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1 // Copyright (c) 2012 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/image/image_skia.h" | |
6 | |
7 #include <algorithm> | |
8 #include <cmath> | |
9 #include <limits> | |
10 | |
11 #include "base/command_line.h" | |
12 #include "base/logging.h" | |
13 #include "base/memory/scoped_ptr.h" | |
14 #include "base/threading/non_thread_safe.h" | |
15 #include "ui/gfx/geometry/size_conversions.h" | |
16 #include "ui/gfx/image/image_skia_operations.h" | |
17 #include "ui/gfx/image/image_skia_source.h" | |
18 #include "ui/gfx/rect.h" | |
19 #include "ui/gfx/size.h" | |
20 #include "ui/gfx/skia_util.h" | |
21 #include "ui/gfx/switches.h" | |
22 | |
23 namespace gfx { | |
24 namespace { | |
25 | |
26 // static | |
27 gfx::ImageSkiaRep& NullImageRep() { | |
28 CR_DEFINE_STATIC_LOCAL(ImageSkiaRep, null_image_rep, ()); | |
29 return null_image_rep; | |
30 } | |
31 | |
32 std::vector<float>* g_supported_scales = NULL; | |
33 | |
34 // The difference to fall back to the smaller scale factor rather than the | |
35 // larger one. For example, assume 1.20 is requested but only 1.0 and 2.0 are | |
36 // supported. In that case, not fall back to 2.0 but 1.0, and then expand | |
37 // the image to 1.25. | |
38 const float kFallbackToSmallerScaleDiff = 0.20f; | |
39 | |
40 } // namespace | |
41 | |
42 namespace internal { | |
43 namespace { | |
44 | |
45 class Matcher { | |
46 public: | |
47 explicit Matcher(float scale) : scale_(scale) { | |
48 } | |
49 | |
50 bool operator()(const ImageSkiaRep& rep) const { | |
51 return rep.scale() == scale_; | |
52 } | |
53 | |
54 private: | |
55 float scale_; | |
56 }; | |
57 | |
58 ImageSkiaRep ScaleImageSkiaRep(const ImageSkiaRep& rep, float target_scale) { | |
59 if (rep.is_null() || rep.scale() == target_scale) | |
60 return rep; | |
61 | |
62 gfx::Size scaled_size = ToCeiledSize( | |
63 gfx::ScaleSize(rep.pixel_size(), target_scale / rep.scale())); | |
64 return ImageSkiaRep(skia::ImageOperations::Resize( | |
65 rep.sk_bitmap(), | |
66 skia::ImageOperations::RESIZE_LANCZOS3, | |
67 scaled_size.width(), | |
68 scaled_size.height()), target_scale); | |
69 } | |
70 | |
71 } // namespace | |
72 | |
73 // A helper class such that ImageSkia can be cheaply copied. ImageSkia holds a | |
74 // refptr instance of ImageSkiaStorage, which in turn holds all of ImageSkia's | |
75 // information. Having both |base::RefCountedThreadSafe| and | |
76 // |base::NonThreadSafe| may sounds strange but necessary to turn | |
77 // the 'thread-non-safe modifiable ImageSkiaStorage' into | |
78 // the 'thread-safe read-only ImageSkiaStorage'. | |
79 class ImageSkiaStorage : public base::RefCountedThreadSafe<ImageSkiaStorage>, | |
80 public base::NonThreadSafe { | |
81 public: | |
82 ImageSkiaStorage(ImageSkiaSource* source, const gfx::Size& size) | |
83 : source_(source), | |
84 size_(size), | |
85 read_only_(false) { | |
86 } | |
87 | |
88 ImageSkiaStorage(ImageSkiaSource* source, float scale) | |
89 : source_(source), | |
90 read_only_(false) { | |
91 ImageSkia::ImageSkiaReps::iterator it = FindRepresentation(scale, true); | |
92 if (it == image_reps_.end() || it->is_null()) | |
93 source_.reset(); | |
94 else | |
95 size_.SetSize(it->GetWidth(), it->GetHeight()); | |
96 } | |
97 | |
98 bool has_source() const { return source_.get() != NULL; } | |
99 | |
100 std::vector<gfx::ImageSkiaRep>& image_reps() { return image_reps_; } | |
101 | |
102 const gfx::Size& size() const { return size_; } | |
103 | |
104 bool read_only() const { return read_only_; } | |
105 | |
106 void DeleteSource() { | |
