src/gpu/GrContext.cpp

/*
 * Copyright 2011 Google Inc.
 *
 * Use of this source code is governed by a BSD-style license that can be
 * found in the LICENSE file.
 */

#include "GrContext.h"

#include "GrAARectRenderer.h"
#include "GrAtlasTextContext.h"
#include "GrBatch.h"
#include "GrBatchFontCache.h"
#include "GrBatchTarget.h"
#include "GrBatchTest.h"
#include "GrDefaultGeoProcFactory.h"
#include "GrGpuResource.h"
#include "GrGpuResourcePriv.h"
#include "GrDrawTargetCaps.h"
#include "GrGpu.h"
#include "GrImmediateDrawTarget.h"
#include "GrIndexBuffer.h"
#include "GrInOrderDrawBuffer.h"
#include "GrLayerCache.h"
#include "GrOvalRenderer.h"
#include "GrPathRenderer.h"
#include "GrPathUtils.h"
#include "GrRenderTargetPriv.h"
#include "GrResourceCache.h"
#include "GrResourceProvider.h"
#include "GrSoftwarePathRenderer.h"
#include "GrStencilAndCoverTextContext.h"
#include "GrStrokeInfo.h"
#include "GrSurfacePriv.h"
#include "GrTextBlobCache.h"
#include "GrTexturePriv.h"
#include "GrTraceMarker.h"
#include "GrTracing.h"
#include "GrVertices.h"
#include "SkDashPathPriv.h"
#include "SkConfig8888.h"
#include "SkGr.h"
#include "SkRRect.h"
#include "SkStrokeRec.h"
#include "SkTLazy.h"
#include "SkTLS.h"
#include "SkTraceEvent.h"

#include "effects/GrConfigConversionEffect.h"
#include "effects/GrDashingEffect.h"
#include "effects/GrSingleTextureEffect.h"

#define ASSERT_OWNED_RESOURCE(R) SkASSERT(!(R) || (R)->getContext() == this)
#define RETURN_IF_ABANDONED if (!fDrawBuffer) { return; }
#define RETURN_FALSE_IF_ABANDONED if (!fDrawBuffer) { return false; }
#define RETURN_NULL_IF_ABANDONED if (!fDrawBuffer) { return NULL; }

class GrContext::AutoCheckFlush {
public:
    AutoCheckFlush(GrContext* context) : fContext(context) { SkASSERT(context); }

    ~AutoCheckFlush() {
        if (fContext->fFlushToReduceCacheSize) {
            fContext->flush();
        }
    }

private:
    GrContext* fContext;
};

GrContext* GrContext::Create(GrBackend backend, GrBackendContext backendContext,
                             const Options* opts) {
    GrContext* context;
    if (NULL == opts) {
        context = SkNEW_ARGS(GrContext, (Options()));
    } else {
        context = SkNEW_ARGS(GrContext, (*opts));
    }

    if (context->init(backend, backendContext)) {
        return context;
    } else {
        context->unref();
        return NULL;
    }
}

static int32_t gNextID = 1;
static int32_t next_id() {
    int32_t id;
    do {
        id = sk_atomic_inc(&gNextID);
    } while (id == SK_InvalidGenID);
    return id;
}

GrContext::GrContext(const Options& opts) : fOptions(opts), fUniqueID(next_id()) {
    fGpu = NULL;
    fResourceCache = NULL;
    fResourceProvider = NULL;
    fPathRendererChain = NULL;
    fSoftwarePathRenderer = NULL;
    fBatchFontCache = NULL;
    fDrawBuffer = NULL;
    fFlushToReduceCacheSize = false;
    fAARectRenderer = NULL;
    fOvalRenderer = NULL;
    fMaxTextureSizeOverride = 1 << 20;
}

bool GrContext::init(GrBackend backend, GrBackendContext backendContext) {
    SkASSERT(NULL == fGpu);

    fGpu = GrGpu::Create(backend, backendContext, this);
    if (NULL == fGpu) {
        return false;
    }
    this->initCommon();
    return true;
}

void GrContext::initCommon() {
    fResourceCache = SkNEW(GrResourceCache);
    fResourceCache->setOverBudgetCallback(OverBudgetCB, this);
    fResourceProvider = SkNEW_ARGS(GrResourceProvider, (fGpu, fResourceCache));

    fLayerCache.reset(SkNEW_ARGS(GrLayerCache, (this)));

    fAARectRenderer = SkNEW(GrAARectRenderer);
    fOvalRenderer = SkNEW(GrOvalRenderer);

    fDidTestPMConversions = false;

#ifdef IMMEDIATE_MODE
    fDrawBuffer = SkNEW_ARGS(GrImmediateDrawTarget, (this));
#else
    fDrawBuffer = SkNEW_ARGS(GrInOrderDrawBuffer, (this));
#endif

    // GrBatchFontCache will eventually replace GrFontCache
    fBatchFontCache = SkNEW_ARGS(GrBatchFontCache, (this));

    fTextBlobCache.reset(SkNEW_ARGS(GrTextBlobCache, (TextBlobCacheOverBudgetCB, this)));
}

GrContext::~GrContext() {
    if (NULL == fGpu) {
        return;
    }

    this->flush();

    for (int i = 0; i < fCleanUpData.count(); ++i) {
        (*fCleanUpData[i].fFunc)(this, fCleanUpData[i].fInfo);
    }

    SkDELETE(fResourceProvider);
    SkDELETE(fResourceCache);
    SkDELETE(fBatchFontCache);
    SkDELETE(fDrawBuffer);

    fAARectRenderer->unref();
    fOvalRenderer->unref();

    fGpu->unref();
    SkSafeUnref(fPathRendererChain);
    SkSafeUnref(fSoftwarePathRenderer);
}

void GrContext::abandonContext() {
    fResourceProvider->abandon();
    // abandon first to so destructors
    // don't try to free the resources in the API.
    fResourceCache->abandonAll();

    fGpu->contextAbandoned();

    // a path renderer may be holding onto resources that
    // are now unusable
    SkSafeSetNull(fPathRendererChain);
    SkSafeSetNull(fSoftwarePathRenderer);

    SkDELETE(fDrawBuffer);
    fDrawBuffer = NULL;

    fBatchFontCache->freeAll();
    fLayerCache->freeAll();
    fTextBlobCache->freeAll();
}

void GrContext::resetContext(uint32_t state) {
    fGpu->markContextDirty(state);
}

void GrContext::freeGpuResources() {
    this->flush();

    if (fDrawBuffer) {
        fDrawBuffer->purgeResources();
    }

    fBatchFontCache->freeAll();
    fLayerCache->freeAll();
    // a path renderer may be holding onto resources
    SkSafeSetNull(fPathRendererChain);
    SkSafeSetNull(fSoftwarePathRenderer);

    fResourceCache->purgeAllUnlocked();
}

void GrContext::getResourceCacheUsage(int* resourceCount, size_t* resourceBytes) const {
    if (resourceCount) {
        *resourceCount = fResourceCache->getBudgetedResourceCount();
    }
    if (resourceBytes) {
        *resourceBytes = fResourceCache->getBudgetedResourceBytes();
    }
}

GrTextContext* GrContext::createTextContext(GrRenderTarget* renderTarget,
                                            SkGpuDevice* gpuDevice,
                                            const SkDeviceProperties&
                                            leakyProperties,
                                            bool enableDistanceFieldFonts) {
    if (fGpu->caps()->shaderCaps()->pathRenderingSupport() && renderTarget->isMultisampled()) {
        GrStencilAttachment* sb = renderTarget->renderTargetPriv().attachStencilAttachment();
        if (sb) {
            return GrStencilAndCoverTextContext::Create(this, gpuDevice, leakyProperties);
        }
    } 

    return GrAtlasTextContext::Create(this, gpuDevice, leakyProperties, enableDistanceFieldFonts);
}

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

bool GrContext::isConfigTexturable(GrPixelConfig config) const {
    return fGpu->caps()->isConfigTexturable(config);
}

bool GrContext::npotTextureTileSupport() const {
    return fGpu->caps()->npotTextureTileSupport();
}

void GrContext::OverBudgetCB(void* data) {
    SkASSERT(data);

    GrContext* context = reinterpret_cast<GrContext*>(data);

    // Flush the InOrderDrawBuffer to possibly free up some textures
    context->fFlushToReduceCacheSize = true;
}

void GrContext::TextBlobCacheOverBudgetCB(void* data) {
    SkASSERT(data);

    // Unlike the GrResourceCache, TextBlobs are drawn at the SkGpuDevice level, therefore they
    // cannot use fFlushTorReduceCacheSize because it uses AutoCheckFlush.  The solution is to move
    // drawText calls to below the GrContext level, but this is not trivial because they call
    // drawPath on SkGpuDevice
    GrContext* context = reinterpret_cast<GrContext*>(data);
    context->flush();
}

int GrContext::getMaxTextureSize() const {
    return SkTMin(fGpu->caps()->maxTextureSize(), fMaxTextureSizeOverride);
}

int GrContext::getMaxRenderTargetSize() const {
    return fGpu->caps()->maxRenderTargetSize();
}

int GrContext::getMaxSampleCount() const {
    return fGpu->caps()->maxSampleCount();
}

