skia2/tools/LazyDecodeBitmap.cpp

77 lines
2.3 KiB
C++

/*
* Copyright 2013 Google Inc.
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#include "LazyDecodeBitmap.h"
#include "PictureRenderingFlags.h" // --deferImageDecoding is defined here.
#include "SkBitmap.h"
#include "SkData.h"
#include "SkImageDecoder.h"
#include "SkForceLinking.h"
#include "SkLruImageCache.h"
#include "SkPurgeableImageCache.h"
#include "SkCommandLineFlags.h"
__SK_FORCE_IMAGE_DECODER_LINKING;
DEFINE_bool(useVolatileCache, false, "Use a volatile cache for deferred image decoding pixels. "
"Only meaningful if --deferImageDecoding is set to true and the platform has an "
"implementation.");
SkLruImageCache gLruImageCache(1024 * 1024);
namespace sk_tools {
// Simple cache selector to choose between a purgeable cache for large images and the standard one
// for smaller images.
//
class CacheSelector : public SkBitmapFactory::CacheSelector {
public:
CacheSelector() {
fPurgeableImageCache = SkPurgeableImageCache::Create();
}
~CacheSelector() {
SkSafeUnref(fPurgeableImageCache);
}
virtual SkImageCache* selectCache(const SkImage::Info& info) SK_OVERRIDE {
if (info.fWidth * info.fHeight > 32 * 1024 && fPurgeableImageCache != NULL) {
return fPurgeableImageCache;
}
return &gLruImageCache;
}
private:
SkImageCache* fPurgeableImageCache;
};
static CacheSelector gCacheSelector;
static SkBitmapFactory gFactory(&SkImageDecoder::DecodeMemoryToTarget);
bool LazyDecodeBitmap(const void* buffer, size_t size, SkBitmap* bitmap) {
void* copiedBuffer = sk_malloc_throw(size);
memcpy(copiedBuffer, buffer, size);
SkAutoDataUnref data(SkData::NewFromMalloc(copiedBuffer, size));
static bool gOnce;
if (!gOnce) {
// Only use the cache selector if there is a purgeable image cache to use for large
// images.
if (FLAGS_useVolatileCache && SkAutoTUnref<SkImageCache>(
SkPurgeableImageCache::Create()).get() != NULL) {
gFactory.setCacheSelector(&gCacheSelector);
} else {
gFactory.setImageCache(&gLruImageCache);
}
gOnce = true;
}
return gFactory.installPixelRef(data, bitmap);
}
} // namespace sk_tools