107 source_.reset(); | |
108 } | |
109 | |
110 void SetReadOnly() { | |
111 read_only_ = true; | |
112 } | |
113 | |
114 void DetachFromThread() { | |
115 base::NonThreadSafe::DetachFromThread(); | |
116 } | |
117 | |
118 // Checks if the current thread can safely modify the storage. | |
119 bool CanModify() const { | |
120 return !read_only_ && CalledOnValidThread(); | |
121 } | |
122 | |
123 // Checks if the current thread can safely read the storage. | |
124 bool CanRead() const { | |
125 return (read_only_ && !source_.get()) || CalledOnValidThread(); | |
126 } | |
127 | |
128 // Add a new representation. This checks if the scale of the added image | |
129 // is not 1.0f, and mark the existing rep as scaled to make | |
130 // the image high DPI aware. | |
131 void AddRepresentation(const ImageSkiaRep& image) { | |
132 if (image.scale() != 1.0f) { | |
133 for (ImageSkia::ImageSkiaReps::iterator it = image_reps_.begin(); | |
134 it < image_reps_.end(); | |
135 ++it) { | |
136 if (it->unscaled()) { | |
137 DCHECK_EQ(1.0f, it->scale()); | |
138 it->SetScaled(); | |
139 break; | |
140 } | |
141 } | |
142 } | |
143 image_reps_.push_back(image); | |
144 } | |
145 | |
146 // Returns the iterator of the image rep whose density best matches | |
147 // |scale|. If the image for the |scale| doesn't exist in the storage and | |
148 // |storage| is set, it fetches new image by calling | |
149 // |ImageSkiaSource::GetImageForScale|. There are two modes to deal with | |
150 // arbitrary scale factors. | |
151 // 1: Invoke GetImageForScale with requested scale and if the source | |
152 // returns the image with different scale (if the image doesn't exist in | |
153 // resource, for example), it will fallback to closest image rep. | |
154 // 2: Invoke GetImageForScale with the closest known scale to the requested | |
155 // one and rescale the image. | |
156 // Right now only Windows uses 2 and other platforms use 1 by default. | |
157 // TODO(mukai, oshima): abandon 1 code path and use 2 for every platforms. | |
158 std::vector<ImageSkiaRep>::iterator FindRepresentation( | |
159 float scale, bool fetch_new_image) const { | |
160 ImageSkiaStorage* non_const = const_cast<ImageSkiaStorage*>(this); | |
161 | |
162 ImageSkia::ImageSkiaReps::iterator closest_iter = | |
163 non_const->image_reps().end(); | |
164 ImageSkia::ImageSkiaReps::iterator exact_iter = | |
165 non_const->image_reps().end(); | |
166 float smallest_diff = std::numeric_limits<float>::max(); | |
167 for (ImageSkia::ImageSkiaReps::iterator it = | |
168 non_const->image_reps().begin(); | |
169 it < image_reps_.end(); ++it) { | |
170 if (it->scale() == scale) { | |
171 // found exact match | |
172 fetch_new_image = false; | |
173 if (it->is_null()) | |
174 continue; | |
175 exact_iter = it; | |
176 break; | |
177 } | |
178 float diff = std::abs(it->scale() - scale); | |
179 if (diff < smallest_diff && !it->is_null()) { | |
180 closest_iter = it; | |
181 smallest_diff = diff; | |
182 } | |
183 } | |
184 | |
185 if (fetch_new_image && source_.get()) { | |
186 DCHECK(CalledOnValidThread()) << | |
187 "An ImageSkia with the source must be accessed by the same thread."; | |
188 | |
189 ImageSkiaRep image; | |
190 float resource_scale = scale; | |
191 if (g_supported_scales) { | |
192 if (g_supported_scales->back() <= scale) { | |
193 resource_scale = g_supported_scales->back(); | |
194 } else { | |
195 for (size_t i = 0; i < g_supported_scales->size(); ++i) { | |
196 if ((*g_supported_scales)[i] + kFallbackToSmallerScaleDiff >= | |
197 scale) { | |
198 resource_scale = (*g_supported_scales)[i]; | |
