src/gpu/GrLayerHoister.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 "SkBigPicture.h"
 #include "SkCanvas.h"
 #include "SkImageFilterCache.h"
 #include "SkLayerInfo.h"
 #include "SkRecordDraw.h"
 #include "SkSpecialImage.h"
 #include "SkSurface.h"

 #include "GrLayerHoister.h"

 #if !defined(SK_IGNORE_GPU_LAYER_HOISTING) && SK_SUPPORT_GPU

 #include "GrContext.h"
 #include "GrLayerCache.h"
 #include "GrRecordReplaceDraw.h"

 // Create the layer information for the hoisted layer and secure the
 // required texture/render target resources.
 static void prepare_for_hoisting(GrLayerCache* layerCache,
                                  const SkPicture* topLevelPicture,
                                  const SkMatrix& initialMat,
                                  const SkLayerInfo::BlockInfo& info,
                                  const SkIRect& srcIR,
                                  const SkIRect& dstIR,
                                  SkTDArray<GrHoistedLayer>* needRendering,
                                  SkTDArray<GrHoistedLayer>* recycled,
                                  bool attemptToAtlas,
                                  int numSamples) {
     const SkPicture* pict = info.fPicture ? info.fPicture : topLevelPicture;

     GrCachedLayer* layer = layerCache->findLayerOrCreate(topLevelPicture->uniqueID(),
                                                          SkToInt(info.fSaveLayerOpID),
                                                          SkToInt(info.fRestoreOpID),
                                                          srcIR,
                                                          dstIR,
                                                          initialMat,
                                                          info.fKey,
                                                          info.fKeySize,
                                                          info.fPaint);
     GrSurfaceDesc desc;
     desc.fFlags = kRenderTarget_GrSurfaceFlag;
     desc.fWidth = srcIR.width();
     desc.fHeight = srcIR.height();
     desc.fConfig = kSkia8888_GrPixelConfig;
     desc.fSampleCnt = numSamples;

     bool locked, needsRendering;
     if (attemptToAtlas) {
         locked = layerCache->tryToAtlas(layer, desc, &needsRendering);
     } else {
         locked = layerCache->lock(layer, desc, &needsRendering);
     }
     if (!locked) {
         // GPU resources could not be secured for the hoisting of this layer
         return;
     }

     if (attemptToAtlas) {
         SkASSERT(layer->isAtlased());
     }

     GrHoistedLayer* hl;

     if (needsRendering) {
         if (!attemptToAtlas) {
             SkASSERT(!layer->isAtlased());
         }
         hl = needRendering->append();
     } else {
         hl = recycled->append();
     }

     layerCache->addUse(layer);
     hl->fLayer = layer;
     hl->fPicture = pict;
     hl->fLocalMat = info.fLocalMat;
     hl->fInitialMat = initialMat;
     hl->fPreMat = initialMat;
     hl->fPreMat.preConcat(info.fPreMat);
 }

 // Compute the source rect and return false if it is empty.
 static bool compute_source_rect(const SkLayerInfo::BlockInfo& info, const SkMatrix& initialMat,
                                 const SkIRect& dstIR, SkIRect* srcIR) {
     SkIRect clipBounds = dstIR;

     SkMatrix totMat = initialMat;
     totMat.preConcat(info.fPreMat);
     totMat.preConcat(info.fLocalMat);

     if (info.fPaint && info.fPaint->getImageFilter()) {
         clipBounds = info.fPaint->getImageFilter()->filterBounds(clipBounds, totMat);
     }

     if (!info.fSrcBounds.isEmpty()) {
         SkRect r;

         totMat.mapRect(&r, info.fSrcBounds);
         r.roundOut(srcIR);

         if (!srcIR->intersect(clipBounds)) {
             return false;
         }
     } else {
         *srcIR = clipBounds;
     }

     return true;
 }

 // Atlased layers must be small enough to fit in the atlas, not have a
 // paint with an image filter and be neither nested nor nesting.
 // TODO: allow leaf nested layers to appear in the atlas.
 void GrLayerHoister::FindLayersToAtlas(GrContext* context,
                                        const SkPicture* topLevelPicture,
                                        const SkMatrix& initialMat,
                                        const SkRect& query,
                                        SkTDArray<GrHoistedLayer>* atlased,
                                        SkTDArray<GrHoistedLayer>* recycled,
                                        int numSamples) {
     if (0 != numSamples) {
         // MSAA layers are currently never atlased
         return;
     }

