C++ GrCachedLayer类代码示例

static void convert_layers_to_replacements(const SkTDArray<GrHoistedLayer>& layers,
                                           GrReplacements* replacements) {
    // TODO: just replace GrReplacements::ReplacementInfo with GrCachedLayer?
    for (int i = 0; i < layers.count(); ++i) {
        GrCachedLayer* layer = layers[i].fLayer;
        const SkPicture* picture = layers[i].fPicture;

        GrReplacements::ReplacementInfo* layerInfo =
                    replacements->newReplacement(picture->uniqueID(),
                                                 layer->start(),
                                                 layers[i].fCTM);
        layerInfo->fStop = layer->stop();
        layerInfo->fPos = layers[i].fOffset;

        SkBitmap bm;
        wrap_texture(layers[i].fLayer->texture(),
                     !layers[i].fLayer->isAtlased() ? layers[i].fLayer->rect().width()
                                                    : layers[i].fLayer->texture()->width(),
                     !layers[i].fLayer->isAtlased() ? layers[i].fLayer->rect().height()
                                                    : layers[i].fLayer->texture()->height(),
                     &bm);
        layerInfo->fImage = SkImage::NewTexture(bm);

        layerInfo->fPaint = layers[i].fLayer->paint()
                                ? SkNEW_ARGS(SkPaint, (*layers[i].fLayer->paint()))
                                : NULL;

        layerInfo->fSrcRect = SkIRect::MakeXYWH(layers[i].fLayer->rect().fLeft,
                                                layers[i].fLayer->rect().fTop,
                                                layers[i].fLayer->rect().width(),
                                                layers[i].fLayer->rect().height());
    }
}

    static bool LessThan(const GrCachedLayer& layer, const PictureLayerKey& key) {
        if (layer.pictureID() == key.pictureID()) {
            return layer.layerID() < key.layerID();
        }

        return layer.pictureID() < key.pictureID();
    }

GrCachedLayer* GrLayerCache::createLayer(const SkPicture* picture, int layerID) {
    GrCachedLayer* layer = fLayerPool.alloc();

    SkASSERT(picture->uniqueID() != SK_InvalidGenID);
    layer->init(picture->uniqueID(), layerID);
    fLayerHash.insert(PictureLayerKey(picture->uniqueID(), layerID), layer);
    return layer;
}

// 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 GrAccelData::SaveLayerInfo& info,
                                 const SkIRect& layerRect,
                                 SkTDArray<GrHoistedLayer>* needRendering,
                                 SkTDArray<GrHoistedLayer>* recycled,
                                 bool attemptToAtlas) {
    const SkPicture* pict = info.fPicture ? info.fPicture : topLevelPicture;

    SkMatrix combined = SkMatrix::Concat(info.fPreMat, info.fLocalMat);

    GrCachedLayer* layer = layerCache->findLayerOrCreate(pict->uniqueID(),
                                                         info.fSaveLayerOpID,
                                                         info.fRestoreOpID,
                                                         layerRect,
                                                         combined,
                                                         info.fPaint);
    GrSurfaceDesc desc;
    desc.fFlags = kRenderTarget_GrSurfaceFlag;
    desc.fWidth = layerRect.width();
    desc.fHeight = layerRect.height();
    desc.fConfig = kSkia8888_GrPixelConfig;
    // TODO: need to deal with sample count

    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->fOffset = SkIPoint::Make(layerRect.fLeft, layerRect.fTop);
    hl->fLocalMat = info.fLocalMat;
    hl->fPreMat = info.fPreMat;
}

// Test out the layer replacement functionality with and w/o a BBH
void test_replacements(skiatest::Reporter* r, GrContext* context, bool doReplace) {
    sk_sp<SkPicture> pic;

    {
        SkPictureRecorder recorder;
        SkCanvas* canvas = recorder.beginRecording(SkIntToScalar(kWidth), SkIntToScalar(kHeight));
        SkPaint paint;
        canvas->saveLayer(nullptr, &paint);
        canvas->clear(SK_ColorRED);
        canvas->restore();
        canvas->drawRect(SkRect::MakeWH(SkIntToScalar(kWidth / 2), SkIntToScalar(kHeight / 2)),
                         SkPaint());
        pic = recorder.finishRecordingAsPicture();
    }

