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| 1 // Copyright (c) 2011 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 "ui/gfx/codec/jpeg_codec.h" | |
| 6 | |
| 7 #include <setjmp.h> | |
| 8 | |
| 9 #include "base/logging.h" | |
| 10 #include "base/memory/scoped_ptr.h" | |
| 11 #include "third_party/skia/include/core/SkBitmap.h" | |
| 12 #include "third_party/skia/include/core/SkColorPriv.h" | |
| 13 | |
| 14 extern "C" { | |
| 15 #if defined(USE_SYSTEM_LIBJPEG) | |
| 16 #include <jpeglib.h> | |
| 17 #elif defined(USE_LIBJPEG_TURBO) | |
| 18 #include "third_party/libjpeg_turbo/jpeglib.h" | |
| 19 #else | |
| 20 #include "third_party/libjpeg/jpeglib.h" | |
| 21 #endif | |
| 22 } | |
| 23 | |
| 24 namespace gfx { | |
| 25 | |
| 26 // Encoder/decoder shared stuff ------------------------------------------------ | |
| 27 | |
| 28 namespace { | |
| 29 | |
| 30 // used to pass error info through the JPEG library | |
| 31 struct CoderErrorMgr { | |
| 32 jpeg_error_mgr pub; | |
| 33 jmp_buf setjmp_buffer; | |
| 34 }; | |
| 35 | |
| 36 void ErrorExit(jpeg_common_struct* cinfo) { | |
| 37 CoderErrorMgr *err = reinterpret_cast<CoderErrorMgr*>(cinfo->err); | |
| 38 | |
| 39 // Return control to the setjmp point. | |
| 40 longjmp(err->setjmp_buffer, false); | |
| 41 } | |
| 42 | |
| 43 } // namespace | |
| 44 | |
| 45 // This method helps identify at run time which library chromium is using. | |
| 46 JPEGCodec::LibraryVariant JPEGCodec::JpegLibraryVariant() { | |
| 47 #if defined(USE_SYSTEM_LIBJPEG) | |
| 48 return SYSTEM_LIBJPEG; | |
| 49 #elif defined(USE_LIBJPEG_TURBO) | |
| 50 return LIBJPEG_TURBO; | |
| 51 #else | |
| 52 return IJG_LIBJPEG; | |
| 53 #endif | |
| 54 } | |
| 55 | |
| 56 // Encoder --------------------------------------------------------------------- | |
| 57 // | |
| 58 // This code is based on nsJPEGEncoder from Mozilla. | |
| 59 // Copyright 2005 Google Inc. (Brett Wilson, contributor) | |
| 60 | |
| 61 namespace { | |
| 62 | |
| 63 // Initial size for the output buffer in the JpegEncoderState below. | |
| 64 static const int initial_output_buffer_size = 8192; | |
| 65 | |
| 66 struct JpegEncoderState { | |
| 67 explicit JpegEncoderState(std::vector<unsigned char>* o) | |
| 68 : out(o), | |
| 69 image_buffer_used(0) { | |
| 70 } | |
| 71 | |
| 72 // Output buffer, of which 'image_buffer_used' bytes are actually used (this | |
| 73 // will often be less than the actual size of the vector because we size it | |
| 74 // so that libjpeg can write directly into it. | |
| 75 std::vector<unsigned char>* out; | |
| 76 | |
| 77 // Number of bytes in the 'out' buffer that are actually used (see above). | |
| 78 size_t image_buffer_used; | |
| 79 }; | |
| 80 | |
| 81 // Initializes the JpegEncoderState for encoding, and tells libjpeg about where | |
| 82 // the output buffer is. | |
| 83 // | |
| 84 // From the JPEG library: | |
| 85 // "Initialize destination. This is called by jpeg_start_compress() before | |
| 86 // any data is actually written. It must initialize next_output_byte and | |
| 87 // free_in_buffer. free_in_buffer must be initialized to a positive value." | |
| 88 void InitDestination(jpeg_compress_struct* cinfo) { | |
| 89 JpegEncoderState* state = static_cast<JpegEncoderState*>(cinfo->client_data); | |
| 90 DCHECK(state->image_buffer_used == 0) << "initializing after use"; | |