     GrLayerCache* layerCache = context->getLayerCache();
     layerCache->processDeletedPictures();

     const SkBigPicture::AccelData* topLevelData = nullptr;
     if (const SkBigPicture* bp = topLevelPicture->asSkBigPicture()) {
         topLevelData = bp->accelData();
     }
     if (!topLevelData) {
         return;
     }

     const SkLayerInfo *topLevelGPUData = static_cast<const SkLayerInfo*>(topLevelData);
     if (0 == topLevelGPUData->numBlocks()) {
         return;
     }

     atlased->setReserve(atlased->count() + topLevelGPUData->numBlocks());

     for (int i = 0; i < topLevelGPUData->numBlocks(); ++i) {
         const SkLayerInfo::BlockInfo& info = topLevelGPUData->block(i);

         // TODO: ignore perspective projected layers here?
         bool disallowAtlasing = info.fHasNestedLayers || info.fIsNested ||
                                 (info.fPaint && info.fPaint->getImageFilter());

         if (disallowAtlasing) {
             continue;
         }

         SkRect layerRect;
         initialMat.mapRect(&layerRect, info.fBounds);
         if (!layerRect.intersect(query)) {
             continue;
         }

         const SkIRect dstIR = layerRect.roundOut();

         SkIRect srcIR;

         if (!compute_source_rect(info, initialMat, dstIR, &srcIR) ||
             !GrLayerCache::PlausiblyAtlasable(srcIR.width(), srcIR.height())) {
             continue;
         }

         prepare_for_hoisting(layerCache, topLevelPicture, initialMat,
                              info, srcIR, dstIR, atlased, recycled, true, 0);
     }

 }

 void GrLayerHoister::FindLayersToHoist(GrContext* context,
                                        const SkPicture* topLevelPicture,
                                        const SkMatrix& initialMat,
                                        const SkRect& query,
                                        SkTDArray<GrHoistedLayer>* needRendering,
                                        SkTDArray<GrHoistedLayer>* recycled,
                                        int numSamples) {
     GrLayerCache* layerCache = context->getLayerCache();

     layerCache->processDeletedPictures();

     const SkBigPicture::AccelData* topLevelData = nullptr;
     if (const SkBigPicture* bp = topLevelPicture->asSkBigPicture()) {
         topLevelData = bp->accelData();
     }
     if (!topLevelData) {
         return;
     }

     const SkLayerInfo *topLevelGPUData = static_cast<const SkLayerInfo*>(topLevelData);
     if (0 == topLevelGPUData->numBlocks()) {
         return;
     }

     // Find and prepare for hoisting all the layers that intersect the query rect
     for (int i = 0; i < topLevelGPUData->numBlocks(); ++i) {
         const SkLayerInfo::BlockInfo& info = topLevelGPUData->block(i);
         if (info.fIsNested) {
             // Parent layers are currently hoisted while nested layers are not.
             continue;
         }

         SkRect layerRect;
         initialMat.mapRect(&layerRect, info.fBounds);
         if (!layerRect.intersect(query)) {
             continue;
         }

         const SkIRect dstIR = layerRect.roundOut();

         SkIRect srcIR;
         if (!compute_source_rect(info, initialMat, dstIR, &srcIR)) {
             continue;
         }

         prepare_for_hoisting(layerCache, topLevelPicture, initialMat, info, srcIR, dstIR,
                              needRendering, recycled, false, numSamples);
     }
 }

 void GrLayerHoister::DrawLayersToAtlas(GrContext* context,
                                        const SkTDArray<GrHoistedLayer>& atlased) {
     if (atlased.count() > 0) {
         // All the atlased layers are rendered into the same GrTexture
         SkSurfaceProps props(0, kUnknown_SkPixelGeometry);
         sk_sp<SkSurface> surface(SkSurface::MakeRenderTargetDirect(
                                         atlased[0].fLayer->texture()->asRenderTarget(), &props));

