tests/SkResourceCacheTest.cpp - platform/external/skia - Gitiles

 /*
  * Copyright 2014 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */

 #include "Test.h"
 #include "SkBitmapCache.h"
 #include "SkCanvas.h"
 #include "SkDiscardableMemoryPool.h"
 #include "SkGraphics.h"
 #include "SkPicture.h"
 #include "SkPictureRecorder.h"
 #include "SkResourceCache.h"
 #include "SkSurface.h"
 #include "SkTypes.h"

 ////////////////////////////////////////////////////////////////////////////////////////

 static void make_bitmap(SkBitmap* bitmap, const SkImageInfo& info, SkBitmap::Allocator* allocator) {
     if (info.colorType() == kIndex_8_SkColorType) {
         bitmap->setInfo(info);
         SkPMColor ctStorage[256];
         memset(ctStorage, 0xFF, sizeof(ctStorage)); // init with opaque-white for the moment
         SkAutoTUnref<SkColorTable> ctable(new SkColorTable(ctStorage, 256));
         bitmap->allocPixels(allocator, ctable);
     } else if (allocator) {
         bitmap->setInfo(info);
         allocator->allocPixelRef(bitmap, 0);
     } else {
         bitmap->allocPixels(info);
     }
 }

 // https://bug.skia.org/2894
 DEF_TEST(BitmapCache_add_rect, reporter) {
     SkResourceCache::DiscardableFactory factory = SkResourceCache::GetDiscardableFactory();
     SkBitmap::Allocator* allocator = SkBitmapCache::GetAllocator();

     SkAutoTDelete<SkResourceCache> cache;
     if (factory) {
         cache.reset(new SkResourceCache(factory));
     } else {
         const size_t byteLimit = 100 * 1024;
         cache.reset(new SkResourceCache(byteLimit));
     }
     SkBitmap cachedBitmap;
     make_bitmap(&cachedBitmap, SkImageInfo::MakeN32Premul(5, 5), allocator);
     cachedBitmap.setImmutable();

     SkBitmap bm;
     SkIRect rect = SkIRect::MakeWH(5, 5);
     uint32_t cachedID = cachedBitmap.getGenerationID();
     SkPixelRef* cachedPR = cachedBitmap.pixelRef();

     // Wrong subset size
     REPORTER_ASSERT(reporter, !SkBitmapCache::Add(cachedPR, SkIRect::MakeWH(4, 6), cachedBitmap, cache));
     REPORTER_ASSERT(reporter, !SkBitmapCache::Find(cachedID, rect, &bm, cache));
     // Wrong offset value
     REPORTER_ASSERT(reporter, !SkBitmapCache::Add(cachedPR, SkIRect::MakeXYWH(-1, 0, 5, 5), cachedBitmap, cache));
     REPORTER_ASSERT(reporter, !SkBitmapCache::Find(cachedID, rect, &bm, cache));

     // Should not be in the cache
     REPORTER_ASSERT(reporter, !SkBitmapCache::Find(cachedID, rect, &bm, cache));

     REPORTER_ASSERT(reporter, SkBitmapCache::Add(cachedPR, rect, cachedBitmap, cache));
     // Should be in the cache, we just added it
     REPORTER_ASSERT(reporter, SkBitmapCache::Find(cachedID, rect, &bm, cache));
 }

 #include "SkMipMap.h"

 enum LockedState {
     kNotLocked,
     kLocked,
 };

 enum CachedState {
     kNotInCache,
     kInCache,
 };

 static void check_data(skiatest::Reporter* reporter, const SkCachedData* data,
                        int refcnt, CachedState cacheState, LockedState lockedState) {
     REPORTER_ASSERT(reporter, data->testing_only_getRefCnt() == refcnt);
     REPORTER_ASSERT(reporter, data->testing_only_isInCache() == (kInCache == cacheState));
     bool isLocked = (data->data() != nullptr);
     REPORTER_ASSERT(reporter, isLocked == (lockedState == kLocked));
 }

 static void test_mipmapcache(skiatest::Reporter* reporter, SkResourceCache* cache) {
     cache->purgeAll();

