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| 1 // Copyright (c) 2009 The Chromium Authors. All rights reserved. | |
| 2 // Use of this source code is governed by a BSD-style license that can be | |
| 3 // found in the LICENSE file. | |
| 4 | |
| 5 #include "gfx/codec/png_codec.h" | |
| 6 | |
| 7 #include "base/logging.h" | |
| 8 #include "base/scoped_ptr.h" | |
| 9 #include "third_party/skia/include/core/SkBitmap.h" | |
| 10 #include "third_party/skia/include/core/SkUnPreMultiply.h" | |
| 11 #include "third_party/skia/include/core/SkColorPriv.h" | |
| 12 | |
| 13 extern "C" { | |
| 14 #if defined(USE_SYSTEM_LIBPNG) | |
| 15 #include <png.h> | |
| 16 #else | |
| 17 #include "third_party/libpng/png.h" | |
| 18 #endif | |
| 19 } | |
| 20 | |
| 21 namespace gfx { | |
| 22 | |
| 23 namespace { | |
| 24 | |
| 25 // Converts BGRA->RGBA and RGBA->BGRA. | |
| 26 void ConvertBetweenBGRAandRGBA(const unsigned char* input, int pixel_width, | |
| 27 unsigned char* output, bool* is_opaque) { | |
| 28 for (int x = 0; x < pixel_width; x++) { | |
| 29 const unsigned char* pixel_in = &input[x * 4]; | |
| 30 unsigned char* pixel_out = &output[x * 4]; | |
| 31 pixel_out[0] = pixel_in[2]; | |
| 32 pixel_out[1] = pixel_in[1]; | |
| 33 pixel_out[2] = pixel_in[0]; | |
| 34 pixel_out[3] = pixel_in[3]; | |
| 35 } | |
| 36 } | |
| 37 | |
| 38 void ConvertRGBAtoRGB(const unsigned char* rgba, int pixel_width, | |
| 39 unsigned char* rgb, bool* is_opaque) { | |
| 40 for (int x = 0; x < pixel_width; x++) { | |
| 41 const unsigned char* pixel_in = &rgba[x * 4]; | |
| 42 unsigned char* pixel_out = &rgb[x * 3]; | |
| 43 pixel_out[0] = pixel_in[0]; | |
| 44 pixel_out[1] = pixel_in[1]; | |
| 45 pixel_out[2] = pixel_in[2]; | |
| 46 } | |
| 47 } | |
| 48 | |
| 49 void ConvertRGBtoSkia(const unsigned char* rgb, int pixel_width, | |
| 50 unsigned char* rgba, bool* is_opaque) { | |
| 51 for (int x = 0; x < pixel_width; x++) { | |
| 52 const unsigned char* pixel_in = &rgb[x * 3]; | |
| 53 uint32_t* pixel_out = reinterpret_cast<uint32_t*>(&rgba[x * 4]); | |
| 54 *pixel_out = SkPackARGB32(0xFF, pixel_in[0], pixel_in[1], pixel_in[2]); | |
| 55 } | |
| 56 } | |
| 57 | |
| 58 void ConvertRGBAtoSkia(const unsigned char* rgb, int pixel_width, | |
| 59 unsigned char* rgba, bool* is_opaque) { | |
| 60 int total_length = pixel_width * 4; | |
| 61 for (int x = 0; x < total_length; x += 4) { | |
| 62 const unsigned char* pixel_in = &rgb[x]; | |
| 63 uint32_t* pixel_out = reinterpret_cast<uint32_t*>(&rgba[x]); | |
| 64 | |
| 65 unsigned char alpha = pixel_in[3]; | |
| 66 if (alpha != 255) { | |
| 67 *is_opaque = false; | |
| 68 *pixel_out = SkPreMultiplyARGB(alpha, | |
| 69 pixel_in[0], pixel_in[1], pixel_in[2]); | |
| 70 } else { | |
| 71 *pixel_out = SkPackARGB32(alpha, | |
| 72 pixel_in[0], pixel_in[1], pixel_in[2]); | |
| 73 } | |
| 74 } | |
| 75 } | |
| 76 | |
| 77 void ConvertSkiatoRGB(const unsigned char* skia, int pixel_width, | |
| 78 unsigned char* rgb, bool* is_opaque) { | |
| 79 for (int x = 0; x < pixel_width; x++) { | |
| 80 const uint32_t pixel_in = *reinterpret_cast<const uint32_t*>(&skia[x * 4]); | |
| 81 unsigned char* pixel_out = &rgb[x * 3]; | |
| 82 | |
| 83 int alpha = SkGetPackedA32(pixel_in); | |
| 84 if (alpha != 0 && alpha != 255) { | |
| 85 SkColor unmultiplied = SkUnPreMultiply::PMColorToColor(pixel_in); | |
