1/*
2 * Copyright 2015 Google Inc.
3 *
4 * Use of this source code is governed by a BSD-style license that can be
5 * found in the LICENSE file.
6 */
7
8#include "src/codec/SkWebpCodec.h"
9
10#include "include/codec/SkCodecAnimation.h"
11#include "include/core/SkBitmap.h"
12#include "include/core/SkCanvas.h"
13#include "include/private/SkTemplates.h"
14#include "include/private/SkTo.h"
15#include "src/codec/SkCodecAnimationPriv.h"
16#include "src/codec/SkCodecPriv.h"
17#include "src/codec/SkParseEncodedOrigin.h"
18#include "src/codec/SkSampler.h"
19#include "src/core/SkRasterPipeline.h"
20#include "src/core/SkStreamPriv.h"
21
22// A WebP decoder on top of (subset of) libwebp
23// For more information on WebP image format, and libwebp library, see:
24// https://code.google.com/speed/webp/
25// http://www.webmproject.org/code/#libwebp-webp-image-library
26// https://chromium.googlesource.com/webm/libwebp
27
28// If moving libwebp out of skia source tree, path for webp headers must be
29// updated accordingly. Here, we enforce using local copy in webp sub-directory.
30#include "webp/decode.h"
31#include "webp/demux.h"
32#include "webp/encode.h"
33
34bool SkWebpCodec::IsWebp(const void* buf, size_t bytesRead) {
35 // WEBP starts with the following:
36 // RIFFXXXXWEBPVP
37 // Where XXXX is unspecified.
38 const char* bytes = static_cast<const char*>(buf);
39 return bytesRead >= 14 && !memcmp(bytes, "RIFF", 4) && !memcmp(&bytes[8], "WEBPVP", 6);
40}
41
42// Parse headers of RIFF container, and check for valid Webp (VP8) content.
43// Returns an SkWebpCodec on success
44std::unique_ptr<SkCodec> SkWebpCodec::MakeFromStream(std::unique_ptr<SkStream> stream,
45 Result* result) {
46 // Webp demux needs a contiguous data buffer.
47 sk_sp<SkData> data = nullptr;
48 if (stream->getMemoryBase()) {
49 // It is safe to make without copy because we'll hold onto the stream.
50 data = SkData::MakeWithoutCopy(stream->getMemoryBase(), stream->getLength());
51 } else {
52 data = SkCopyStreamToData(stream.get());
53
54 // If we are forced to copy the stream to a data, we can go ahead and delete the stream.
55 stream.reset(nullptr);
56 }
57
58 // It's a little strange that the |demux| will outlive |webpData|, though it needs the
59 // pointer in |webpData| to remain valid. This works because the pointer remains valid
60 // until the SkData is freed.
61 WebPData webpData = { data->bytes(), data->size() };
62 WebPDemuxState state;
63 SkAutoTCallVProc<WebPDemuxer, WebPDemuxDelete> demux(WebPDemuxPartial(&webpData, &state));
64 switch (state) {
65 case WEBP_DEMUX_PARSE_ERROR:
66 *result = kInvalidInput;
67 return nullptr;
68 case WEBP_DEMUX_PARSING_HEADER:
69 *result = kIncompleteInput;
70 return nullptr;
71 case WEBP_DEMUX_PARSED_HEADER:
72 case WEBP_DEMUX_DONE:
73 SkASSERT(demux);
74 break;
75 }
76
77 const int width = WebPDemuxGetI(demux, WEBP_FF_CANVAS_WIDTH);
78 const int height = WebPDemuxGetI(demux, WEBP_FF_CANVAS_HEIGHT);
79
80 // Validate the image size that's about to be decoded.