         SkCanvas* atlasCanvas = surface->getCanvas();

         for (int i = 0; i < atlased.count(); ++i) {
             const GrCachedLayer* layer = atlased[i].fLayer;
             const SkBigPicture* pict = atlased[i].fPicture->asSkBigPicture();
             if (!pict) {
                 // TODO: can we assume / assert this?
                 continue;
             }
             const SkIPoint offset = SkIPoint::Make(layer->srcIR().fLeft, layer->srcIR().fTop);
             SkDEBUGCODE(const SkPaint* layerPaint = layer->paint();)

             SkASSERT(!layerPaint || !layerPaint->getImageFilter());
             SkASSERT(!layer->filter());

             atlasCanvas->save();

             // Add a rect clip to make sure the rendering doesn't
             // extend beyond the boundaries of the atlased sub-rect
             const SkRect bound = SkRect::Make(layer->rect());
             atlasCanvas->clipRect(bound);
             atlasCanvas->clear(0);

             // '-offset' maps the layer's top/left to the origin.
             // Since this layer is atlased, the top/left corner needs
             // to be offset to the correct location in the backing texture.
             SkMatrix initialCTM;
             initialCTM.setTranslate(SkIntToScalar(-offset.fX), SkIntToScalar(-offset.fY));
             initialCTM.preTranslate(bound.fLeft, bound.fTop);
             initialCTM.preConcat(atlased[i].fPreMat);

             atlasCanvas->setMatrix(initialCTM);
             atlasCanvas->concat(atlased[i].fLocalMat);

             pict->partialPlayback(atlasCanvas, layer->start() + 1, layer->stop(), initialCTM);
             atlasCanvas->restore();
         }

         atlasCanvas->flush();
     }
 }

 void GrLayerHoister::FilterLayer(GrContext* context,
                                  const SkSurfaceProps* props,
                                  const GrHoistedLayer& info) {
     GrCachedLayer* layer = info.fLayer;

     SkASSERT(layer->filter());

     static const int kDefaultCacheSize = 32 * 1024 * 1024;

     const SkIPoint filterOffset = SkIPoint::Make(layer->srcIR().fLeft, layer->srcIR().fTop);

     SkMatrix totMat(info.fPreMat);
     totMat.preConcat(info.fLocalMat);
     totMat.postTranslate(-SkIntToScalar(filterOffset.fX), -SkIntToScalar(filterOffset.fY));

     SkASSERT(0 == layer->rect().fLeft && 0 == layer->rect().fTop);
     const SkIRect& clipBounds = layer->rect();

     // This cache is transient, and is freed (along with all its contained
     // textures) when it goes out of scope.
     SkAutoTUnref<SkImageFilterCache> cache(SkImageFilterCache::Create(kDefaultCacheSize));
     SkImageFilter::Context filterContext(totMat, clipBounds, cache);

     // TODO: should the layer hoister store stand alone layers as SkSpecialImages internally?
     SkASSERT(layer->rect().width() == layer->texture()->width() &&
              layer->rect().height() == layer->texture()->height());
     const SkIRect subset = SkIRect::MakeWH(layer->rect().width(), layer->rect().height());
     sk_sp<SkSpecialImage> img(SkSpecialImage::MakeFromGpu(subset,
                                                           kNeedNewImageUniqueID_SpecialImage,
                                                           sk_ref_sp(layer->texture()),
                                                           props));

     SkIPoint offset = SkIPoint::Make(0, 0);
     sk_sp<SkSpecialImage> result(layer->filter()->filterImage(img.get(),
                                                               filterContext,
                                                               &offset));
     if (!result) {
         // Filtering failed. Press on with the unfiltered version.
         return;
     }

     SkASSERT(result->isTextureBacked());
     sk_sp<GrTexture> texture(result->asTextureRef(context));
     layer->setTexture(texture.get(), result->subset(), false);
     layer->setOffset(offset);
 }

 void GrLayerHoister::DrawLayers(GrContext* context, const SkTDArray<GrHoistedLayer>& layers) {
     for (int i = 0; i < layers.count(); ++i) {
         GrCachedLayer* layer = layers[i].fLayer;
         const SkBigPicture* pict = layers[i].fPicture->asSkBigPicture();
         if (!pict) {
             // TODO: can we assume / assert this?
             continue;
         }
         const SkIPoint offset = SkIPoint::Make(layer->srcIR().fLeft, layer->srcIR().fTop);