     SkBitmap src;
     src.allocN32Pixels(5, 5);
     src.setImmutable();

     const SkMipMap* mipmap = SkMipMapCache::FindAndRef(SkBitmapCacheDesc::Make(src), cache);
     REPORTER_ASSERT(reporter, nullptr == mipmap);

     mipmap = SkMipMapCache::AddAndRef(src, cache);
     REPORTER_ASSERT(reporter, mipmap);

     {
         const SkMipMap* mm = SkMipMapCache::FindAndRef(SkBitmapCacheDesc::Make(src), cache);
         REPORTER_ASSERT(reporter, mm);
         REPORTER_ASSERT(reporter, mm == mipmap);
         mm->unref();
     }

     check_data(reporter, mipmap, 2, kInCache, kLocked);

     mipmap->unref();
     // tricky, since technically after this I'm no longer an owner, but since the cache is
     // local, I know it won't get purged behind my back
     check_data(reporter, mipmap, 1, kInCache, kNotLocked);

     // find us again
     mipmap = SkMipMapCache::FindAndRef(SkBitmapCacheDesc::Make(src), cache);
     check_data(reporter, mipmap, 2, kInCache, kLocked);

     cache->purgeAll();
     check_data(reporter, mipmap, 1, kNotInCache, kLocked);

     mipmap->unref();
 }

 static void test_mipmap_notify(skiatest::Reporter* reporter, SkResourceCache* cache) {
     const int N = 3;
     SkBitmap src[N];
     for (int i = 0; i < N; ++i) {
         src[i].allocN32Pixels(5, 5);
         src[i].setImmutable();
         SkMipMapCache::AddAndRef(src[i], cache)->unref();
     }

     for (int i = 0; i < N; ++i) {
         const SkMipMap* mipmap = SkMipMapCache::FindAndRef(SkBitmapCacheDesc::Make(src[i]), cache);
         if (cache) {
             // if cache is null, we're working on the global cache, and other threads might purge
             // it, making this check fragile.
             REPORTER_ASSERT(reporter, mipmap);
         }
         SkSafeUnref(mipmap);

         src[i].reset(); // delete the underlying pixelref, which *should* remove us from the cache

         mipmap = SkMipMapCache::FindAndRef(SkBitmapCacheDesc::Make(src[i]), cache);
         REPORTER_ASSERT(reporter, !mipmap);
     }
 }

 static void test_bitmap_notify(skiatest::Reporter* reporter, SkResourceCache* cache) {
     const SkIRect subset = SkIRect::MakeWH(5, 5);
     const int N = 3;
     SkBitmap src[N], dst[N];
     for (int i = 0; i < N; ++i) {
         src[i].allocN32Pixels(5, 5);
         src[i].setImmutable();
         dst[i].allocN32Pixels(5, 5);
         dst[i].setImmutable();
         SkBitmapCache::Add(src[i].pixelRef(), subset, dst[i], cache);
     }

     for (int i = 0; i < N; ++i) {
         const uint32_t genID = src[i].getGenerationID();
         SkBitmap result;
         bool found = SkBitmapCache::Find(genID, subset, &result, cache);
         if (cache) {
             // if cache is null, we're working on the global cache, and other threads might purge
             // it, making this check fragile.
             REPORTER_ASSERT(reporter, found);
         }

         src[i].reset(); // delete the underlying pixelref, which *should* remove us from the cache

         found = SkBitmapCache::Find(genID, subset, &result, cache);
         REPORTER_ASSERT(reporter, !found);
     }
 }