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

void GrContext::clear(const SkIRect* rect,
                      const GrColor color,
                      bool canIgnoreRect,
                      GrRenderTarget* renderTarget) {
    RETURN_IF_ABANDONED
    ASSERT_OWNED_RESOURCE(renderTarget);
    SkASSERT(renderTarget);

    AutoCheckFlush acf(this);
    GR_CREATE_TRACE_MARKER_CONTEXT("GrContext::clear", this);
    GrDrawTarget* target = this->prepareToDraw();
    if (NULL == target) {
        return;
    }
    target->clear(rect, color, canIgnoreRect, renderTarget);
}

void GrContext::drawPaint(GrRenderTarget* rt,
                          const GrClip& clip,
                          const GrPaint& origPaint,
                          const SkMatrix& viewMatrix) {
    RETURN_IF_ABANDONED
    // set rect to be big enough to fill the space, but not super-huge, so we
    // don't overflow fixed-point implementations
    SkRect r;
    r.setLTRB(0, 0,
              SkIntToScalar(rt->width()),
              SkIntToScalar(rt->height()));
    SkTCopyOnFirstWrite<GrPaint> paint(origPaint);

    // by definition this fills the entire clip, no need for AA
    if (paint->isAntiAlias()) {
        paint.writable()->setAntiAlias(false);
    }

    bool isPerspective = viewMatrix.hasPerspective();

    // We attempt to map r by the inverse matrix and draw that. mapRect will
    // map the four corners and bound them with a new rect. This will not
    // produce a correct result for some perspective matrices.
    if (!isPerspective) {
        SkMatrix inverse;
        if (!viewMatrix.invert(&inverse)) {
            SkDebugf("Could not invert matrix\n");
            return;
        }
        inverse.mapRect(&r);
        this->drawRect(rt, clip, *paint, viewMatrix, r);
    } else {
        SkMatrix localMatrix;
        if (!viewMatrix.invert(&localMatrix)) {
            SkDebugf("Could not invert matrix\n");
            return;
        }

        AutoCheckFlush acf(this);
        GrPipelineBuilder pipelineBuilder;
        GrDrawTarget* target = this->prepareToDraw(&pipelineBuilder, rt, clip, paint, &acf);
        if (NULL == target) {
            return;
        }

        GR_CREATE_TRACE_MARKER("GrContext::drawPaintWithPerspective", target);
        target->drawRect(&pipelineBuilder,
                         paint->getColor(),
                         SkMatrix::I(),
                         r,
                         NULL,
                         &localMatrix);
    }
}

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

static inline bool is_irect(const SkRect& r) {
  return SkScalarIsInt(r.fLeft)  && SkScalarIsInt(r.fTop) &&
         SkScalarIsInt(r.fRight) && SkScalarIsInt(r.fBottom);
}

static bool apply_aa_to_rect(GrDrawTarget* target,
                             GrPipelineBuilder* pipelineBuilder,
                             SkRect* devBoundRect,
                             const SkRect& rect,
                             SkScalar strokeWidth,
                             const SkMatrix& combinedMatrix,
                             GrColor color) {
    if (pipelineBuilder->getRenderTarget()->isMultisampled()) {
        return false;
    }

#if defined(SHADER_AA_FILL_RECT) || !defined(IGNORE_ROT_AA_RECT_OPT)
    if (strokeWidth >= 0) {
#endif
        if (!combinedMatrix.preservesAxisAlignment()) {
            return false;
        }

#if defined(SHADER_AA_FILL_RECT) || !defined(IGNORE_ROT_AA_RECT_OPT)
    } else {
        if (!combinedMatrix.preservesRightAngles()) {
            return false;
        }
    }
#endif

    combinedMatrix.mapRect(devBoundRect, rect);
    if (!combinedMatrix.rectStaysRect()) {
        return true;
    }

    if (strokeWidth < 0) {
        return !is_irect(*devBoundRect);
    }

    return true;
}

static inline bool rect_contains_inclusive(const SkRect& rect, const SkPoint& point) {
    return point.fX >= rect.fLeft && point.fX <= rect.fRight &&
           point.fY >= rect.fTop && point.fY <= rect.fBottom;
}

class StrokeRectBatch : public GrBatch {
public:
    struct Geometry {
        GrColor fColor;
        SkMatrix fViewMatrix;
        SkRect fRect;
        SkScalar fStrokeWidth;
    };

    static GrBatch* Create(const Geometry& geometry, bool snapToPixelCenters) {
        return SkNEW_ARGS(StrokeRectBatch, (geometry, snapToPixelCenters));
    }

    const char* name() const override { return "StrokeRectBatch"; }

    void getInvariantOutputColor(GrInitInvariantOutput* out) const override {
        // When this is called on a batch, there is only one geometry bundle
        out->setKnownFourComponents(fGeoData[0].fColor);
    }

    void getInvariantOutputCoverage(GrInitInvariantOutput* out) const override {
        out->setKnownSingleComponent(0xff);
    }

    void initBatchTracker(const GrPipelineInfo& init) override {
        // Handle any color overrides
        if (init.fColorIgnored) {
            fGeoData[0].fColor = GrColor_ILLEGAL;
        } else if (GrColor_ILLEGAL != init.fOverrideColor) {
            fGeoData[0].fColor = init.fOverrideColor;
        }

        // setup batch properties
        fBatch.fColorIgnored = init.fColorIgnored;
        fBatch.fColor = fGeoData[0].fColor;
        fBatch.fUsesLocalCoords = init.fUsesLocalCoords;
        fBatch.fCoverageIgnored = init.fCoverageIgnored;
    }

    void generateGeometry(GrBatchTarget* batchTarget, const GrPipeline* pipeline) override {
        SkAutoTUnref<const GrGeometryProcessor> gp(
                GrDefaultGeoProcFactory::Create(GrDefaultGeoProcFactory::kPosition_GPType,
                                                this->color(),
                                                this->usesLocalCoords(),
                                                this->coverageIgnored(),
                                                this->viewMatrix(),
                                                SkMatrix::I()));

        batchTarget->initDraw(gp, pipeline);

        size_t vertexStride = gp->getVertexStride();

        SkASSERT(vertexStride == sizeof(GrDefaultGeoProcFactory::PositionAttr));

        Geometry& args = fGeoData[0];

        int vertexCount = kVertsPerHairlineRect;
        if (args.fStrokeWidth > 0) {
            vertexCount = kVertsPerStrokeRect;
        }

        const GrVertexBuffer* vertexBuffer;
        int firstVertex;

        void* verts = batchTarget->makeVertSpace(vertexStride, vertexCount,
                                                 &vertexBuffer, &firstVertex);

        if (!verts) {
            SkDebugf("Could not allocate vertices\n");
            return;
        }

        SkPoint* vertex = reinterpret_cast<SkPoint*>(verts);

        GrPrimitiveType primType;

        if (args.fStrokeWidth > 0) {;
            primType = kTriangleStrip_GrPrimitiveType;
            args.fRect.sort();
            this->setStrokeRectStrip(vertex, args.fRect, args.fStrokeWidth);
        } else {
            // hairline
            primType = kLineStrip_GrPrimitiveType;
            vertex[0].set(args.fRect.fLeft, args.fRect.fTop);
            vertex[1].set(args.fRect.fRight, args.fRect.fTop);
            vertex[2].set(args.fRect.fRight, args.fRect.fBottom);
            vertex[3].set(args.fRect.fLeft, args.fRect.fBottom);
            vertex[4].set(args.fRect.fLeft, args.fRect.fTop);
        }

        GrVertices vertices;
        vertices.init(primType, vertexBuffer, firstVertex, vertexCount);
        batchTarget->draw(vertices);
    }

    SkSTArray<1, Geometry, true>* geoData() { return &fGeoData; }

private:
    StrokeRectBatch(const Geometry& geometry, bool snapToPixelCenters) {
        this->initClassID<StrokeRectBatch>();

        fBatch.fHairline = geometry.fStrokeWidth == 0;

        fGeoData.push_back(geometry);

        // setup bounds
        fBounds = geometry.fRect;
        SkScalar rad = SkScalarHalf(geometry.fStrokeWidth);
        fBounds.outset(rad, rad);
        geometry.fViewMatrix.mapRect(&fBounds);

        // If our caller snaps to pixel centers then we have to round out the bounds
        if (snapToPixelCenters) {
            fBounds.roundOut();
        }
    }

    /*  create a triangle strip that strokes the specified rect. There are 8
     unique vertices, but we repeat the last 2 to close up. Alternatively we
     could use an indices array, and then only send 8 verts, but not sure that
     would be faster.
     */
    void setStrokeRectStrip(SkPoint verts[10], const SkRect& rect, SkScalar width) {
        const SkScalar rad = SkScalarHalf(width);
        // TODO we should be able to enable this assert, but we'd have to filter these draws
        // this is a bug
        //SkASSERT(rad < rect.width() / 2 && rad < rect.height() / 2);

        verts[0].set(rect.fLeft + rad, rect.fTop + rad);
        verts[1].set(rect.fLeft - rad, rect.fTop - rad);
        verts[2].set(rect.fRight - rad, rect.fTop + rad);
        verts[3].set(rect.fRight + rad, rect.fTop - rad);
        verts[4].set(rect.fRight - rad, rect.fBottom - rad);
        verts[5].set(rect.fRight + rad, rect.fBottom + rad);
        verts[6].set(rect.fLeft + rad, rect.fBottom - rad);
        verts[7].set(rect.fLeft - rad, rect.fBottom + rad);
        verts[8] = verts[0];
        verts[9] = verts[1];
    }