         // Each non-atlased layer has its own GrTexture
         SkSurfaceProps props(0, kUnknown_SkPixelGeometry);
         auto surface(SkSurface::MakeRenderTargetDirect(
                                         layer->texture()->asRenderTarget(), &props));

         SkCanvas* layerCanvas = surface->getCanvas();

         SkASSERT(0 == layer->rect().fLeft && 0 == layer->rect().fTop);

         // Add a rect clip to make sure the rendering doesn't
         // extend beyond the boundaries of the layer
         const SkRect bound = SkRect::Make(layer->rect());
         layerCanvas->clipRect(bound);
         layerCanvas->clear(SK_ColorTRANSPARENT);

         SkMatrix initialCTM;
         initialCTM.setTranslate(SkIntToScalar(-offset.fX), SkIntToScalar(-offset.fY));
         initialCTM.preConcat(layers[i].fPreMat);

         layerCanvas->setMatrix(initialCTM);
         layerCanvas->concat(layers[i].fLocalMat);

         pict->partialPlayback(layerCanvas, layer->start()+1, layer->stop(), initialCTM);
         layerCanvas->flush();

         if (layer->filter()) {
             FilterLayer(context, &surface->props(), layers[i]);
         }
     }
 }

 void GrLayerHoister::UnlockLayers(GrContext* context,
                                   const SkTDArray<GrHoistedLayer>& layers) {
     GrLayerCache* layerCache = context->getLayerCache();

     for (int i = 0; i < layers.count(); ++i) {
         layerCache->removeUse(layers[i].fLayer);
     }

     SkDEBUGCODE(layerCache->validate();)
 }

 void GrLayerHoister::Begin(GrContext* context) {
     GrLayerCache* layerCache = context->getLayerCache();

     layerCache->begin();
 }

 void GrLayerHoister::End(GrContext* context) {
     GrLayerCache* layerCache = context->getLayerCache();

 #if !GR_CACHE_HOISTED_LAYERS

     // This code completely clears out the atlas. It is required when
     // caching is disabled so the atlas doesn't fill up and force more
     // free floating layers
     layerCache->purgeAll();
 #endif

     layerCache->end();
 }

 #endif
	/*
	* 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 "SkBigPicture.h"
	#include "SkCanvas.h"
	#include "SkImageFilterCache.h"
	#include "SkLayerInfo.h"
	#include "SkRecordDraw.h"
	#include "SkSpecialImage.h"
	#include "SkSurface.h"

	#include "GrLayerHoister.h"

	#if !defined(SK_IGNORE_GPU_LAYER_HOISTING) && SK_SUPPORT_GPU

	#include "GrContext.h"
	#include "GrLayerCache.h"
	#include "GrRecordReplaceDraw.h"

	// Create the layer information for the hoisted layer and secure the
	// required texture/render target resources.
	static void prepare_for_hoisting(GrLayerCache* layerCache,
	const SkPicture* topLevelPicture,
	const SkMatrix& initialMat,
	const SkLayerInfo::BlockInfo& info,
	const SkIRect& srcIR,
	const SkIRect& dstIR,
	SkTDArray<GrHoistedLayer>* needRendering,
	SkTDArray<GrHoistedLayer>* recycled,
	bool attemptToAtlas,
	int numSamples) {
	const SkPicture* pict = info.fPicture ? info.fPicture : topLevelPicture;

	GrCachedLayer* layer = layerCache->findLayerOrCreate(topLevelPicture->uniqueID(),
	SkToInt(info.fSaveLayerOpID),
	SkToInt(info.fRestoreOpID),
	srcIR,
	dstIR,
	initialMat,
	info.fKey,
	info.fKeySize,
	info.fPaint);
	GrSurfaceDesc desc;
	desc.fFlags = kRenderTarget_GrSurfaceFlag;
	desc.fWidth = srcIR.width();
	desc.fHeight = srcIR.height();
	desc.fConfig = kSkia8888_GrPixelConfig;
	desc.fSampleCnt = numSamples;

