1 /*
2 * Copyright (C) 2010 Google Inc. All rights reserved.
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
6 * are met:
7 *
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 * 3. Neither the name of Apple Computer, Inc. ("Apple") nor the names of
14 * its contributors may be used to endorse or promote products derived
15 * from this software without specific prior written permission.
16 *
17 * THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY
18 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
19 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
20 * DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR ANY
21 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
22 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
23 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
24 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
26 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27 */
28
29 #include "config.h"
30 #include "platform/image-decoders/webp/WEBPImageDecoder.h"
31
32 #include "platform/PlatformInstrumentation.h"
33 #include "platform/RuntimeEnabledFeatures.h"
34
35 #if USE(QCMSLIB)
36 #include "qcms.h"
37 #endif
38
39 #if CPU(BIG_ENDIAN) || CPU(MIDDLE_ENDIAN)
40 #error Blink assumes a little-endian target.
41 #endif
42
43 #if SK_B32_SHIFT // Output little-endian RGBA pixels (Android).
outputMode(bool hasAlpha)44 inline WEBP_CSP_MODE outputMode(bool hasAlpha) { return hasAlpha ? MODE_rgbA : MODE_RGBA; }
45 #else // Output little-endian BGRA pixels.
outputMode(bool hasAlpha)46 inline WEBP_CSP_MODE outputMode(bool hasAlpha) { return hasAlpha ? MODE_bgrA : MODE_BGRA; }
47 #endif
48
blendChannel(uint8_t src,uint8_t srcA,uint8_t dst,uint8_t dstA,unsigned scale)49 inline uint8_t blendChannel(uint8_t src, uint8_t srcA, uint8_t dst, uint8_t dstA, unsigned scale)
50 {
51 unsigned blendUnscaled = src * srcA + dst * dstA;
52 ASSERT(blendUnscaled < (1ULL << 32) / scale);
53 return (blendUnscaled * scale) >> 24;
54 }
55
blendSrcOverDstNonPremultiplied(uint32_t src,uint32_t dst)56 inline uint32_t blendSrcOverDstNonPremultiplied(uint32_t src, uint32_t dst)
57 {
58 uint8_t srcA = SkGetPackedA32(src);
59 if (srcA == 0)
60 return dst;
61
62 uint8_t dstA = SkGetPackedA32(dst);
63 uint8_t dstFactorA = (dstA * SkAlpha255To256(255 - srcA)) >> 8;
64 ASSERT(srcA + dstFactorA < (1U << 8));
65 uint8_t blendA = srcA + dstFactorA;
66 unsigned scale = (1UL << 24) / blendA;
67
68 uint8_t blendR = blendChannel(SkGetPackedR32(src), srcA, SkGetPackedR32(dst), dstFactorA, scale);
69 uint8_t blendG = blendChannel(SkGetPackedG32(src), srcA, SkGetPackedG32(dst), dstFactorA, scale);
70 uint8_t blendB = blendChannel(SkGetPackedB32(src), srcA, SkGetPackedB32(dst), dstFactorA, scale);
71
72 return SkPackARGB32NoCheck(blendA, blendR, blendG, blendB);
73 }
74
75 // Returns two point ranges (<left, width> pairs) at row 'canvasY', that belong to 'src' but not 'dst'.
76 // A point range is empty if the corresponding width is 0.