    GrColor color() const { return fBatch.fColor; }
    bool usesLocalCoords() const { return fBatch.fUsesLocalCoords; }
    bool colorIgnored() const { return fBatch.fColorIgnored; }
    const SkMatrix& viewMatrix() const { return fGeoData[0].fViewMatrix; }
    bool hairline() const { return fBatch.fHairline; }
    bool coverageIgnored() const { return fBatch.fCoverageIgnored; }

    bool onCombineIfPossible(GrBatch* t) override {
        // StrokeRectBatch* that = t->cast<StrokeRectBatch>();

        // NonAA stroke rects cannot batch right now
        // TODO make these batchable
        return false;
    }

    struct BatchTracker {
        GrColor fColor;
        bool fUsesLocalCoords;
        bool fColorIgnored;
        bool fCoverageIgnored;
        bool fHairline;
    };

    const static int kVertsPerHairlineRect = 5;
    const static int kVertsPerStrokeRect = 10;

    BatchTracker fBatch;
    SkSTArray<1, Geometry, true> fGeoData;
};

void GrContext::drawRect(GrRenderTarget* rt,
                         const GrClip& clip,
                         const GrPaint& paint,
                         const SkMatrix& viewMatrix,
                         const SkRect& rect,
                         const GrStrokeInfo* strokeInfo) {
    RETURN_IF_ABANDONED
    if (strokeInfo && strokeInfo->isDashed()) {
        SkPath path;
        path.setIsVolatile(true);
        path.addRect(rect);
        this->drawPath(rt, clip, paint, viewMatrix, path, *strokeInfo);
        return;
    }

    AutoCheckFlush acf(this);
    GrPipelineBuilder pipelineBuilder;
    GrDrawTarget* target = this->prepareToDraw(&pipelineBuilder, rt, clip, &paint, &acf);
    if (NULL == target) {
        return;
    }

    GR_CREATE_TRACE_MARKER("GrContext::drawRect", target);
    SkScalar width = NULL == strokeInfo ? -1 : strokeInfo->getWidth();

    // Check if this is a full RT draw and can be replaced with a clear. We don't bother checking
    // cases where the RT is fully inside a stroke.
    if (width < 0) {
        SkRect rtRect;
        pipelineBuilder.getRenderTarget()->getBoundsRect(&rtRect);
        SkRect clipSpaceRTRect = rtRect;
        bool checkClip = GrClip::kWideOpen_ClipType != clip.clipType();
        if (checkClip) {
            clipSpaceRTRect.offset(SkIntToScalar(clip.origin().fX),
                                   SkIntToScalar(clip.origin().fY));
        }
        // Does the clip contain the entire RT?
        if (!checkClip || clip.quickContains(clipSpaceRTRect)) {
            SkMatrix invM;
            if (!viewMatrix.invert(&invM)) {
                return;
            }
            // Does the rect bound the RT?
            SkPoint srcSpaceRTQuad[4];
            invM.mapRectToQuad(srcSpaceRTQuad, rtRect);
            if (rect_contains_inclusive(rect, srcSpaceRTQuad[0]) &&
                rect_contains_inclusive(rect, srcSpaceRTQuad[1]) &&
                rect_contains_inclusive(rect, srcSpaceRTQuad[2]) &&
                rect_contains_inclusive(rect, srcSpaceRTQuad[3])) {
                // Will it blend?
                GrColor clearColor;
                if (paint.isOpaqueAndConstantColor(&clearColor)) {
                    target->clear(NULL, clearColor, true, rt);
                    return;
                }
            }
        }
    }

    GrColor color = paint.getColor();
    SkRect devBoundRect;
    bool needAA = paint.isAntiAlias() && !pipelineBuilder.getRenderTarget()->isMultisampled();
    bool doAA = needAA && apply_aa_to_rect(target, &pipelineBuilder, &devBoundRect, rect, width,
                                           viewMatrix, color);

    if (doAA) {
        if (width >= 0) {
            fAARectRenderer->strokeAARect(target,
                                          &pipelineBuilder,
                                          color,
                                          viewMatrix,
                                          rect,
                                          devBoundRect,
                                          *strokeInfo);
        } else {
            // filled AA rect
            fAARectRenderer->fillAARect(target,
                                        &pipelineBuilder,
                                        color,
                                        viewMatrix,
                                        rect,
                                        devBoundRect);
        }
        return;
    }

    if (width >= 0) {
        StrokeRectBatch::Geometry geometry;
        geometry.fViewMatrix = viewMatrix;
        geometry.fColor = color;
        geometry.fRect = rect;
        geometry.fStrokeWidth = width;

        // Non-AA hairlines are snapped to pixel centers to make which pixels are hit deterministic
        bool snapToPixelCenters = (0 == width && !rt->isMultisampled());
        SkAutoTUnref<GrBatch> batch(StrokeRectBatch::Create(geometry, snapToPixelCenters));

        // Depending on sub-pixel coordinates and the particular GPU, we may lose a corner of
        // hairline rects. We jam all the vertices to pixel centers to avoid this, but not when MSAA
        // is enabled because it can cause ugly artifacts.
        pipelineBuilder.setState(GrPipelineBuilder::kSnapVerticesToPixelCenters_Flag,
                                 snapToPixelCenters);
        target->drawBatch(&pipelineBuilder, batch);
    } else {
        // filled BW rect
        target->drawSimpleRect(&pipelineBuilder, color, viewMatrix, rect);
    }
}

void GrContext::drawNonAARectToRect(GrRenderTarget* rt,
                                    const GrClip& clip,
                                    const GrPaint& paint,
                                    const SkMatrix& viewMatrix,
                                    const SkRect& rectToDraw,
                                    const SkRect& localRect,
                                    const SkMatrix* localMatrix) {
    RETURN_IF_ABANDONED
    AutoCheckFlush acf(this);
    GrPipelineBuilder pipelineBuilder;
    GrDrawTarget* target = this->prepareToDraw(&pipelineBuilder, rt, clip, &paint, &acf);
    if (NULL == target) {
        return;
    }

    GR_CREATE_TRACE_MARKER("GrContext::drawRectToRect", target);

    target->drawRect(&pipelineBuilder,
                     paint.getColor(),
                     viewMatrix,
                     rectToDraw,
                     &localRect,
                     localMatrix);
}

static const GrGeometryProcessor* set_vertex_attributes(bool hasLocalCoords,
                                                        bool hasColors,
                                                        int* colorOffset,
                                                        int* texOffset,
                                                        GrColor color,
                                                        const SkMatrix& viewMatrix,
                                                        bool coverageIgnored) {
    *texOffset = -1;
    *colorOffset = -1;
    uint32_t flags = GrDefaultGeoProcFactory::kPosition_GPType;
    if (hasLocalCoords && hasColors) {
        *colorOffset = sizeof(SkPoint);
        *texOffset = sizeof(SkPoint) + sizeof(GrColor);
        flags |= GrDefaultGeoProcFactory::kColor_GPType |
                 GrDefaultGeoProcFactory::kLocalCoord_GPType;
    } else if (hasLocalCoords) {
        *texOffset = sizeof(SkPoint);
        flags |= GrDefaultGeoProcFactory::kLocalCoord_GPType;
    } else if (hasColors) {
        *colorOffset = sizeof(SkPoint);
        flags |= GrDefaultGeoProcFactory::kColor_GPType;
    }
    return GrDefaultGeoProcFactory::Create(flags, color, hasLocalCoords, coverageIgnored,
                                           viewMatrix, SkMatrix::I());
}

class DrawVerticesBatch : public GrBatch {
public:
    struct Geometry {
        GrColor fColor;
        SkTDArray<SkPoint> fPositions;
        SkTDArray<uint16_t> fIndices;
        SkTDArray<GrColor> fColors;
        SkTDArray<SkPoint> fLocalCoords;
    };

    static GrBatch* Create(const Geometry& geometry, GrPrimitiveType primitiveType,
                           const SkMatrix& viewMatrix,
                           const SkPoint* positions, int vertexCount,
                           const uint16_t* indices, int indexCount,
                           const GrColor* colors, const SkPoint* localCoords,
                           const SkRect& bounds) {
        return SkNEW_ARGS(DrawVerticesBatch, (geometry, primitiveType, viewMatrix, positions,
                                              vertexCount, indices, indexCount, colors,
                                              localCoords, bounds));
    }

    const char* name() const override { return "DrawVerticesBatch"; }

    void getInvariantOutputColor(GrInitInvariantOutput* out) const override {
        // When this is called on a batch, there is only one geometry bundle
        if (this->hasColors()) {
            out->setUnknownFourComponents();
        } else {
            out->setKnownFourComponents(fGeoData[0].fColor);
        }
    }

    void getInvariantOutputCoverage(GrInitInvariantOutput* out) const override {
        out->setKnownSingleComponent(0xff);
    }

    void initBatchTracker(const GrPipelineInfo& init) override {
        // Handle any color overrides
        if (init.fColorIgnored) {
            fGeoData[0].fColor = GrColor_ILLEGAL;
        } else if (GrColor_ILLEGAL != init.fOverrideColor) {
            fGeoData[0].fColor = init.fOverrideColor;
        }