199 break; | |
200 } | |
201 } | |
202 } | |
203 } | |
204 if (scale != resource_scale) { | |
205 std::vector<ImageSkiaRep>::iterator iter = FindRepresentation( | |
206 resource_scale, fetch_new_image); | |
207 DCHECK(iter != image_reps_.end()); | |
208 image = iter->unscaled() ? (*iter) : ScaleImageSkiaRep(*iter, scale); | |
209 } else { | |
210 image = source_->GetImageForScale(scale); | |
211 // Image may be missing for the specified scale in some cases, such like | |
212 // looking up 2x resources but the 2x resource pack is missing. Falls | |
213 // back to 1x and re-scale it. | |
214 if (image.is_null() && scale != 1.0f) | |
215 image = ScaleImageSkiaRep(source_->GetImageForScale(1.0f), scale); | |
216 } | |
217 | |
218 // If the source returned the new image, store it. | |
219 if (!image.is_null() && | |
220 std::find_if(image_reps_.begin(), image_reps_.end(), | |
221 Matcher(image.scale())) == image_reps_.end()) { | |
222 non_const->image_reps().push_back(image); | |
223 } | |
224 | |
225 // If the result image's scale isn't same as the expected scale, create | |
226 // null ImageSkiaRep with the |scale| so that the next lookup will | |
227 // fallback to the closest scale. | |
228 if (image.is_null() || image.scale() != scale) { | |
229 non_const->image_reps().push_back(ImageSkiaRep(SkBitmap(), scale)); | |
230 } | |
231 | |
232 // image_reps_ must have the exact much now, so find again. | |
233 return FindRepresentation(scale, false); | |
234 } | |
235 return exact_iter != image_reps_.end() ? exact_iter : closest_iter; | |
236 } | |
237 | |
238 private: | |
239 virtual ~ImageSkiaStorage() { | |
240 // We only care if the storage is modified by the same thread. | |
241 // Don't blow up even if someone else deleted the ImageSkia. | |
242 DetachFromThread(); | |
243 } | |
244 | |
245 // Vector of bitmaps and their associated scale. | |
246 std::vector<gfx::ImageSkiaRep> image_reps_; | |
247 | |
248 scoped_ptr<ImageSkiaSource> source_; | |
249 | |
250 // Size of the image in DIP. | |
251 gfx::Size size_; | |
252 | |
253 bool read_only_; | |
254 | |
255 friend class base::RefCountedThreadSafe<ImageSkiaStorage>; | |
256 }; | |
257 | |
258 } // internal | |
259 | |
260 ImageSkia::ImageSkia() : storage_(NULL) { | |
261 } | |
262 | |
263 ImageSkia::ImageSkia(ImageSkiaSource* source, const gfx::Size& size) | |
264 : storage_(new internal::ImageSkiaStorage(source, size)) { | |
265 DCHECK(source); | |
266 // No other thread has reference to this, so it's safe to detach the thread. | |
267 DetachStorageFromThread(); | |
268 } | |
269 | |
270 ImageSkia::ImageSkia(ImageSkiaSource* source, float scale) | |
271 : storage_(new internal::ImageSkiaStorage(source, scale)) { | |
272 DCHECK(source); | |
273 if (!storage_->has_source()) | |
274 storage_ = NULL; | |
275 // No other thread has reference to this, so it's safe to detach the thread. | |
276 DetachStorageFromThread(); | |
277 } | |
278 | |
279 ImageSkia::ImageSkia(const ImageSkiaRep& image_rep) { | |
280 Init(image_rep); | |
281 // No other thread has reference to this, so it's safe to detach the thread. | |
282 DetachStorageFromThread(); | |
283 } | |
284 | |
285 ImageSkia::ImageSkia(const ImageSkia& other) : storage_(other.storage_) { | |
286 } | |
287 | |
288 ImageSkia& ImageSkia::operator=(const ImageSkia& other) { | |
289 storage_ = other.storage_; | |
290 return *this; | |
291 } | |
292 | |
293 ImageSkia::~ImageSkia() { | |
294 } | |
295 | |
296 // static | |
297 void ImageSkia::SetSupportedScales(const std::vector<float>& supported_scales) { | |