81 {
82 const int64_t size = sk_64_mul(width, height);
83 // now check that if we are 4-bytes per pixel, we also don't overflow
84 if (!SkTFitsIn<int32_t>(size) || SkTo<int32_t>(size) > (0x7FFFFFFF >> 2)) {
85 *result = kInvalidInput;
86 return nullptr;
87 }
88 }
89
90 std::unique_ptr<SkEncodedInfo::ICCProfile> profile = nullptr;
91 {
92 WebPChunkIterator chunkIterator;
93 SkAutoTCallVProc<WebPChunkIterator, WebPDemuxReleaseChunkIterator> autoCI(&chunkIterator);
94 if (WebPDemuxGetChunk(demux, "ICCP", 1, &chunkIterator)) {
95 // FIXME: I think this could be MakeWithoutCopy
96 auto chunk = SkData::MakeWithCopy(chunkIterator.chunk.bytes, chunkIterator.chunk.size);
97 profile = SkEncodedInfo::ICCProfile::Make(std::move(chunk));
98 }
99 if (profile && profile->profile()->data_color_space != skcms_Signature_RGB) {
100 profile = nullptr;
101 }
102 }
103
104 SkEncodedOrigin origin = kDefault_SkEncodedOrigin;
105 {
106 WebPChunkIterator chunkIterator;
107 SkAutoTCallVProc<WebPChunkIterator, WebPDemuxReleaseChunkIterator> autoCI(&chunkIterator);
108 if (WebPDemuxGetChunk(demux, "EXIF", 1, &chunkIterator)) {
109 SkParseEncodedOrigin(chunkIterator.chunk.bytes, chunkIterator.chunk.size, &origin);
110 }
111 }
112
113 // Get the first frame and its "features" to determine the color and alpha types.
114 WebPIterator frame;
115 SkAutoTCallVProc<WebPIterator, WebPDemuxReleaseIterator> autoFrame(&frame);
116 if (!WebPDemuxGetFrame(demux, 1, &frame)) {
117 *result = kIncompleteInput;
118 return nullptr;
119 }
120
121 WebPBitstreamFeatures features;
122 switch (WebPGetFeatures(frame.fragment.bytes, frame.fragment.size, &features)) {
123 case VP8_STATUS_OK:
124 break;
125 case VP8_STATUS_SUSPENDED:
126 case VP8_STATUS_NOT_ENOUGH_DATA:
127 *result = kIncompleteInput;
128 return nullptr;
129 default:
130 *result = kInvalidInput;
131 return nullptr;
132 }
133
134 const bool hasAlpha = SkToBool(frame.has_alpha)
135 || frame.width != width || frame.height != height;
136 SkEncodedInfo::Color color;
137 SkEncodedInfo::Alpha alpha;
138 switch (features.format) {
139 case 0:
140 // This indicates a "mixed" format. We could see this for
141 // animated webps (multiple fragments).
142 // We could also guess kYUV here, but I think it makes more
143 // sense to guess kBGRA which is likely closer to the final
144 // output. Otherwise, we might end up converting
145 // BGRA->YUVA->BGRA.
146 [[fallthrough]];
147 case 2:
148 // This is the lossless format (BGRA).
149 if (hasAlpha) {
150 color = SkEncodedInfo::kBGRA_Color;
151 alpha = SkEncodedInfo::kUnpremul_Alpha;
152 } else {
153 color = SkEncodedInfo::kBGRX_Color;
154 alpha = SkEncodedInfo::kOpaque_Alpha;
155 }
156 break;
157 case 1:
158 // This is the lossy format (YUV).
159 if (hasAlpha) {
160 color = SkEncodedInfo::kYUVA_Color;
161 alpha = SkEncodedInfo::kUnpremul_Alpha;
162 } else {
163 color = SkEncodedInfo::kYUV_Color;
164 alpha = SkEncodedInfo::kOpaque_Alpha;
165 }
166 break;
167 default:
168 *result = kInvalidInput;
169 return nullptr;
170 }
171
172
173 *result = kSuccess;
174 SkEncodedInfo info = SkEncodedInfo::Make(width, height, color, alpha, 8, std::move(profile));
175 return std::unique_ptr<SkCodec>(new SkWebpCodec(std::move(info), std::move(stream),
176 demux.release(), std::move(data), origin));
177}
178
179static WEBP_CSP_MODE webp_decode_mode(SkColorType dstCT, bool premultiply) {
180 switch (dstCT) {
181 case kBGRA_8888_SkColorType:
182 return premultiply ? MODE_bgrA : MODE_BGRA;
183 case kRGBA_8888_SkColorType:
184 return premultiply ? MODE_rgbA : MODE_RGBA;
185 case kRGB_565_SkColorType:
186 return MODE_RGB_565;
187 default:
188 return MODE_LAST;
189 }
190}
191
192SkWebpCodec::Frame* SkWebpCodec::FrameHolder::appendNewFrame(bool hasAlpha) {
193 const int i = this->size();
194 fFrames.emplace_back(i, hasAlpha ? SkEncodedInfo::kUnpremul_Alpha
195 : SkEncodedInfo::kOpaque_Alpha);
196 return &fFrames[i];
197}
198
199bool SkWebpCodec::onGetValidSubset(SkIRect* desiredSubset) const {
200 if (!desiredSubset) {
201 return false;
202 }
203
204 if (!this->bounds().contains(*desiredSubset)) {
205 return false;
206 }
207
208 // As stated below, libwebp snaps to even left and top. Make sure top and left are even, so we
209 // decode this exact subset.