        // setup batch properties
        fBatch.fColorIgnored = init.fColorIgnored;
        fBatch.fColor = fGeoData[0].fColor;
        fBatch.fUsesLocalCoords = init.fUsesLocalCoords;
        fBatch.fCoverageIgnored = init.fCoverageIgnored;
    }

    void generateGeometry(GrBatchTarget* batchTarget, const GrPipeline* pipeline) override {
        int colorOffset = -1, texOffset = -1;
        SkAutoTUnref<const GrGeometryProcessor> gp(
                set_vertex_attributes(this->hasLocalCoords(), this->hasColors(), &colorOffset,
                                      &texOffset, this->color(), this->viewMatrix(),
                                      this->coverageIgnored()));

        batchTarget->initDraw(gp, pipeline);

        size_t vertexStride = gp->getVertexStride();

        SkASSERT(vertexStride == sizeof(SkPoint) + (this->hasLocalCoords() ? sizeof(SkPoint) : 0)
                                                 + (this->hasColors() ? sizeof(GrColor) : 0));

        int instanceCount = fGeoData.count();

        const GrVertexBuffer* vertexBuffer;
        int firstVertex;

        void* verts = batchTarget->makeVertSpace(vertexStride, this->vertexCount(),
                                                 &vertexBuffer, &firstVertex);

        if (!verts) {
            SkDebugf("Could not allocate vertices\n");
            return;
        }

        const GrIndexBuffer* indexBuffer = NULL;
        int firstIndex = 0;

        uint16_t* indices = NULL;
        if (this->hasIndices()) {
            indices = batchTarget->makeIndexSpace(this->indexCount(), &indexBuffer, &firstIndex);

            if (!indices) {
                SkDebugf("Could not allocate indices\n");
                return;
            }
        }

        int indexOffset = 0;
        int vertexOffset = 0;
        for (int i = 0; i < instanceCount; i++) {
            const Geometry& args = fGeoData[i];

            // TODO we can actually cache this interleaved and then just memcopy
            if (this->hasIndices()) {
                for (int j = 0; j < args.fIndices.count(); ++j, ++indexOffset) {
                    *(indices + indexOffset) = args.fIndices[j] + vertexOffset;
                }
            }

            for (int j = 0; j < args.fPositions.count(); ++j) {
                *((SkPoint*)verts) = args.fPositions[j];
                if (this->hasColors()) {
                    *(GrColor*)((intptr_t)verts + colorOffset) = args.fColors[j];
                }
                if (this->hasLocalCoords()) {
                    *(SkPoint*)((intptr_t)verts + texOffset) = args.fLocalCoords[j];
                }
                verts = (void*)((intptr_t)verts + vertexStride);
                vertexOffset++;
            }
        }

        GrVertices vertices;
        if (this->hasIndices()) {
            vertices.initIndexed(this->primitiveType(), vertexBuffer, indexBuffer, firstVertex,
                                 firstIndex, this->vertexCount(), this->indexCount());

        } else {
            vertices.init(this->primitiveType(), vertexBuffer, firstVertex, this->vertexCount());
        }
        batchTarget->draw(vertices);
    }

    SkSTArray<1, Geometry, true>* geoData() { return &fGeoData; }

private:
    DrawVerticesBatch(const Geometry& geometry, GrPrimitiveType primitiveType,
                      const SkMatrix& viewMatrix,
                      const SkPoint* positions, int vertexCount,
                      const uint16_t* indices, int indexCount,
                      const GrColor* colors, const SkPoint* localCoords, const SkRect& bounds) {
        this->initClassID<DrawVerticesBatch>();
        SkASSERT(positions);

        fBatch.fViewMatrix = viewMatrix;
        Geometry& installedGeo = fGeoData.push_back(geometry);

        installedGeo.fPositions.append(vertexCount, positions);
        if (indices) {
            installedGeo.fIndices.append(indexCount, indices);
            fBatch.fHasIndices = true;
        } else {
            fBatch.fHasIndices = false;
        }

        if (colors) {
            installedGeo.fColors.append(vertexCount, colors);
            fBatch.fHasColors = true;
        } else {
            fBatch.fHasColors = false;
        }

        if (localCoords) {
            installedGeo.fLocalCoords.append(vertexCount, localCoords);
            fBatch.fHasLocalCoords = true;
        } else {
            fBatch.fHasLocalCoords = false;
        }
        fBatch.fVertexCount = vertexCount;
        fBatch.fIndexCount = indexCount;
        fBatch.fPrimitiveType = primitiveType;

        this->setBounds(bounds);
    }

    GrPrimitiveType primitiveType() const { return fBatch.fPrimitiveType; }
    bool batchablePrimitiveType() const {
        return kTriangles_GrPrimitiveType == fBatch.fPrimitiveType ||
               kLines_GrPrimitiveType == fBatch.fPrimitiveType ||
               kPoints_GrPrimitiveType == fBatch.fPrimitiveType;
    }
    GrColor color() const { return fBatch.fColor; }
    bool usesLocalCoords() const { return fBatch.fUsesLocalCoords; }
    bool colorIgnored() const { return fBatch.fColorIgnored; }
    const SkMatrix& viewMatrix() const { return fBatch.fViewMatrix; }
    bool hasColors() const { return fBatch.fHasColors; }
    bool hasIndices() const { return fBatch.fHasIndices; }
    bool hasLocalCoords() const { return fBatch.fHasLocalCoords; }
    int vertexCount() const { return fBatch.fVertexCount; }
    int indexCount() const { return fBatch.fIndexCount; }
    bool coverageIgnored() const { return fBatch.fCoverageIgnored; }

    bool onCombineIfPossible(GrBatch* t) override {
        DrawVerticesBatch* that = t->cast<DrawVerticesBatch>();

        if (!this->batchablePrimitiveType() || this->primitiveType() != that->primitiveType()) {
            return false;
        }

        SkASSERT(this->usesLocalCoords() == that->usesLocalCoords());

        // We currently use a uniform viewmatrix for this batch
        if (!this->viewMatrix().cheapEqualTo(that->viewMatrix())) {
            return false;
        }

        if (this->hasColors() != that->hasColors()) {
            return false;
        }

        if (this->hasIndices() != that->hasIndices()) {
            return false;
        }

        if (this->hasLocalCoords() != that->hasLocalCoords()) {
            return false;
        }

        if (!this->hasColors() && this->color() != that->color()) {
            return false;
        }

        if (this->color() != that->color()) {
            fBatch.fColor = GrColor_ILLEGAL;
        }
        fGeoData.push_back_n(that->geoData()->count(), that->geoData()->begin());
        fBatch.fVertexCount += that->vertexCount();
        fBatch.fIndexCount += that->indexCount();

        this->joinBounds(that->bounds());
        return true;
    }

    struct BatchTracker {
        GrPrimitiveType fPrimitiveType;
        SkMatrix fViewMatrix;
        GrColor fColor;
        bool fUsesLocalCoords;
        bool fColorIgnored;
        bool fCoverageIgnored;
        bool fHasColors;
        bool fHasIndices;
        bool fHasLocalCoords;
        int fVertexCount;
        int fIndexCount;
    };

    BatchTracker fBatch;
    SkSTArray<1, Geometry, true> fGeoData;
};

void GrContext::drawVertices(GrRenderTarget* rt,
                             const GrClip& clip,
                             const GrPaint& paint,
                             const SkMatrix& viewMatrix,
                             GrPrimitiveType primitiveType,
                             int vertexCount,
                             const SkPoint positions[],
                             const SkPoint texCoords[],
                             const GrColor colors[],
                             const uint16_t indices[],
                             int indexCount) {
    RETURN_IF_ABANDONED
    AutoCheckFlush acf(this);
    GrPipelineBuilder pipelineBuilder;

    GrDrawTarget* target = this->prepareToDraw(&pipelineBuilder, rt, clip, &paint, &acf);
    if (NULL == target) {
        return;
    }

    GR_CREATE_TRACE_MARKER("GrContext::drawVertices", target);

    // TODO clients should give us bounds
    SkRect bounds;
    if (!bounds.setBoundsCheck(positions, vertexCount)) {
        SkDebugf("drawVertices call empty bounds\n");
        return;
    }

    viewMatrix.mapRect(&bounds);

    // If we don't have AA then we outset for a half pixel in each direction to account for
    // snapping
    if (!paint.isAntiAlias()) {
        bounds.outset(0.5f, 0.5f);
    }