    SkAutoTUnref<GrTexture> texture;
    SkPaint paint;
    GrLayerCache* layerCache = context->getLayerCache();

    if (doReplace) {
        int key[1] = { 0 };

        GrCachedLayer* layer = layerCache->findLayerOrCreate(pic->uniqueID(), 0, 2,
                                                             SkIRect::MakeWH(kWidth, kHeight),
                                                             SkIRect::MakeWH(kWidth, kHeight),
                                                             SkMatrix::I(), key, 1, &paint);

        GrSurfaceDesc desc;
        desc.fConfig = kSkia8888_GrPixelConfig;
        desc.fFlags = kRenderTarget_GrSurfaceFlag;
        desc.fWidth = kWidth;
        desc.fHeight = kHeight;
        desc.fSampleCnt = 0;

        // Giving the texture some initial data so the Gpu (specifically vulkan) does not complain
        // when reading from an uninitialized texture.
        SkAutoTMalloc<uint32_t> srcBuffer(kWidth*kHeight);
        memset(srcBuffer.get(), 0, kWidth*kHeight*sizeof(uint32_t));

        texture.reset(context->textureProvider()->createTexture(
                desc, SkBudgeted::kNo, srcBuffer.get(), 0));
        layer->setTexture(texture, SkIRect::MakeWH(kWidth, kHeight), false);
    }

    SkRecord rerecord;
    SkRecorder canvas(&rerecord, kWidth, kHeight);
    GrRecordReplaceDraw(pic.get(), &canvas, layerCache, SkMatrix::I(), nullptr/*callback*/);

    int numLayers = count_instances_of_type<SkRecords::SaveLayer>(rerecord);
    if (doReplace) {
        REPORTER_ASSERT(r, 0 == numLayers);
    } else {
        REPORTER_ASSERT(r, 1 == numLayers);
    }
}

// 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 GrAccelData::SaveLayerInfo& info,
                                 const SkIRect& layerRect,
                                 SkTDArray<GrHoistedLayer>* atlased,
                                 SkTDArray<GrHoistedLayer>* nonAtlased,
                                 SkTDArray<GrHoistedLayer>* recycled) {
    const SkPicture* pict = info.fPicture ? info.fPicture : topLevelPicture;

    GrCachedLayer* layer = layerCache->findLayerOrCreate(pict->uniqueID(),
                                                         info.fSaveLayerOpID,
                                                         info.fRestoreOpID,
                                                         layerRect,
                                                         info.fOriginXform,
                                                         info.fPaint);

    GrTextureDesc desc;
    desc.fFlags = kRenderTarget_GrTextureFlagBit;
    desc.fWidth = layerRect.width();
    desc.fHeight = layerRect.height();
    desc.fConfig = kSkia8888_GrPixelConfig;
    // TODO: need to deal with sample count


    bool disallowAtlasing = info.fHasNestedLayers || info.fIsNested ||
                            (layer->paint() && layer->paint()->getImageFilter());

    bool needsRendering = layerCache->lock(layer, desc, disallowAtlasing);
    if (NULL == layer->texture()) {
        // GPU resources could not be secured for the hoisting of this layer
        return;
    }

    GrHoistedLayer* hl;

    if (needsRendering) {
        if (layer->isAtlased()) {
            hl = atlased->append();
        } else {
            hl = nonAtlased->append();
        }
    } else {
        hl = recycled->append();
    }
    
    layerCache->addUse(layer);
    hl->fLayer = layer;
    hl->fPicture = pict;
    hl->fOffset = SkIPoint::Make(layerRect.fLeft, layerRect.fTop);
    hl->fCTM = info.fOriginXform;
}

// Test out the layer replacement functionality with and w/o a BBH
void test_replacements(skiatest::Reporter* r, GrContext* context, bool doReplace) {
    SkAutoTUnref<const SkPicture> pic;

    {
        SkPictureRecorder recorder;
        SkCanvas* canvas = recorder.beginRecording(SkIntToScalar(kWidth), SkIntToScalar(kHeight));
        SkPaint paint;
        canvas->saveLayer(nullptr, &paint);
        canvas->clear(SK_ColorRED);
        canvas->restore();
        canvas->drawRect(SkRect::MakeWH(SkIntToScalar(kWidth / 2), SkIntToScalar(kHeight / 2)),
                         SkPaint());
        pic.reset(recorder.endRecording());
    }

