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1 /* | 1 /* |
2 * Copyright (C) 2006 Apple Computer, Inc. All rights reserved. | 2 * Copyright (C) 2006 Apple Computer, Inc. All rights reserved. |
3 * | 3 * |
4 * Redistribution and use in source and binary forms, with or without | 4 * Redistribution and use in source and binary forms, with or without |
5 * modification, are permitted provided that the following conditions | 5 * modification, are permitted provided that the following conditions |
6 * are met: | 6 * are met: |
7 * 1. Redistributions of source code must retain the above copyright | 7 * 1. Redistributions of source code must retain the above copyright |
8 * notice, this list of conditions and the following disclaimer. | 8 * notice, this list of conditions and the following disclaimer. |
9 * 2. Redistributions in binary form must reproduce the above copyright | 9 * 2. Redistributions in binary form must reproduce the above copyright |
10 * notice, this list of conditions and the following disclaimer in the | 10 * notice, this list of conditions and the following disclaimer in the |
11 * documentation and/or other materials provided with the distribution. | 11 * documentation and/or other materials provided with the distribution. |
12 * | 12 * |
13 * THIS SOFTWARE IS PROVIDED BY APPLE COMPUTER, INC. ``AS IS'' AND ANY | 13 * THIS SOFTWARE IS PROVIDED BY APPLE COMPUTER, INC. ``AS IS'' AND ANY |
14 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE | 14 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
15 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR | 15 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR |
16 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE COMPUTER, INC. OR | 16 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE COMPUTER, INC. OR |
17 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, | 17 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, |
18 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, | 18 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, |
19 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR | 19 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR |
20 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY | 20 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY |
21 * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT | 21 * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
22 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE | 22 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE |
23 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. | 23 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
24 */ | 24 */ |
25 | 25 |
26 #include "platform/image-decoders/gif/GIFImageDecoder.h" | 26 #include "platform/image-decoders/gif/GIFImageDecoder.h" |
27 | 27 |
28 #include <limits> | 28 #include <limits> |
29 #include "platform/image-decoders/gif/GIFImageReader.h" | |
30 #include "platform/wtf/NotFound.h" | 29 #include "platform/wtf/NotFound.h" |
31 #include "platform/wtf/PtrUtil.h" | 30 #include "platform/wtf/PtrUtil.h" |
31 #include "third_party/skia/include/core/SkImageInfo.h" | |
32 | 32 |
33 namespace blink { | 33 namespace blink { |
34 | 34 |
35 GIFImageDecoder::GIFImageDecoder(AlphaOption alpha_option, | 35 GIFImageDecoder::GIFImageDecoder(AlphaOption alpha_option, |
36 const ColorBehavior& color_behavior, | 36 const ColorBehavior& color_behavior, |
37 size_t max_decoded_bytes) | 37 size_t max_decoded_bytes) |
38 : ImageDecoder(alpha_option, color_behavior, max_decoded_bytes), | 38 : ImageDecoder(alpha_option, color_behavior, max_decoded_bytes), |
39 repetition_count_(kCAnimationLoopOnce) {} | 39 codec_(), |
40 | 40 segment_stream_(nullptr), |
41 GIFImageDecoder::~GIFImageDecoder() {} | 41 frame_infos_() {} |
42 | |
43 GIFImageDecoder::~GIFImageDecoder() { | |
44 if (!codec_) { | |
45 // if we did not create |codec_| and thus did not pass ownership to it | |
46 if (segment_stream_) | |
47 delete segment_stream_; | |
48 } | |
49 } | |
42 | 50 |
43 void GIFImageDecoder::OnSetData(SegmentReader* data) { | 51 void GIFImageDecoder::OnSetData(SegmentReader* data) { |
44 if (reader_) | 52 if (!data) { |
45 reader_->setData(data); | 53 if (segment_stream_) |
54 segment_stream_->SetReader(nullptr); | |
55 return; | |
56 } | |
57 | |
58 if (!segment_stream_) | |
59 segment_stream_ = new SegmentStream(); | |
60 | |
61 segment_stream_->SetReader(data); | |
62 | |
63 // If we don't have a SkCodec yet, create one from the stream | |
64 if (!codec_) { | |
65 codec_.reset(SkCodec::NewFromStream(segment_stream_, nullptr)); | |
66 if (!codec_) { | |
67 // |segment_stream_|'s ownership is passed into NewFromStream. | |
68 // It is deleted if NewFromStream fails. | |
69 // If NewFromStream fails, we set |segment_stream_| to null so | |
70 // we aren't pointing to reclaimed memory. | |
71 segment_stream_ = nullptr; | |
72 return; | |
73 } | |
74 | |
75 // SkCodec::NewFromStream will read enough of the image to get the image | |
76 // size. | |
77 SkImageInfo image_info = codec_->getInfo(); | |
78 SetSize(image_info.width(), image_info.height()); | |
79 } | |
46 } | 80 } |
47 | 81 |
48 int GIFImageDecoder::RepetitionCount() const { | 82 int GIFImageDecoder::RepetitionCount() const { |
83 if (!codec_ || Failed()) | |
scroggo_chromium
2017/04/24 15:06:54
SetFailed deletes codec_, so I don't think the sec
cblume
2017/04/24 18:22:33
Done.