| 86 pixel_out[0] = SkColorGetR(unmultiplied); | |
| 87 pixel_out[1] = SkColorGetG(unmultiplied); | |
| 88 pixel_out[2] = SkColorGetB(unmultiplied); | |
| 89 } else { | |
| 90 pixel_out[0] = SkGetPackedR32(pixel_in); | |
| 91 pixel_out[1] = SkGetPackedG32(pixel_in); | |
| 92 pixel_out[2] = SkGetPackedB32(pixel_in); | |
| 93 } | |
| 94 } | |
| 95 } | |
| 96 | |
| 97 void ConvertSkiatoRGBA(const unsigned char* skia, int pixel_width, | |
| 98 unsigned char* rgba, bool* is_opaque) { | |
| 99 int total_length = pixel_width * 4; | |
| 100 for (int i = 0; i < total_length; i += 4) { | |
| 101 const uint32_t pixel_in = *reinterpret_cast<const uint32_t*>(&skia[i]); | |
| 102 | |
| 103 // Pack the components here. | |
| 104 int alpha = SkGetPackedA32(pixel_in); | |
| 105 if (alpha != 0 && alpha != 255) { | |
| 106 SkColor unmultiplied = SkUnPreMultiply::PMColorToColor(pixel_in); | |
| 107 rgba[i + 0] = SkColorGetR(unmultiplied); | |
| 108 rgba[i + 1] = SkColorGetG(unmultiplied); | |
| 109 rgba[i + 2] = SkColorGetB(unmultiplied); | |
| 110 rgba[i + 3] = alpha; | |
| 111 } else { | |
| 112 rgba[i + 0] = SkGetPackedR32(pixel_in); | |
| 113 rgba[i + 1] = SkGetPackedG32(pixel_in); | |
| 114 rgba[i + 2] = SkGetPackedB32(pixel_in); | |
| 115 rgba[i + 3] = alpha; | |
| 116 } | |
| 117 } | |
| 118 } | |
| 119 | |
| 120 } // namespace | |
| 121 | |
| 122 // Decoder -------------------------------------------------------------------- | |
| 123 // | |
| 124 // This code is based on WebKit libpng interface (PNGImageDecoder), which is | |
| 125 // in turn based on the Mozilla png decoder. | |
| 126 | |
| 127 namespace { | |
| 128 | |
| 129 // Gamma constants: We assume we're on Windows which uses a gamma of 2.2. | |
| 130 const double kMaxGamma = 21474.83; // Maximum gamma accepted by png library. | |
| 131 const double kDefaultGamma = 2.2; | |
| 132 const double kInverseGamma = 1.0 / kDefaultGamma; | |
| 133 | |
| 134 class PngDecoderState { | |
| 135 public: | |
| 136 // Output is a vector<unsigned char>. | |
| 137 PngDecoderState(PNGCodec::ColorFormat ofmt, std::vector<unsigned char>* o) | |
| 138 : output_format(ofmt), | |
| 139 output_channels(0), | |
| 140 bitmap(NULL), | |
| 141 is_opaque(true), | |
| 142 output(o), | |
| 143 row_converter(NULL), | |
| 144 width(0), | |
| 145 height(0), | |
| 146 done(false) { | |
| 147 } | |
| 148 | |
| 149 // Output is an SkBitmap. | |
| 150 explicit PngDecoderState(SkBitmap* skbitmap) | |
| 151 : output_format(PNGCodec::FORMAT_SkBitmap), | |
| 152 output_channels(0), | |
| 153 bitmap(skbitmap), | |
| 154 is_opaque(true), | |
| 155 output(NULL), | |
| 156 row_converter(NULL), | |
| 157 width(0), | |
| 158 height(0), | |
| 159 done(false) { | |
| 160 } | |
| 161 | |
| 162 PNGCodec::ColorFormat output_format; | |
| 163 int output_channels; | |
| 164 | |
| 165 // An incoming SkBitmap to write to. If NULL, we write to output instead. | |
| 166 SkBitmap* bitmap; | |
| 167 | |
| 168 // Used during the reading of an SkBitmap. Defaults to true until we see a | |
| 169 // pixel with anything other than an alpha of 255. | |
| 170 bool is_opaque; | |
| 171 | |
| 172 // The other way to decode output, where we write into an intermediary buffer | |
| 173 // instead of directly to an SkBitmap. | |
| 174 std::vector<unsigned char>* output; | |
| 175 | |
| 176 // Called to convert a row from the library to the correct output format. | |