    SkAutoTUnref<GrTexture> texture;
    SkPaint paint;
    GrLayerCache* layerCache = context->getLayerCache();

    if (doReplace) {
        int key[1] = { 0 };

        GrCachedLayer* layer = layerCache->findLayerOrCreate(pic->uniqueID(), 0, 2,
                                                             SkIRect::MakeWH(kWidth, kHeight),
                                                             SkIRect::MakeWH(kWidth, kHeight),
                                                             SkMatrix::I(), key, 1, &paint);

        GrSurfaceDesc desc;
        desc.fConfig = kSkia8888_GrPixelConfig;
        desc.fFlags = kRenderTarget_GrSurfaceFlag;
        desc.fWidth = kWidth;
        desc.fHeight = kHeight;
        desc.fSampleCnt = 0;

        texture.reset(context->textureProvider()->createTexture(
                desc, SkBudgeted::kNo, nullptr, 0));
        layer->setTexture(texture, SkIRect::MakeWH(kWidth, kHeight), false);
    }

    SkRecord rerecord;
    SkRecorder canvas(&rerecord, kWidth, kHeight);
    GrRecordReplaceDraw(pic, &canvas, layerCache, SkMatrix::I(), nullptr/*callback*/);

    int numLayers = count_instances_of_type<SkRecords::SaveLayer>(rerecord);
    if (doReplace) {
        REPORTER_ASSERT(r, 0 == numLayers);
    } else {
        REPORTER_ASSERT(r, 1 == numLayers);    
    }
}

GrLayerCache::~GrLayerCache() {

    SkTDynamicHash<GrCachedLayer, GrCachedLayer::Key>::Iter iter(&fLayerHash);
    for (; !iter.done(); ++iter) {
        GrCachedLayer* layer = &(*iter);
        SkASSERT(0 == layer->uses());
        this->unlock(layer);
        SkDELETE(layer);
    }

    SkASSERT(0 == fPictureHash.count());

    // The atlas only lets go of its texture when the atlas is deleted.
    fAtlas.free();
}

// Add several layers to the cache
static void create_layers(skiatest::Reporter* reporter,
                          GrLayerCache* cache,
                          const SkPicture& picture,
                          int numToAdd,
                          int idOffset) {

    for (int i = 0; i < numToAdd; ++i) {
        GrCachedLayer* layer = cache->findLayerOrCreate(&picture,
                               idOffset+i+1, idOffset+i+2,
                               SkMatrix::I());
        REPORTER_ASSERT(reporter, NULL != layer);
        GrCachedLayer* temp = cache->findLayer(&picture, idOffset+i+1, idOffset+i+2, SkMatrix::I());
        REPORTER_ASSERT(reporter, temp == layer);

        REPORTER_ASSERT(reporter, TestingAccess::NumLayers(cache) == idOffset + i + 1);

        REPORTER_ASSERT(reporter, picture.uniqueID() == layer->pictureID());
        REPORTER_ASSERT(reporter, layer->start() == idOffset + i + 1);
        REPORTER_ASSERT(reporter, layer->stop() == idOffset + i + 2);
        REPORTER_ASSERT(reporter, layer->ctm() == SkMatrix::I());
        REPORTER_ASSERT(reporter, NULL == layer->texture());
        REPORTER_ASSERT(reporter, !layer->isAtlased());
    }

    cache->trackPicture(&picture);
}

// Add several layers to the cache
static void create_layers(skiatest::Reporter* reporter,
                          GrLayerCache* cache,
                          const SkPicture& picture,
                          unsigned numToAdd,
                          unsigned idOffset) {

    for (unsigned i = 0; i < numToAdd; ++i) {
        unsigned indices[1] = { idOffset+i+1 };
        GrCachedLayer* layer = cache->findLayerOrCreate(picture.uniqueID(), 
                                                        idOffset+i+1, idOffset+i+2, 
                                                        SkIRect::MakeEmpty(),
                                                        SkIRect::MakeEmpty(),
                                                        SkMatrix::I(),
                                                        indices, 1,
                                                        NULL);
        REPORTER_ASSERT(reporter, layer);
        GrCachedLayer* temp = TestingAccess::Find(cache, picture.uniqueID(), SkMatrix::I(), 
                                                  indices, 1);
        REPORTER_ASSERT(reporter, temp == layer);

        REPORTER_ASSERT(reporter, TestingAccess::NumLayers(cache) == idOffset + i + 1);

