1 /* 2 * Small jpeg decoder library 3 * 4 * Copyright (c) 2006, Luc Saillard <luc (at) saillard.org> 5 * All rights reserved. 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions are met: 8 * 9 * - Redistributions of source code must retain the above copyright notice, 10 * this list of conditions and the following disclaimer. 11 * 12 * - Redistributions in binary form must reproduce the above copyright notice, 13 * this list of conditions and the following disclaimer in the documentation 14 * and/or other materials provided with the distribution. 15 * 16 * - Neither the name of the author nor the names of its contributors may be 17 * used to endorse or promote products derived from this software without 18 * specific prior written permission. 19 * 20 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" 21 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE 24 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 25 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 26 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 27 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 28 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 29 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 30 * POSSIBILITY OF SUCH DAMAGE. 31 * 32 */ 33 34 #include <stdio.h> 35 #include <stdlib.h> 36 #include <string.h> 37 #include <stdint.h> 38 39 #include "tinyjpeg.h" 40 #include "tinyjpeg-internal.h" 41 42 /******************************************************************************* 43 * 44 * Colorspace conversion routine 45 * 46 * 47 * Note: 48 * YCbCr is defined per CCIR 601-1, except that Cb and Cr are 49 * normalized to the range 0..MAXJSAMPLE rather than -0.5 .. 0.5. 50 * The conversion equations to be implemented are therefore 51 * R = Y + 1.40200 * Cr 52 * G = Y - 0.34414 * Cb - 0.71414 * Cr 53 * B = Y + 1.77200 * Cb 54 * 55 ******************************************************************************/ 56 static unsigned char clamp(int i) 57 { 58 if (i<0) 59 return 0; 60 else if (i>255) 61 return 255; 62 else 63 return i; 64 } 65 66 /** 67 * YCrCb -> RGB24 (1x1) 68 * .---. 69 * | 1 | 70 * `---' 71 */ 72 static void YCrCB_to_RGB24_1x1(struct jdec_private *priv, int sx, int sy) 73 { 74 const unsigned char *Y, *Cb, *Cr; 75 unsigned char *p; 76 int i,j; 77 int offset_to_next_row; 78 79 #define SCALEBITS 10 80 #define ONE_HALF (1UL << (SCALEBITS-1)) 81 #define FIX(x) ((int)((x) * (1UL<<SCALEBITS) + 0.5)) 82 83 p = priv->plane[0]; 84 Y = priv->Y; 85 Cb = priv->Cb; 86 Cr = priv->Cr; 87 offset_to_next_row = priv->bytes_per_row[0] - 8*3; 88 for (i = sy; i > 0; i--) { 89 for (j = sx; j > 0; j++) { 90 int y, cb, cr; 91 int add_r, add_g, add_b; 92 int r, g , b; 93 94 y = Y[0] << SCALEBITS; 95 cb = *Cb++ - 128; 96 cr = *Cr++ - 128; 97 add_r = FIX(1.40200) * cr + ONE_HALF; 98 add_g = - FIX(0.34414) * cb - FIX(0.71414) * cr + ONE_HALF; 99 add_b = FIX(1.77200) * cb + ONE_HALF; 100 101 r = (y + add_r) >> SCALEBITS; 102 *p++ = clamp(r); 103 g = (y + add_g) >> SCALEBITS; 104 *p++ = clamp(g); 105 b = (y + add_b) >> SCALEBITS; 106 *p++ = clamp(b); 107 108 Y++; 109 } 110 111 p += offset_to_next_row; 112 } 113 114 #undef SCALEBITS 115 #undef ONE_HALF 116 #undef FIX 117 118 } 119 120 /** 121 * YCrCb -> RGB24 (2x1) 122 * .