| 177 // When NULL, no conversion is necessary. | |
| 178 void (*row_converter)(const unsigned char* in, int w, unsigned char* out, | |
| 179 bool* is_opaque); | |
| 180 | |
| 181 // Size of the image, set in the info callback. | |
| 182 int width; | |
| 183 int height; | |
| 184 | |
| 185 // Set to true when we've found the end of the data. | |
| 186 bool done; | |
| 187 | |
| 188 private: | |
| 189 DISALLOW_COPY_AND_ASSIGN(PngDecoderState); | |
| 190 }; | |
| 191 | |
| 192 void ConvertRGBtoRGBA(const unsigned char* rgb, int pixel_width, | |
| 193 unsigned char* rgba, bool* is_opaque) { | |
| 194 for (int x = 0; x < pixel_width; x++) { | |
| 195 const unsigned char* pixel_in = &rgb[x * 3]; | |
| 196 unsigned char* pixel_out = &rgba[x * 4]; | |
| 197 pixel_out[0] = pixel_in[0]; | |
| 198 pixel_out[1] = pixel_in[1]; | |
| 199 pixel_out[2] = pixel_in[2]; | |
| 200 pixel_out[3] = 0xff; | |
| 201 } | |
| 202 } | |
| 203 | |
| 204 void ConvertRGBtoBGRA(const unsigned char* rgb, int pixel_width, | |
| 205 unsigned char* bgra, bool* is_opaque) { | |
| 206 for (int x = 0; x < pixel_width; x++) { | |
| 207 const unsigned char* pixel_in = &rgb[x * 3]; | |
| 208 unsigned char* pixel_out = &bgra[x * 4]; | |
| 209 pixel_out[0] = pixel_in[2]; | |
| 210 pixel_out[1] = pixel_in[1]; | |
| 211 pixel_out[2] = pixel_in[0]; | |
| 212 pixel_out[3] = 0xff; | |
| 213 } | |
| 214 } | |
| 215 | |
| 216 // Called when the png header has been read. This code is based on the WebKit | |
| 217 // PNGImageDecoder | |
| 218 void DecodeInfoCallback(png_struct* png_ptr, png_info* info_ptr) { | |
| 219 PngDecoderState* state = static_cast<PngDecoderState*>( | |
| 220 png_get_progressive_ptr(png_ptr)); | |
| 221 | |
| 222 int bit_depth, color_type, interlace_type, compression_type; | |
| 223 int filter_type, channels; | |
| 224 png_uint_32 w, h; | |
| 225 png_get_IHDR(png_ptr, info_ptr, &w, &h, &bit_depth, &color_type, | |
| 226 &interlace_type, &compression_type, &filter_type); | |
| 227 | |
| 228 // Bounds check. When the image is unreasonably big, we'll error out and | |
| 229 // end up back at the setjmp call when we set up decoding. "Unreasonably big" | |
| 230 // means "big enough that w * h * 32bpp might overflow an int"; we choose this | |
| 231 // threshold to match WebKit and because a number of places in code assume | |
| 232 // that an image's size (in bytes) fits in a (signed) int. | |
| 233 unsigned long long total_size = | |
| 234 static_cast<unsigned long long>(w) * static_cast<unsigned long long>(h); | |
| 235 if (total_size > ((1 << 29) - 1)) | |
| 236 longjmp(png_jmpbuf(png_ptr), 1); | |
| 237 state->width = static_cast<int>(w); | |
| 238 state->height = static_cast<int>(h); | |
| 239 | |
| 240 // Expand to ensure we use 24-bit for RGB and 32-bit for RGBA. | |
| 241 if (color_type == PNG_COLOR_TYPE_PALETTE || | |
| 242 (color_type == PNG_COLOR_TYPE_GRAY && bit_depth < 8)) | |
| 243 png_set_expand(png_ptr); | |
| 244 | |
| 245 // Transparency for paletted images. | |
| 246 if (png_get_valid(png_ptr, info_ptr, PNG_INFO_tRNS)) | |
| 247 png_set_expand(png_ptr); | |
| 248 | |
| 249 // Convert 16-bit to 8-bit. | |
| 250 if (bit_depth == 16) | |
| 251 png_set_strip_16(png_ptr); | |
| 252 | |
| 253 // Expand grayscale to RGB. | |
| 254 if (color_type == PNG_COLOR_TYPE_GRAY || | |
| 255 color_type == PNG_COLOR_TYPE_GRAY_ALPHA) | |