findBlendRangeAtRow(const blink::IntRect & src,const blink::IntRect & dst,int canvasY,int & left1,int & width1,int & left2,int & width2)77 inline void findBlendRangeAtRow(const blink::IntRect& src, const blink::IntRect& dst, int canvasY, int& left1, int& width1, int& left2, int& width2)
78 {
79 ASSERT_WITH_SECURITY_IMPLICATION(canvasY >= src.y() && canvasY < src.maxY());
80 left1 = -1;
81 width1 = 0;
82 left2 = -1;
83 width2 = 0;
84
85 if (canvasY < dst.y() || canvasY >= dst.maxY() || src.x() >= dst.maxX() || src.maxX() <= dst.x()) {
86 left1 = src.x();
87 width1 = src.width();
88 return;
89 }
90
91 if (src.x() < dst.x()) {
92 left1 = src.x();
93 width1 = dst.x() - src.x();
94 }
95
96 if (src.maxX() > dst.maxX()) {
97 left2 = dst.maxX();
98 width2 = src.maxX() - dst.maxX();
99 }
100 }
101
alphaBlendPremultiplied(blink::ImageFrame & src,blink::ImageFrame & dst,int canvasY,int left,int width)102 void alphaBlendPremultiplied(blink::ImageFrame& src, blink::ImageFrame& dst, int canvasY, int left, int width)
103 {
104 for (int x = 0; x < width; ++x) {
105 int canvasX = left + x;
106 blink::ImageFrame::PixelData& pixel = *src.getAddr(canvasX, canvasY);
107 if (SkGetPackedA32(pixel) != 0xff) {
108 blink::ImageFrame::PixelData prevPixel = *dst.getAddr(canvasX, canvasY);
109 pixel = SkPMSrcOver(pixel, prevPixel);
110 }
111 }
112 }
113
alphaBlendNonPremultiplied(blink::ImageFrame & src,blink::ImageFrame & dst,int canvasY,int left,int width)114 void alphaBlendNonPremultiplied(blink::ImageFrame& src, blink::ImageFrame& dst, int canvasY, int left, int width)
115 {
116 for (int x = 0; x < width; ++x) {
117 int canvasX = left + x;
118 blink::ImageFrame::PixelData& pixel = *src.getAddr(canvasX, canvasY);
119 if (SkGetPackedA32(pixel) != 0xff) {
120 blink::ImageFrame::PixelData prevPixel = *dst.getAddr(canvasX, canvasY);
121 pixel = blendSrcOverDstNonPremultiplied(pixel, prevPixel);
122 }
123 }
124 }
125
126 namespace blink {
127
WEBPImageDecoder(ImageSource::AlphaOption alphaOption,ImageSource::GammaAndColorProfileOption gammaAndColorProfileOption,size_t maxDecodedBytes)128 WEBPImageDecoder::WEBPImageDecoder(ImageSource::AlphaOption alphaOption,
129 ImageSource::GammaAndColorProfileOption gammaAndColorProfileOption,
130 size_t maxDecodedBytes)
131 : ImageDecoder(alphaOption, gammaAndColorProfileOption, maxDecodedBytes)
132 , m_decoder(0)
133 , m_formatFlags(0)
134 , m_frameBackgroundHasAlpha(false)
135 , m_hasColorProfile(false)
136 #if USE(QCMSLIB)
137 , m_haveReadProfile(false)
138 , m_transform(0)
139 #endif
140 , m_demux(0)
141 , m_demuxState(WEBP_DEMUX_PARSING_HEADER)
142 , m_haveAlreadyParsedThisData(false)
143 , m_haveReadAnimationParameters(false)
144 , m_repetitionCount(cAnimationLoopOnce)
145 , m_decodedHeight(0)
146 {
147 m_blendFunction = (alphaOption == ImageSource::AlphaPremultiplied) ? alphaBlendPremultiplied : alphaBlendNonPremultiplied;
148 }
149
~WEBPImageDecoder()150 WEBPImageDecoder::~WEBPImageDecoder()
151 {
152 clear();
153 }
154
clear()155 void WEBPImageDecoder::clear()
156 {
157 #if USE(QCMSLIB)
158 clearColorTransform();
159 #endif
160 WebPDemuxDelete(m_demux);
161 m_demux = 0;
162 clearDecoder();
163 }
164
clearDecoder()165 void WEBPImageDecoder::clearDecoder()
166 {
167 WebPIDelete(m_decoder);
168 m_decoder = 0;
169 m_decodedHeight = 0;
170 m_frameBackgroundHasAlpha = false;
171 }
172
isSizeAvailable()173 bool WEBPImageDecoder::isSizeAvailable()
174 {
175 if (!ImageDecoder::isSizeAvailable())
176 updateDemuxer();
177
178 return ImageDecoder::isSizeAvailable();
179 }
180
frameCount()181 size_t WEBPImageDecoder::frameCount()
182 {
183 if (!updateDemuxer())
184 return 0;
185
186 return m_frameBufferCache.size();
187 }
188
frameBufferAtIndex(size_t index)189 ImageFrame* WEBPImageDecoder::frameBufferAtIndex(size_t index)
190 {
191 if (index >= frameCount())
192 return 0;
193
194 ImageFrame& frame = m_frameBufferCache[index];
195 if (frame.status() == ImageFrame::FrameComplete)
196 return &frame;
197
198 Vector<size_t> framesToDecode;
199 size_t frameToDecode = index;
200 do {
201 framesToDecode.append(frameToDecode);
202 frameToDecode = m_frameBufferCache[frameToDecode].requiredPreviousFrameIndex();
203 } while (frameToDecode != kNotFound && m_frameBufferCache[frameToDecode].status() != ImageFrame::FrameComplete);
204
205 ASSERT(m_demux);
206 for (size_t i = framesToDecode.size(); i > 0; --i) {
207 size_t frameIndex = framesToDecode[i - 1];
208 if ((m_formatFlags & ANIMATION_FLAG) && !initFrameBuffer(frameIndex))
209 return 0;
210 WebPIterator webpFrame;
211 if (!WebPDemuxGetFrame(m_demux, frameIndex + 1, &webpFrame))
212 return 0;
213 PlatformInstrumentation::willDecodeImage("WEBP");
214 decode(webpFrame.fragment.bytes, webpFrame.fragment.size, false, frameIndex);
215 PlatformInstrumentation::didDecodeImage();
216 WebPDemuxReleaseIterator(&webpFrame);
217
218 if (failed())
219 return 0;
220
221 // We need more data to continue decoding.
