 0, 0, 0); |
| 25 | if(p == 0) { |
| 26 | LOG("%s: failed to allocate png read struct\n", fn); |
| 27 | return 0; |
| 28 | } |
| 29 | |
| 30 | pi = png_create_info_struct(p); |
| 31 | if(pi == 0) { |
| 32 | LOG("%s: failed to allocate png info struct\n", fn); |
| 33 | goto oops; |
| 34 | } |
| 35 | |
| 36 | fp = fopen(fn, "rb"); |
| 37 | if(fp == 0) { |
| 38 | LOG("%s: failed to open file\n", fn); |
| 39 | return 0; |
| 40 | } |
| 41 | |
| 42 | if(fread(header, 8, 1, fp) != 1) { |
| 43 | LOG("%s: failed to read header\n", fn); |
| 44 | goto oops; |
| 45 | } |
| 46 | |
| 47 | if(png_sig_cmp(header, 0, 8)) { |
| 48 | LOG("%s: header is not a PNG header\n", fn); |
| 49 | goto oops; |
| 50 | } |
| 51 | |
| 52 | if(setjmp(png_jmpbuf(p))) { |
| 53 | LOG("%s: png library error\n", fn); |
| 54 | oops: |
| 55 | png_destroy_read_struct(&p, &pi, 0); |
| 56 | if(fp != 0) fclose(fp); |
| 57 | if(data != 0) free(data); |
| 58 | if(rowptrs != 0) free(rowptrs); |
| 59 | return 0; |
| 60 | } |
| 61 | |
| 62 | png_init_io(p, fp); |
| 63 | png_set_sig_bytes(p, 8); |
| 64 | |
| 65 | png_read_info(p, pi); |
| 66 | |
| 67 | png_get_IHDR(p, pi, &width, &height, &bitdepth, &colortype, |
| 68 | &imethod, &cmethod, &fmethod); |
| 69 | // printf("PNG: %d x %d (d=%d, c=%d)\n", |
| 70 | // width, height, bitdepth, colortype); |
| 71 | |
| 72 | switch(colortype){ |
| 73 | case PNG_COLOR_TYPE_PALETTE: |
| 74 | png_set_palette_to_rgb(p); |
| 75 | break; |
| 76 | |
| 77 | case PNG_COLOR_TYPE_RGB: |
| 78 | if(png_get_valid(p, pi, PNG_INFO_tRNS)) { |
| 79 | png_set_tRNS_to_alpha(p); |
| 80 | } else { |
| 81 | png_set_filler(p, 0xff, PNG_FILLER_AFTER); |
| 82 | } |
| 83 | break; |
| 84 | |
| 85 | case PNG_COLOR_TYPE_RGB_ALPHA: |
| 86 | break; |
| 87 | |
| 88 | case PNG_COLOR_TYPE_GRAY: |
| 89 | if(bitdepth < 8) { |
| 90 | png_set_gray_1_2_4_to_8(p); |
| 91 | } |
| 92 | |
| 93 | default: |
| 94 | LOG("%s: unsupported (grayscale?) color type\n"); |
| 95 | goto oops; |
| 96 | } |
| 97 | |
| 98 | if(bitdepth == 16) { |
| 99 | png_set_strip_16(p); |
| 100 | } |
| 101 | |
| 102 | data = (unsigned char*) malloc((width * 4) * height); |
| 103 | rowptrs = (unsigned char **) malloc(sizeof(unsigned char*) * height); |
| 104 | |
| 105 | if((data == 0) || (rowptrs == 0)){ |
| 106 | LOG("could not allocate data buffer\n"); |
| 107 | goto oops; |
| 108 | } |
| 109 | |
| 110 | for(i = 0; i < height; i++) { |
| 111 | rowptrs[i] = data + ((width * 4) * i); |
| 112 | } |
| 113 | |
| 114 | png_read_image(p, rowptrs); |
| 115 | |
| 116 | png_destroy_read_struct(&p, &pi, 0); |
| 117 | fclose(fp); |
| 118 | if(rowptrs != 0) free(rowptrs); |
| 119 | |
| 120 | *_width = width; |
| 121 | *_height = height; |
| 122 | |
| 123 | return (void*) data; |
| 124 | } |
| 125 | |
| 126 | |
| 127 | typedef struct |
| 128 | { |
| 129 | const unsigned char* base; |
| 130 | const unsigned char* end; |
| 131 | const unsigned char* cursor; |
| 132 | |
| 133 | } PngReader; |
| 134 | |
| 135 | static void |
| 136 | png_reader_read_data( png_structp png_ptr, |
| 137 | png_bytep data, |
| 138 | png_size_t length ) |
| 139 | { |
| 140 | PngReader* reader = png_get_io_ptr(png_ptr); |
| 141 | png_size_t avail = (png_size_t)(reader->end - reader->cursor); |
| 142 | |
| 143 | if (avail > length) |
| 144 | avail = length; |
| 145 | |
| 146 | memcpy( data, reader->cursor, avail ); |
| 147 | reader->cursor += avail; |
| 148 | } |
| 149 | |
| 150 | |
| 151 | void *readpng(const unsigned char *base, size_t size, unsigned *_width, unsigned *_height) |