| |
84 return kCAnimationLoopOnce; | |
85 | |
49 // This value can arrive at any point in the image data stream. Most GIFs | 86 // This value can arrive at any point in the image data stream. Most GIFs |
50 // in the wild declare it near the beginning of the file, so it usually is | 87 // in the wild declare it near the beginning of the file, so it usually is |
51 // set by the time we've decoded the size, but (depending on the GIF and the | 88 // set by the time we've decoded the size, but (depending on the GIF and the |
52 // packets sent back by the webserver) not always. If the reader hasn't | 89 // packets sent back by the webserver) not always. |
53 // seen a loop count yet, it will return cLoopCountNotSeen, in which case we | |
54 // should default to looping once (the initial value for | |
55 // |m_repetitionCount|). | |
56 // | 90 // |
57 // There are some additional wrinkles here. First, ImageSource::clear() | 91 // SkCodec will parse forward in the file if the repetition count has not been |
58 // may destroy the reader, making the result from the reader _less_ | 92 // seen yet. |
59 // authoritative on future calls if the recreated reader hasn't seen the | 93 int repetition_count = codec_->getRepetitionCount(); |
60 // loop count. We don't need to special-case this because in this case the | 94 |
61 // new reader will once again return cLoopCountNotSeen, and we won't | 95 switch (repetition_count) { |
62 // overwrite the cached correct value. | 96 case 0: { |
63 // | 97 std::vector<SkCodec::FrameInfo> frame_infos = codec_->getFrameInfo(); |
64 // Second, a GIF might never set a loop count at all, in which case we | 98 size_t frame_count = frame_infos.size(); |
65 // should continue to treat it as a "loop once" animation. We don't need | 99 if (IsAllDataReceived() && frame_count == 1) |
cblume
2017/04/23 23:13:53
I would prefer to not make a needless copy of the
scroggo_chromium
2017/04/24 15:06:54
You can call codec->getFrameCount() to avoid the c
cblume
2017/04/24 18:22:33
Done.
| |
66 // special code here either, because in this case we'll never change | 100 return kCAnimationNone; |
67 // |m_repetitionCount| from its default value. | 101 |
68 // | 102 return kCAnimationLoopOnce; |
69 // Third, we use the same GIFImageReader for counting frames and we might | 103 } |
70 // see the loop count and then encounter a decoding error which happens | 104 case SkCodec::kRepetitionCountInfinite: |
71 // later in the stream. It is also possible that no frames are in the | 105 return kCAnimationLoopInfinite; |
72 // stream. In these cases we should just loop once. | 106 default: |
73 if (IsAllDataReceived() && ParseCompleted() && reader_->imagesCount() == 1) | 107 return repetition_count; |
74 repetition_count_ = kCAnimationNone; | 108 } |
75 else if (Failed() || (reader_ && (!reader_->imagesCount()))) | |
76 repetition_count_ = kCAnimationLoopOnce; | |
77 else if (reader_ && reader_->loopCount() != cLoopCountNotSeen) | |
78 repetition_count_ = reader_->loopCount(); | |
79 return repetition_count_; | |
80 } | 109 } |
81 | 110 |
82 bool GIFImageDecoder::FrameIsCompleteAtIndex(size_t index) const { | 111 bool GIFImageDecoder::FrameIsCompleteAtIndex(size_t index) const { |
83 return reader_ && (index < reader_->imagesCount()) && | 112 if (!codec_) |
84 reader_->frameContext(index)->isComplete(); | 113 return false; |
114 | |
115 if (frame_infos_.size() <= index) | |
116 return false; | |
117 | |
118 return frame_infos_[index].fFullyReceived; | |
85 } | 119 } |
86 | 120 |