 #include "SkDiscardableMemoryPool.h"

 static SkDiscardableMemoryPool* gPool = 0;
 static SkDiscardableMemory* pool_factory(size_t bytes) {
     SkASSERT(gPool);
     return gPool->create(bytes);
 }

 static void testBitmapCache_discarded_bitmap(skiatest::Reporter* reporter, SkResourceCache* cache,
                                              SkResourceCache::DiscardableFactory factory) {
     SkBitmap::Allocator* allocator = cache->allocator();
     const SkColorType testTypes[] = {
         kAlpha_8_SkColorType,
         kRGB_565_SkColorType,
         kRGBA_8888_SkColorType,
         kBGRA_8888_SkColorType,
         kIndex_8_SkColorType,
         kGray_8_SkColorType
     };
     for (const SkColorType testType : testTypes) {
         SkBitmap cachedBitmap;
         make_bitmap(&cachedBitmap, SkImageInfo::Make(5, 5, testType, kPremul_SkAlphaType),
                     allocator);
         cachedBitmap.setImmutable();
         cachedBitmap.unlockPixels();

         SkBitmap bm;
         SkIRect rect = SkIRect::MakeWH(5, 5);

         // Add a bitmap to the cache.
         REPORTER_ASSERT(reporter, SkBitmapCache::Add(cachedBitmap.pixelRef(), rect, cachedBitmap,
                                                      cache));
         REPORTER_ASSERT(reporter, SkBitmapCache::Find(cachedBitmap.getGenerationID(), rect, &bm,
                                                       cache));

         // Finding more than once works fine.
         REPORTER_ASSERT(reporter, SkBitmapCache::Find(cachedBitmap.getGenerationID(), rect, &bm,
                                                       cache));
         bm.unlockPixels();

         // Drop the pixels in the bitmap.
         if (factory) {
             REPORTER_ASSERT(reporter, gPool->getRAMUsed() > 0);
             gPool->dumpPool();

             // The bitmap is not in the cache since it has been dropped.
             REPORTER_ASSERT(reporter, !SkBitmapCache::Find(cachedBitmap.getGenerationID(), rect,
                                                            &bm, cache));
         }

         make_bitmap(&cachedBitmap, SkImageInfo::Make(5, 5, testType, kPremul_SkAlphaType),
                     allocator);
         cachedBitmap.setImmutable();
         cachedBitmap.unlockPixels();

         // We can add the bitmap back to the cache and find it again.
         REPORTER_ASSERT(reporter, SkBitmapCache::Add(cachedBitmap.pixelRef(), rect, cachedBitmap,
                                                      cache));
         REPORTER_ASSERT(reporter, SkBitmapCache::Find(cachedBitmap.getGenerationID(), rect, &bm,
                                                       cache));
     }
     test_mipmapcache(reporter, cache);
     test_bitmap_notify(reporter, cache);
     test_mipmap_notify(reporter, cache);
 }

 DEF_TEST(BitmapCache_discarded_bitmap, reporter) {
     const size_t byteLimit = 100 * 1024;
     {
         SkResourceCache cache(byteLimit);
         testBitmapCache_discarded_bitmap(reporter, &cache, nullptr);
     }
     {
         SkAutoTUnref<SkDiscardableMemoryPool> pool(
             SkDiscardableMemoryPool::Create(byteLimit, nullptr));
         gPool = pool.get();
         SkResourceCache::DiscardableFactory factory = pool_factory;
         SkResourceCache cache(factory);
         testBitmapCache_discarded_bitmap(reporter, &cache, factory);
     }
 }

 static void test_discarded_image(skiatest::Reporter* reporter, const SkMatrix& transform,
                                  SkImage* (*buildImage)()) {
     SkAutoTUnref<SkSurface> surface(SkSurface::NewRasterN32Premul(10, 10));
     SkCanvas* canvas = surface->getCanvas();

     // SkBitmapCache is global, so other threads could be evicting our bitmaps.  Loop a few times
     // to mitigate this risk.
     const unsigned kRepeatCount = 42;
     for (unsigned i = 0; i < kRepeatCount; ++i) {
         SkAutoCanvasRestore acr(canvas, true);

         SkAutoTUnref<SkImage> image(buildImage());