| 152 | { |
| 153 | PngReader reader; |
| 154 | unsigned char *data = 0; |
| 155 | unsigned char **rowptrs = 0; |
| 156 | png_structp p = 0; |
| 157 | png_infop pi = 0; |
| 158 | |
| 159 | png_uint_32 width, height; |
| 160 | int bitdepth, colortype, imethod, cmethod, fmethod, i; |
| 161 | |
| 162 | p = png_create_read_struct(PNG_LIBPNG_VER_STRING, 0, 0, 0); |
| 163 | if(p == 0) { |
| 164 | LOG("%s: failed to allocate png read struct\n", fn); |
| 165 | return 0; |
| 166 | } |
| 167 | |
| 168 | pi = png_create_info_struct(p); |
| 169 | if(pi == 0) { |
| 170 | LOG("%s: failed to allocate png info struct\n", fn); |
| 171 | goto oops; |
| 172 | } |
| 173 | |
| 174 | reader.base = base; |
| 175 | reader.end = base + size; |
| 176 | reader.cursor = base; |
| 177 | |
| 178 | if(size < 8 || png_sig_cmp((unsigned char*)base, 0, 8)) { |
| 179 | LOG("%s: header is not a PNG header\n", fn); |
| 180 | goto oops; |
| 181 | } |
| 182 | |
| 183 | reader.cursor += 8; |
| 184 | |
| 185 | if(setjmp(png_jmpbuf(p))) { |
| 186 | LOG("%s: png library error\n", fn); |
| 187 | oops: |
| 188 | png_destroy_read_struct(&p, &pi, 0); |
| 189 | if(data != 0) free(data); |
| 190 | if(rowptrs != 0) free(rowptrs); |
| 191 | return 0; |
| 192 | } |
| 193 | |
| 194 | png_set_read_fn (p, &reader, png_reader_read_data); |
| 195 | png_set_sig_bytes(p, 8); |
| 196 | |
| 197 | png_read_info(p, pi); |
| 198 | |
| 199 | png_get_IHDR(p, pi, &width, &height, &bitdepth, &colortype, |
| 200 | &imethod, &cmethod, &fmethod); |
| 201 | // printf("PNG: %d x %d (d=%d, c=%d)\n", |
| 202 | // width, height, bitdepth, colortype); |
| 203 | |
| 204 | switch(colortype){ |
| 205 | case PNG_COLOR_TYPE_PALETTE: |
| 206 | png_set_palette_to_rgb(p); |
| 207 | break; |
| 208 | |
| 209 | case PNG_COLOR_TYPE_RGB: |
| 210 | if(png_get_valid(p, pi, PNG_INFO_tRNS)) { |
| 211 | png_set_tRNS_to_alpha(p); |
| 212 | } else { |
| 213 | png_set_filler(p, 0xff, PNG_FILLER_AFTER); |
| 214 | } |
| 215 | break; |
| 216 | |
| 217 | case PNG_COLOR_TYPE_RGB_ALPHA: |
| 218 | break; |
| 219 | |
| 220 | case PNG_COLOR_TYPE_GRAY: |
| 221 | if(bitdepth < 8) { |
| 222 | png_set_gray_1_2_4_to_8(p); |
| 223 | } |
| 224 | |
| 225 | default: |
| 226 | LOG("%s: unsupported (grayscale?) color type\n"); |
| 227 | goto oops; |
| 228 | } |
| 229 | |
| 230 | if(bitdepth == 16) { |
| 231 | png_set_strip_16(p); |
| 232 | } |
| 233 | |
| 234 | data = (unsigned char*) malloc((width * 4) * height); |
| 235 | rowptrs = (unsigned char **) malloc(sizeof(unsigned char*) * height); |
| 236 | |
| 237 | if((data == 0) || (rowptrs == 0)){ |
| 238 | LOG("could not allocate data buffer\n"); |
| 239 | goto oops; |
| 240 | } |
| 241 | |
| 242 | for(i = 0; i < height; i++) { |
| 243 | rowptrs[i] = data + ((width * 4) * i); |
| 244 | } |
| 245 | |
| 246 | png_read_image(p, rowptrs); |
| 247 | |
| 248 | png_destroy_read_struct(&p, &pi, 0); |
| 249 | if(rowptrs != 0) free(rowptrs); |
| 250 | |
| 251 | *_width = width; |
| 252 | *_height = height; |
| 253 | |
| 254 | return (void*) data; |
| 255 | } |
| 256 | |
| 257 | |
| 258 | #if 0 |
| 259 | int main(int argc, char **argv) |
| 260 | { |
| 261 | unsigned w,h; |
| 262 | unsigned char *data; |
| 263 | |
| 264 | if(argc < 2) return 0; |
| 265 | |
| 266 | |
| 267 | data = loadpng(argv[1], &w, &h); |
| 268 | |
| 269 | if(data != 0) { |
| 270 | printf("w: %d h: %d\n", w, h); |
| 271 | } |
| 272 | |
| 273 | return 0; |
| 274 | } |
| 275 | #endif |