| 256 png_set_gray_to_rgb(png_ptr); | |
| 257 | |
| 258 // Deal with gamma and keep it under our control. | |
| 259 double gamma; | |
| 260 if (png_get_gAMA(png_ptr, info_ptr, &gamma)) { | |
| 261 if (gamma <= 0.0 || gamma > kMaxGamma) { | |
| 262 gamma = kInverseGamma; | |
| 263 png_set_gAMA(png_ptr, info_ptr, gamma); | |
| 264 } | |
| 265 png_set_gamma(png_ptr, kDefaultGamma, gamma); | |
| 266 } else { | |
| 267 png_set_gamma(png_ptr, kDefaultGamma, kInverseGamma); | |
| 268 } | |
| 269 | |
| 270 // Tell libpng to send us rows for interlaced pngs. | |
| 271 if (interlace_type == PNG_INTERLACE_ADAM7) | |
| 272 png_set_interlace_handling(png_ptr); | |
| 273 | |
| 274 // Update our info now | |
| 275 png_read_update_info(png_ptr, info_ptr); | |
| 276 channels = png_get_channels(png_ptr, info_ptr); | |
| 277 | |
| 278 // Pick our row format converter necessary for this data. | |
| 279 if (channels == 3) { | |
| 280 switch (state->output_format) { | |
| 281 case PNGCodec::FORMAT_RGB: | |
| 282 state->row_converter = NULL; // no conversion necessary | |
| 283 state->output_channels = 3; | |
| 284 break; | |
| 285 case PNGCodec::FORMAT_RGBA: | |
| 286 state->row_converter = &ConvertRGBtoRGBA; | |
| 287 state->output_channels = 4; | |
| 288 break; | |
| 289 case PNGCodec::FORMAT_BGRA: | |
| 290 state->row_converter = &ConvertRGBtoBGRA; | |
| 291 state->output_channels = 4; | |
| 292 break; | |
| 293 case PNGCodec::FORMAT_SkBitmap: | |
| 294 state->row_converter = &ConvertRGBtoSkia; | |
| 295 state->output_channels = 4; | |
| 296 break; | |
| 297 default: | |
| 298 NOTREACHED() << "Unknown output format"; | |
| 299 break; | |
| 300 } | |
| 301 } else if (channels == 4) { | |
| 302 switch (state->output_format) { | |
| 303 case PNGCodec::FORMAT_RGB: | |
| 304 state->row_converter = &ConvertRGBAtoRGB; | |
| 305 state->output_channels = 3; | |
| 306 break; | |
| 307 case PNGCodec::FORMAT_RGBA: | |
| 308 state->row_converter = NULL; // no conversion necessary | |
| 309 state->output_channels = 4; | |
| 310 break; | |
| 311 case PNGCodec::FORMAT_BGRA: | |
| 312 state->row_converter = &ConvertBetweenBGRAandRGBA; | |
| 313 state->output_channels = 4; | |
| 314 break; | |
| 315 case PNGCodec::FORMAT_SkBitmap: | |
| 316 state->row_converter = &ConvertRGBAtoSkia; | |
| 317 state->output_channels = 4; | |
| 318 break; | |
| 319 default: | |
| 320 NOTREACHED() << "Unknown output format"; | |
| 321 break; | |
| 322 } | |
| 323 } else { | |
| 324 NOTREACHED() << "Unknown input channels"; | |
| 325 longjmp(png_jmpbuf(png_ptr), 1); | |
| 326 } | |
| 327 | |
| 328 if (state->bitmap) { | |
| 329 state->bitmap->setConfig(SkBitmap::kARGB_8888_Config, | |
| 330 state->width, state->height); | |
| 331 state->bitmap->allocPixels(); | |
| 332 } else if (state->output) { | |
| 333 state->output->resize( | |
| 334 state->width * state->output_channels * state->height); | |
| 335 } | |
| 336 } | |
| 337 | |
| 338 void DecodeRowCallback(png_struct* png_ptr, png_byte* new_row, | |
| 339 png_uint_32 row_num, int pass) { | |
| 340 PngDecoderState* state = static_cast<PngDecoderState*>( | |
| 341 png_get_progressive_ptr(png_ptr)); | |
| 342 | |
| 343 DCHECK(pass == 0) << "We didn't turn on interlace handling, but libpng is " | |
| 344 "giving us interlaced data."; | |
| 345 if (static_cast<int>(row_num) > state->height) { | |