298 if (g_supported_scales != NULL) | |
299 delete g_supported_scales; | |
300 g_supported_scales = new std::vector<float>(supported_scales); | |
301 std::sort(g_supported_scales->begin(), g_supported_scales->end()); | |
302 } | |
303 | |
304 // static | |
305 const std::vector<float>& ImageSkia::GetSupportedScales() { | |
306 DCHECK(g_supported_scales != NULL); | |
307 return *g_supported_scales; | |
308 } | |
309 | |
310 // static | |
311 float ImageSkia::GetMaxSupportedScale() { | |
312 return g_supported_scales->back(); | |
313 } | |
314 | |
315 // static | |
316 ImageSkia ImageSkia::CreateFrom1xBitmap(const SkBitmap& bitmap) { | |
317 return ImageSkia(ImageSkiaRep(bitmap, 0.0f)); | |
318 } | |
319 | |
320 scoped_ptr<ImageSkia> ImageSkia::DeepCopy() const { | |
321 ImageSkia* copy = new ImageSkia; | |
322 if (isNull()) | |
323 return scoped_ptr<ImageSkia>(copy); | |
324 | |
325 CHECK(CanRead()); | |
326 | |
327 std::vector<gfx::ImageSkiaRep>& reps = storage_->image_reps(); | |
328 for (std::vector<gfx::ImageSkiaRep>::iterator iter = reps.begin(); | |
329 iter != reps.end(); ++iter) { | |
330 copy->AddRepresentation(*iter); | |
331 } | |
332 // The copy has its own storage. Detach the copy from the current | |
333 // thread so that other thread can use this. | |
334 if (!copy->isNull()) | |
335 copy->storage_->DetachFromThread(); | |
336 return scoped_ptr<ImageSkia>(copy); | |
337 } | |
338 | |
339 bool ImageSkia::BackedBySameObjectAs(const gfx::ImageSkia& other) const { | |
340 return storage_.get() == other.storage_.get(); | |
341 } | |
342 | |
343 void ImageSkia::AddRepresentation(const ImageSkiaRep& image_rep) { | |
344 DCHECK(!image_rep.is_null()); | |
345 | |
346 // TODO(oshima): This method should be called |SetRepresentation| | |
347 // and replace the existing rep if there is already one with the | |
348 // same scale so that we can guarantee that a ImageSkia instance contains only | |
349 // one image rep per scale. This is not possible now as ImageLoader currently | |
350 // stores need this feature, but this needs to be fixed. | |
351 if (isNull()) { | |
352 Init(image_rep); | |
353 } else { | |
354 CHECK(CanModify()); | |
355 // If someone is adding ImageSkia explicitly, check if we should | |
356 // make the image high DPI aware. | |
357 storage_->AddRepresentation(image_rep); | |
358 } | |
359 } | |
360 | |
361 void ImageSkia::RemoveRepresentation(float scale) { | |
362 if (isNull()) | |
363 return; | |
364 CHECK(CanModify()); | |
365 | |
366 ImageSkiaReps& image_reps = storage_->image_reps(); | |
367 ImageSkiaReps::iterator it = | |
368 storage_->FindRepresentation(scale, false); | |
369 if (it != image_reps.end() && it->scale() == scale) | |
370 image_reps.erase(it); | |
371 } | |
372 | |
373 bool ImageSkia::HasRepresentation(float scale) const { | |
374 if (isNull()) | |
375 return false; | |
376 CHECK(CanRead()); | |
377 | |
378 ImageSkiaReps::iterator it = storage_->FindRepresentation(scale, false); | |
379 return (it != storage_->image_reps().end() && it->scale() == scale); | |
380 } | |
381 | |
382 const ImageSkiaRep& ImageSkia::GetRepresentation(float scale) const { | |
383 if (isNull()) | |
384 return NullImageRep(); | |
385 | |
386 CHECK(CanRead()); | |
387 | |
388 ImageSkiaReps::iterator it = storage_->FindRepresentation(scale, true); | |
389 if (it == storage_->image_reps().end()) | |
390 return NullImageRep(); | |
391 | |
392 return *it; | |
393 } | |
394 | |
395 void ImageSkia::SetReadOnly() { | |
396 CHECK(storage_.get()); | |
397 storage_->SetReadOnly(); | |
398 DetachStorageFromThread(); | |
399 } | |
400 | |