| 91 | |
| 92 state->out->resize(initial_output_buffer_size); | |
| 93 state->image_buffer_used = 0; | |
| 94 | |
| 95 cinfo->dest->next_output_byte = &(*state->out)[0]; | |
| 96 cinfo->dest->free_in_buffer = initial_output_buffer_size; | |
| 97 } | |
| 98 | |
| 99 // Resize the buffer that we give to libjpeg and update our and its state. | |
| 100 // | |
| 101 // From the JPEG library: | |
| 102 // "Callback used by libjpeg whenever the buffer has filled (free_in_buffer | |
| 103 // reaches zero). In typical applications, it should write out the *entire* | |
| 104 // buffer (use the saved start address and buffer length; ignore the current | |
| 105 // state of next_output_byte and free_in_buffer). Then reset the pointer & | |
| 106 // count to the start of the buffer, and return TRUE indicating that the | |
| 107 // buffer has been dumped. free_in_buffer must be set to a positive value | |
| 108 // when TRUE is returned. A FALSE return should only be used when I/O | |
| 109 // suspension is desired (this operating mode is discussed in the next | |
| 110 // section)." | |
| 111 boolean EmptyOutputBuffer(jpeg_compress_struct* cinfo) { | |
| 112 JpegEncoderState* state = static_cast<JpegEncoderState*>(cinfo->client_data); | |
| 113 | |
| 114 // note the new size, the buffer is full | |
| 115 state->image_buffer_used = state->out->size(); | |
| 116 | |
| 117 // expand buffer, just double size each time | |
| 118 state->out->resize(state->out->size() * 2); | |
| 119 | |
| 120 // tell libjpeg where to write the next data | |
| 121 cinfo->dest->next_output_byte = &(*state->out)[state->image_buffer_used]; | |
| 122 cinfo->dest->free_in_buffer = state->out->size() - state->image_buffer_used; | |
| 123 return 1; | |
| 124 } | |
| 125 | |
| 126 // Cleans up the JpegEncoderState to prepare for returning in the final form. | |
| 127 // | |
| 128 // From the JPEG library: | |
| 129 // "Terminate destination --- called by jpeg_finish_compress() after all data | |
| 130 // has been written. In most applications, this must flush any data | |
| 131 // remaining in the buffer. Use either next_output_byte or free_in_buffer to | |
| 132 // determine how much data is in the buffer." | |
| 133 void TermDestination(jpeg_compress_struct* cinfo) { | |
| 134 JpegEncoderState* state = static_cast<JpegEncoderState*>(cinfo->client_data); | |
| 135 DCHECK(state->out->size() >= state->image_buffer_used); | |
| 136 | |
| 137 // update the used byte based on the next byte libjpeg would write to | |
| 138 state->image_buffer_used = cinfo->dest->next_output_byte - &(*state->out)[0]; | |
| 139 DCHECK(state->image_buffer_used < state->out->size()) << | |
| 140 "JPEG library busted, got a bad image buffer size"; | |
| 141 | |
| 142 // update our buffer so that it exactly encompases the desired data | |
| 143 state->out->resize(state->image_buffer_used); | |
| 144 } | |
| 145 | |
| 146 #if !defined(JCS_EXTENSIONS) | |
| 147 // Converts RGBA to RGB (removing the alpha values) to prepare to send data to | |
| 148 // libjpeg. This converts one row of data in rgba with the given width in | |
| 149 // pixels the the given rgb destination buffer (which should have enough space | |
| 150 // reserved for the final data). | |
| 151 void StripAlpha(const unsigned char* rgba, int pixel_width, unsigned char* rgb) | |