	bool locked, needsRendering;
	if (attemptToAtlas) {
	locked = layerCache->tryToAtlas(layer, desc, &needsRendering);
	} else {
	locked = layerCache->lock(layer, desc, &needsRendering);
	}
	if (!locked) {
	// GPU resources could not be secured for the hoisting of this layer
	return;
	}

	if (attemptToAtlas) {
	SkASSERT(layer->isAtlased());
	}

	GrHoistedLayer* hl;

	if (needsRendering) {
	if (!attemptToAtlas) {
	SkASSERT(!layer->isAtlased());
	}
	hl = needRendering->append();
	} else {
	hl = recycled->append();
	}

	layerCache->addUse(layer);
	hl->fLayer = layer;
	hl->fPicture = pict;
	hl->fLocalMat = info.fLocalMat;
	hl->fInitialMat = initialMat;
	hl->fPreMat = initialMat;
	hl->fPreMat.preConcat(info.fPreMat);
	}

	// Compute the source rect and return false if it is empty.
	static bool compute_source_rect(const SkLayerInfo::BlockInfo& info, const SkMatrix& initialMat,
	const SkIRect& dstIR, SkIRect* srcIR) {
	SkIRect clipBounds = dstIR;

	SkMatrix totMat = initialMat;
	totMat.preConcat(info.fPreMat);
	totMat.preConcat(info.fLocalMat);

	if (info.fPaint && info.fPaint->getImageFilter()) {
	clipBounds = info.fPaint->getImageFilter()->filterBounds(clipBounds, totMat);
	}

	if (!info.fSrcBounds.isEmpty()) {
	SkRect r;

	totMat.mapRect(&r, info.fSrcBounds);
	r.roundOut(srcIR);

	if (!srcIR->intersect(clipBounds)) {
	return false;
	}
	} else {
	*srcIR = clipBounds;
	}

	return true;
	}

	// Atlased layers must be small enough to fit in the atlas, not have a
	// paint with an image filter and be neither nested nor nesting.
	// TODO: allow leaf nested layers to appear in the atlas.
	void GrLayerHoister::FindLayersToAtlas(GrContext* context,
	const SkPicture* topLevelPicture,
	const SkMatrix& initialMat,
	const SkRect& query,
	SkTDArray<GrHoistedLayer>* atlased,
	SkTDArray<GrHoistedLayer>* recycled,
	int numSamples) {
	if (0 != numSamples) {
	// MSAA layers are currently never atlased
	return;
	}

	GrLayerCache* layerCache = context->getLayerCache();
	layerCache->processDeletedPictures();

	const SkBigPicture::AccelData* topLevelData = nullptr;
	if (const SkBigPicture* bp = topLevelPicture->asSkBigPicture()) {
	topLevelData = bp->accelData();
	}
	if (!topLevelData) {
	return;
	}

	const SkLayerInfo topLevelGPUData = static_cast<const SkLayerInfo>(topLevelData);
	if (0 == topLevelGPUData->numBlocks()) {
	return;
	}

	atlased->setReserve(atlased->count() + topLevelGPUData->numBlocks());

	for (int i = 0; i < topLevelGPUData->numBlocks(); ++i) {
	const SkLayerInfo::BlockInfo& info = topLevelGPUData->block(i);

	// TODO: ignore perspective projected layers here?
	bool disallowAtlasing = info.fHasNestedLayers \|\| info.fIsNested \|\|
	(info.fPaint && info.fPaint->getImageFilter());

	if (disallowAtlasing) {
	continue;
	}

	SkRect layerRect;
	initialMat.mapRect(&layerRect, info.fBounds);
	if (!layerRect.intersect(query)) {
	continue;
	}

	const SkIRect dstIR = layerRect.roundOut();

	SkIRect srcIR;

	if (!compute_source_rect(info, initialMat, dstIR, &srcIR) \|\|
	!GrLayerCache::PlausiblyAtlasable(srcIR.width(), srcIR.height())) {
	continue;
	}

	prepare_for_hoisting(layerCache, topLevelPicture, initialMat,
	info, srcIR, dstIR, atlased, recycled, true, 0);
	}

