C++ GrClip类代码示例

////////////////////////////////////////////////////////////////////////////////
// Shared preamble between gpu and SW-only AA clip mask creation paths.
// Handles caching, determination of clip mask bound & allocation (if needed)
// of the result texture
// Returns true if there is no more work to be done (i.e., we got a cache hit)
bool GrClipMaskManager::clipMaskPreamble(GrGpu* gpu,
                                         const GrClip& clipIn,
                                         GrTexture** result,
                                         GrIRect *resultBounds) {
    GrDrawState* origDrawState = gpu->drawState();
    GrAssert(origDrawState->isClipState());

    GrRenderTarget* rt = origDrawState->getRenderTarget();
    GrAssert(NULL != rt);

    GrRect rtRect;
    rtRect.setLTRB(0, 0,
                    GrIntToScalar(rt->width()), GrIntToScalar(rt->height()));

    // unlike the stencil path the alpha path is not bound to the size of the
    // render target - determine the minimum size required for the mask
    GrRect bounds;

    if (clipIn.hasConservativeBounds()) {
        bounds = clipIn.getConservativeBounds();
        if (!bounds.intersect(rtRect)) {
            // the mask will be empty in this case
            GrAssert(false);
            bounds.setEmpty();
        }
    } else {
        // still locked to the size of the render target
        bounds = rtRect;
    }

    GrIRect intBounds;
    bounds.roundOut(&intBounds);

    // need to outset a pixel since the standard bounding box computation
    // path doesn't leave any room for antialiasing (esp. w.r.t. rects)
    intBounds.outset(1, 1);

    // TODO: make sure we don't outset if bounds are still 0,0 @ min

    if (fAACache.canReuse(clipIn, 
                          intBounds.width(),
                          intBounds.height())) {
        *result = fAACache.getLastMask();
        fAACache.getLastBound(resultBounds);
        return true;
    }

    this->setupCache(clipIn, intBounds);

    *resultBounds = intBounds;
    return false;
}

bool GrClipMaskManager::drawClipShape(GrGpu* gpu,
                                      GrTexture* target,
                                      const GrClip& clipIn,
                                      int index) {
    GrDrawState* drawState = gpu->drawState();
    GrAssert(NULL != drawState);

    drawState->setRenderTarget(target->asRenderTarget());

    if (kRect_ClipType == clipIn.getElementType(index)) {
        if (clipIn.getDoAA(index)) {
            // convert the rect to a path for AA
            SkPath temp;
            temp.addRect(clipIn.getRect(index));

            return this->drawPath(gpu, temp,
                                  kEvenOdd_PathFill, clipIn.getDoAA(index));
        } else {
            gpu->drawSimpleRect(clipIn.getRect(index), NULL, 0);
        }
    } else {
        return this->drawPath(gpu,
                              clipIn.getPath(index),
                              clipIn.getPathFill(index),
                              clipIn.getDoAA(index));
    }
    return true;
}

static void add_rect_to_clip(const GrClip& clip, const SkRect& devRect, GrClip* out) {
    switch (clip.clipType()) {
        case GrClip::kClipStack_ClipType: {
            SkClipStack* stack = new SkClipStack;
            *stack = *clip.clipStack();
            // The stack is actually in clip space not device space.
            SkRect clipRect = devRect;
            SkPoint origin = { SkIntToScalar(clip.origin().fX), SkIntToScalar(clip.origin().fY) };
            clipRect.offset(origin);
            SkIRect iclipRect;
            clipRect.roundOut(&iclipRect);
            clipRect = SkRect::Make(iclipRect);
            stack->clipDevRect(clipRect, SkRegion::kIntersect_Op, false);
            out->setClipStack(stack, &clip.origin());
            break;
        }
        case GrClip::kWideOpen_ClipType:
            *out = GrClip(devRect);
            break;
        case GrClip::kIRect_ClipType: {
            SkIRect intersect;
            devRect.roundOut(&intersect);
            if (intersect.intersect(clip.irect())) {
                *out = GrClip(intersect);
            } else {
                *out = clip;
            }
            break;
        }
    }
}

void GrDrawTarget::stencilPath(const GrPipelineBuilder& pipelineBuilder,
                               GrDrawContext* drawContext,
                               const GrClip& clip,
                               const SkMatrix& viewMatrix,
                               const GrPath* path,
                               GrPathRendering::FillType fill) {
    // TODO: extract portions of checkDraw that are relevant to path stenciling.
    SkASSERT(path);
    SkASSERT(this->caps()->shaderCaps()->pathRenderingSupport());

    // Setup clip
    GrAppliedClip appliedClip;
    if (!clip.apply(fContext, pipelineBuilder, drawContext, nullptr, &appliedClip)) {
        return;
    }
    // TODO: respect fClipBatchToBounds if we ever start computing bounds here.