        REPORTER_ASSERT(reporter, picture.uniqueID() == layer->pictureID());
        REPORTER_ASSERT(reporter, layer->start() == idOffset + i + 1);
        REPORTER_ASSERT(reporter, layer->stop() == idOffset + i + 2);
        REPORTER_ASSERT(reporter, NULL == layer->texture());
        REPORTER_ASSERT(reporter, NULL == layer->paint());
        REPORTER_ASSERT(reporter, !layer->isAtlased());
    }
}

    void operator()(const SkRecords::SaveLayer& sl) {

        // For a saveLayer command, check if it can be replaced by a drawBitmap
        // call and, if so, draw it and then update the current op index accordingly.
        int startOffset;
        if (fOps.count()) {
            startOffset = fOps[fIndex];
        } else {
            startOffset = fIndex;
        }

        fOpIndexStack.push(startOffset);

        GrCachedLayer* layer = fLayerCache->findLayer(fTopLevelPicture->uniqueID(),
                                                      fInitialMatrix,
                                                      fOpIndexStack.begin(),
                                                      fOpIndexStack.count());

        if (layer) {
            fNumReplaced++;

            draw_replacement_bitmap(layer, fCanvas);

            if (fPicture->bbh()) {
                while (fOps[fIndex] < layer->stop()) {
                    ++fIndex;
                }
                SkASSERT(fOps[fIndex] == layer->stop());
            } else {
                fIndex = layer->stop();
            }
            fOpIndexStack.pop();
            return;
        }

        // This is a fail for layer hoisting
        this->INHERITED::operator()(sl);

        fOpIndexStack.pop();
    }

// 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);
}

// This test case exercises the public API of the GrLayerCache class.
// In particular it checks its interaction with the resource cache (w.r.t.
// locking & unlocking textures).
// TODO: need to add checks on VRAM usage!
DEF_GPUTEST(GpuLayerCache, reporter, factory) {
    static const int kInitialNumLayers = 5;

    for (int i= 0; i < GrContextFactory::kGLContextTypeCnt; ++i) {
        GrContextFactory::GLContextType glCtxType = (GrContextFactory::GLContextType) i;

        if (!GrContextFactory::IsRenderingGLContext(glCtxType)) {
            continue;
        }

        GrContext* context = factory->get(glCtxType);

        if (NULL == context) {
            continue;
        }

        SkPictureRecorder recorder;
        recorder.beginRecording(1, 1);
        SkAutoTUnref<const SkPicture> picture(recorder.endRecording());

        GrLayerCache cache(context);

        create_layers(reporter, &cache, *picture, kInitialNumLayers, 0);

        for (int i = 0; i < kInitialNumLayers; ++i) {
            GrCachedLayer* layer = cache.findLayer(picture, i+1, i+2, SkMatrix::I());
            REPORTER_ASSERT(reporter, NULL != layer);

            lock_layer(reporter, &cache, layer);

            // The first 4 layers should be in the atlas (and thus have non-empty
            // rects)
            if (i < 4) {
                REPORTER_ASSERT(reporter, layer->isAtlased());
            } else {
                // The 5th layer couldn't fit in the atlas
                REPORTER_ASSERT(reporter, !layer->isAtlased());
            }
        }

        // Unlock the textures
        for (int i = 0; i < kInitialNumLayers; ++i) {
            GrCachedLayer* layer = cache.findLayer(picture, i+1, i+2, SkMatrix::I());
            REPORTER_ASSERT(reporter, NULL != layer);

            cache.unlock(layer);
        }

        for (int i = 0; i < kInitialNumLayers; ++i) {
            GrCachedLayer* layer = cache.findLayer(picture, i+1, i+2, SkMatrix::I());
            REPORTER_ASSERT(reporter, NULL != layer);

            REPORTER_ASSERT(reporter, !layer->locked());
            // The first 4 layers should still be in the atlas.
            if (i < 4) {
                REPORTER_ASSERT(reporter, NULL != layer->texture());
                REPORTER_ASSERT(reporter, layer->isAtlased());
            } else {
                // The final layer should be unlocked.
                REPORTER_ASSERT(reporter, NULL == layer->texture());
                REPORTER_ASSERT(reporter, !layer->isAtlased());
            }
        }