         // always use high quality to ensure caching when scaled
         SkPaint paint;
         paint.setFilterQuality(kHigh_SkFilterQuality);

         // draw the image (with a transform, to tickle different code paths) to ensure
         // any associated resources get cached
         canvas->concat(transform);
         canvas->drawImage(image, 0, 0, &paint);

         auto imageId = image->uniqueID();

         // delete the image
         image.reset(nullptr);

         // all resources should have been purged
         SkBitmap result;
         REPORTER_ASSERT(reporter, !SkBitmapCache::Find(imageId, &result));
     }
 }


 // Verify that associated bitmap cache entries are purged on SkImage destruction.
 DEF_TEST(BitmapCache_discarded_image, reporter) {
     // Cache entries associated with SkImages fall into two categories:
     //
     // 1) generated image bitmaps (managed by the image cacherator)
     // 2) scaled/resampled bitmaps (cached when HQ filters are used)
     //
     // To exercise the first cache type, we use generated/picture-backed SkImages.
     // To exercise the latter, we draw scaled bitmap images using HQ filters.

     const SkMatrix xforms[] = {
         SkMatrix::MakeScale(1, 1),
         SkMatrix::MakeScale(1.7f, 0.5f),
     };

     for (size_t i = 0; i < SK_ARRAY_COUNT(xforms); ++i) {
         test_discarded_image(reporter, xforms[i], []() {
             SkAutoTUnref<SkSurface> surface(SkSurface::NewRasterN32Premul(10, 10));
             surface->getCanvas()->clear(SK_ColorCYAN);
             return surface->newImageSnapshot();
         });

         test_discarded_image(reporter, xforms[i], []() {
             SkPictureRecorder recorder;
             SkCanvas* canvas = recorder.beginRecording(10, 10);
             canvas->clear(SK_ColorCYAN);
             SkAutoTUnref<SkPicture> picture(recorder.endRecording());
             return SkImage::NewFromPicture(picture, SkISize::Make(10, 10), nullptr, nullptr);
         });
     }
 }
	/*
	* Copyright 2014 Google Inc.
	*
	* Use of this source code is governed by a BSD-style license that can be
	* found in the LICENSE file.
	*/

	#include "Test.h"
	#include "SkBitmapCache.h"
	#include "SkCanvas.h"
	#include "SkDiscardableMemoryPool.h"
	#include "SkGraphics.h"
	#include "SkPicture.h"
	#include "SkPictureRecorder.h"
	#include "SkResourceCache.h"
	#include "SkSurface.h"
	#include "SkTypes.h"

	////////////////////////////////////////////////////////////////////////////////////////

	static void make_bitmap(SkBitmap* bitmap, const SkImageInfo& info, SkBitmap::Allocator* allocator) {
	if (info.colorType() == kIndex_8_SkColorType) {
	bitmap->setInfo(info);
	SkPMColor ctStorage[256];
	memset(ctStorage, 0xFF, sizeof(ctStorage)); // init with opaque-white for the moment
	SkAutoTUnref<SkColorTable> ctable(new SkColorTable(ctStorage, 256));
	bitmap->allocPixels(allocator, ctable);
	} else if (allocator) {
	bitmap->setInfo(info);
	allocator->allocPixelRef(bitmap, 0);
	} else {
	bitmap->allocPixels(info);
	}
	}

	// https://bug.skia.org/2894
	DEF_TEST(BitmapCache_add_rect, reporter) {
	SkResourceCache::DiscardableFactory factory = SkResourceCache::GetDiscardableFactory();
	SkBitmap::Allocator* allocator = SkBitmapCache::GetAllocator();

	SkAutoTDelete<SkResourceCache> cache;
	if (factory) {
	cache.reset(new SkResourceCache(factory));
	} else {
	const size_t byteLimit = 100 * 1024;
	cache.reset(new SkResourceCache(byteLimit));
	}
	SkBitmap cachedBitmap;
	make_bitmap(&cachedBitmap, SkImageInfo::MakeN32Premul(5, 5), allocator);
	cachedBitmap.setImmutable();