222 if (m_frameBufferCache[frameIndex].status() != ImageFrame::FrameComplete)
223 break;
224 }
225
226 // It is also a fatal error if all data is received and we have decoded all
227 // frames available but the file is truncated.
228 if (index >= m_frameBufferCache.size() - 1 && isAllDataReceived() && m_demux && m_demuxState != WEBP_DEMUX_DONE)
229 setFailed();
230
231 frame.notifyBitmapIfPixelsChanged();
232 return &frame;
233 }
234
setData(SharedBuffer * data,bool allDataReceived)235 void WEBPImageDecoder::setData(SharedBuffer* data, bool allDataReceived)
236 {
237 if (failed())
238 return;
239 ImageDecoder::setData(data, allDataReceived);
240 m_haveAlreadyParsedThisData = false;
241 }
242
repetitionCount() const243 int WEBPImageDecoder::repetitionCount() const
244 {
245 return failed() ? cAnimationLoopOnce : m_repetitionCount;
246 }
247
frameIsCompleteAtIndex(size_t index) const248 bool WEBPImageDecoder::frameIsCompleteAtIndex(size_t index) const
249 {
250 if (!m_demux || m_demuxState <= WEBP_DEMUX_PARSING_HEADER)
251 return false;
252 if (!(m_formatFlags & ANIMATION_FLAG))
253 return ImageDecoder::frameIsCompleteAtIndex(index);
254 bool frameIsLoadedAtIndex = index < m_frameBufferCache.size();
255 return frameIsLoadedAtIndex;
256 }
257
frameDurationAtIndex(size_t index) const258 float WEBPImageDecoder::frameDurationAtIndex(size_t index) const
259 {
260 return index < m_frameBufferCache.size() ? m_frameBufferCache[index].duration() : 0;
261 }
262
updateDemuxer()263 bool WEBPImageDecoder::updateDemuxer()
264 {
265 if (failed())
266 return false;
267
268 if (m_haveAlreadyParsedThisData)
269 return true;
270
271 m_haveAlreadyParsedThisData = true;
272
273 const unsigned webpHeaderSize = 20;
274 if (m_data->size() < webpHeaderSize)
275 return false; // Wait for headers so that WebPDemuxPartial doesn't return null.
276
277 WebPDemuxDelete(m_demux);
278 WebPData inputData = { reinterpret_cast<const uint8_t*>(m_data->data()), m_data->size() };
279 m_demux = WebPDemuxPartial(&inputData, &m_demuxState);
280 if (!m_demux || (isAllDataReceived() && m_demuxState != WEBP_DEMUX_DONE))
281 return setFailed();
282
283 if (m_demuxState <= WEBP_DEMUX_PARSING_HEADER)
284 return false; // Not enough data for parsing canvas width/height yet.
285
286 bool hasAnimation = (m_formatFlags & ANIMATION_FLAG);
287 if (!ImageDecoder::isSizeAvailable()) {
288 m_formatFlags = WebPDemuxGetI(m_demux, WEBP_FF_FORMAT_FLAGS);
289 hasAnimation = (m_formatFlags & ANIMATION_FLAG);
290 if (!hasAnimation)
291 m_repetitionCount = cAnimationNone;
292 else
293 m_formatFlags &= ~ICCP_FLAG; // FIXME: Implement ICC profile support for animated images.