| 152 { | |
| 153 for (int x = 0; x < pixel_width; x++) | |
| 154 memcpy(&rgb[x * 3], &rgba[x * 4], 3); | |
| 155 } | |
| 156 | |
| 157 // Converts BGRA to RGB by reordering the color components and dropping the | |
| 158 // alpha. This converts one row of data in rgba with the given width in | |
| 159 // pixels the the given rgb destination buffer (which should have enough space | |
| 160 // reserved for the final data). | |
| 161 void BGRAtoRGB(const unsigned char* bgra, int pixel_width, unsigned char* rgb) | |
| 162 { | |
| 163 for (int x = 0; x < pixel_width; x++) { | |
| 164 const unsigned char* pixel_in = &bgra[x * 4]; | |
| 165 unsigned char* pixel_out = &rgb[x * 3]; | |
| 166 pixel_out[0] = pixel_in[2]; | |
| 167 pixel_out[1] = pixel_in[1]; | |
| 168 pixel_out[2] = pixel_in[0]; | |
| 169 } | |
| 170 } | |
| 171 #endif // !defined(JCS_EXTENSIONS) | |
| 172 | |
| 173 // This class destroys the given jpeg_compress object when it goes out of | |
| 174 // scope. It simplifies the error handling in Encode (and even applies to the | |
| 175 // success case). | |
| 176 class CompressDestroyer { | |
| 177 public: | |
| 178 CompressDestroyer() : cinfo_(NULL) { | |
| 179 } | |
| 180 ~CompressDestroyer() { | |
| 181 DestroyManagedObject(); | |
| 182 } | |
| 183 void SetManagedObject(jpeg_compress_struct* ci) { | |
| 184 DestroyManagedObject(); | |
| 185 cinfo_ = ci; | |
| 186 } | |
| 187 void DestroyManagedObject() { | |
| 188 if (cinfo_) { | |
| 189 jpeg_destroy_compress(cinfo_); | |
| 190 cinfo_ = NULL; | |
| 191 } | |
| 192 } | |
| 193 private: | |
| 194 jpeg_compress_struct* cinfo_; | |
| 195 }; | |
| 196 | |
| 197 } // namespace | |
| 198 | |
| 199 bool JPEGCodec::Encode(const unsigned char* input, ColorFormat format, | |
| 200 int w, int h, int row_byte_width, | |
| 201 int quality, std::vector<unsigned char>* output) { | |
| 202 jpeg_compress_struct cinfo; | |
| 203 CompressDestroyer destroyer; | |
| 204 destroyer.SetManagedObject(&cinfo); | |
| 205 output->clear(); | |
| 206 #if !defined(JCS_EXTENSIONS) | |
| 207 unsigned char* row_buffer = NULL; | |
| 208 #endif | |
| 209 | |
| 210 // We set up the normal JPEG error routines, then override error_exit. | |
| 211 // This must be done before the call to create_compress. | |
| 212 CoderErrorMgr errmgr; | |
| 213 cinfo.err = jpeg_std_error(&errmgr.pub); | |
| 214 errmgr.pub.error_exit = ErrorExit; | |
| 215 | |
| 216 // Establish the setjmp return context for ErrorExit to use. | |
| 217 if (setjmp(errmgr.setjmp_buffer)) { | |
| 218 // If we get here, the JPEG code has signaled an error. | |
| 219 // MSDN notes: "if you intend your code to be portable, do not rely on | |
| 220 // correct destruction of frame-based objects when executing a nonlocal | |
| 221 // goto using a call to longjmp." So we delete the CompressDestroyer's | |
| 222 // object manually instead. | |
| 223 destroyer.DestroyManagedObject(); | |
| 224 #if !defined(JCS_EXTENSIONS) | |
| 225 delete[] row_buffer; | |
| 226 #endif | |
| 227 return false; | |
| 228 } | |
| 229 | |
| 230 // The destroyer will destroy() cinfo on exit. | |
| 231 jpeg_create_compress(&cinfo); | |
| 232 | |
| 233 cinfo.image_width = w; | |
| 234 cinfo.image_height = h; | |
| 235 cinfo.input_components = 3; | |
| 236 #ifdef JCS_EXTENSIONS | |