-------. 123 * | 1 | 2 | 124 * `-------' 125 */ 126 static void YCrCB_to_RGB24_2x1(struct jdec_private *priv, int sx, int sy) 127 { 128 const unsigned char *Y, *Cb, *Cr; 129 unsigned char *p; 130 int i,j; 131 int offset_to_next_row; 132 133 #define SCALEBITS 10 134 #define ONE_HALF (1UL << (SCALEBITS-1)) 135 #define FIX(x) ((int)((x) * (1UL<<SCALEBITS) + 0.5)) 136 137 p = priv->plane[0]; 138 Y = priv->Y; 139 Cb = priv->Cb; 140 Cr = priv->Cr; 141 offset_to_next_row = priv->bytes_per_row[0] - 16*3; 142 for (i = sy; i > 0; i--) { 143 144 for (j = sx; j > 0; j -= 2) { 145 146 int y, cb, cr; 147 int add_r, add_g, add_b; 148 int r, g , b; 149 150 y = Y[0] << SCALEBITS; 151 cb = *Cb++ - 128; 152 cr = *Cr++ - 128; 153 add_r = FIX(1.40200) * cr + ONE_HALF; 154 add_g = - FIX(0.34414) * cb - FIX(0.71414) * cr + ONE_HALF; 155 add_b = FIX(1.77200) * cb + ONE_HALF; 156 157 r = (y + add_r) >> SCALEBITS; 158 *p++ = clamp(r); 159 g = (y + add_g) >> SCALEBITS; 160 *p++ = clamp(g); 161 b = (y + add_b) >> SCALEBITS; 162 *p++ = clamp(b); 163 164 if (j > 1) { 165 y = Y[1] << SCALEBITS; 166 r = (y + add_r) >> SCALEBITS; 167 *p++ = clamp(r); 168 g = (y + add_g) >> SCALEBITS; 169 *p++ = clamp(g); 170 b = (y + add_b) >> SCALEBITS; 171 *p++ = clamp(b); 172 } 173 174 Y += 2; 175 } 176 177 p += offset_to_next_row; 178 } 179 180 #undef SCALEBITS 181 #undef ONE_HALF 182 #undef FIX 183 184 } 185 186 187 /** 188 * YCrCb -> RGB24 (1x2) 189 * .---. 190 * | 1 | 191 * |---| 192 * | 2 | 193 * `---' 194 */ 195 static void YCrCB_to_RGB24_1x2(struct jdec_private *priv, int sx, int sy) 196 { 197 const unsigned char *Y, *Cb, *Cr; 198 unsigned char *p, *p2; 199 int i,j; 200 int offset_to_next_row; 201 202 #define SCALEBITS 10 203 #define ONE_HALF (1UL << (SCALEBITS-1)) 204 #define FIX(x) ((int)((x) * (1UL<<SCALEBITS) + 0.5)) 205 206 p = priv->plane[0]; 207 p2 = priv->plane[0] + priv->bytes_per_row[0]; 208 Y = priv->Y; 209 Cb = priv->Cb; 210 Cr = priv->Cr; 211 offset_to_next_row = 2*priv->bytes_per_row[0] - 8*3; 212 for (i = sy; i > 0; i -= 2) { 213 for (j = sx; j > 0; j--) { 214 215 int y, cb, cr; 216 int add_r, add_g, add_b; 217 int r, g , b; 218 219 cb = *Cb++ - 128; 220 cr = *Cr++ - 128; 221 add_r = FIX(1.40200) * cr + ONE_HALF; 222 add_g = - FIX(0.34414) * cb - FIX(0.71414) * cr + ONE_HALF; 223 add_b = FIX(1.77200) * cb + ONE_HALF; 224 225 y = Y[0] << SCALEBITS; 226 r = (y + add_r) >> SCALEBITS; 227 *p++ = clamp(r); 228 g = (y + add_g) >> SCALEBITS; 229 *p++ = clamp(g); 230 b = (y + add_b) >> SCALEBITS; 231 *p++ = clamp(b); 232 233 if (i > 1) { 234 y = Y[8] << SCALEBITS; 235 r = (y + add_r) >> SCALEBITS; 236 *p2++ = clamp(r); 237 g = (y + add_g) >> SCALEBITS; 238 *p2++ = clamp(g); 239 b = (y + add_b) >> SCALEBITS; 240 *p2++ = clamp(b); 241 } 242 243 Y++; 244 } 245 Y += 8; 246 p += offset_to_next_row; 247 p2 += offset_to_next_row; 248 } 249 250 #undef SCALEBITS 251 #undef ONE_HALF 252 #undef FIX 253 254 } 255 256 /** 257 * YCrCb -> RGB24 (2x2) 258 * .