87 float GIFImageDecoder::FrameDurationAtIndex(size_t index) const { | 121 float GIFImageDecoder::FrameDurationAtIndex(size_t index) const { |
88 return (reader_ && (index < reader_->imagesCount()) && | 122 if (index < frame_buffer_cache_.size()) |
89 reader_->frameContext(index)->isHeaderDefined()) | 123 return frame_buffer_cache_[index].Duration(); |
90 ? reader_->frameContext(index)->delayTime() | 124 return 0; |
91 : 0; | |
92 } | 125 } |
93 | 126 |
94 bool GIFImageDecoder::SetFailed() { | 127 bool GIFImageDecoder::SetFailed() { |
95 reader_.reset(); | 128 if (!codec_) |
129 delete segment_stream_; | |
130 | |
131 segment_stream_ = nullptr; | |
132 codec_ = nullptr; | |
96 return ImageDecoder::SetFailed(); | 133 return ImageDecoder::SetFailed(); |
97 } | 134 } |
98 | 135 |
99 bool GIFImageDecoder::HaveDecodedRow(size_t frame_index, | 136 size_t GIFImageDecoder::DecodeFrameCount() { |
100 GIFRow::const_iterator row_begin, | 137 if (!codec_) |
101 size_t width, | 138 return 0; |
102 size_t row_number, | 139 |
103 unsigned repeat_count, | 140 if (!Failed() && (segment_stream_ && !segment_stream_->IsCleared())) |
104 bool write_transparent_pixels) { | 141 frame_infos_ = codec_->getFrameInfo(); |
105 const GIFFrameContext* frame_context = reader_->frameContext(frame_index); | 142 return frame_infos_.size(); |
106 // The pixel data and coordinates supplied to us are relative to the frame's | 143 } |
107 // origin within the entire image size, i.e. | 144 |
108 // (frameContext->xOffset, frameContext->yOffset). There is no guarantee | 145 void GIFImageDecoder::InitializeNewFrame(size_t index) { |
109 // that width == (size().width() - frameContext->xOffset), so | 146 DCHECK(codec_); |
110 // we must ensure we don't run off the end of either the source data or the | 147 |
111 // row's X-coordinates. | 148 ImageFrame& frame = frame_buffer_cache_[index]; |
112 const int x_begin = frame_context->xOffset(); | 149 // SkCodec does not inform us if only a portion of the image was updated |
113 const int y_begin = frame_context->yOffset() + row_number; | 150 // in the current frame. Because of this, rather than correctly filling in |
114 const int x_end = std::min(static_cast<int>(frame_context->xOffset() + width), | 151 // the frame rect, we set the frame rect to be the image's full size. |
115 Size().Width()); | 152 IntSize full_image_size = Size(); |
116 const int y_end = std::min( | 153 frame.SetOriginalFrameRect(IntRect(IntPoint(), full_image_size)); |
117 static_cast<int>(frame_context->yOffset() + row_number + repeat_count), | 154 frame.SetDuration(frame_infos_[index].fDuration); |
118 Size().Height()); | 155 frame.SetHasAlpha(!SkAlphaTypeIsOpaque(frame_infos_[index].fAlphaType)); |
119 if (!width || (x_begin < 0) || (y_begin < 0) || (x_end <= x_begin) || | 156 size_t required_previous_frame_index; |
120 (y_end <= y_begin)) | 157 if (frame_infos_[index].fRequiredFrame == SkCodec::kNone) { |
121 return true; | 158 required_previous_frame_index = WTF::kNotFound; |
122 | 159 } else { |
123 const GIFColorMap::Table& color_table = | 160 required_previous_frame_index = |
124 frame_context->localColorMap().isDefined() | 161 static_cast<size_t>(frame_infos_[index].fRequiredFrame); |
125 ? frame_context->localColorMap().getTable() | 162 } |
126 : reader_->globalColorMap().getTable(); | 163 frame.SetRequiredPreviousFrameIndex(required_previous_frame_index); |
127 | 164 // The disposal method is not required any more, but is left in place |
128 if (color_table.IsEmpty()) | 165 // for the other image decoders that do not yet rely on SkCodec. |
129 return true; | 166 // For now, fill it with DisposeKeep. |