| 237 // Choose an input colorspace and return if it is an unsupported one. Since | |
| 238 // libjpeg-turbo supports all input formats used by Chromium (i.e. RGB, RGBA, | |
| 239 // and BGRA), we just map the input parameters to a colorspace used by | |
| 240 // libjpeg-turbo. | |
| 241 if (format == FORMAT_RGB) { | |
| 242 cinfo.input_components = 3; | |
| 243 cinfo.in_color_space = JCS_RGB; | |
| 244 } else if (format == FORMAT_RGBA || | |
| 245 (format == FORMAT_SkBitmap && SK_R32_SHIFT == 0)) { | |
| 246 cinfo.input_components = 4; | |
| 247 cinfo.in_color_space = JCS_EXT_RGBX; | |
| 248 } else if (format == FORMAT_BGRA || | |
| 249 (format == FORMAT_SkBitmap && SK_B32_SHIFT == 0)) { | |
| 250 cinfo.input_components = 4; | |
| 251 cinfo.in_color_space = JCS_EXT_BGRX; | |
| 252 } else { | |
| 253 // We can exit this function without calling jpeg_destroy_compress() because | |
| 254 // CompressDestroyer automaticaly calls it. | |
| 255 NOTREACHED() << "Invalid pixel format"; | |
| 256 return false; | |
| 257 } | |
| 258 #else | |
| 259 cinfo.in_color_space = JCS_RGB; | |
| 260 #endif | |
| 261 cinfo.data_precision = 8; | |
| 262 | |
| 263 jpeg_set_defaults(&cinfo); | |
| 264 jpeg_set_quality(&cinfo, quality, 1); // quality here is 0-100 | |
| 265 | |
| 266 // set up the destination manager | |
| 267 jpeg_destination_mgr destmgr; | |
| 268 destmgr.init_destination = InitDestination; | |
| 269 destmgr.empty_output_buffer = EmptyOutputBuffer; | |
| 270 destmgr.term_destination = TermDestination; | |
| 271 cinfo.dest = &destmgr; | |
| 272 | |
| 273 JpegEncoderState state(output); | |
| 274 cinfo.client_data = &state; | |
| 275 | |
| 276 jpeg_start_compress(&cinfo, 1); | |
| 277 | |
| 278 // feed it the rows, doing necessary conversions for the color format | |
| 279 #ifdef JCS_EXTENSIONS | |
| 280 // This function already returns when the input format is not supported by | |
| 281 // libjpeg-turbo and needs conversion. Therefore, we just encode lines without | |
| 282 // conversions. | |
| 283 while (cinfo.next_scanline < cinfo.image_height) { | |
| 284 const unsigned char* row = &input[cinfo.next_scanline * row_byte_width]; | |
| 285 jpeg_write_scanlines(&cinfo, const_cast<unsigned char**>(&row), 1); | |
| 286 } | |
| 287 #else | |
| 288 if (format == FORMAT_RGB) { | |
| 289 // no conversion necessary | |
| 290 while (cinfo.next_scanline < cinfo.image_height) { | |
| 291 const unsigned char* row = &input[cinfo.next_scanline * row_byte_width]; | |
| 292 jpeg_write_scanlines(&cinfo, const_cast<unsigned char**>(&row), 1); | |
| 293 } | |
| 294 } else { | |
| 295 // get the correct format converter | |
| 296 void (*converter)(const unsigned char* in, int w, unsigned char* rgb); | |
| 297 if (format == FORMAT_RGBA || | |
| 298 (format == FORMAT_SkBitmap && SK_R32_SHIFT == 0)) { | |
| 299 converter = StripAlpha; | |
| 300 } else if (format == FORMAT_BGRA || | |
| 301 (format == FORMAT_SkBitmap && SK_B32_SHIFT == 0)) { | |
| 302 converter = BGRAtoRGB; | |
| 303 } else { | |
| 304 NOTREACHED() << "Invalid pixel format"; | |
| 305 return false; | |
| 306 } | |
| 307 | |
| 308 // output row after converting | |
| 309 row_buffer = new unsigned char[w * 3]; | |
| 310 | |
| 311 while (cinfo.next_scanline < cinfo.image_height) { | |
| 312 converter(&input[cinfo.next_scanline * row_byte_width], w, row_buffer); | |