	SkBitmap bm;
	SkIRect rect = SkIRect::MakeWH(5, 5);
	uint32_t cachedID = cachedBitmap.getGenerationID();
	SkPixelRef* cachedPR = cachedBitmap.pixelRef();

	// Wrong subset size
	REPORTER_ASSERT(reporter, !SkBitmapCache::Add(cachedPR, SkIRect::MakeWH(4, 6), cachedBitmap, cache));
	REPORTER_ASSERT(reporter, !SkBitmapCache::Find(cachedID, rect, &bm, cache));
	// Wrong offset value
	REPORTER_ASSERT(reporter, !SkBitmapCache::Add(cachedPR, SkIRect::MakeXYWH(-1, 0, 5, 5), cachedBitmap, cache));
	REPORTER_ASSERT(reporter, !SkBitmapCache::Find(cachedID, rect, &bm, cache));

	// Should not be in the cache
	REPORTER_ASSERT(reporter, !SkBitmapCache::Find(cachedID, rect, &bm, cache));

	REPORTER_ASSERT(reporter, SkBitmapCache::Add(cachedPR, rect, cachedBitmap, cache));
	// Should be in the cache, we just added it
	REPORTER_ASSERT(reporter, SkBitmapCache::Find(cachedID, rect, &bm, cache));
	}

	#include "SkMipMap.h"

	enum LockedState {
	kNotLocked,
	kLocked,
	};

	enum CachedState {
	kNotInCache,
	kInCache,
	};

	static void check_data(skiatest::Reporter* reporter, const SkCachedData* data,
	int refcnt, CachedState cacheState, LockedState lockedState) {
	REPORTER_ASSERT(reporter, data->testing_only_getRefCnt() == refcnt);
	REPORTER_ASSERT(reporter, data->testing_only_isInCache() == (kInCache == cacheState));
	bool isLocked = (data->data() != nullptr);
	REPORTER_ASSERT(reporter, isLocked == (lockedState == kLocked));
	}

	static void test_mipmapcache(skiatest::Reporter* reporter, SkResourceCache* cache) {
	cache->purgeAll();

	SkBitmap src;
	src.allocN32Pixels(5, 5);
	src.setImmutable();

	const SkMipMap* mipmap = SkMipMapCache::FindAndRef(SkBitmapCacheDesc::Make(src), cache);
	REPORTER_ASSERT(reporter, nullptr == mipmap);

	mipmap = SkMipMapCache::AddAndRef(src, cache);
	REPORTER_ASSERT(reporter, mipmap);

	{
	const SkMipMap* mm = SkMipMapCache::FindAndRef(SkBitmapCacheDesc::Make(src), cache);
	REPORTER_ASSERT(reporter, mm);
	REPORTER_ASSERT(reporter, mm == mipmap);
	mm->unref();
	}

	check_data(reporter, mipmap, 2, kInCache, kLocked);

	mipmap->unref();
	// tricky, since technically after this I'm no longer an owner, but since the cache is
	// local, I know it won't get purged behind my back
	check_data(reporter, mipmap, 1, kInCache, kNotLocked);

	// find us again
	mipmap = SkMipMapCache::FindAndRef(SkBitmapCacheDesc::Make(src), cache);
	check_data(reporter, mipmap, 2, kInCache, kLocked);

	cache->purgeAll();
	check_data(reporter, mipmap, 1, kNotInCache, kLocked);

	mipmap->unref();
	}

	static void test_mipmap_notify(skiatest::Reporter* reporter, SkResourceCache* cache) {
	const int N = 3;
	SkBitmap src[N];
	for (int i = 0; i < N; ++i) {
	src[i].allocN32Pixels(5, 5);
	src[i].setImmutable();
	SkMipMapCache::AddAndRef(src[i], cache)->unref();
	}