| 346 NOTREACHED() << "Invalid row"; | |
| 347 return; | |
| 348 } | |
| 349 | |
| 350 unsigned char* base = NULL; | |
| 351 if (state->bitmap) | |
| 352 base = reinterpret_cast<unsigned char*>(state->bitmap->getAddr32(0, 0)); | |
| 353 else if (state->output) | |
| 354 base = &state->output->front(); | |
| 355 | |
| 356 unsigned char* dest = &base[state->width * state->output_channels * row_num]; | |
| 357 if (state->row_converter) | |
| 358 state->row_converter(new_row, state->width, dest, &state->is_opaque); | |
| 359 else | |
| 360 memcpy(dest, new_row, state->width * state->output_channels); | |
| 361 } | |
| 362 | |
| 363 void DecodeEndCallback(png_struct* png_ptr, png_info* info) { | |
| 364 PngDecoderState* state = static_cast<PngDecoderState*>( | |
| 365 png_get_progressive_ptr(png_ptr)); | |
| 366 | |
| 367 // Mark the image as complete, this will tell the Decode function that we | |
| 368 // have successfully found the end of the data. | |
| 369 state->done = true; | |
| 370 } | |
| 371 | |
| 372 // Automatically destroys the given read structs on destruction to make | |
| 373 // cleanup and error handling code cleaner. | |
| 374 class PngReadStructDestroyer { | |
| 375 public: | |
| 376 PngReadStructDestroyer(png_struct** ps, png_info** pi) : ps_(ps), pi_(pi) { | |
| 377 } | |
| 378 ~PngReadStructDestroyer() { | |
| 379 png_destroy_read_struct(ps_, pi_, NULL); | |
| 380 } | |
| 381 private: | |
| 382 png_struct** ps_; | |
| 383 png_info** pi_; | |
| 384 }; | |
| 385 | |
| 386 bool BuildPNGStruct(const unsigned char* input, size_t input_size, | |
| 387 png_struct** png_ptr, png_info** info_ptr) { | |
| 388 if (input_size < 8) | |
| 389 return false; // Input data too small to be a png | |
| 390 | |
| 391 // Have libpng check the signature, it likes the first 8 bytes. | |
| 392 if (png_sig_cmp(const_cast<unsigned char*>(input), 0, 8) != 0) | |
| 393 return false; | |
| 394 | |
| 395 *png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING, NULL, NULL, NULL); | |
| 396 if (!*png_ptr) | |
| 397 return false; | |
| 398 | |
| 399 *info_ptr = png_create_info_struct(*png_ptr); | |
| 400 if (!*info_ptr) { | |
| 401 png_destroy_read_struct(png_ptr, NULL, NULL); | |
| 402 return false; | |
| 403 } | |
| 404 | |
| 405 return true; | |
| 406 } | |
| 407 | |
| 408 } // namespace | |
| 409 | |
| 410 // static | |
| 411 bool PNGCodec::Decode(const unsigned char* input, size_t input_size, | |
| 412 ColorFormat format, std::vector<unsigned char>* output, | |
| 413 int* w, int* h) { | |
| 414 png_struct* png_ptr = NULL; | |
| 415 png_info* info_ptr = NULL; | |
| 416 if (!BuildPNGStruct(input, input_size, &png_ptr, &info_ptr)) | |
| 417 return false; | |
| 418 | |
| 419 PngReadStructDestroyer destroyer(&png_ptr, &info_ptr); | |
| 420 if (setjmp(png_jmpbuf(png_ptr))) { | |
| 421 // The destroyer will ensure that the structures are cleaned up in this | |
| 422 // case, even though we may get here as a jump from random parts of the | |
| 423 // PNG library called below. | |
| 424 return false; | |
| 425 } | |
| 426 | |
| 427 PngDecoderState state(format, output); | |
| 428 | |
| 429 png_set_progressive_read_fn(png_ptr, &state, &DecodeInfoCallback, | |
| 430 &DecodeRowCallback, &DecodeEndCallback); | |
| 431 png_process_data(png_ptr, | |
| 432 info_ptr, | |
| 433 const_cast<unsigned char*>(input), | |