| 313 jpeg_write_scanlines(&cinfo, &row_buffer, 1); | |
| 314 } | |
| 315 delete[] row_buffer; | |
| 316 } | |
| 317 #endif | |
| 318 | |
| 319 jpeg_finish_compress(&cinfo); | |
| 320 return true; | |
| 321 } | |
| 322 | |
| 323 // Decoder -------------------------------------------------------------------- | |
| 324 | |
| 325 namespace { | |
| 326 | |
| 327 struct JpegDecoderState { | |
| 328 JpegDecoderState(const unsigned char* in, size_t len) | |
| 329 : input_buffer(in), input_buffer_length(len) { | |
| 330 } | |
| 331 | |
| 332 const unsigned char* input_buffer; | |
| 333 size_t input_buffer_length; | |
| 334 }; | |
| 335 | |
| 336 // Callback to initialize the source. | |
| 337 // | |
| 338 // From the JPEG library: | |
| 339 // "Initialize source. This is called by jpeg_read_header() before any data is | |
| 340 // actually read. May leave bytes_in_buffer set to 0 (in which case a | |
| 341 // fill_input_buffer() call will occur immediately)." | |
| 342 void InitSource(j_decompress_ptr cinfo) { | |
| 343 JpegDecoderState* state = static_cast<JpegDecoderState*>(cinfo->client_data); | |
| 344 cinfo->src->next_input_byte = state->input_buffer; | |
| 345 cinfo->src->bytes_in_buffer = state->input_buffer_length; | |
| 346 } | |
| 347 | |
| 348 // Callback to fill the buffer. Since our buffer already contains all the data, | |
| 349 // we should never need to provide more data. If libjpeg thinks it needs more | |
| 350 // data, our input is probably corrupt. | |
| 351 // | |
| 352 // From the JPEG library: | |
| 353 // "This is called whenever bytes_in_buffer has reached zero and more data is | |
| 354 // wanted. In typical applications, it should read fresh data into the buffer | |
| 355 // (ignoring the current state of next_input_byte and bytes_in_buffer), reset | |
| 356 // the pointer & count to the start of the buffer, and return TRUE indicating | |
| 357 // that the buffer has been reloaded. It is not necessary to fill the buffer | |
| 358 // entirely, only to obtain at least one more byte. bytes_in_buffer MUST be | |
| 359 // set to a positive value if TRUE is returned. A FALSE return should only | |
| 360 // be used when I/O suspension is desired." | |
| 361 boolean FillInputBuffer(j_decompress_ptr cinfo) { | |
| 362 return false; | |
| 363 } | |
| 364 | |
| 365 // Skip data in the buffer. Since we have all the data at once, this operation | |
| 366 // is easy. It is not clear if this ever gets called because the JPEG library | |
| 367 // should be able to do the skip itself (it has all the data). | |
| 368 // | |
| 369 // From the JPEG library: | |
| 370 // "Skip num_bytes worth of data. The buffer pointer and count should be | |
| 371 // advanced over num_bytes input bytes, refilling the buffer as needed. This | |
| 372 // is used to skip over a potentially large amount of uninteresting data | |
| 373 // (such as an APPn marker). In some applications it may be possible to | |
| 374 // optimize away the reading of the skipped data, but it's not clear that | |
| 375 // being smart is worth much trouble; large skips are uncommon. | |
| 376 // bytes_in_buffer may be zero on return. A zero or negative skip count | |
| 377 // should be treated as a no-op." | |
| 378 void SkipInputData(j_decompress_ptr cinfo, long num_bytes) { | |