294 #if USE(QCMSLIB)
295 if ((m_formatFlags & ICCP_FLAG) && !ignoresGammaAndColorProfile())
296 m_hasColorProfile = true;
297 #endif
298 if (!setSize(WebPDemuxGetI(m_demux, WEBP_FF_CANVAS_WIDTH), WebPDemuxGetI(m_demux, WEBP_FF_CANVAS_HEIGHT)))
299 return setFailed();
300 }
301
302 ASSERT(ImageDecoder::isSizeAvailable());
303 const size_t newFrameCount = WebPDemuxGetI(m_demux, WEBP_FF_FRAME_COUNT);
304 if (hasAnimation && !m_haveReadAnimationParameters && newFrameCount) {
305 // As we have parsed at least one frame (even if partially),
306 // we must already have parsed the animation properties.
307 // This is because ANIM chunk always precedes ANMF chunks.
308 m_repetitionCount = WebPDemuxGetI(m_demux, WEBP_FF_LOOP_COUNT);
309 ASSERT(m_repetitionCount == (m_repetitionCount & 0xffff)); // Loop count is always <= 16 bits.
310 // |m_repetitionCount| is the total number of animation cycles to show,
311 // with 0 meaning "infinite". But ImageSource::repetitionCount()
312 // returns -1 for "infinite", and 0 and up for "show the animation one
313 // cycle more than this value". By subtracting one here, we convert
314 // both finite and infinite cases correctly.
315 --m_repetitionCount;
316 m_haveReadAnimationParameters = true;
317 }
318
319 const size_t oldFrameCount = m_frameBufferCache.size();
320 if (newFrameCount > oldFrameCount) {
321 m_frameBufferCache.resize(newFrameCount);
322 for (size_t i = oldFrameCount; i < newFrameCount; ++i) {
323 m_frameBufferCache[i].setPremultiplyAlpha(m_premultiplyAlpha);
324 if (!hasAnimation) {
325 ASSERT(!i);
326 m_frameBufferCache[i].setRequiredPreviousFrameIndex(kNotFound);
327 continue;
328 }
329 WebPIterator animatedFrame;
330 WebPDemuxGetFrame(m_demux, i + 1, &animatedFrame);
331 ASSERT(animatedFrame.complete == 1);
332 m_frameBufferCache[i].setDuration(animatedFrame.duration);
333 m_frameBufferCache[i].setDisposalMethod(animatedFrame.dispose_method == WEBP_MUX_DISPOSE_BACKGROUND ? ImageFrame::DisposeOverwriteBgcolor : ImageFrame::DisposeKeep);
334 m_frameBufferCache[i].setAlphaBlendSource(animatedFrame.blend_method == WEBP_MUX_BLEND ? ImageFrame::BlendAtopPreviousFrame : ImageFrame::BlendAtopBgcolor);
335 IntRect frameRect(animatedFrame.x_offset, animatedFrame.y_offset, animatedFrame.width, animatedFrame.height);
336 // Make sure the frameRect doesn't extend outside the buffer.
337 if (frameRect.maxX() > size().width())
338 frameRect.setWidth(size().width() - animatedFrame.x_offset);
339 if (frameRect.maxY() > size().height())
340 frameRect.setHeight(size().height() - animatedFrame.y_offset);
341 m_frameBufferCache[i].setOriginalFrameRect(frameRect);
342 m_frameBufferCache[i].setRequiredPreviousFrameIndex(findRequiredPreviousFrame(i, !animatedFrame.has_alpha));
343 WebPDemuxReleaseIterator(&animatedFrame);
344 }
345 }
346
347 return true;
348 }
349
initFrameBuffer(size_t frameIndex)350 bool WEBPImageDecoder::initFrameBuffer(size_t frameIndex)
351 {
352 ImageFrame& buffer = m_frameBufferCache[frameIndex];
353 if (buffer.status() != ImageFrame::FrameEmpty) // Already initialized.
354 return true;
355
356 const size_t requiredPreviousFrameIndex = buffer.requiredPreviousFrameIndex();
357 if (requiredPreviousFrameIndex == kNotFound) {
358 // This frame doesn't rely on any previous data.