| 434 input_size); | |
| 435 | |
| 436 if (!state.done) { | |
| 437 // Fed it all the data but the library didn't think we got all the data, so | |
| 438 // this file must be truncated. | |
| 439 output->clear(); | |
| 440 return false; | |
| 441 } | |
| 442 | |
| 443 *w = state.width; | |
| 444 *h = state.height; | |
| 445 return true; | |
| 446 } | |
| 447 | |
| 448 // static | |
| 449 bool PNGCodec::Decode(const unsigned char* input, size_t input_size, | |
| 450 SkBitmap* bitmap) { | |
| 451 DCHECK(bitmap); | |
| 452 png_struct* png_ptr = NULL; | |
| 453 png_info* info_ptr = NULL; | |
| 454 if (!BuildPNGStruct(input, input_size, &png_ptr, &info_ptr)) | |
| 455 return false; | |
| 456 | |
| 457 PngReadStructDestroyer destroyer(&png_ptr, &info_ptr); | |
| 458 if (setjmp(png_jmpbuf(png_ptr))) { | |
| 459 // The destroyer will ensure that the structures are cleaned up in this | |
| 460 // case, even though we may get here as a jump from random parts of the | |
| 461 // PNG library called below. | |
| 462 return false; | |
| 463 } | |
| 464 | |
| 465 PngDecoderState state(bitmap); | |
| 466 | |
| 467 png_set_progressive_read_fn(png_ptr, &state, &DecodeInfoCallback, | |
| 468 &DecodeRowCallback, &DecodeEndCallback); | |
| 469 png_process_data(png_ptr, | |
| 470 info_ptr, | |
| 471 const_cast<unsigned char*>(input), | |
| 472 input_size); | |
| 473 | |
| 474 if (!state.done) { | |
| 475 return false; | |
| 476 } | |
| 477 | |
| 478 // Set the bitmap's opaqueness based on what we saw. | |
| 479 bitmap->setIsOpaque(state.is_opaque); | |
| 480 | |
| 481 return true; | |
| 482 } | |
| 483 | |
| 484 // static | |
| 485 SkBitmap* PNGCodec::CreateSkBitmapFromBGRAFormat( | |
| 486 std::vector<unsigned char>& bgra, int width, int height) { | |
| 487 SkBitmap* bitmap = new SkBitmap(); | |
| 488 bitmap->setConfig(SkBitmap::kARGB_8888_Config, width, height); | |
| 489 bitmap->allocPixels(); | |
| 490 | |
| 491 bool opaque = false; | |
| 492 unsigned char* bitmap_data = | |
| 493 reinterpret_cast<unsigned char*>(bitmap->getAddr32(0, 0)); | |
| 494 for (int i = width * height * 4 - 4; i >= 0; i -= 4) { | |
| 495 unsigned char alpha = bgra[i + 3]; | |
| 496 if (!opaque && alpha != 255) { | |
| 497 opaque = false; | |
| 498 } | |
| 499 bitmap_data[i + 3] = alpha; | |
| 500 bitmap_data[i] = (bgra[i] * alpha) >> 8; | |
| 501 bitmap_data[i + 1] = (bgra[i + 1] * alpha) >> 8; | |
| 502 bitmap_data[i + 2] = (bgra[i + 2] * alpha) >> 8; | |
| 503 } | |
| 504 | |
| 505 bitmap->setIsOpaque(opaque); | |
| 506 return bitmap; | |
| 507 } | |
| 508 | |
| 509 // Encoder -------------------------------------------------------------------- | |
| 510 // | |
| 511 // This section of the code is based on nsPNGEncoder.cpp in Mozilla | |
| 512 // (Copyright 2005 Google Inc.) | |
| 513 | |
| 514 namespace { | |
| 515 | |
| 516 // Passed around as the io_ptr in the png structs so our callbacks know where | |
| 517 // to write data. | |
| 518 struct PngEncoderState { | |
| 519 explicit PngEncoderState(std::vector<unsigned char>* o) : out(o) {} | |
| 520 std::vector<unsigned char>* out; | |
| 521 }; | |
| 522 | |
| 523 // Called by libpng to flush its internal buffer to ours. | |
| 524 void EncoderWriteCallback(png_structp png, png_bytep data, png_size_t size) { | |
| 525 PngEncoderState* state = static_cast<PngEncoderState*>(png_get_io_ptr(png)); | |