| 379 if (num_bytes > static_cast<long>(cinfo->src->bytes_in_buffer)) { | |
| 380 // Since all our data should be in the buffer, trying to skip beyond it | |
| 381 // means that there is some kind of error or corrupt input data. A 0 for | |
| 382 // bytes left means it will call FillInputBuffer which will then fail. | |
| 383 cinfo->src->next_input_byte += cinfo->src->bytes_in_buffer; | |
| 384 cinfo->src->bytes_in_buffer = 0; | |
| 385 } else if (num_bytes > 0) { | |
| 386 cinfo->src->bytes_in_buffer -= static_cast<size_t>(num_bytes); | |
| 387 cinfo->src->next_input_byte += num_bytes; | |
| 388 } | |
| 389 } | |
| 390 | |
| 391 // Our source doesn't need any cleanup, so this is a NOP. | |
| 392 // | |
| 393 // From the JPEG library: | |
| 394 // "Terminate source --- called by jpeg_finish_decompress() after all data has | |
| 395 // been read to clean up JPEG source manager. NOT called by jpeg_abort() or | |
| 396 // jpeg_destroy()." | |
| 397 void TermSource(j_decompress_ptr cinfo) { | |
| 398 } | |
| 399 | |
| 400 #if !defined(JCS_EXTENSIONS) | |
| 401 // Converts one row of rgb data to rgba data by adding a fully-opaque alpha | |
| 402 // value. | |
| 403 void AddAlpha(const unsigned char* rgb, int pixel_width, unsigned char* rgba) { | |
| 404 for (int x = 0; x < pixel_width; x++) { | |
| 405 memcpy(&rgba[x * 4], &rgb[x * 3], 3); | |
| 406 rgba[x * 4 + 3] = 0xff; | |
| 407 } | |
| 408 } | |
| 409 | |
| 410 // Converts one row of RGB data to BGRA by reordering the color components and | |
| 411 // adding alpha values of 0xff. | |
| 412 void RGBtoBGRA(const unsigned char* bgra, int pixel_width, unsigned char* rgb) | |
| 413 { | |
| 414 for (int x = 0; x < pixel_width; x++) { | |
| 415 const unsigned char* pixel_in = &bgra[x * 3]; | |
| 416 unsigned char* pixel_out = &rgb[x * 4]; | |
| 417 pixel_out[0] = pixel_in[2]; | |
| 418 pixel_out[1] = pixel_in[1]; | |
| 419 pixel_out[2] = pixel_in[0]; | |
| 420 pixel_out[3] = 0xff; | |
| 421 } | |
| 422 } | |
| 423 #endif // !defined(JCS_EXTENSIONS) | |
| 424 | |
| 425 // This class destroys the given jpeg_decompress object when it goes out of | |
| 426 // scope. It simplifies the error handling in Decode (and even applies to the | |
| 427 // success case). | |
| 428 class DecompressDestroyer { | |
| 429 public: | |
| 430 DecompressDestroyer() : cinfo_(NULL) { | |
| 431 } | |
| 432 ~DecompressDestroyer() { | |
| 433 DestroyManagedObject(); | |
| 434 } | |
| 435 void SetManagedObject(jpeg_decompress_struct* ci) { | |
| 436 DestroyManagedObject(); | |
| 437 cinfo_ = ci; | |
| 438 } | |
| 439 void DestroyManagedObject() { | |
| 440 if (cinfo_) { | |
| 441 jpeg_destroy_decompress(cinfo_); | |
| 442 cinfo_ = NULL; | |
| 443 } | |
| 444 } | |
| 445 private: | |
| 446 jpeg_decompress_struct* cinfo_; | |
| 447 }; | |
| 448 | |
| 449 } // namespace | |
| 450 | |
| 451 bool JPEGCodec::Decode(const unsigned char* input, size_t input_size, | |
| 452 ColorFormat format, std::vector<unsigned char>* output, | |
| 453 int* w, int* h) { | |
| 454 jpeg_decompress_struct cinfo; | |
| 455 DecompressDestroyer destroyer; | |
| 456 destroyer.SetManagedObject(&cinfo); | |
| 457 output->clear(); | |
| 458 | |
| 459 // We set up the normal JPEG error routines, then override error_exit. | |
| 460 // This must be done before the call to create_decompress. | |
| 461 CoderErrorMgr errmgr; | |