359 if (!buffer.setSize(size().width(), size().height()))
360 return setFailed();
361 m_frameBackgroundHasAlpha = !buffer.originalFrameRect().contains(IntRect(IntPoint(), size()));
362 } else {
363 const ImageFrame& prevBuffer = m_frameBufferCache[requiredPreviousFrameIndex];
364 ASSERT(prevBuffer.status() == ImageFrame::FrameComplete);
365
366 // Preserve the last frame as the starting state for this frame.
367 if (!buffer.copyBitmapData(prevBuffer))
368 return setFailed();
369
370 if (prevBuffer.disposalMethod() == ImageFrame::DisposeOverwriteBgcolor) {
371 // We want to clear the previous frame to transparent, without
372 // affecting pixels in the image outside of the frame.
373 const IntRect& prevRect = prevBuffer.originalFrameRect();
374 ASSERT(!prevRect.contains(IntRect(IntPoint(), size())));
375 buffer.zeroFillFrameRect(prevRect);
376 }
377
378 m_frameBackgroundHasAlpha = prevBuffer.hasAlpha() || (prevBuffer.disposalMethod() == ImageFrame::DisposeOverwriteBgcolor);
379 }
380
381 buffer.setStatus(ImageFrame::FramePartial);
382 // The buffer is transparent outside the decoded area while the image is loading.
383 // The correct value of 'hasAlpha' for the frame will be set when it is fully decoded.
384 buffer.setHasAlpha(true);
385 return true;
386 }
387
clearCacheExceptFrame(size_t clearExceptFrame)388 size_t WEBPImageDecoder::clearCacheExceptFrame(size_t clearExceptFrame)
389 {
390 // If |clearExceptFrame| has status FrameComplete, we preserve that frame.
391 // Otherwise, we preserve a previous frame with status FrameComplete whose data is required
392 // to decode |clearExceptFrame|, either in initFrameBuffer() or ApplyPostProcessing().
393 // All other frames can be cleared.
394 while ((clearExceptFrame < m_frameBufferCache.size()) && (m_frameBufferCache[clearExceptFrame].status() != ImageFrame::FrameComplete))
395 clearExceptFrame = m_frameBufferCache[clearExceptFrame].requiredPreviousFrameIndex();
396
397 return ImageDecoder::clearCacheExceptFrame(clearExceptFrame);
398 }
399
clearFrameBuffer(size_t frameIndex)400 void WEBPImageDecoder::clearFrameBuffer(size_t frameIndex)
401 {
402 if (m_demux && m_demuxState >= WEBP_DEMUX_PARSED_HEADER && m_frameBufferCache[frameIndex].status() == ImageFrame::FramePartial) {
403 // Clear the decoder state so that this partial frame can be decoded again when requested.
404 clearDecoder();
405 }
406 ImageDecoder::clearFrameBuffer(frameIndex);
407 }
408
409 #if USE(QCMSLIB)
410
clearColorTransform()411 void WEBPImageDecoder::clearColorTransform()
412 {
413 if (m_transform)
414 qcms_transform_release(m_transform);
415 m_transform = 0;
416 }
417
createColorTransform(const char * data,size_t size)418 bool WEBPImageDecoder::createColorTransform(const char* data, size_t size)
419 {
420 clearColorTransform();
421
422 qcms_profile* deviceProfile = ImageDecoder::qcmsOutputDeviceProfile();
423 if (!deviceProfile)
424 return false;
425 qcms_profile* inputProfile = qcms_profile_from_memory(data, size);
426 if (!inputProfile)
427 return false;
428
429 // We currently only support color profiles for RGB profiled images.
430 ASSERT(icSigRgbData == qcms_profile_get_color_space(inputProfile));
431 // The input image pixels are RGBA format.
432 qcms_data_type format = QCMS_DATA_RGBA_8;
433 // FIXME: Don't force perceptual intent if the image profile contains an intent.
434 m_transform = qcms_transform_create(inputProfile, format, deviceProfile, QCMS_DATA_RGBA_8, QCMS_INTENT_PERCEPTUAL);
435
436 qcms_profile_release(inputProfile);
437 return !!m_transform;
438 }
439
readColorProfile()440 void WEBPImageDecoder::readColorProfile()
441 {
442 WebPChunkIterator chunkIterator;
443 if (!WebPDemuxGetChunk(m_demux, "ICCP", 1, &chunkIterator)) {
444 WebPDemuxReleaseChunkIterator(&chunkIterator);
445 return;
446 }
447
448 const char* profileData = reinterpret_cast<const char*>(chunkIterator.chunk.bytes);
449 size_t profileSize = chunkIterator.chunk.size;
450
451 // Only accept RGB color profiles from input class devices.