    DrawVerticesBatch::Geometry geometry;
    geometry.fColor = paint.getColor();
    SkAutoTUnref<GrBatch> batch(DrawVerticesBatch::Create(geometry, primitiveType, viewMatrix,
                                                          positions, vertexCount, indices,
                                                          indexCount, colors, texCoords,
                                                          bounds));

    target->drawBatch(&pipelineBuilder, batch);
}

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

void GrContext::drawRRect(GrRenderTarget*rt,
                          const GrClip& clip,
                          const GrPaint& paint,
                          const SkMatrix& viewMatrix,
                          const SkRRect& rrect,
                          const GrStrokeInfo& strokeInfo) {
    RETURN_IF_ABANDONED
    if (rrect.isEmpty()) {
       return;
    }

    if (strokeInfo.isDashed()) {
        SkPath path;
        path.setIsVolatile(true);
        path.addRRect(rrect);
        this->drawPath(rt, clip, paint, viewMatrix, path, strokeInfo);
        return;
    }

    AutoCheckFlush acf(this);
    GrPipelineBuilder pipelineBuilder;
    GrDrawTarget* target = this->prepareToDraw(&pipelineBuilder, rt, clip, &paint, &acf);
    if (NULL == target) {
        return;
    }

    GR_CREATE_TRACE_MARKER("GrContext::drawRRect", target);

    GrColor color = paint.getColor();
    if (!fOvalRenderer->drawRRect(target,
                                  &pipelineBuilder,
                                  color,
                                  viewMatrix,
                                  paint.isAntiAlias(),
                                  rrect,
                                  strokeInfo)) {
        SkPath path;
        path.setIsVolatile(true);
        path.addRRect(rrect);
        this->internalDrawPath(target, &pipelineBuilder, viewMatrix, color, paint.isAntiAlias(),
                               path, strokeInfo);
    }
}

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

void GrContext::drawDRRect(GrRenderTarget* rt,
                           const GrClip& clip,
                           const GrPaint& paint,
                           const SkMatrix& viewMatrix,
                           const SkRRect& outer,
                           const SkRRect& inner) {
    RETURN_IF_ABANDONED
    if (outer.isEmpty()) {
       return;
    }

    AutoCheckFlush acf(this);
    GrPipelineBuilder pipelineBuilder;
    GrDrawTarget* target = this->prepareToDraw(&pipelineBuilder, rt, clip, &paint, &acf);

    GR_CREATE_TRACE_MARKER("GrContext::drawDRRect", target);

    GrColor color = paint.getColor();
    if (!fOvalRenderer->drawDRRect(target,
                                   &pipelineBuilder,
                                   color,
                                   viewMatrix,
                                   paint.isAntiAlias(),
                                   outer,
                                   inner)) {
        SkPath path;
        path.setIsVolatile(true);
        path.addRRect(inner);
        path.addRRect(outer);
        path.setFillType(SkPath::kEvenOdd_FillType);
        GrStrokeInfo fillRec(SkStrokeRec::kFill_InitStyle);
        this->internalDrawPath(target, &pipelineBuilder, viewMatrix, color, paint.isAntiAlias(),
                               path, fillRec);
    }
}

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

void GrContext::drawOval(GrRenderTarget* rt,
                         const GrClip& clip,
                         const GrPaint& paint,
                         const SkMatrix& viewMatrix,
                         const SkRect& oval,
                         const GrStrokeInfo& strokeInfo) {
    RETURN_IF_ABANDONED
    if (oval.isEmpty()) {
       return;
    }

    if (strokeInfo.isDashed()) {
        SkPath path;
        path.setIsVolatile(true);
        path.addOval(oval);
        this->drawPath(rt, clip, paint, viewMatrix, path, strokeInfo);
        return;
    }

    AutoCheckFlush acf(this);
    GrPipelineBuilder pipelineBuilder;
    GrDrawTarget* target = this->prepareToDraw(&pipelineBuilder, rt, clip, &paint, &acf);
    if (NULL == target) {
        return;
    }

    GR_CREATE_TRACE_MARKER("GrContext::drawOval", target);

    GrColor color = paint.getColor();
    if (!fOvalRenderer->drawOval(target,
                                 &pipelineBuilder,
                                 color,
                                 viewMatrix,
                                 paint.isAntiAlias(),
                                 oval,
                                 strokeInfo)) {
        SkPath path;
        path.setIsVolatile(true);
        path.addOval(oval);
        this->internalDrawPath(target, &pipelineBuilder, viewMatrix, color, paint.isAntiAlias(),
                               path, strokeInfo);
    }
}

// Can 'path' be drawn as a pair of filled nested rectangles?
static bool is_nested_rects(GrDrawTarget* target,
                            GrPipelineBuilder* pipelineBuilder,
                            GrColor color,
                            const SkMatrix& viewMatrix,
                            const SkPath& path,
                            const SkStrokeRec& stroke,
                            SkRect rects[2]) {
    SkASSERT(stroke.isFillStyle());

    if (path.isInverseFillType()) {
        return false;
    }

    // TODO: this restriction could be lifted if we were willing to apply
    // the matrix to all the points individually rather than just to the rect
    if (!viewMatrix.preservesAxisAlignment()) {
        return false;
    }

    SkPath::Direction dirs[2];
    if (!path.isNestedFillRects(rects, dirs)) {
        return false;
    }

    if (SkPath::kWinding_FillType == path.getFillType() && dirs[0] == dirs[1]) {
        // The two rects need to be wound opposite to each other
        return false;
    }

    // Right now, nested rects where the margin is not the same width
    // all around do not render correctly
    const SkScalar* outer = rects[0].asScalars();
    const SkScalar* inner = rects[1].asScalars();

    bool allEq = true;

    SkScalar margin = SkScalarAbs(outer[0] - inner[0]);
    bool allGoE1 = margin >= SK_Scalar1;

    for (int i = 1; i < 4; ++i) {
        SkScalar temp = SkScalarAbs(outer[i] - inner[i]);
        if (temp < SK_Scalar1) {
            allGoE1 = false;
        }
        if (!SkScalarNearlyEqual(margin, temp)) {
            allEq = false;
        }
    }

    return allEq || allGoE1;
}

void GrContext::drawPath(GrRenderTarget* rt,
                         const GrClip& clip,
                         const GrPaint& paint,
                         const SkMatrix& viewMatrix,
                         const SkPath& path,
                         const GrStrokeInfo& strokeInfo) {
    RETURN_IF_ABANDONED
    if (path.isEmpty()) {
       if (path.isInverseFillType()) {
           this->drawPaint(rt, clip, paint, viewMatrix);
       }
       return;
    }

    GrColor color = paint.getColor();

    // Note that internalDrawPath may sw-rasterize the path into a scratch texture.
    // Scratch textures can be recycled after they are returned to the texture
    // cache. This presents a potential hazard for buffered drawing. However,
    // the writePixels that uploads to the scratch will perform a flush so we're
    // OK.
    AutoCheckFlush acf(this);
    GrPipelineBuilder pipelineBuilder;
    GrDrawTarget* target = this->prepareToDraw(&pipelineBuilder, rt, clip, &paint, &acf);
    if (NULL == target) {
        return;
    }

    GR_CREATE_TRACE_MARKER1("GrContext::drawPath", target, "Is Convex", path.isConvex());

    if (!strokeInfo.isDashed()) {
        bool useCoverageAA = paint.isAntiAlias() &&
                !pipelineBuilder.getRenderTarget()->isMultisampled();

        if (useCoverageAA && strokeInfo.getWidth() < 0 && !path.isConvex()) {
            // Concave AA paths are expensive - try to avoid them for special cases
            SkRect rects[2];

            if (is_nested_rects(target, &pipelineBuilder, color, viewMatrix, path, strokeInfo,
                                rects)) {
                fAARectRenderer->fillAANestedRects(target, &pipelineBuilder, color, viewMatrix,
                                                   rects);
                return;
            }
        }
        SkRect ovalRect;
        bool isOval = path.isOval(&ovalRect);

        if (isOval && !path.isInverseFillType()) {
            if (fOvalRenderer->drawOval(target,
                                        &pipelineBuilder,
                                        color,
                                        viewMatrix,
                                        paint.isAntiAlias(),
                                        ovalRect,
                                        strokeInfo)) {
                return;
            }
        }
    }
    this->internalDrawPath(target, &pipelineBuilder, viewMatrix, color, paint.isAntiAlias(),
                           path, strokeInfo);
}

void GrContext::internalDrawPath(GrDrawTarget* target,
                                 GrPipelineBuilder* pipelineBuilder,
                                 const SkMatrix& viewMatrix,
                                 GrColor color,
                                 bool useAA,
                                 const SkPath& path,
                                 const GrStrokeInfo& strokeInfo) {
    RETURN_IF_ABANDONED
    SkASSERT(!path.isEmpty());

    GR_CREATE_TRACE_MARKER("GrContext::internalDrawPath", target);


    // An Assumption here is that path renderer would use some form of tweaking
    // the src color (either the input alpha or in the frag shader) to implement
    // aa. If we have some future driver-mojo path AA that can do the right
    // thing WRT to the blend then we'll need some query on the PR.
    bool useCoverageAA = useAA &&
        !pipelineBuilder->getRenderTarget()->isMultisampled();