| 462 cinfo.err = jpeg_std_error(&errmgr.pub); | |
| 463 errmgr.pub.error_exit = ErrorExit; | |
| 464 // Establish the setjmp return context for ErrorExit to use. | |
| 465 if (setjmp(errmgr.setjmp_buffer)) { | |
| 466 // If we get here, the JPEG code has signaled an error. | |
| 467 // See note in JPEGCodec::Encode() for why we need to destroy the cinfo | |
| 468 // manually here. | |
| 469 destroyer.DestroyManagedObject(); | |
| 470 return false; | |
| 471 } | |
| 472 | |
| 473 // The destroyer will destroy() cinfo on exit. We don't want to set the | |
| 474 // destroyer's object until cinfo is initialized. | |
| 475 jpeg_create_decompress(&cinfo); | |
| 476 | |
| 477 // set up the source manager | |
| 478 jpeg_source_mgr srcmgr; | |
| 479 srcmgr.init_source = InitSource; | |
| 480 srcmgr.fill_input_buffer = FillInputBuffer; | |
| 481 srcmgr.skip_input_data = SkipInputData; | |
| 482 srcmgr.resync_to_restart = jpeg_resync_to_restart; // use default routine | |
| 483 srcmgr.term_source = TermSource; | |
| 484 cinfo.src = &srcmgr; | |
| 485 | |
| 486 JpegDecoderState state(input, input_size); | |
| 487 cinfo.client_data = &state; | |
| 488 | |
| 489 // fill the file metadata into our buffer | |
| 490 if (jpeg_read_header(&cinfo, true) != JPEG_HEADER_OK) | |
| 491 return false; | |
| 492 | |
| 493 // we want to always get RGB data out | |
| 494 switch (cinfo.jpeg_color_space) { | |
| 495 case JCS_GRAYSCALE: | |
| 496 case JCS_RGB: | |
| 497 case JCS_YCbCr: | |
| 498 #ifdef JCS_EXTENSIONS | |
| 499 // Choose an output colorspace and return if it is an unsupported one. | |
| 500 // Same as JPEGCodec::Encode(), libjpeg-turbo supports all input formats | |
| 501 // used by Chromium (i.e. RGB, RGBA, and BGRA) and we just map the input | |
| 502 // parameters to a colorspace. | |
| 503 if (format == FORMAT_RGB) { | |
| 504 cinfo.out_color_space = JCS_RGB; | |
| 505 cinfo.output_components = 3; | |
| 506 } else if (format == FORMAT_RGBA || | |
| 507 (format == FORMAT_SkBitmap && SK_R32_SHIFT == 0)) { | |
| 508 cinfo.out_color_space = JCS_EXT_RGBX; | |
| 509 cinfo.output_components = 4; | |
| 510 } else if (format == FORMAT_BGRA || | |
| 511 (format == FORMAT_SkBitmap && SK_B32_SHIFT == 0)) { | |
| 512 cinfo.out_color_space = JCS_EXT_BGRX; | |
| 513 cinfo.output_components = 4; | |
| 514 } else { | |
| 515 // We can exit this function without calling jpeg_destroy_decompress() | |
| 516 // because DecompressDestroyer automaticaly calls it. | |
| 517 NOTREACHED() << "Invalid pixel format"; | |
| 518 return false; | |
| 519 } | |
| 520 #else | |
| 521 cinfo.out_color_space = JCS_RGB; | |
| 522 #endif | |
| 523 break; | |
| 524 case JCS_CMYK: | |
| 525 case JCS_YCCK: | |
| 526 default: | |
| 527 // Mozilla errors out on these color spaces, so I presume that the jpeg | |
| 528 // library can't do automatic color space conversion for them. We don't | |
| 529 // care about these anyway. | |
| 530 return false; | |
| 531 } | |
| 532 #ifndef JCS_EXTENSIONS | |
| 533 cinfo.output_components = 3; | |
| 534 #endif | |
| 535 | |
| 536 jpeg_calc_output_dimensions(&cinfo); | |
| 537 *w = cinfo.output_width; | |
| 538 *h = cinfo.output_height; | |
| 539 | |
| 540 jpeg_start_decompress(&cinfo); | |
| 541 | |
| 542 // FIXME(brettw) we may want to allow the capability for callers to request | |