452 bool ignoreProfile = false;
453 if (profileSize < ImageDecoder::iccColorProfileHeaderLength)
454 ignoreProfile = true;
455 else if (!ImageDecoder::rgbColorProfile(profileData, profileSize))
456 ignoreProfile = true;
457 else if (!ImageDecoder::inputDeviceColorProfile(profileData, profileSize))
458 ignoreProfile = true;
459
460 if (!ignoreProfile)
461 createColorTransform(profileData, profileSize);
462
463 WebPDemuxReleaseChunkIterator(&chunkIterator);
464 }
465
466 #endif // USE(QCMSLIB)
467
applyPostProcessing(size_t frameIndex)468 void WEBPImageDecoder::applyPostProcessing(size_t frameIndex)
469 {
470 ImageFrame& buffer = m_frameBufferCache[frameIndex];
471 int width;
472 int decodedHeight;
473 if (!WebPIDecGetRGB(m_decoder, &decodedHeight, &width, 0, 0))
474 return; // See also https://bugs.webkit.org/show_bug.cgi?id=74062
475 if (decodedHeight <= 0)
476 return;
477
478 const IntRect& frameRect = buffer.originalFrameRect();
479 ASSERT_WITH_SECURITY_IMPLICATION(width == frameRect.width());
480 ASSERT_WITH_SECURITY_IMPLICATION(decodedHeight <= frameRect.height());
481 const int left = frameRect.x();
482 const int top = frameRect.y();
483
484 #if USE(QCMSLIB)
485 if ((m_formatFlags & ICCP_FLAG) && !ignoresGammaAndColorProfile()) {
486 if (!m_haveReadProfile) {
487 readColorProfile();
488 m_haveReadProfile = true;
489 }
490 for (int y = m_decodedHeight; y < decodedHeight; ++y) {
491 const int canvasY = top + y;
492 uint8_t* row = reinterpret_cast<uint8_t*>(buffer.getAddr(left, canvasY));
493 if (qcms_transform* transform = colorTransform())
494 qcms_transform_data_type(transform, row, row, width, QCMS_OUTPUT_RGBX);
495 uint8_t* pixel = row;
496 for (int x = 0; x < width; ++x, pixel += 4) {
497 const int canvasX = left + x;
498 buffer.setRGBA(canvasX, canvasY, pixel[0], pixel[1], pixel[2], pixel[3]);
499 }
500 }
501 }
502 #endif // USE(QCMSLIB)
503
504 // During the decoding of current frame, we may have set some pixels to be transparent (i.e. alpha < 255).
505 // However, the value of each of these pixels should have been determined by blending it against the value
506 // of that pixel in the previous frame if alpha blend source was 'BlendAtopPreviousFrame'. So, we correct these
507 // pixels based on disposal method of the previous frame and the previous frame buffer.
508 // FIXME: This could be avoided if libwebp decoder had an API that used the previous required frame
509 // to do the alpha-blending by itself.
510 if ((m_formatFlags & ANIMATION_FLAG) && frameIndex && buffer.alphaBlendSource() == ImageFrame::BlendAtopPreviousFrame && buffer.requiredPreviousFrameIndex() != kNotFound) {
511 ImageFrame& prevBuffer = m_frameBufferCache[frameIndex - 1];
512 ASSERT(prevBuffer.status() == ImageFrame::FrameComplete);
513 ImageFrame::DisposalMethod prevDisposalMethod = prevBuffer.disposalMethod();
514 if (prevDisposalMethod == ImageFrame::DisposeKeep) { // Blend transparent pixels with pixels in previous canvas.
515 for (int y = m_decodedHeight; y < decodedHeight; ++y) {
516 m_blendFunction(buffer, prevBuffer, top + y, left, width);
517 }
518 } else if (prevDisposalMethod == ImageFrame::DisposeOverwriteBgcolor) {
519 const IntRect& prevRect = prevBuffer.originalFrameRect();
520 // We need to blend a transparent pixel with its value just after initFrame() call. That is:
521 // * Blend with fully transparent pixel if it belongs to prevRect <-- This is a no-op.
522 // * Blend with the pixel in the previous canvas otherwise <-- Needs alpha-blending.