    GrPathRendererChain::DrawType type =
        useCoverageAA ? GrPathRendererChain::kColorAntiAlias_DrawType :
                        GrPathRendererChain::kColor_DrawType;

    const SkPath* pathPtr = &path;
    SkTLazy<SkPath> tmpPath;
    const GrStrokeInfo* strokeInfoPtr = &strokeInfo;

    // Try a 1st time without stroking the path and without allowing the SW renderer
    GrPathRenderer* pr = this->getPathRenderer(target, pipelineBuilder, viewMatrix, *pathPtr,
                                               *strokeInfoPtr, false, type);

    GrStrokeInfo dashlessStrokeInfo(strokeInfo, false);
    if (NULL == pr && strokeInfo.isDashed()) {
        // It didn't work above, so try again with dashed stroke converted to a dashless stroke.
        if (!strokeInfo.applyDashToPath(tmpPath.init(), &dashlessStrokeInfo, *pathPtr)) {
            return;
        }
        pathPtr = tmpPath.get();
        if (pathPtr->isEmpty()) {
            return;
        }
        strokeInfoPtr = &dashlessStrokeInfo;
        pr = this->getPathRenderer(target, pipelineBuilder, viewMatrix, *pathPtr, *strokeInfoPtr,
                                   false, type);
    }

    if (NULL == pr) {
        if (!GrPathRenderer::IsStrokeHairlineOrEquivalent(*strokeInfoPtr, viewMatrix, NULL) &&
            !strokeInfoPtr->isFillStyle()) {
            // It didn't work above, so try again with stroke converted to a fill.
            if (!tmpPath.isValid()) {
                tmpPath.init();
            }
            dashlessStrokeInfo.setResScale(SkScalarAbs(viewMatrix.getMaxScale()));
            if (!dashlessStrokeInfo.applyToPath(tmpPath.get(), *pathPtr)) {
                return;
            }
            pathPtr = tmpPath.get();
            if (pathPtr->isEmpty()) {
                return;
            }
            dashlessStrokeInfo.setFillStyle();
            strokeInfoPtr = &dashlessStrokeInfo;
        }

        // This time, allow SW renderer
        pr = this->getPathRenderer(target, pipelineBuilder, viewMatrix, *pathPtr, *strokeInfoPtr,
                                   true, type);
    }

    if (NULL == pr) {
#ifdef SK_DEBUG
        SkDebugf("Unable to find path renderer compatible with path.\n");
#endif
        return;
    }

    pr->drawPath(target, pipelineBuilder, color, viewMatrix, *pathPtr, *strokeInfoPtr, useCoverageAA);
}

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

void GrContext::flush(int flagsBitfield) {
    if (NULL == fDrawBuffer) {
        return;
    }

    if (kDiscard_FlushBit & flagsBitfield) {
        fDrawBuffer->reset();
    } else {
        fDrawBuffer->flush();
    }
    fResourceCache->notifyFlushOccurred();
    fFlushToReduceCacheSize = false;
}

bool sw_convert_to_premul(GrPixelConfig srcConfig, int width, int height, size_t inRowBytes,
                          const void* inPixels, size_t outRowBytes, void* outPixels) {
    SkSrcPixelInfo srcPI;
    if (!GrPixelConfig2ColorAndProfileType(srcConfig, &srcPI.fColorType, NULL)) {
        return false;
    }
    srcPI.fAlphaType = kUnpremul_SkAlphaType;
    srcPI.fPixels = inPixels;
    srcPI.fRowBytes = inRowBytes;

    SkDstPixelInfo dstPI;
    dstPI.fColorType = srcPI.fColorType;
    dstPI.fAlphaType = kPremul_SkAlphaType;
    dstPI.fPixels = outPixels;
    dstPI.fRowBytes = outRowBytes;

    return srcPI.convertPixelsTo(&dstPI, width, height);
}

bool GrContext::writeSurfacePixels(GrSurface* surface,
                                   int left, int top, int width, int height,
                                   GrPixelConfig srcConfig, const void* buffer, size_t rowBytes,
                                   uint32_t pixelOpsFlags) {
    RETURN_FALSE_IF_ABANDONED
    {
        GrTexture* texture = NULL;
        if (!(kUnpremul_PixelOpsFlag & pixelOpsFlags) && (texture = surface->asTexture()) &&
            fGpu->canWriteTexturePixels(texture, srcConfig)) {

            if (!(kDontFlush_PixelOpsFlag & pixelOpsFlags) &&
                surface->surfacePriv().hasPendingIO()) {
                this->flush();
            }
            return fGpu->writeTexturePixels(texture, left, top, width, height,
                                            srcConfig, buffer, rowBytes);
            // Don't need to check kFlushWrites_PixelOp here, we just did a direct write so the
            // upload is already flushed.
        }
    }

    // If we didn't do a direct texture write then we upload the pixels to a texture and draw.
    GrRenderTarget* renderTarget = surface->asRenderTarget();
    if (NULL == renderTarget) {
        return false;
    }

    // We ignore the preferred config unless it is a R/B swap of the src config. In that case
    // we will upload the original src data to a scratch texture but we will spoof it as the swapped
    // config. This scratch will then have R and B swapped. We correct for this by swapping again
    // when drawing the scratch to the dst using a conversion effect.
    bool swapRAndB = false;
    GrPixelConfig writeConfig = srcConfig;
    if (GrPixelConfigSwapRAndB(srcConfig) ==
        fGpu->preferredWritePixelsConfig(srcConfig, renderTarget->config())) {
        writeConfig = GrPixelConfigSwapRAndB(srcConfig);
        swapRAndB = true;
    }

    GrSurfaceDesc desc;
    desc.fWidth = width;
    desc.fHeight = height;
    desc.fConfig = writeConfig;
    SkAutoTUnref<GrTexture> texture(this->textureProvider()->refScratchTexture(desc,
        GrTextureProvider::kApprox_ScratchTexMatch));
    if (!texture) {
        return false;
    }

    SkAutoTUnref<const GrFragmentProcessor> fp;
    SkMatrix textureMatrix;
    textureMatrix.setIDiv(texture->width(), texture->height());

    // allocate a tmp buffer and sw convert the pixels to premul
    SkAutoSTMalloc<128 * 128, uint32_t> tmpPixels(0);

    if (kUnpremul_PixelOpsFlag & pixelOpsFlags) {
        if (!GrPixelConfigIs8888(srcConfig)) {
            return false;
        }
        fp.reset(this->createUPMToPMEffect(texture, swapRAndB, textureMatrix));
        // handle the unpremul step on the CPU if we couldn't create an effect to do it.
        if (NULL == fp) {
            size_t tmpRowBytes = 4 * width;
            tmpPixels.reset(width * height);
            if (!sw_convert_to_premul(srcConfig, width, height, rowBytes, buffer, tmpRowBytes,
                                      tmpPixels.get())) {
                return false;
            }
            rowBytes = tmpRowBytes;
            buffer = tmpPixels.get();
        }
    }
    if (NULL == fp) {
        fp.reset(GrConfigConversionEffect::Create(texture,
                                                  swapRAndB,
                                                  GrConfigConversionEffect::kNone_PMConversion,
                                                  textureMatrix));
    }

    // Even if the client told us not to flush, we still flush here. The client may have known that
    // writes to the original surface caused no data hazards, but they can't know that the scratch
    // we just got is safe.
    if (texture->surfacePriv().hasPendingIO()) {
        this->flush();
    }
    if (!fGpu->writeTexturePixels(texture, 0, 0, width, height,
                                  writeConfig, buffer, rowBytes)) {
        return false;
    }

    SkMatrix matrix;
    matrix.setTranslate(SkIntToScalar(left), SkIntToScalar(top));

    // This function can be called in the midst of drawing another object (e.g., when uploading a
    // SW-rasterized clip while issuing a draw). So we push the current geometry state before
    // drawing a rect to the render target.
    // The bracket ensures we pop the stack if we wind up flushing below.
    {
        GrDrawTarget* drawTarget = this->prepareToDraw();
        if (!drawTarget) {
            return false;
        }

        GrPipelineBuilder pipelineBuilder;
        pipelineBuilder.addColorProcessor(fp);
        pipelineBuilder.setRenderTarget(renderTarget);
        drawTarget->drawSimpleRect(&pipelineBuilder,
                                   GrColor_WHITE,
                                   matrix,
                                   SkRect::MakeWH(SkIntToScalar(width), SkIntToScalar(height)));
    }

    if (kFlushWrites_PixelOp & pixelOpsFlags) {
        this->flushSurfaceWrites(surface);
    }

    return true;
}

// toggles between RGBA and BGRA
static SkColorType toggle_colortype32(SkColorType ct) {
    if (kRGBA_8888_SkColorType == ct) {
        return kBGRA_8888_SkColorType;
    } else {
        SkASSERT(kBGRA_8888_SkColorType == ct);
        return kRGBA_8888_SkColorType;
    }
}

bool GrContext::readRenderTargetPixels(GrRenderTarget* target,
                                       int left, int top, int width, int height,
                                       GrPixelConfig dstConfig, void* buffer, size_t rowBytes,
                                       uint32_t flags) {
    RETURN_FALSE_IF_ABANDONED
    ASSERT_OWNED_RESOURCE(target);
    SkASSERT(target);

    if (!(kDontFlush_PixelOpsFlag & flags) && target->surfacePriv().hasPendingWrite()) {
        this->flush();
    }

    // Determine which conversions have to be applied: flipY, swapRAnd, and/or unpremul.