210 // Leave right and bottom unmodified, so we suggest a slightly larger subset than requested.
211 desiredSubset->fLeft = (desiredSubset->fLeft >> 1) << 1;
212 desiredSubset->fTop = (desiredSubset->fTop >> 1) << 1;
213 return true;
214}
215
216int SkWebpCodec::onGetRepetitionCount() {
217 auto flags = WebPDemuxGetI(fDemux.get(), WEBP_FF_FORMAT_FLAGS);
218 if (!(flags & ANIMATION_FLAG)) {
219 return 0;
220 }
221
222 int loopCount = WebPDemuxGetI(fDemux.get(), WEBP_FF_LOOP_COUNT);
223 if (0 == loopCount) {
224 return kRepetitionCountInfinite;
225 }
226
227 loopCount--;
228 return loopCount;
229}
230
231int SkWebpCodec::onGetFrameCount() {
232 auto flags = WebPDemuxGetI(fDemux.get(), WEBP_FF_FORMAT_FLAGS);
233 if (!(flags & ANIMATION_FLAG)) {
234 return 1;
235 }
236
237 const uint32_t oldFrameCount = fFrameHolder.size();
238 if (fFailed) {
239 return oldFrameCount;
240 }
241
242 const uint32_t frameCount = WebPDemuxGetI(fDemux, WEBP_FF_FRAME_COUNT);
243 if (oldFrameCount == frameCount) {
244 // We have already parsed this.
245 return frameCount;
246 }
247
248 fFrameHolder.reserve(frameCount);
249
250 for (uint32_t i = oldFrameCount; i < frameCount; i++) {
251 WebPIterator iter;
252 SkAutoTCallVProc<WebPIterator, WebPDemuxReleaseIterator> autoIter(&iter);
253
254 if (!WebPDemuxGetFrame(fDemux.get(), i + 1, &iter)) {
255 fFailed = true;
256 break;
257 }
258
259 // libwebp only reports complete frames of an animated image.
260 SkASSERT(iter.complete);
261
262 Frame* frame = fFrameHolder.appendNewFrame(iter.has_alpha);
263 frame->setXYWH(iter.x_offset, iter.y_offset, iter.width, iter.height);
264 frame->setDisposalMethod(iter.dispose_method == WEBP_MUX_DISPOSE_BACKGROUND ?
265 SkCodecAnimation::DisposalMethod::kRestoreBGColor :
266 SkCodecAnimation::DisposalMethod::kKeep);
267 frame->setDuration(iter.duration);
268 if (WEBP_MUX_BLEND != iter.blend_method) {
269 frame->setBlend(SkCodecAnimation::Blend::kBG);
270 }
271 fFrameHolder.setAlphaAndRequiredFrame(frame);
272 }
273
274 return fFrameHolder.size();
275
276}
277
278const SkFrame* SkWebpCodec::FrameHolder::onGetFrame(int i) const {
279 return static_cast<const SkFrame*>(this->frame(i));
280}
281
282const SkWebpCodec::Frame* SkWebpCodec::FrameHolder::frame(int i) const {
283 SkASSERT(i >= 0 && i < this->size());
284 return &fFrames[i];
285}
286
287bool SkWebpCodec::onGetFrameInfo(int i, FrameInfo* frameInfo) const {
288 if (i >= fFrameHolder.size()) {
289 return false;
290 }
291
292 const Frame* frame = fFrameHolder.frame(i);
293 if (!frame) {
294 return false;
295 }
296
297 if (frameInfo) {
298 frameInfo->fRequiredFrame = frame->getRequiredFrame();
299 frameInfo->fDuration = frame->getDuration();
300 // libwebp only reports fully received frames for an
301 // animated image.