523 for (int y = m_decodedHeight; y < decodedHeight; ++y) {
524 int canvasY = top + y;
525 int left1, width1, left2, width2;
526 findBlendRangeAtRow(frameRect, prevRect, canvasY, left1, width1, left2, width2);
527 if (width1 > 0)
528 m_blendFunction(buffer, prevBuffer, canvasY, left1, width1);
529 if (width2 > 0)
530 m_blendFunction(buffer, prevBuffer, canvasY, left2, width2);
531 }
532 }
533 }
534
535 m_decodedHeight = decodedHeight;
536 buffer.setPixelsChanged(true);
537 }
538
decode(const uint8_t * dataBytes,size_t dataSize,bool onlySize,size_t frameIndex)539 bool WEBPImageDecoder::decode(const uint8_t* dataBytes, size_t dataSize, bool onlySize, size_t frameIndex)
540 {
541 if (failed())
542 return false;
543
544 if (!ImageDecoder::isSizeAvailable()) {
545 static const size_t imageHeaderSize = 30;
546 if (dataSize < imageHeaderSize)
547 return false;
548 int width, height;
549 WebPBitstreamFeatures features;
550 if (WebPGetFeatures(dataBytes, dataSize, &features) != VP8_STATUS_OK)
551 return setFailed();
552 width = features.width;
553 height = features.height;
554 m_formatFlags = features.has_alpha ? ALPHA_FLAG : 0;
555 if (!setSize(width, height))
556 return setFailed();
557 }
558
559 ASSERT(ImageDecoder::isSizeAvailable());
560 if (onlySize)
561 return true;
562
563 ASSERT(m_frameBufferCache.size() > frameIndex);
564 ImageFrame& buffer = m_frameBufferCache[frameIndex];
565 ASSERT(buffer.status() != ImageFrame::FrameComplete);
566
567 if (buffer.status() == ImageFrame::FrameEmpty) {
568 if (!buffer.setSize(size().width(), size().height()))
569 return setFailed();
570 buffer.setStatus(ImageFrame::FramePartial);
571 // The buffer is transparent outside the decoded area while the image is loading.
572 // The correct value of 'hasAlpha' for the frame will be set when it is fully decoded.
573 buffer.setHasAlpha(true);
574 buffer.setOriginalFrameRect(IntRect(IntPoint(), size()));
575 }
576
577 const IntRect& frameRect = buffer.originalFrameRect();
578 if (!m_decoder) {
579 WEBP_CSP_MODE mode = outputMode(m_formatFlags & ALPHA_FLAG);
580 if (!m_premultiplyAlpha)
581 mode = outputMode(false);
582 #if USE(QCMSLIB)
583 if ((m_formatFlags & ICCP_FLAG) && !ignoresGammaAndColorProfile())
584 mode = MODE_RGBA; // Decode to RGBA for input to libqcms.
585 #endif
586 WebPInitDecBuffer(&m_decoderBuffer);
587 m_decoderBuffer.colorspace = mode;
588 m_decoderBuffer.u.RGBA.stride = size().width() * sizeof(ImageFrame::PixelData);
589 m_decoderBuffer.u.RGBA.size = m_decoderBuffer.u.RGBA.stride * frameRect.height();
590 m_decoderBuffer.is_external_memory = 1;
591 m_decoder = WebPINewDecoder(&m_decoderBuffer);
592 if (!m_decoder)
593 return setFailed();
594 }
595
596 m_decoderBuffer.u.RGBA.rgba = reinterpret_cast<uint8_t*>(buffer.getAddr(frameRect.x(), frameRect.y()));
597
598 switch (WebPIUpdate(m_decoder, dataBytes, dataSize)) {
599 case VP8_STATUS_OK:
600 applyPostProcessing(frameIndex);
601 buffer.setHasAlpha((m_formatFlags & ALPHA_FLAG) || m_frameBackgroundHasAlpha);
602 buffer.setStatus(ImageFrame::FrameComplete);
603 clearDecoder();
604 return true;
605 case VP8_STATUS_SUSPENDED:
606 if (!isAllDataReceived() && !frameIsCompleteAtIndex(frameIndex)) {
607 applyPostProcessing(frameIndex);
608 return false;
609 }
610 // FALLTHROUGH
611 default:
612 clear();
613 return setFailed();
614 }
615 }
616
617 } // namespace blink
618