    // If fGpu->readPixels would incur a y-flip cost then we will read the pixels upside down. We'll
    // either do the flipY by drawing into a scratch with a matrix or on the cpu after the read.
    bool flipY = fGpu->readPixelsWillPayForYFlip(target, left, top,
                                                 width, height, dstConfig,
                                                 rowBytes);
    // We ignore the preferred config if it is different than our config unless it is an R/B swap.
    // In that case we'll perform an R and B swap while drawing to a scratch texture of the swapped
    // config. Then we will call readPixels on the scratch with the swapped config. The swaps during
    // the draw cancels out the fact that we call readPixels with a config that is R/B swapped from
    // dstConfig.
    GrPixelConfig readConfig = dstConfig;
    bool swapRAndB = false;
    if (GrPixelConfigSwapRAndB(dstConfig) ==
        fGpu->preferredReadPixelsConfig(dstConfig, target->config())) {
        readConfig = GrPixelConfigSwapRAndB(readConfig);
        swapRAndB = true;
    }

    bool unpremul = SkToBool(kUnpremul_PixelOpsFlag & flags);

    if (unpremul && !GrPixelConfigIs8888(dstConfig)) {
        // The unpremul flag is only allowed for these two configs.
        return false;
    }

    SkAutoTUnref<GrTexture> tempTexture;

    // If the src is a texture and we would have to do conversions after read pixels, we instead
    // do the conversions by drawing the src to a scratch texture. If we handle any of the
    // conversions in the draw we set the corresponding bool to false so that we don't reapply it
    // on the read back pixels.
    GrTexture* src = target->asTexture();
    if (src && (swapRAndB || unpremul || flipY)) {
        // Make the scratch a render so we can read its pixels.
        GrSurfaceDesc desc;
        desc.fFlags = kRenderTarget_GrSurfaceFlag;
        desc.fWidth = width;
        desc.fHeight = height;
        desc.fConfig = readConfig;
        desc.fOrigin = kTopLeft_GrSurfaceOrigin;

        // When a full read back is faster than a partial we could always make the scratch exactly
        // match the passed rect. However, if we see many different size rectangles we will trash
        // our texture cache and pay the cost of creating and destroying many textures. So, we only
        // request an exact match when the caller is reading an entire RT.
        GrTextureProvider::ScratchTexMatch match = GrTextureProvider::kApprox_ScratchTexMatch;
        if (0 == left &&
            0 == top &&
            target->width() == width &&
            target->height() == height &&
            fGpu->fullReadPixelsIsFasterThanPartial()) {
            match = GrTextureProvider::kExact_ScratchTexMatch;
        }
        tempTexture.reset(this->textureProvider()->refScratchTexture(desc, match));
        if (tempTexture) {
            // compute a matrix to perform the draw
            SkMatrix textureMatrix;
            textureMatrix.setTranslate(SK_Scalar1 *left, SK_Scalar1 *top);
            textureMatrix.postIDiv(src->width(), src->height());

            SkAutoTUnref<const GrFragmentProcessor> fp;
            if (unpremul) {
                fp.reset(this->createPMToUPMEffect(src, swapRAndB, textureMatrix));
                if (fp) {
                    unpremul = false; // we no longer need to do this on CPU after the read back.
                }
            }
            // If we failed to create a PM->UPM effect and have no other conversions to perform then
            // there is no longer any point to using the scratch.
            if (fp || flipY || swapRAndB) {
                if (!fp) {
                    fp.reset(GrConfigConversionEffect::Create(
                            src, swapRAndB, GrConfigConversionEffect::kNone_PMConversion,
                            textureMatrix));
                }
                swapRAndB = false; // we will handle the swap in the draw.

                // We protect the existing geometry here since it may not be
                // clear to the caller that a draw operation (i.e., drawSimpleRect)
                // can be invoked in this method
                {
                    GrPipelineBuilder pipelineBuilder;
                    SkASSERT(fp);
                    pipelineBuilder.addColorProcessor(fp);

                    pipelineBuilder.setRenderTarget(tempTexture->asRenderTarget());
                    SkRect rect = SkRect::MakeWH(SkIntToScalar(width), SkIntToScalar(height));
                    fDrawBuffer->drawSimpleRect(&pipelineBuilder,
                                                GrColor_WHITE,
                                                SkMatrix::I(),
                                                rect);
                    // we want to read back from the scratch's origin
                    left = 0;
                    top = 0;
                    target = tempTexture->asRenderTarget();
                }
                this->flushSurfaceWrites(target);
            }
        }
    }

    if (!fGpu->readPixels(target,
                          left, top, width, height,
                          readConfig, buffer, rowBytes)) {
        return false;
    }
    // Perform any conversions we weren't able to perform using a scratch texture.
    if (unpremul || swapRAndB) {
        SkDstPixelInfo dstPI;
        if (!GrPixelConfig2ColorAndProfileType(dstConfig, &dstPI.fColorType, NULL)) {
            return false;
        }
        dstPI.fAlphaType = kUnpremul_SkAlphaType;
        dstPI.fPixels = buffer;
        dstPI.fRowBytes = rowBytes;

        SkSrcPixelInfo srcPI;
        srcPI.fColorType = swapRAndB ? toggle_colortype32(dstPI.fColorType) : dstPI.fColorType;
        srcPI.fAlphaType = kPremul_SkAlphaType;
        srcPI.fPixels = buffer;
        srcPI.fRowBytes = rowBytes;

        return srcPI.convertPixelsTo(&dstPI, width, height);
    }
    return true;
}

void GrContext::prepareSurfaceForExternalRead(GrSurface* surface) {
    RETURN_IF_ABANDONED
    SkASSERT(surface);
    ASSERT_OWNED_RESOURCE(surface);
    if (surface->surfacePriv().hasPendingIO()) {
        this->flush();
    }
    GrRenderTarget* rt = surface->asRenderTarget();
    if (fGpu && rt) {
        fGpu->resolveRenderTarget(rt);
    }
}

void GrContext::discardRenderTarget(GrRenderTarget* renderTarget) {
    RETURN_IF_ABANDONED
    SkASSERT(renderTarget);
    ASSERT_OWNED_RESOURCE(renderTarget);
    AutoCheckFlush acf(this);
    GrDrawTarget* target = this->prepareToDraw();
    if (NULL == target) {
        return;
    }
    target->discard(renderTarget);
}

void GrContext::copySurface(GrSurface* dst, GrSurface* src, const SkIRect& srcRect,
                            const SkIPoint& dstPoint, uint32_t pixelOpsFlags) {
    RETURN_IF_ABANDONED
    if (NULL == src || NULL == dst) {
        return;
    }
    ASSERT_OWNED_RESOURCE(src);
    ASSERT_OWNED_RESOURCE(dst);

    // Since we're going to the draw target and not GPU, no need to check kNoFlush
    // here.

    GrDrawTarget* target = this->prepareToDraw();
    if (NULL == target) {
        return;
    }
    target->copySurface(dst, src, srcRect, dstPoint);

    if (kFlushWrites_PixelOp & pixelOpsFlags) {
        this->flush();
    }
}

void GrContext::flushSurfaceWrites(GrSurface* surface) {
    RETURN_IF_ABANDONED
    if (surface->surfacePriv().hasPendingWrite()) {
        this->flush();
    }
}

GrDrawTarget* GrContext::prepareToDraw(GrPipelineBuilder* pipelineBuilder,
                                       GrRenderTarget* rt,
                                       const GrClip& clip,
                                       const GrPaint* paint,
                                       const AutoCheckFlush* acf) {
    if (NULL == fGpu || NULL == fDrawBuffer) {
        return NULL;
    }

    ASSERT_OWNED_RESOURCE(rt);
    SkASSERT(rt && paint && acf);
    pipelineBuilder->setFromPaint(*paint, rt, clip);
    return fDrawBuffer;
}

GrDrawTarget* GrContext::prepareToDraw() {
    if (NULL == fGpu) {
        return NULL;
    }
    return fDrawBuffer;
}

/*
 * This method finds a path renderer that can draw the specified path on
 * the provided target.
 * Due to its expense, the software path renderer has split out so it can
 * can be individually allowed/disallowed via the "allowSW" boolean.
 */
GrPathRenderer* GrContext::getPathRenderer(const GrDrawTarget* target,
                                           const GrPipelineBuilder* pipelineBuilder,
                                           const SkMatrix& viewMatrix,
                                           const SkPath& path,
                                           const GrStrokeInfo& stroke,
                                           bool allowSW,
                                           GrPathRendererChain::DrawType drawType,
                                           GrPathRendererChain::StencilSupport* stencilSupport) {

    if (NULL == fPathRendererChain) {
        fPathRendererChain = SkNEW_ARGS(GrPathRendererChain, (this));
    }