        {
            // Add an additional layer. Since all the layers are unlocked this
            // will force out the first atlased layer
            create_layers(reporter, &cache, *picture, 1, kInitialNumLayers);
            GrCachedLayer* layer = cache.findLayer(picture,
                                                   kInitialNumLayers+1, kInitialNumLayers+2,
                                                   SkMatrix::I());
            REPORTER_ASSERT(reporter, NULL != layer);

            lock_layer(reporter, &cache, layer);
            cache.unlock(layer);
        }

        for (int i = 0; i < kInitialNumLayers+1; ++i) {
            GrCachedLayer* layer = cache.findLayer(picture, i+1, i+2, SkMatrix::I());
            // 3 old layers plus the new one should be in the atlas.
            if (1 == i || 2 == i || 3 == i || 5 == i) {
                REPORTER_ASSERT(reporter, NULL != layer);
                REPORTER_ASSERT(reporter, !layer->locked());
                REPORTER_ASSERT(reporter, NULL != layer->texture());
                REPORTER_ASSERT(reporter, layer->isAtlased());
            } else if (4 == i) {
                // The one that was never atlased should still be around
                REPORTER_ASSERT(reporter, NULL != layer);

                REPORTER_ASSERT(reporter, NULL == layer->texture());
                REPORTER_ASSERT(reporter, !layer->isAtlased());
            } else {
                // The one bumped out of the atlas (i.e., 0) should be gone
                REPORTER_ASSERT(reporter, NULL == layer);
            }
        }
//.........这里部分代码省略.........

// This test case exercises the public API of the GrLayerCache class.
// In particular it checks its interaction with the resource cache (w.r.t.
// locking & unlocking textures).
// TODO: need to add checks on VRAM usage!
DEF_GPUTEST(GpuLayerCache, reporter, factory) {

    GrContext* context = factory->get(GrContextFactory::kNative_GLContextType);
    if (NULL == context) {
        return;
    }

    SkPicture picture;

    GrLayerCache cache(context);

    create_layers(reporter, &cache, picture);

    // Lock the layers making them all 512x512
    GrTextureDesc desc;
    desc.fWidth = 512;
    desc.fHeight = 512;
    desc.fConfig = kSkia8888_GrPixelConfig;

    for (int i = 0; i < kNumLayers; ++i) {
        GrCachedLayer* layer = cache.findLayer(&picture, i);
        REPORTER_ASSERT(reporter, NULL != layer);

        bool foundInCache = cache.lock(layer, desc);
        REPORTER_ASSERT(reporter, !foundInCache);
        foundInCache = cache.lock(layer, desc);
        REPORTER_ASSERT(reporter, foundInCache);

        REPORTER_ASSERT(reporter, NULL != layer->texture());
#if USE_ATLAS
        // The first 4 layers should be in the atlas (and thus have non-empty
        // rects)
        if (i < 4) {
            REPORTER_ASSERT(reporter, !layer->rect().isEmpty());
        } else {
#endif
            REPORTER_ASSERT(reporter, layer->rect().isEmpty());
#if USE_ATLAS
        }
#endif
    }

    // Unlock the textures
    for (int i = 0; i < kNumLayers; ++i) {
        GrCachedLayer* layer = cache.findLayer(&picture, i);
        REPORTER_ASSERT(reporter, NULL != layer);

        cache.unlock(layer);
    }

    for (int i = 0; i < kNumLayers; ++i) {
        GrCachedLayer* layer = cache.findLayer(&picture, i);
        REPORTER_ASSERT(reporter, NULL != layer);

#if USE_ATLAS
        // The first 4 layers should be in the atlas (and thus do not 
        // currently unlock). The final layer should be unlocked.
        if (i < 4) {
            REPORTER_ASSERT(reporter, NULL != layer->texture());
            REPORTER_ASSERT(reporter, !layer->rect().isEmpty());
        } else {
#endif
            REPORTER_ASSERT(reporter, NULL == layer->texture());
            REPORTER_ASSERT(reporter, layer->rect().isEmpty());
#if USE_ATLAS
        }
#endif
    }

    // Free them all SkGpuDevice-style. This will not free up the
    // atlas' texture but will eliminate all the layers.
    cache.purge(&picture);

    REPORTER_ASSERT(reporter, GetNumLayers::NumLayers(&cache) == 0);
    // TODO: add VRAM/resource cache check here
#if 0
    // Re-create the layers
    create_layers(reporter, &cache, picture);