	}

	void GrLayerHoister::FindLayersToHoist(GrContext* context,
	const SkPicture* topLevelPicture,
	const SkMatrix& initialMat,
	const SkRect& query,
	SkTDArray<GrHoistedLayer>* needRendering,
	SkTDArray<GrHoistedLayer>* recycled,
	int numSamples) {
	GrLayerCache* layerCache = context->getLayerCache();

	layerCache->processDeletedPictures();

	const SkBigPicture::AccelData* topLevelData = nullptr;
	if (const SkBigPicture* bp = topLevelPicture->asSkBigPicture()) {
	topLevelData = bp->accelData();
	}
	if (!topLevelData) {
	return;
	}

	const SkLayerInfo topLevelGPUData = static_cast<const SkLayerInfo>(topLevelData);
	if (0 == topLevelGPUData->numBlocks()) {
	return;
	}

	// Find and prepare for hoisting all the layers that intersect the query rect
	for (int i = 0; i < topLevelGPUData->numBlocks(); ++i) {
	const SkLayerInfo::BlockInfo& info = topLevelGPUData->block(i);
	if (info.fIsNested) {
	// Parent layers are currently hoisted while nested layers are not.
	continue;
	}

	SkRect layerRect;
	initialMat.mapRect(&layerRect, info.fBounds);
	if (!layerRect.intersect(query)) {
	continue;
	}

	const SkIRect dstIR = layerRect.roundOut();

	SkIRect srcIR;
	if (!compute_source_rect(info, initialMat, dstIR, &srcIR)) {
	continue;
	}

	prepare_for_hoisting(layerCache, topLevelPicture, initialMat, info, srcIR, dstIR,
	needRendering, recycled, false, numSamples);
	}
	}

	void GrLayerHoister::DrawLayersToAtlas(GrContext* context,
	const SkTDArray<GrHoistedLayer>& atlased) {
	if (atlased.count() > 0) {
	// All the atlased layers are rendered into the same GrTexture
	SkSurfaceProps props(0, kUnknown_SkPixelGeometry);
	sk_sp<SkSurface> surface(SkSurface::MakeRenderTargetDirect(
	atlased[0].fLayer->texture()->asRenderTarget(), &props));

	SkCanvas* atlasCanvas = surface->getCanvas();

	for (int i = 0; i < atlased.count(); ++i) {
	const GrCachedLayer* layer = atlased[i].fLayer;
	const SkBigPicture* pict = atlased[i].fPicture->asSkBigPicture();
	if (!pict) {
	// TODO: can we assume / assert this?
	continue;
	}
	const SkIPoint offset = SkIPoint::Make(layer->srcIR().fLeft, layer->srcIR().fTop);
	SkDEBUGCODE(const SkPaint* layerPaint = layer->paint();)

	SkASSERT(!layerPaint \|\| !layerPaint->getImageFilter());
	SkASSERT(!layer->filter());

	atlasCanvas->save();

	// Add a rect clip to make sure the rendering doesn't
	// extend beyond the boundaries of the atlased sub-rect
	const SkRect bound = SkRect::Make(layer->rect());
	atlasCanvas->clipRect(bound);
	atlasCanvas->clear(0);

	// '-offset' maps the layer's top/left to the origin.
	// Since this layer is atlased, the top/left corner needs
	// to be offset to the correct location in the backing texture.
	SkMatrix initialCTM;
	initialCTM.setTranslate(SkIntToScalar(-offset.fX), SkIntToScalar(-offset.fY));
	initialCTM.preTranslate(bound.fLeft, bound.fTop);
	initialCTM.preConcat(atlased[i].fPreMat);

	atlasCanvas->setMatrix(initialCTM);
	atlasCanvas->concat(atlased[i].fLocalMat);

	pict->partialPlayback(atlasCanvas, layer->start() + 1, layer->stop(), initialCTM);
	atlasCanvas->restore();
	}

	atlasCanvas->flush();
	}
	}

	void GrLayerHoister::FilterLayer(GrContext* context,
	const SkSurfaceProps* props,
	const GrHoistedLayer& info) {
	GrCachedLayer* layer = info.fLayer;

	SkASSERT(layer->filter());

	static const int kDefaultCacheSize = 32 * 1024 * 1024;

	const SkIPoint filterOffset = SkIPoint::Make(layer->srcIR().fLeft, layer->srcIR().fTop);

	SkMatrix totMat(info.fPreMat);
	totMat.preConcat(info.fLocalMat);
	totMat.postTranslate(-SkIntToScalar(filterOffset.fX), -SkIntToScalar(filterOffset.fY));