    GrPathRenderer* pr = fPathRendererChain->getPathRenderer(target,
                                                             pipelineBuilder,
                                                             viewMatrix,
                                                             path,
                                                             stroke,
                                                             drawType,
                                                             stencilSupport);

    if (NULL == pr && allowSW) {
        if (NULL == fSoftwarePathRenderer) {
            fSoftwarePathRenderer = SkNEW_ARGS(GrSoftwarePathRenderer, (this));
        }
        pr = fSoftwarePathRenderer;
    }

    return pr;
}

////////////////////////////////////////////////////////////////////////////////
bool GrContext::isConfigRenderable(GrPixelConfig config, bool withMSAA) const {
    return fGpu->caps()->isConfigRenderable(config, withMSAA);
}

int GrContext::getRecommendedSampleCount(GrPixelConfig config,
                                         SkScalar dpi) const {
    if (!this->isConfigRenderable(config, true)) {
        return 0;
    }
    int chosenSampleCount = 0;
    if (fGpu->caps()->shaderCaps()->pathRenderingSupport()) {
        if (dpi >= 250.0f) {
            chosenSampleCount = 4;
        } else {
            chosenSampleCount = 16;
        }
    }
    return chosenSampleCount <= fGpu->caps()->maxSampleCount() ?
        chosenSampleCount : 0;
}

GrDrawTarget* GrContext::getTextTarget() {
    return this->prepareToDraw();
}

namespace {
void test_pm_conversions(GrContext* ctx, int* pmToUPMValue, int* upmToPMValue) {
    GrConfigConversionEffect::PMConversion pmToUPM;
    GrConfigConversionEffect::PMConversion upmToPM;
    GrConfigConversionEffect::TestForPreservingPMConversions(ctx, &pmToUPM, &upmToPM);
    *pmToUPMValue = pmToUPM;
    *upmToPMValue = upmToPM;
}
}

const GrFragmentProcessor* GrContext::createPMToUPMEffect(GrTexture* texture,
                                                          bool swapRAndB,
                                                          const SkMatrix& matrix) {
    if (!fDidTestPMConversions) {
        test_pm_conversions(this, &fPMToUPMConversion, &fUPMToPMConversion);
        fDidTestPMConversions = true;
    }
    GrConfigConversionEffect::PMConversion pmToUPM =
        static_cast<GrConfigConversionEffect::PMConversion>(fPMToUPMConversion);
    if (GrConfigConversionEffect::kNone_PMConversion != pmToUPM) {
        return GrConfigConversionEffect::Create(texture, swapRAndB, pmToUPM, matrix);
    } else {
        return NULL;
    }
}

const GrFragmentProcessor* GrContext::createUPMToPMEffect(GrTexture* texture,
                                                          bool swapRAndB,
                                                          const SkMatrix& matrix) {
    if (!fDidTestPMConversions) {
        test_pm_conversions(this, &fPMToUPMConversion, &fUPMToPMConversion);
        fDidTestPMConversions = true;
    }
    GrConfigConversionEffect::PMConversion upmToPM =
        static_cast<GrConfigConversionEffect::PMConversion>(fUPMToPMConversion);
    if (GrConfigConversionEffect::kNone_PMConversion != upmToPM) {
        return GrConfigConversionEffect::Create(texture, swapRAndB, upmToPM, matrix);
    } else {
        return NULL;
    }
}

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

void GrContext::getResourceCacheLimits(int* maxTextures, size_t* maxTextureBytes) const {
    if (maxTextures) {
        *maxTextures = fResourceCache->getMaxResourceCount();
    }
    if (maxTextureBytes) {
        *maxTextureBytes = fResourceCache->getMaxResourceBytes();
    }
}

void GrContext::setResourceCacheLimits(int maxTextures, size_t maxTextureBytes) {
    fResourceCache->setLimits(maxTextures, maxTextureBytes);
}

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

void GrContext::addGpuTraceMarker(const GrGpuTraceMarker* marker) {
    fGpu->addGpuTraceMarker(marker);
    if (fDrawBuffer) {
        fDrawBuffer->addGpuTraceMarker(marker);
    }
}

void GrContext::removeGpuTraceMarker(const GrGpuTraceMarker* marker) {
    fGpu->removeGpuTraceMarker(marker);
    if (fDrawBuffer) {
        fDrawBuffer->removeGpuTraceMarker(marker);
    }
}

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

#ifdef GR_TEST_UTILS

BATCH_TEST_DEFINE(StrokeRectBatch) {
    StrokeRectBatch::Geometry geometry;
    geometry.fViewMatrix = GrTest::TestMatrix(random);
    geometry.fColor = GrRandomColor(random);
    geometry.fRect = GrTest::TestRect(random);
    geometry.fStrokeWidth = random->nextBool() ? 0.0f : 1.0f;

    return StrokeRectBatch::Create(geometry, random->nextBool());
}

static uint32_t seed_vertices(GrPrimitiveType type) {
    switch (type) {
        case kTriangles_GrPrimitiveType:
        case kTriangleStrip_GrPrimitiveType:
        case kTriangleFan_GrPrimitiveType:
            return 3;
        case kPoints_GrPrimitiveType:
            return 1;
        case kLines_GrPrimitiveType:
        case kLineStrip_GrPrimitiveType:
            return 2;
    }
    SkFAIL("Incomplete switch\n");
    return 0;
}

static uint32_t primitive_vertices(GrPrimitiveType type) {
    switch (type) {
        case kTriangles_GrPrimitiveType:
            return 3;
        case kLines_GrPrimitiveType:
            return 2;
        case kTriangleStrip_GrPrimitiveType:
        case kTriangleFan_GrPrimitiveType:
        case kPoints_GrPrimitiveType:
        case kLineStrip_GrPrimitiveType:
            return 1;
    }
    SkFAIL("Incomplete switch\n");
    return 0;
}

static SkPoint random_point(SkRandom* random, SkScalar min, SkScalar max) {
    SkPoint p;
    p.fX = random->nextRangeScalar(min, max);
    p.fY = random->nextRangeScalar(min, max);
    return p;
}

static void randomize_params(size_t count, size_t maxVertex, SkScalar min, SkScalar max,
                             SkRandom* random,
                             SkTArray<SkPoint>* positions,
                             SkTArray<SkPoint>* texCoords, bool hasTexCoords,
                             SkTArray<GrColor>* colors, bool hasColors,
                             SkTArray<uint16_t>* indices, bool hasIndices) {
    for (uint32_t v = 0; v < count; v++) {
        positions->push_back(random_point(random, min, max));
        if (hasTexCoords) {
            texCoords->push_back(random_point(random, min, max));
        }
        if (hasColors) {
            colors->push_back(GrRandomColor(random));
        }
        if (hasIndices) {
            SkASSERT(maxVertex <= SK_MaxU16);
            indices->push_back(random->nextULessThan((uint16_t)maxVertex));
        }
    }
}

BATCH_TEST_DEFINE(VerticesBatch) {
    GrPrimitiveType type = GrPrimitiveType(random->nextULessThan(kLast_GrPrimitiveType + 1));
    uint32_t primitiveCount = random->nextRangeU(1, 100);

    // TODO make 'sensible' indexbuffers
    SkTArray<SkPoint> positions;
    SkTArray<SkPoint> texCoords;
    SkTArray<GrColor> colors;
    SkTArray<uint16_t> indices;

    bool hasTexCoords = random->nextBool();
    bool hasIndices = random->nextBool();
    bool hasColors = random->nextBool();

    uint32_t vertexCount = seed_vertices(type) + (primitiveCount - 1) * primitive_vertices(type);

    static const SkScalar kMinVertExtent = -100.f;
    static const SkScalar kMaxVertExtent = 100.f;
    randomize_params(seed_vertices(type), vertexCount, kMinVertExtent, kMaxVertExtent,
                     random,
                     &positions,
                     &texCoords, hasTexCoords,
                     &colors, hasColors,
                     &indices, hasIndices);

    for (uint32_t i = 1; i < primitiveCount; i++) {
        randomize_params(primitive_vertices(type), vertexCount, kMinVertExtent, kMaxVertExtent,
                         random,
                         &positions,
                         &texCoords, hasTexCoords,
                         &colors, hasColors,
                         &indices, hasIndices);
    }

    SkMatrix viewMatrix = GrTest::TestMatrix(random);
    SkRect bounds;
    SkDEBUGCODE(bool result = ) bounds.setBoundsCheck(positions.begin(), vertexCount);
    SkASSERT(result);

    viewMatrix.mapRect(&bounds);

    DrawVerticesBatch::Geometry geometry;
    geometry.fColor = GrRandomColor(random);
    return DrawVerticesBatch::Create(geometry, type, viewMatrix,
                                     positions.begin(), vertexCount,
                                     indices.begin(), hasIndices ? vertexCount : 0,
                                     colors.begin(),
                                     texCoords.begin(),
                                     bounds);
}

#endif