| 526 DCHECK(state->out); | |
| 527 | |
| 528 size_t old_size = state->out->size(); | |
| 529 state->out->resize(old_size + size); | |
| 530 memcpy(&(*state->out)[old_size], data, size); | |
| 531 } | |
| 532 | |
| 533 void FakeFlushCallback(png_structp png) { | |
| 534 // We don't need to perform any flushing since we aren't doing real IO, but | |
| 535 // we're required to provide this function by libpng. | |
| 536 } | |
| 537 | |
| 538 void ConvertBGRAtoRGB(const unsigned char* bgra, int pixel_width, | |
| 539 unsigned char* rgb, bool* is_opaque) { | |
| 540 for (int x = 0; x < pixel_width; x++) { | |
| 541 const unsigned char* pixel_in = &bgra[x * 4]; | |
| 542 unsigned char* pixel_out = &rgb[x * 3]; | |
| 543 pixel_out[0] = pixel_in[2]; | |
| 544 pixel_out[1] = pixel_in[1]; | |
| 545 pixel_out[2] = pixel_in[0]; | |
| 546 } | |
| 547 } | |
| 548 | |
| 549 // The type of functions usable for converting between pixel formats. | |
| 550 typedef void (*FormatConverter)(const unsigned char* in, int w, | |
| 551 unsigned char* out, bool* is_opaque); | |
| 552 | |
| 553 // libpng uses a wacky setjmp-based API, which makes the compiler nervous. | |
| 554 // We constrain all of the calls we make to libpng where the setjmp() is in | |
| 555 // place to this function. | |
| 556 // Returns true on success. | |
| 557 bool DoLibpngWrite(png_struct* png_ptr, png_info* info_ptr, | |
| 558 PngEncoderState* state, | |
| 559 int width, int height, int row_byte_width, | |
| 560 const unsigned char* input, | |
| 561 int png_output_color_type, int output_color_components, | |
| 562 FormatConverter converter) { | |
| 563 // Make sure to not declare any locals here -- locals in the presence | |
| 564 // of setjmp() in C++ code makes gcc complain. | |
| 565 | |
| 566 if (setjmp(png_jmpbuf(png_ptr))) | |
| 567 return false; | |
| 568 | |
| 569 // Set our callback for libpng to give us the data. | |
| 570 png_set_write_fn(png_ptr, state, EncoderWriteCallback, FakeFlushCallback); | |
| 571 | |
| 572 png_set_IHDR(png_ptr, info_ptr, width, height, 8, png_output_color_type, | |
| 573 PNG_INTERLACE_NONE, PNG_COMPRESSION_TYPE_DEFAULT, | |
| 574 PNG_FILTER_TYPE_DEFAULT); | |
| 575 png_write_info(png_ptr, info_ptr); | |
| 576 | |
| 577 if (!converter) { | |
| 578 // No conversion needed, give the data directly to libpng. | |
| 579 for (int y = 0; y < height; y ++) { | |
| 580 png_write_row(png_ptr, | |
| 581 const_cast<unsigned char*>(&input[y * row_byte_width])); | |
| 582 } | |
| 583 } else { | |
| 584 // Needs conversion using a separate buffer. | |
| 585 unsigned char* row = new unsigned char[width * output_color_components]; | |
| 586 for (int y = 0; y < height; y ++) { | |
| 587 converter(&input[y * row_byte_width], width, row, NULL); | |
| 588 png_write_row(png_ptr, row); | |
| 589 } | |
| 590 delete[] row; | |
| 591 } | |
| 592 | |
| 593 png_write_end(png_ptr, info_ptr); | |
| 594 return true; | |
| 595 } | |
| 596 | |
| 597 } // namespace | |
| 598 | |
| 599 // static | |
| 600 bool PNGCodec::Encode(const unsigned char* input, ColorFormat format, | |
| 601 int w, int h, int row_byte_width, | |
| 602 bool discard_transparency, | |
| 603 std::vector<unsigned char>* output) { | |
| 604 // Run to convert an input row into the output row format, NULL means no | |
| 605 // conversion is necessary. | |
| 606 FormatConverter converter = NULL; | |