	SkASSERT(0 == layer->rect().fLeft && 0 == layer->rect().fTop);
	const SkIRect& clipBounds = layer->rect();

	// This cache is transient, and is freed (along with all its contained
	// textures) when it goes out of scope.
	SkAutoTUnref<SkImageFilterCache> cache(SkImageFilterCache::Create(kDefaultCacheSize));
	SkImageFilter::Context filterContext(totMat, clipBounds, cache);

	// TODO: should the layer hoister store stand alone layers as SkSpecialImages internally?
	SkASSERT(layer->rect().width() == layer->texture()->width() &&
	layer->rect().height() == layer->texture()->height());
	const SkIRect subset = SkIRect::MakeWH(layer->rect().width(), layer->rect().height());
	sk_sp<SkSpecialImage> img(SkSpecialImage::MakeFromGpu(subset,
	kNeedNewImageUniqueID_SpecialImage,
	sk_ref_sp(layer->texture()),
	props));

	SkIPoint offset = SkIPoint::Make(0, 0);
	sk_sp<SkSpecialImage> result(layer->filter()->filterImage(img.get(),
	filterContext,
	&offset));
	if (!result) {
	// Filtering failed. Press on with the unfiltered version.
	return;
	}

	SkASSERT(result->isTextureBacked());
	sk_sp<GrTexture> texture(result->asTextureRef(context));
	layer->setTexture(texture.get(), result->subset(), false);
	layer->setOffset(offset);
	}

	void GrLayerHoister::DrawLayers(GrContext* context, const SkTDArray<GrHoistedLayer>& layers) {
	for (int i = 0; i < layers.count(); ++i) {
	GrCachedLayer* layer = layers[i].fLayer;
	const SkBigPicture* pict = layers[i].fPicture->asSkBigPicture();
	if (!pict) {
	// TODO: can we assume / assert this?
	continue;
	}
	const SkIPoint offset = SkIPoint::Make(layer->srcIR().fLeft, layer->srcIR().fTop);

	// Each non-atlased layer has its own GrTexture
	SkSurfaceProps props(0, kUnknown_SkPixelGeometry);
	auto surface(SkSurface::MakeRenderTargetDirect(
	layer->texture()->asRenderTarget(), &props));

	SkCanvas* layerCanvas = surface->getCanvas();

	SkASSERT(0 == layer->rect().fLeft && 0 == layer->rect().fTop);

	// Add a rect clip to make sure the rendering doesn't
	// extend beyond the boundaries of the layer
	const SkRect bound = SkRect::Make(layer->rect());
	layerCanvas->clipRect(bound);
	layerCanvas->clear(SK_ColorTRANSPARENT);

	SkMatrix initialCTM;
	initialCTM.setTranslate(SkIntToScalar(-offset.fX), SkIntToScalar(-offset.fY));
	initialCTM.preConcat(layers[i].fPreMat);

	layerCanvas->setMatrix(initialCTM);
	layerCanvas->concat(layers[i].fLocalMat);

	pict->partialPlayback(layerCanvas, layer->start()+1, layer->stop(), initialCTM);
	layerCanvas->flush();

	if (layer->filter()) {
	FilterLayer(context, &surface->props(), layers[i]);
	}
	}
	}

	void GrLayerHoister::UnlockLayers(GrContext* context,
	const SkTDArray<GrHoistedLayer>& layers) {
	GrLayerCache* layerCache = context->getLayerCache();

	for (int i = 0; i < layers.count(); ++i) {
	layerCache->removeUse(layers[i].fLayer);
	}

	SkDEBUGCODE(layerCache->validate();)
	}

	void GrLayerHoister::Begin(GrContext* context) {
	GrLayerCache* layerCache = context->getLayerCache();

	layerCache->begin();
	}

	void GrLayerHoister::End(GrContext* context) {
	GrLayerCache* layerCache = context->getLayerCache();

	#if !GR_CACHE_HOISTED_LAYERS

	// This code completely clears out the atlas. It is required when
	// caching is disabled so the atlas doesn't fill up and force more
	// free floating layers
	layerCache->purgeAll();
	#endif

	layerCache->end();
	}

	#endif