401 void ImageSkia::MakeThreadSafe() { | |
402 CHECK(storage_.get()); | |
403 EnsureRepsForSupportedScales(); | |
404 // Delete source as we no longer needs it. | |
405 if (storage_.get()) | |
406 storage_->DeleteSource(); | |
407 storage_->SetReadOnly(); | |
408 CHECK(IsThreadSafe()); | |
409 } | |
410 | |
411 bool ImageSkia::IsThreadSafe() const { | |
412 return !storage_.get() || (storage_->read_only() && !storage_->has_source()); | |
413 } | |
414 | |
415 int ImageSkia::width() const { | |
416 return isNull() ? 0 : storage_->size().width(); | |
417 } | |
418 | |
419 gfx::Size ImageSkia::size() const { | |
420 return gfx::Size(width(), height()); | |
421 } | |
422 | |
423 int ImageSkia::height() const { | |
424 return isNull() ? 0 : storage_->size().height(); | |
425 } | |
426 | |
427 std::vector<ImageSkiaRep> ImageSkia::image_reps() const { | |
428 if (isNull()) | |
429 return std::vector<ImageSkiaRep>(); | |
430 | |
431 CHECK(CanRead()); | |
432 | |
433 ImageSkiaReps internal_image_reps = storage_->image_reps(); | |
434 // Create list of image reps to return, skipping null image reps which were | |
435 // added for caching purposes only. | |
436 ImageSkiaReps image_reps; | |
437 for (ImageSkiaReps::iterator it = internal_image_reps.begin(); | |
438 it != internal_image_reps.end(); ++it) { | |
439 if (!it->is_null()) | |
440 image_reps.push_back(*it); | |
441 } | |
442 | |
443 return image_reps; | |
444 } | |
445 | |
446 void ImageSkia::EnsureRepsForSupportedScales() const { | |
447 DCHECK(g_supported_scales != NULL); | |
448 // Don't check ReadOnly because the source may generate images | |
449 // even for read only ImageSkia. Concurrent access will be protected | |
450 // by |DCHECK(CalledOnValidThread())| in FindRepresentation. | |
451 if (storage_.get() && storage_->has_source()) { | |
452 for (std::vector<float>::const_iterator it = g_supported_scales->begin(); | |
453 it != g_supported_scales->end(); ++it) | |
454 storage_->FindRepresentation(*it, true); | |
455 } | |
456 } | |
457 | |
458 void ImageSkia::Init(const ImageSkiaRep& image_rep) { | |
459 // TODO(pkotwicz): The image should be null whenever image rep is null. | |
460 if (image_rep.sk_bitmap().empty()) { | |
461 storage_ = NULL; | |
462 return; | |
463 } | |
464 storage_ = new internal::ImageSkiaStorage( | |
465 NULL, gfx::Size(image_rep.GetWidth(), image_rep.GetHeight())); | |
466 storage_->image_reps().push_back(image_rep); | |
467 } | |
468 | |
469 SkBitmap& ImageSkia::GetBitmap() const { | |
470 if (isNull()) { | |
471 // Callers expect a ImageSkiaRep even if it is |isNull()|. | |
472 // TODO(pkotwicz): Fix this. | |
473 return NullImageRep().mutable_sk_bitmap(); | |
474 } | |
475 | |
476 // TODO(oshima): This made a few tests flaky on Windows. | |
477 // Fix the root cause and re-enable this. crbug.com/145623. | |
478 #if !defined(OS_WIN) | |
479 CHECK(CanRead()); | |
480 #endif | |
481 | |
482 ImageSkiaReps::iterator it = storage_->FindRepresentation(1.0f, true); | |
483 if (it != storage_->image_reps().end()) | |
484 return it->mutable_sk_bitmap(); | |
485 return NullImageRep().mutable_sk_bitmap(); | |
486 } | |
487 | |
488 bool ImageSkia::CanRead() const { | |
489 return !storage_.get() || storage_->CanRead(); | |
490 } | |
491 | |
492 bool ImageSkia::CanModify() const { | |
493 return !storage_.get() || storage_->CanModify(); | |
494 } | |
495 | |
496 void ImageSkia::DetachStorageFromThread() { | |
497 if (storage_.get()) | |
498 storage_->DetachFromThread(); | |
499 } | |
500 | |
501 } // namespace gfx | |
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