    // Free them again GrContext-style. This should free up everything.
    cache.freeAll();

    REPORTER_ASSERT(reporter, GetNumLayers::NumLayers(&cache) == 0);
    // TODO: add VRAM/resource cache check here
#endif
}

void GrLayerHoister::DrawLayers(const SkTDArray<GrHoistedLayer>& atlased,
                                const SkTDArray<GrHoistedLayer>& nonAtlased,
                                const SkTDArray<GrHoistedLayer>& recycled,
                                GrReplacements* replacements) {
    // Render the atlased layers that require it
    if (atlased.count() > 0) {
        // All the atlased layers are rendered into the same GrTexture
        SkAutoTUnref<SkSurface> surface(SkSurface::NewRenderTargetDirect(
                                        atlased[0].fLayer->texture()->asRenderTarget(), NULL));

        SkCanvas* atlasCanvas = surface->getCanvas();

        SkPaint paint;
        paint.setColor(SK_ColorTRANSPARENT);
        paint.setXfermode(SkXfermode::Create(SkXfermode::kSrc_Mode))->unref();

        for (int i = 0; i < atlased.count(); ++i) {
            GrCachedLayer* layer = atlased[i].fLayer;
            const SkPicture* pict = atlased[i].fPicture;
            const SkIPoint offset = atlased[i].fOffset;

            atlasCanvas->save();

            // Add a rect clip to make sure the rendering doesn't
            // extend beyond the boundaries of the atlased sub-rect
            SkRect bound = SkRect::MakeXYWH(SkIntToScalar(layer->rect().fLeft),
                                            SkIntToScalar(layer->rect().fTop),
                                            SkIntToScalar(layer->rect().width()),
                                            SkIntToScalar(layer->rect().height()));
            atlasCanvas->clipRect(bound);

            // Since 'clear' doesn't respect the clip we need to draw a rect
            // TODO: ensure none of the atlased layers contain a clear call!
            atlasCanvas->drawRect(bound, paint);

            // info.fCTM 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.postTranslate(bound.fLeft, bound.fTop);
            
            atlasCanvas->translate(SkIntToScalar(-offset.fX), 
                                   SkIntToScalar(-offset.fY));
            atlasCanvas->translate(bound.fLeft, bound.fTop);
            atlasCanvas->concat(atlased[i].fCTM);

            SkRecordPartialDraw(*pict->fRecord.get(), atlasCanvas, bound,
                                layer->start()+1, layer->stop(), initialCTM);

            atlasCanvas->restore();
        }

        atlasCanvas->flush();
    }

    // Render the non-atlased layers that require it
    for (int i = 0; i < nonAtlased.count(); ++i) {
        GrCachedLayer* layer = nonAtlased[i].fLayer;
        const SkPicture* pict = nonAtlased[i].fPicture;
        const SkIPoint offset = nonAtlased[i].fOffset;

        // Each non-atlased layer has its own GrTexture
        SkAutoTUnref<SkSurface> surface(SkSurface::NewRenderTargetDirect(
                                        layer->texture()->asRenderTarget(), NULL));

        SkCanvas* layerCanvas = surface->getCanvas();

        // Add a rect clip to make sure the rendering doesn't
        // extend beyond the boundaries of the atlased sub-rect
        SkRect bound = SkRect::MakeXYWH(SkIntToScalar(layer->rect().fLeft),
                                        SkIntToScalar(layer->rect().fTop),
                                        SkIntToScalar(layer->rect().width()),
                                        SkIntToScalar(layer->rect().height()));

        layerCanvas->clipRect(bound); // TODO: still useful?

        layerCanvas->clear(SK_ColorTRANSPARENT);

        SkMatrix initialCTM;
        initialCTM.setTranslate(SkIntToScalar(-offset.fX), 
                                SkIntToScalar(-offset.fY));

        layerCanvas->translate(SkIntToScalar(-offset.fX), 
                               SkIntToScalar(-offset.fY));
        layerCanvas->concat(nonAtlased[i].fCTM);

        SkRecordPartialDraw(*pict->fRecord.get(), layerCanvas, bound,
                            layer->start()+1, layer->stop(), initialCTM);

        layerCanvas->flush();
    }

    convert_layers_to_replacements(atlased, replacements);
    convert_layers_to_replacements(nonAtlased, replacements);
    convert_layers_to_replacements(recycled, replacements);
}