130 | 167 frame.SetDisposalMethod(ImageFrame::kDisposeKeep); |
131 GIFColorMap::Table::const_iterator color_table_iter = color_table.begin(); | 168 } |
132 | 169 |
133 // Initialize the frame if necessary. | 170 void GIFImageDecoder::Decode(size_t index) { |
134 ImageFrame& buffer = frame_buffer_cache_[frame_index]; | 171 if (Failed()) |
135 if (!InitFrameBuffer(frame_index)) | 172 return; |
136 return false; | 173 |
137 | 174 if (!codec_) |
138 const size_t transparent_pixel = frame_context->transparentPixel(); | 175 return; |
139 GIFRow::const_iterator row_end = row_begin + (x_end - x_begin); | 176 |
140 ImageFrame::PixelData* current_address = buffer.GetAddr(x_begin, y_begin); | 177 if (segment_stream_->IsCleared()) |
141 | 178 return; |
142 // We may or may not need to write transparent pixels to the buffer. | 179 |
143 // If we're compositing against a previous image, it's wrong, and if | 180 if (frame_buffer_cache_.size() <= index) { |
144 // we're writing atop a cleared, fully transparent buffer, it's | 181 // It is a fatal error if all data is received and we have decoded all |
145 // unnecessary; but if we're decoding an interlaced gif and | 182 // frames available but the file is truncated. |
146 // displaying it "Haeberli"-style, we must write these for passes | 183 if (IsAllDataReceived()) |
147 // beyond the first, or the initial passes will "show through" the | 184 SetFailed(); |
148 // later ones. | 185 |
149 // | 186 return; |
150 // The loops below are almost identical. One writes a transparent pixel | 187 } |
151 // and one doesn't based on the value of |writeTransparentPixels|. | 188 |
152 // The condition check is taken out of the loop to enhance performance. | 189 UpdateAggressivePurging(index); |
153 // This optimization reduces decoding time by about 15% for a 3MB image. | 190 SkImageInfo image_info = codec_->getInfo().makeColorType(kN32_SkColorType); |
154 if (write_transparent_pixels) { | 191 |
155 for (; row_begin != row_end; ++row_begin, ++current_address) { | 192 SkCodec::Options options; |
156 const size_t source_value = *row_begin; | 193 options.fFrameIndex = index; |
157 if ((source_value != transparent_pixel) && | 194 options.fHasPriorFrame = false; |
158 (source_value < color_table.size())) { | 195 options.fZeroInitialized = SkCodec::kNo_ZeroInitialized; |
159 *current_address = color_table_iter[source_value]; | 196 |
160 } else { | 197 ImageFrame& frame = frame_buffer_cache_[index]; |
161 *current_address = 0; | 198 if (frame.GetStatus() == ImageFrame::kFrameEmpty) { |
162 current_buffer_saw_alpha_ = true; | 199 size_t required_previous_frame_index = frame.RequiredPreviousFrameIndex(); |
200 if (required_previous_frame_index == WTF::kNotFound) { | |
201 frame.AllocatePixelData(Size().Width(), Size().Height(), | |
202 ColorSpaceForSkImages()); | |
203 frame.SetHasAlpha(!SkAlphaTypeIsOpaque(frame_infos_[index].fAlphaType)); | |
204 } else { | |
205 ImageFrame& required_previous_frame = | |
206 frame_buffer_cache_[required_previous_frame_index]; | |
207 | |
208 if (required_previous_frame.GetStatus() != ImageFrame::kFrameComplete) | |
209 Decode(required_previous_frame_index); | |
210 | |
211 // We try to reuse |required_previous_frame| as starting state to avoid | |
212 // copying. If CanReusePreviousFrameBuffer returns false, we must copy | |
213 // the data since |required_previous_frame| is necessary to decode this | |
214 // or later frames. In that case copy the data instead. | |
215 if ((!CanReusePreviousFrameBuffer(index) || | |
216 !frame.TakeBitmapDataIfWritable(&required_previous_frame)) && | |