| 543 // how to align row lengths as we do for the compressor. | |
| 544 int row_read_stride = cinfo.output_width * cinfo.output_components; | |
| 545 | |
| 546 #ifdef JCS_EXTENSIONS | |
| 547 // Create memory for a decoded image and write decoded lines to the memory | |
| 548 // without conversions same as JPEGCodec::Encode(). | |
| 549 int row_write_stride = row_read_stride; | |
| 550 output->resize(row_write_stride * cinfo.output_height); | |
| 551 | |
| 552 for (int row = 0; row < static_cast<int>(cinfo.output_height); row++) { | |
| 553 unsigned char* rowptr = &(*output)[row * row_write_stride]; | |
| 554 if (!jpeg_read_scanlines(&cinfo, &rowptr, 1)) | |
| 555 return false; | |
| 556 } | |
| 557 #else | |
| 558 if (format == FORMAT_RGB) { | |
| 559 // easy case, row needs no conversion | |
| 560 int row_write_stride = row_read_stride; | |
| 561 output->resize(row_write_stride * cinfo.output_height); | |
| 562 | |
| 563 for (int row = 0; row < static_cast<int>(cinfo.output_height); row++) { | |
| 564 unsigned char* rowptr = &(*output)[row * row_write_stride]; | |
| 565 if (!jpeg_read_scanlines(&cinfo, &rowptr, 1)) | |
| 566 return false; | |
| 567 } | |
| 568 } else { | |
| 569 // Rows need conversion to output format: read into a temporary buffer and | |
| 570 // expand to the final one. Performance: we could avoid the extra | |
| 571 // allocation by doing the expansion in-place. | |
| 572 int row_write_stride; | |
| 573 void (*converter)(const unsigned char* rgb, int w, unsigned char* out); | |
| 574 if (format == FORMAT_RGBA || | |
| 575 (format == FORMAT_SkBitmap && SK_R32_SHIFT == 0)) { | |
| 576 row_write_stride = cinfo.output_width * 4; | |
| 577 converter = AddAlpha; | |
| 578 } else if (format == FORMAT_BGRA || | |
| 579 (format == FORMAT_SkBitmap && SK_B32_SHIFT == 0)) { | |
| 580 row_write_stride = cinfo.output_width * 4; | |
| 581 converter = RGBtoBGRA; | |
| 582 } else { | |
| 583 NOTREACHED() << "Invalid pixel format"; | |
| 584 jpeg_destroy_decompress(&cinfo); | |
| 585 return false; | |
| 586 } | |
| 587 | |
| 588 output->resize(row_write_stride * cinfo.output_height); | |
| 589 | |
| 590 scoped_ptr<unsigned char[]> row_data(new unsigned char[row_read_stride]); | |
| 591 unsigned char* rowptr = row_data.get(); | |
| 592 for (int row = 0; row < static_cast<int>(cinfo.output_height); row++) { | |
| 593 if (!jpeg_read_scanlines(&cinfo, &rowptr, 1)) | |
| 594 return false; | |
| 595 converter(rowptr, *w, &(*output)[row * row_write_stride]); | |
| 596 } | |
| 597 } | |
| 598 #endif | |
| 599 | |
| 600 jpeg_finish_decompress(&cinfo); | |
| 601 jpeg_destroy_decompress(&cinfo); | |
| 602 return true; | |
| 603 } | |
| 604 | |
| 605 // static | |
| 606 SkBitmap* JPEGCodec::Decode(const unsigned char* input, size_t input_size) { | |
| 607 int w, h; | |
| 608 std::vector<unsigned char> data_vector; | |
| 609 if (!Decode(input, input_size, FORMAT_SkBitmap, &data_vector, &w, &h)) | |
| 610 return NULL; | |
| 611 | |
| 612 // Skia only handles 32 bit images. | |
| 613 int data_length = w * h * 4; | |
| 614 | |
| 615 SkBitmap* bitmap = new SkBitmap(); | |
| 616 bitmap->allocN32Pixels(w, h); | |
| 617 memcpy(bitmap->getAddr32(0, 0), &data_vector[0], data_length); | |
| 618 | |
| 619 return bitmap; | |
| 620 } | |
| 621 | |
| 622 } // namespace gfx | |
| OLD | NEW |