| 607 | |
| 608 int input_color_components, output_color_components; | |
| 609 int png_output_color_type; | |
| 610 switch (format) { | |
| 611 case FORMAT_RGB: | |
| 612 input_color_components = 3; | |
| 613 output_color_components = 3; | |
| 614 png_output_color_type = PNG_COLOR_TYPE_RGB; | |
| 615 discard_transparency = false; | |
| 616 break; | |
| 617 | |
| 618 case FORMAT_RGBA: | |
| 619 input_color_components = 4; | |
| 620 if (discard_transparency) { | |
| 621 output_color_components = 3; | |
| 622 png_output_color_type = PNG_COLOR_TYPE_RGB; | |
| 623 converter = ConvertRGBAtoRGB; | |
| 624 } else { | |
| 625 output_color_components = 4; | |
| 626 png_output_color_type = PNG_COLOR_TYPE_RGB_ALPHA; | |
| 627 converter = NULL; | |
| 628 } | |
| 629 break; | |
| 630 | |
| 631 case FORMAT_BGRA: | |
| 632 input_color_components = 4; | |
| 633 if (discard_transparency) { | |
| 634 output_color_components = 3; | |
| 635 png_output_color_type = PNG_COLOR_TYPE_RGB; | |
| 636 converter = ConvertBGRAtoRGB; | |
| 637 } else { | |
| 638 output_color_components = 4; | |
| 639 png_output_color_type = PNG_COLOR_TYPE_RGB_ALPHA; | |
| 640 converter = ConvertBetweenBGRAandRGBA; | |
| 641 } | |
| 642 break; | |
| 643 | |
| 644 case FORMAT_SkBitmap: | |
| 645 input_color_components = 4; | |
| 646 if (discard_transparency) { | |
| 647 output_color_components = 3; | |
| 648 png_output_color_type = PNG_COLOR_TYPE_RGB; | |
| 649 converter = ConvertSkiatoRGB; | |
| 650 } else { | |
| 651 output_color_components = 4; | |
| 652 png_output_color_type = PNG_COLOR_TYPE_RGB_ALPHA; | |
| 653 converter = ConvertSkiatoRGBA; | |
| 654 } | |
| 655 break; | |
| 656 | |
| 657 default: | |
| 658 NOTREACHED() << "Unknown pixel format"; | |
| 659 return false; | |
| 660 } | |
| 661 | |
| 662 // Row stride should be at least as long as the length of the data. | |
| 663 DCHECK(input_color_components * w <= row_byte_width); | |
| 664 | |
| 665 png_struct* png_ptr = png_create_write_struct(PNG_LIBPNG_VER_STRING, | |
| 666 NULL, NULL, NULL); | |
| 667 if (!png_ptr) | |
| 668 return false; | |
| 669 png_info* info_ptr = png_create_info_struct(png_ptr); | |
| 670 if (!info_ptr) { | |
| 671 png_destroy_write_struct(&png_ptr, NULL); | |
| 672 return false; | |
| 673 } | |
| 674 | |
| 675 PngEncoderState state(output); | |
| 676 bool success = DoLibpngWrite(png_ptr, info_ptr, &state, | |
| 677 w, h, row_byte_width, input, | |
| 678 png_output_color_type, output_color_components, | |
| 679 converter); | |
| 680 png_destroy_write_struct(&png_ptr, &info_ptr); | |
| 681 | |
| 682 return success; | |
| 683 } | |
| 684 | |
| 685 // static | |
| 686 bool PNGCodec::EncodeBGRASkBitmap(const SkBitmap& input, | |
| 687 bool discard_transparency, | |
| 688 std::vector<unsigned char>* output) { | |
| 689 static const int bbp = 4; | |
| 690 | |
| 691 SkAutoLockPixels lock_input(input); | |
| 692 DCHECK(input.empty() || input.bytesPerPixel() == bbp); | |
| 693 | |
| 694 return Encode(reinterpret_cast<unsigned char*>(input.getAddr32(0, 0)), | |
| 695 FORMAT_SkBitmap, input.width(), input.height(), | |
| 696 input.width() * bbp, discard_transparency, output); | |
| 697 } | |
| 698 | |
| 699 } // namespace gfx | |
| OLD | NEW |
|---|
Chromium Code Reviews
Issue 6246027:
Move src/gfx/ to src/ui/gfx... (Closed)
Base URL: svn://svn.chromium.org/chrome/trunk/src/