217 !frame.CopyBitmapData(required_previous_frame)) { | |
218 SetFailed(); | |
219 return; | |
163 } | 220 } |
164 } | 221 options.fHasPriorFrame = true; |
165 } else { | 222 } |
166 for (; row_begin != row_end; ++row_begin, ++current_address) { | 223 frame.SetStatus(ImageFrame::kFrameAllocated); |
167 const size_t source_value = *row_begin; | 224 } |
168 if ((source_value != transparent_pixel) && | 225 |
169 (source_value < color_table.size())) | 226 if (frame.GetStatus() == ImageFrame::kFrameAllocated) { |
170 *current_address = color_table_iter[source_value]; | 227 SkCodec::Result start_incremental_decode_result = |
171 else | 228 codec_->startIncrementalDecode(image_info, frame.Bitmap().getPixels(), |
172 current_buffer_saw_alpha_ = true; | 229 frame.Bitmap().rowBytes(), &options, |
173 } | 230 nullptr, nullptr); |
174 } | 231 switch (start_incremental_decode_result) { |
175 | 232 case SkCodec::kSuccess: |
176 // Tell the frame to copy the row data if need be. | 233 break; |
177 if (repeat_count > 1) | 234 case SkCodec::kIncompleteInput: |
178 buffer.CopyRowNTimes(x_begin, x_end, y_begin, y_end); | 235 return; |
179 | 236 default: |
180 buffer.SetPixelsChanged(true); | 237 SetFailed(); |
181 return true; | 238 return; |
182 } | 239 } |
183 | 240 frame.SetStatus(ImageFrame::kFramePartial); |
184 bool GIFImageDecoder::ParseCompleted() const { | 241 } |
185 return reader_ && reader_->parseCompleted(); | 242 int rows_decoded = 0; |
186 } | 243 SkCodec::Result incremental_decode_result = |
187 | 244 codec_->incrementalDecode(&rows_decoded); |
188 bool GIFImageDecoder::FrameComplete(size_t frame_index) { | 245 switch (incremental_decode_result) { |
189 // Initialize the frame if necessary. Some GIFs insert do-nothing frames, | 246 case SkCodec::kSuccess: |
190 // in which case we never reach haveDecodedRow() before getting here. | 247 frame.SetHasAlpha(!SkAlphaTypeIsOpaque(frame_infos_[index].fAlphaType)); |
191 if (!InitFrameBuffer(frame_index)) | 248 frame.SetPixelsChanged(true); |
192 return SetFailed(); | 249 frame.SetStatus(ImageFrame::kFrameComplete); |
193 | 250 PostDecodeProcessing(index); |
194 if (!current_buffer_saw_alpha_) | 251 break; |
195 CorrectAlphaWhenFrameBufferSawNoAlpha(frame_index); | 252 case SkCodec::kIncompleteInput: |
196 | 253 if (FrameIsCompleteAtIndex(index) || IsAllDataReceived()) { |
197 frame_buffer_cache_[frame_index].SetStatus(ImageFrame::kFrameComplete); | 254 SetFailed(); |
198 | 255 return; |
199 return true; | 256 } |
200 } | 257 { |
201 | 258 IntRect remaining_rect = frame.OriginalFrameRect(); |
202 void GIFImageDecoder::ClearFrameBuffer(size_t frame_index) { | 259 remaining_rect.SetY(rows_decoded); |
203 if (reader_ && frame_buffer_cache_[frame_index].GetStatus() == | 260 remaining_rect.SetHeight(remaining_rect.Height() - rows_decoded); |
204 ImageFrame::kFramePartial) { | 261 frame.ZeroFillFrameRect(remaining_rect); |
205 // Reset the state of the partial frame in the reader so that the frame | 262 frame.SetHasAlpha(true); |
206 // can be decoded again when requested. | 263 } |
207 reader_->clearDecodeState(frame_index); | 264 |
208 } | 265 frame.SetPixelsChanged(true); |
209 ImageDecoder::ClearFrameBuffer(frame_index); | 266 break; |
210 } | 267 default: |
211 | |
212 size_t GIFImageDecoder::DecodeFrameCount() { | |
213 Parse(kGIFFrameCountQuery); | |
214 // If decoding fails, |m_reader| will have been destroyed. Instead of | |
215 // returning 0 in this case, return the existing number of frames. This way | |
216 // if we get halfway through the image before decoding fails, we won't | |