302 frameInfo->fFullyReceived = true;
303 frameInfo->fAlphaType = frame->hasAlpha() ? kUnpremul_SkAlphaType
304 : kOpaque_SkAlphaType;
305 frameInfo->fDisposalMethod = frame->getDisposalMethod();
306 }
307
308 return true;
309}
310
311static bool is_8888(SkColorType colorType) {
312 switch (colorType) {
313 case kRGBA_8888_SkColorType:
314 case kBGRA_8888_SkColorType:
315 return true;
316 default:
317 return false;
318 }
319}
320
321// Requires that the src input be unpremultiplied (or opaque).
322static void blend_line(SkColorType dstCT, void* dst,
323 SkColorType srcCT, const void* src,
324 SkAlphaType dstAt,
325 bool srcHasAlpha,
326 int width) {
327 SkRasterPipeline_MemoryCtx dst_ctx = { (void*)dst, 0 },
328 src_ctx = { (void*)src, 0 };
329
330 SkRasterPipeline_<256> p;
331
332 p.append_load_dst(dstCT, &dst_ctx);
333 if (kUnpremul_SkAlphaType == dstAt) {
334 p.append(SkRasterPipeline::premul_dst);
335 }
336
337 p.append_load(srcCT, &src_ctx);
338 if (srcHasAlpha) {
339 p.append(SkRasterPipeline::premul);
340 }
341
342 p.append(SkRasterPipeline::srcover);
343
344 if (kUnpremul_SkAlphaType == dstAt) {
345 p.append(SkRasterPipeline::unpremul);
346 }
347 p.append_store(dstCT, &dst_ctx);
348
349 p.run(0,0, width,1);
350}
351
352SkCodec::Result SkWebpCodec::onGetPixels(const SkImageInfo& dstInfo, void* dst, size_t rowBytes,
353 const Options& options, int* rowsDecodedPtr) {
354 const int index = options.fFrameIndex;
355 SkASSERT(0 == index || index < fFrameHolder.size());
356 SkASSERT(0 == index || !options.fSubset);
357
358 WebPDecoderConfig config;
359 if (0 == WebPInitDecoderConfig(&config)) {
360 // ABI mismatch.
361 // FIXME: New enum for this?
362 return kInvalidInput;
363 }
364
365 // Free any memory associated with the buffer. Must be called last, so we declare it first.
366 SkAutoTCallVProc<WebPDecBuffer, WebPFreeDecBuffer> autoFree(&(config.output));
367
368 WebPIterator frame;
369 SkAutoTCallVProc<WebPIterator, WebPDemuxReleaseIterator> autoFrame(&frame);
370 // If this succeeded in onGetFrameCount(), it should succeed again here.
371 SkAssertResult(WebPDemuxGetFrame(fDemux, index + 1, &frame));
372
373 const bool independent = index == 0 ? true :
374 (fFrameHolder.frame(index)->getRequiredFrame() == kNoFrame);
375 // Get the frameRect. libwebp will have already signaled an error if this is not fully
376 // contained by the canvas.