-------. 259 * | 1 | 2 | 260 * |---+---| 261 * | 3 | 4 | 262 * `-------' 263 */ 264 static void YCrCB_to_RGB24_2x2(struct jdec_private *priv, int sx, int sy) 265 { 266 const unsigned char *Y, *Cb, *Cr; 267 unsigned char *p, *p2; 268 int i,j; 269 int offset_to_next_row; 270 271 #define SCALEBITS 10 272 #define ONE_HALF (1UL << (SCALEBITS-1)) 273 #define FIX(x) ((int)((x) * (1UL<<SCALEBITS) + 0.5)) 274 275 p = priv->plane[0]; 276 p2 = priv->plane[0] + priv->bytes_per_row[0]; 277 Y = priv->Y; 278 Cb = priv->Cb; 279 Cr = priv->Cr; 280 offset_to_next_row = 2*priv->bytes_per_row[0] - 16*3; 281 for (i = sy; i > 0; i -= 2) { 282 for (j = sx; j > 0; j -= 2) { 283 284 int y, cb, cr; 285 int add_r, add_g, add_b; 286 int r, g , b; 287 288 cb = *Cb++ - 128; 289 cr = *Cr++ - 128; 290 add_r = FIX(1.40200) * cr + ONE_HALF; 291 add_g = - FIX(0.34414) * cb - FIX(0.71414) * cr + ONE_HALF; 292 add_b = FIX(1.77200) * cb + ONE_HALF; 293 294 y = Y[0] << SCALEBITS; 295 r = (y + add_r) >> SCALEBITS; 296 *p++ = clamp(r); 297 g = (y + add_g) >> SCALEBITS; 298 *p++ = clamp(g); 299 b = (y + add_b) >> SCALEBITS; 300 *p++ = clamp(b); 301 302 if (j > 1) { 303 y = Y[1] << SCALEBITS; 304 r = (y + add_r) >> SCALEBITS; 305 *p++ = clamp(r); 306 g = (y + add_g) >> SCALEBITS; 307 *p++ = clamp(g); 308 b = (y + add_b) >> SCALEBITS; 309 *p++ = clamp(b); 310 } 311 312 if (i > 1) { 313 y = Y[16+0] << SCALEBITS; 314 r = (y + add_r) >> SCALEBITS; 315 *p2++ = clamp(r); 316 g = (y + add_g) >> SCALEBITS; 317 *p2++ = clamp(g); 318 b = (y + add_b) >> SCALEBITS; 319 *p2++ = clamp(b); 320 321 if (j > 1) { 322 y = Y[16+1] << SCALEBITS; 323 r = (y + add_r) >> SCALEBITS; 324 *p2++ = clamp(r); 325 g = (y + add_g) >> SCALEBITS; 326 *p2++ = clamp(g); 327 b = (y + add_b) >> SCALEBITS; 328 *p2++ = clamp(b); 329 } 330 } 331 332 Y += 2; 333 } 334 Y += 16; 335 p += offset_to_next_row; 336 p2 += offset_to_next_row; 337 } 338 339 #undef SCALEBITS 340 #undef ONE_HALF 341 #undef FIX 342 343 } 344 345 static int initialize_rgb24(struct jdec_private *priv, 346 unsigned int *bytes_per_blocklines, 347 unsigned int *bytes_per_mcu) 348 { 349 if (!priv->bytes_per_row[0]) 350 priv->bytes_per_row[0] = priv->width * 3; 351 if (priv->components[0] == NULL) 352 priv->components[0] = malloc(priv->height * priv->bytes_per_row[0]); 353 354 bytes_per_blocklines[0] = priv->bytes_per_row[0] << 3; 355 bytes_per_mcu[0] = 3*8; 356 357 return !priv->components[0]; 358 } 359 360 static const struct tinyjpeg_colorspace format_rgb24 = 361 { 362 { 363 YCrCB_to_RGB24_1x1, 364 YCrCB_to_RGB24_1x2, 365 YCrCB_to_RGB24_2x1, 366 YCrCB_to_RGB24_2x2, 367 }, 368 tinyjpeg_decode_mcu_3comp_table, 369 initialize_rgb24 370 }; 371 372 const tinyjpeg_colorspace_t TINYJPEG_FMT_RGB24 = &format_rgb24; 373