217 // suddenly start reporting that the image has zero frames. | |
218 return Failed() ? frame_buffer_cache_.size() : reader_->imagesCount(); | |
219 } | |
220 | |
221 void GIFImageDecoder::InitializeNewFrame(size_t index) { | |
222 ImageFrame* buffer = &frame_buffer_cache_[index]; | |
223 const GIFFrameContext* frame_context = reader_->frameContext(index); | |
224 buffer->SetOriginalFrameRect( | |
225 Intersection(frame_context->frameRect(), IntRect(IntPoint(), Size()))); | |
226 buffer->SetDuration(frame_context->delayTime()); | |
227 buffer->SetDisposalMethod(frame_context->getDisposalMethod()); | |
228 buffer->SetRequiredPreviousFrameIndex( | |
229 FindRequiredPreviousFrame(index, false)); | |
230 } | |
231 | |
232 void GIFImageDecoder::Decode(size_t index) { | |
233 Parse(kGIFFrameCountQuery); | |
234 | |
235 if (Failed()) | |
236 return; | |
237 | |
238 UpdateAggressivePurging(index); | |
239 | |
240 Vector<size_t> frames_to_decode = FindFramesToDecode(index); | |
241 for (auto i = frames_to_decode.rbegin(); i != frames_to_decode.rend(); ++i) { | |
242 if (!reader_->decode(*i)) { | |
243 SetFailed(); | 268 SetFailed(); |
244 return; | 269 return; |
245 } | 270 } |
246 | 271 } |
247 // If this returns false, we need more data to continue decoding. | 272 |
248 if (!PostDecodeProcessing(*i)) | 273 bool GIFImageDecoder::CanReusePreviousFrameBuffer(size_t index) const { |
249 break; | 274 DCHECK(index < frame_buffer_cache_.size()); |
250 } | 275 |
251 | 276 // If the current frame and the next frame depend on the same frame, we cannot |
252 // It is also a fatal error if all data is received and we have decoded all | 277 // reuse the old frame. We must preserve it for the next frame. |
253 // frames available but the file is truncated. | 278 // |
254 if (index >= frame_buffer_cache_.size() - 1 && IsAllDataReceived() && | 279 // However, if the current and next frame depend on different frames then we |
255 reader_ && !reader_->parseCompleted()) | 280 // know the current frame is the last one to use the frame it depends on. That |
256 SetFailed(); | 281 // means the current frame can reuse the previous frame buffer. |
257 } | 282 // |
258 | 283 // If we do not have information about the next frame yet, we cannot assume it |
259 void GIFImageDecoder::Parse(GIFParseQuery query) { | 284 // is safe to reuse the previous frame buffer. |
260 if (Failed()) | 285 |
261 return; | 286 if (index + 1 >= frame_buffer_cache_.size()) |
262 | 287 return false; |
263 if (!reader_) { | 288 |
264 reader_ = WTF::MakeUnique<GIFImageReader>(this); | 289 const ImageFrame& frame = frame_buffer_cache_[index]; |
265 reader_->setData(data_); | 290 size_t required_frame_index = frame.RequiredPreviousFrameIndex(); |
266 } | 291 |
267 | 292 const ImageFrame& next_frame = frame_buffer_cache_[index + 1]; |
268 if (!reader_->parse(query)) | 293 size_t next_required_frame_index = next_frame.RequiredPreviousFrameIndex(); |
269 SetFailed(); | 294 |
270 } | 295 return required_frame_index != next_required_frame_index; |
271 | |
272 void GIFImageDecoder::OnInitFrameBuffer(size_t frame_index) { | |
273 current_buffer_saw_alpha_ = false; | |
274 } | |
275 | |
276 bool GIFImageDecoder::CanReusePreviousFrameBuffer(size_t frame_index) const { | |
277 DCHECK(frame_index < frame_buffer_cache_.size()); | |
278 return frame_buffer_cache_[frame_index].GetDisposalMethod() != | |
279 ImageFrame::kDisposeOverwritePrevious; | |
280 } | 296 } |
281 | 297 |
282 } // namespace blink | 298 } // namespace blink |
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