377 auto frameRect = SkIRect::MakeXYWH(frame.x_offset, frame.y_offset, frame.width, frame.height);
378 SkASSERT(this->bounds().contains(frameRect));
379 const bool frameIsSubset = frameRect != this->bounds();
380 if (independent && frameIsSubset) {
381 SkSampler::Fill(dstInfo, dst, rowBytes, options.fZeroInitialized);
382 }
383
384 int dstX = frameRect.x();
385 int dstY = frameRect.y();
386 int subsetWidth = frameRect.width();
387 int subsetHeight = frameRect.height();
388 if (options.fSubset) {
389 SkIRect subset = *options.fSubset;
390 SkASSERT(this->bounds().contains(subset));
391 SkASSERT(SkIsAlign2(subset.fLeft) && SkIsAlign2(subset.fTop));
392 SkASSERT(this->getValidSubset(&subset) && subset == *options.fSubset);
393
394 if (!SkIRect::Intersects(subset, frameRect)) {
395 return kSuccess;
396 }
397
398 int minXOffset = std::min(dstX, subset.x());
399 int minYOffset = std::min(dstY, subset.y());
400 dstX -= minXOffset;
401 dstY -= minYOffset;
402 frameRect.offset(-minXOffset, -minYOffset);
403 subset.offset(-minXOffset, -minYOffset);
404
405 // Just like we require that the requested subset x and y offset are even, libwebp
406 // guarantees that the frame x and y offset are even (it's actually impossible to specify
407 // an odd frame offset). So we can still guarantee that the adjusted offsets are even.
408 SkASSERT(SkIsAlign2(subset.fLeft) && SkIsAlign2(subset.fTop));
409
410 SkIRect intersection;
411 SkAssertResult(intersection.intersect(frameRect, subset));
412 subsetWidth = intersection.width();
413 subsetHeight = intersection.height();
414
415 config.options.use_cropping = 1;
416 config.options.crop_left = subset.x();
417 config.options.crop_top = subset.y();
418 config.options.crop_width = subsetWidth;
419 config.options.crop_height = subsetHeight;
420 }
421
422 // Ignore the frame size and offset when determining if scaling is necessary.
423 int scaledWidth = subsetWidth;
424 int scaledHeight = subsetHeight;
425 SkISize srcSize = options.fSubset ? options.fSubset->size() : this->dimensions();
426 if (srcSize != dstInfo.dimensions()) {
427 config.options.use_scaling = 1;
428
429 if (frameIsSubset) {
430 float scaleX = ((float) dstInfo.width()) / srcSize.width();
431 float scaleY = ((float) dstInfo.height()) / srcSize.height();
432
433 // We need to be conservative here and floor rather than round.
434 // Otherwise, we may find ourselves decoding off the end of memory.
435 dstX = scaleX * dstX;
436 scaledWidth = scaleX * scaledWidth;
437 dstY = scaleY * dstY;
438 scaledHeight = scaleY * scaledHeight;
439 if (0 == scaledWidth || 0 == scaledHeight) {
440 return kSuccess;
441 }
442 } else {
443 scaledWidth = dstInfo.width();
444 scaledHeight = dstInfo.height();
445 }
446
447 config.options.scaled_width = scaledWidth;
448 config.options.scaled_height = scaledHeight;
449 }
450
451 const bool blendWithPrevFrame = !independent && frame.blend_method == WEBP_MUX_BLEND
452 && frame.has_alpha;
453
454 SkBitmap webpDst;
455 auto webpInfo = dstInfo;
456 if (!frame.has_alpha) {
457 webpInfo = webpInfo.makeAlphaType(kOpaque_SkAlphaType);
458 }
459 if (this->colorXform()) {
460 // Swizzling between RGBA and BGRA is zero cost in a color transform. So when we have a
461 // color transform, we should decode to whatever is easiest for libwebp, and then let the
462 // color transform swizzle if necessary.
463 // Lossy webp is encoded as YUV (so RGBA and BGRA are the same cost). Lossless webp is
464 // encoded as BGRA. This means decoding to BGRA is either faster or the same cost as RGBA.
465 webpInfo = webpInfo.makeColorType(kBGRA_8888_SkColorType);
466
467 if (webpInfo.alphaType() == kPremul_SkAlphaType) {
468 webpInfo = webpInfo.makeAlphaType(kUnpremul_SkAlphaType);
469 }
470 }
471
472 if ((this->colorXform() && !is_8888(dstInfo.colorType())) || blendWithPrevFrame) {
473 // We will decode the entire image and then perform the color transform. libwebp
474 // does not provide a row-by-row API. This is a shame particularly when we do not want
475 // 8888, since we will need to create another image sized buffer.