	for (int i = 0; i < N; ++i) {
	const SkMipMap* mipmap = SkMipMapCache::FindAndRef(SkBitmapCacheDesc::Make(src[i]), cache);
	if (cache) {
	// if cache is null, we're working on the global cache, and other threads might purge
	// it, making this check fragile.
	REPORTER_ASSERT(reporter, mipmap);
	}
	SkSafeUnref(mipmap);

	src[i].reset(); // delete the underlying pixelref, which should remove us from the cache

	mipmap = SkMipMapCache::FindAndRef(SkBitmapCacheDesc::Make(src[i]), cache);
	REPORTER_ASSERT(reporter, !mipmap);
	}
	}

	static void test_bitmap_notify(skiatest::Reporter* reporter, SkResourceCache* cache) {
	const SkIRect subset = SkIRect::MakeWH(5, 5);
	const int N = 3;
	SkBitmap src[N], dst[N];
	for (int i = 0; i < N; ++i) {
	src[i].allocN32Pixels(5, 5);
	src[i].setImmutable();
	dst[i].allocN32Pixels(5, 5);
	dst[i].setImmutable();
	SkBitmapCache::Add(src[i].pixelRef(), subset, dst[i], cache);
	}

	for (int i = 0; i < N; ++i) {
	const uint32_t genID = src[i].getGenerationID();
	SkBitmap result;
	bool found = SkBitmapCache::Find(genID, subset, &result, cache);
	if (cache) {
	// if cache is null, we're working on the global cache, and other threads might purge
	// it, making this check fragile.
	REPORTER_ASSERT(reporter, found);
	}

	src[i].reset(); // delete the underlying pixelref, which should remove us from the cache

	found = SkBitmapCache::Find(genID, subset, &result, cache);
	REPORTER_ASSERT(reporter, !found);
	}
	}

	#include "SkDiscardableMemoryPool.h"

	static SkDiscardableMemoryPool* gPool = 0;
	static SkDiscardableMemory* pool_factory(size_t bytes) {
	SkASSERT(gPool);
	return gPool->create(bytes);
	}

	static void testBitmapCache_discarded_bitmap(skiatest::Reporter* reporter, SkResourceCache* cache,
	SkResourceCache::DiscardableFactory factory) {
	SkBitmap::Allocator* allocator = cache->allocator();
	const SkColorType testTypes[] = {
	kAlpha_8_SkColorType,
	kRGB_565_SkColorType,
	kRGBA_8888_SkColorType,
	kBGRA_8888_SkColorType,
	kIndex_8_SkColorType,
	kGray_8_SkColorType
	};
	for (const SkColorType testType : testTypes) {
	SkBitmap cachedBitmap;
	make_bitmap(&cachedBitmap, SkImageInfo::Make(5, 5, testType, kPremul_SkAlphaType),
	allocator);
	cachedBitmap.setImmutable();
	cachedBitmap.unlockPixels();

	SkBitmap bm;
	SkIRect rect = SkIRect::MakeWH(5, 5);

	// Add a bitmap to the cache.
	REPORTER_ASSERT(reporter, SkBitmapCache::Add(cachedBitmap.pixelRef(), rect, cachedBitmap,
	cache));
	REPORTER_ASSERT(reporter, SkBitmapCache::Find(cachedBitmap.getGenerationID(), rect, &bm,
	cache));

	// Finding more than once works fine.
	REPORTER_ASSERT(reporter, SkBitmapCache::Find(cachedBitmap.getGenerationID(), rect, &bm,
	cache));
	bm.unlockPixels();

	// Drop the pixels in the bitmap.
	if (factory) {
	REPORTER_ASSERT(reporter, gPool->getRAMUsed() > 0);
	gPool->dumpPool();

	// The bitmap is not in the cache since it has been dropped.
	REPORTER_ASSERT(reporter, !SkBitmapCache::Find(cachedBitmap.getGenerationID(), rect,
	&bm, cache));
	}

	make_bitmap(&cachedBitmap, SkImageInfo::Make(5, 5, testType, kPremul_SkAlphaType),
	allocator);
	cachedBitmap.setImmutable();
	cachedBitmap.unlockPixels();

	// We can add the bitmap back to the cache and find it again.
	REPORTER_ASSERT(reporter, SkBitmapCache::Add(cachedBitmap.pixelRef(), rect, cachedBitmap,
	cache));
	REPORTER_ASSERT(reporter, SkBitmapCache::Find(cachedBitmap.getGenerationID(), rect, &bm,
	cache));
	}
	test_mipmapcache(reporter, cache);
	test_bitmap_notify(reporter, cache);
	test_mipmap_notify(reporter, cache);
	}

	DEF_TEST(BitmapCache_discarded_bitmap, reporter) {
	const size_t byteLimit = 100 * 1024;
	{
	SkResourceCache cache(byteLimit);
	testBitmapCache_discarded_bitmap(reporter, &cache, nullptr);
	}
	{
	SkAutoTUnref<SkDiscardableMemoryPool> pool(
	SkDiscardableMemoryPool::Create(byteLimit, nullptr));
	gPool = pool.get();
	SkResourceCache::DiscardableFactory factory = pool_factory;
	SkResourceCache cache(factory);
	testBitmapCache_discarded_bitmap(reporter, &cache, factory);
	}
	}

	static void test_discarded_image(skiatest::Reporter* reporter, const SkMatrix& transform,
	SkImage* (*buildImage)()) {
	SkAutoTUnref<SkSurface> surface(SkSurface::NewRasterN32Premul(10, 10));
	SkCanvas* canvas = surface->getCanvas();

	// SkBitmapCache is global, so other threads could be evicting our bitmaps. Loop a few times
	// to mitigate this risk.
	const unsigned kRepeatCount = 42;
	for (unsigned i = 0; i < kRepeatCount; ++i) {
	SkAutoCanvasRestore acr(canvas, true);

	SkAutoTUnref<SkImage> image(buildImage());

	// always use high quality to ensure caching when scaled
	SkPaint paint;
	paint.setFilterQuality(kHigh_SkFilterQuality);

	// draw the image (with a transform, to tickle different code paths) to ensure
	// any associated resources get cached
	canvas->concat(transform);
	canvas->drawImage(image, 0, 0, &paint);

	auto imageId = image->uniqueID();

	// delete the image
	image.reset(nullptr);

	// all resources should have been purged
	SkBitmap result;
	REPORTER_ASSERT(reporter, !SkBitmapCache::Find(imageId, &result));
	}
	}


	// Verify that associated bitmap cache entries are purged on SkImage destruction.
	DEF_TEST(BitmapCache_discarded_image, reporter) {
	// Cache entries associated with SkImages fall into two categories:
	//
	// 1) generated image bitmaps (managed by the image cacherator)
	// 2) scaled/resampled bitmaps (cached when HQ filters are used)
	//
	// To exercise the first cache type, we use generated/picture-backed SkImages.
	// To exercise the latter, we draw scaled bitmap images using HQ filters.

	const SkMatrix xforms[] = {
	SkMatrix::MakeScale(1, 1),
	SkMatrix::MakeScale(1.7f, 0.5f),
	};

	for (size_t i = 0; i < SK_ARRAY_COUNT(xforms); ++i) {
	test_discarded_image(reporter, xforms[i], []() {
	SkAutoTUnref<SkSurface> surface(SkSurface::NewRasterN32Premul(10, 10));
	surface->getCanvas()->clear(SK_ColorCYAN);
	return surface->newImageSnapshot();
	});

	test_discarded_image(reporter, xforms[i], []() {
	SkPictureRecorder recorder;
	SkCanvas* canvas = recorder.beginRecording(10, 10);
	canvas->clear(SK_ColorCYAN);
	SkAutoTUnref<SkPicture> picture(recorder.endRecording());
	return SkImage::NewFromPicture(picture, SkISize::Make(10, 10), nullptr, nullptr);
	});
	}
	}