476 webpDst.allocPixels(webpInfo);
477 } else {
478 // libwebp can decode directly into the output memory.
479 webpDst.installPixels(webpInfo, dst, rowBytes);
480 }
481
482 config.output.colorspace = webp_decode_mode(webpInfo.colorType(),
483 frame.has_alpha && dstInfo.alphaType() == kPremul_SkAlphaType && !this->colorXform());
484 config.output.is_external_memory = 1;
485
486 config.output.u.RGBA.rgba = reinterpret_cast<uint8_t*>(webpDst.getAddr(dstX, dstY));
487 config.output.u.RGBA.stride = static_cast<int>(webpDst.rowBytes());
488 config.output.u.RGBA.size = webpDst.computeByteSize();
489
490 SkAutoTCallVProc<WebPIDecoder, WebPIDelete> idec(WebPIDecode(nullptr, 0, &config));
491 if (!idec) {
492 return kInvalidInput;
493 }
494
495 int rowsDecoded = 0;
496 SkCodec::Result result;
497 switch (WebPIUpdate(idec, frame.fragment.bytes, frame.fragment.size)) {
498 case VP8_STATUS_OK:
499 rowsDecoded = scaledHeight;
500 result = kSuccess;
501 break;
502 case VP8_STATUS_SUSPENDED:
503 if (!WebPIDecGetRGB(idec, &rowsDecoded, nullptr, nullptr, nullptr)
504 || rowsDecoded <= 0) {
505 return kInvalidInput;
506 }
507 *rowsDecodedPtr = rowsDecoded + dstY;
508 result = kIncompleteInput;
509 break;
510 default:
511 return kInvalidInput;
512 }
513
514 const size_t dstBpp = dstInfo.bytesPerPixel();
515 dst = SkTAddOffset<void>(dst, dstBpp * dstX + rowBytes * dstY);
516 const size_t srcRowBytes = config.output.u.RGBA.stride;
517
518 const auto dstCT = dstInfo.colorType();
519 if (this->colorXform()) {
520 uint32_t* xformSrc = (uint32_t*) config.output.u.RGBA.rgba;
521 SkBitmap tmp;
522 void* xformDst;
523
524 if (blendWithPrevFrame) {
525 // Xform into temporary bitmap big enough for one row.
526 tmp.allocPixels(dstInfo.makeWH(scaledWidth, 1));
527 xformDst = tmp.getPixels();
528 } else {
529 xformDst = dst;
530 }
531
532 for (int y = 0; y < rowsDecoded; y++) {
533 this->applyColorXform(xformDst, xformSrc, scaledWidth);
534 if (blendWithPrevFrame) {
535 blend_line(dstCT, dst, dstCT, xformDst,
536 dstInfo.alphaType(), frame.has_alpha, scaledWidth);
537 dst = SkTAddOffset<void>(dst, rowBytes);
538 } else {
539 xformDst = SkTAddOffset<void>(xformDst, rowBytes);
540 }
541 xformSrc = SkTAddOffset<uint32_t>(xformSrc, srcRowBytes);
542 }
543 } else if (blendWithPrevFrame) {
544 const uint8_t* src = config.output.u.RGBA.rgba;
545
546 for (int y = 0; y < rowsDecoded; y++) {
547 blend_line(dstCT, dst, webpDst.colorType(), src,
548 dstInfo.alphaType(), frame.has_alpha, scaledWidth);
549 src = SkTAddOffset<const uint8_t>(src, srcRowBytes);
550 dst = SkTAddOffset<void>(dst, rowBytes);
551 }
552 }
553
554 return result;
555}
556
557SkWebpCodec::SkWebpCodec(SkEncodedInfo&& info, std::unique_ptr<SkStream> stream,
558 WebPDemuxer* demux, sk_sp<SkData> data, SkEncodedOrigin origin)
559 : INHERITED(std::move(info), skcms_PixelFormat_BGRA_8888, std::move(stream),
560 origin)
561 , fDemux(demux)
562 , fData(std::move(data))
563 , fFailed(false)
564{
565 const auto& eInfo = this->getEncodedInfo();
566 fFrameHolder.setScreenSize(eInfo.width(), eInfo.height());
567}
568