    // Coverage AA does not make sense when rendering to the stencil buffer. The caller should never
    // attempt this in a situation that would require coverage AA.
    SkASSERT(!appliedClip.getClipCoverageFragmentProcessor());

    GrStencilAttachment* stencilAttachment = fResourceProvider->attachStencilAttachment(
                                                drawContext->accessRenderTarget());
    if (!stencilAttachment) {
        SkDebugf("ERROR creating stencil attachment. Draw skipped.\n");
        return;
    }

    GrBatch* batch = GrStencilPathBatch::Create(viewMatrix,
                                                pipelineBuilder.isHWAntialias(),
                                                fill,
                                                appliedClip.hasStencilClip(),
                                                stencilAttachment->bits(),
                                                appliedClip.scissorState(),
                                                drawContext->accessRenderTarget(),
                                                path);
    this->recordBatch(batch);
    batch->unref();
}

void SkInternalAtlasTextTarget::addDrawOp(const GrClip& clip, std::unique_ptr<GrAtlasTextOp> op) {
    SkASSERT(clip.quickContains(SkRect::MakeIWH(fWidth, fHeight)));
    // The SkAtlasTextRenderer currently only handles grayscale SDF glyphs.
    if (op->maskType() != GrAtlasTextOp::kGrayscaleDistanceField_MaskType) {
        return;
    }
    const GrCaps& caps = *this->context()->internal().grContext()->contextPriv().caps();
    op->finalizeForTextTarget(fColor, caps);
    int n = SkTMin(kMaxBatchLookBack, fOps.count());
    for (int i = 0; i < n; ++i) {
        GrAtlasTextOp* other = fOps.fromBack(i).get();
        if (other->combineIfPossible(op.get(), caps) == GrOp::CombineResult::kMerged) {
            fOpMemoryPool->release(std::move(op));
            return;
        }
        if (GrRectsOverlap(op->bounds(), other->bounds())) {
            break;
        }
    }
    op->visitProxies([](GrSurfaceProxy*) {});
    fOps.emplace_back(std::move(op));
}

////////////////////////////////////////////////////////////////////////////////
// sort out what kind of clip mask needs to be created: alpha, stencil,
// scissor, or entirely software
bool GrClipMaskManager::createClipMask(GrGpu* gpu, 
                                       const GrClip& clipIn,
                                       ScissoringSettings* scissorSettings) {

    GrAssert(scissorSettings);

    scissorSettings->fEnableScissoring = false;
    fClipMaskInStencil = false;
    fClipMaskInAlpha = false;

    GrDrawState* drawState = gpu->drawState();
    if (!drawState->isClipState()) {
        return true;
    }

    GrRenderTarget* rt = drawState->getRenderTarget();

    // GrDrawTarget should have filtered this for us
    GrAssert(NULL != rt);

#if GR_SW_CLIP
    if (create_mask_in_sw()) {
        // The clip geometry is complex enough that it will be more
        // efficient to create it entirely in software
        GrTexture* result = NULL;
        GrIRect bound;
        if (this->createSoftwareClipMask(gpu, clipIn, &result, &bound)) {
            fClipMaskInAlpha = true;

            setup_drawstate_aaclip(gpu, result, bound);
            return true;
        }
    }
#endif

#if GR_AA_CLIP
    // If MSAA is enabled use the (faster) stencil path for AA clipping
    // otherwise the alpha clip mask is our only option
    if (clipIn.requiresAA() && 0 == rt->numSamples()) {
        // Since we are going to create a destination texture of the correct
        // size for the mask (rather than being bound by the size of the
        // render target) we aren't going to use scissoring like the stencil
        // path does (see scissorSettings below)
        GrTexture* result = NULL;
        GrIRect bound;
        if (this->createAlphaClipMask(gpu, clipIn, &result, &bound)) {
            fClipMaskInAlpha = true;

            setup_drawstate_aaclip(gpu, result, bound);
            return true;
        }

        // if alpha clip mask creation fails fall through to the stencil
        // buffer method
    }
#endif // GR_AA_CLIP

    GrRect bounds;
    GrRect rtRect;
    rtRect.setLTRB(0, 0,
                    GrIntToScalar(rt->width()), GrIntToScalar(rt->height()));
    if (clipIn.hasConservativeBounds()) {
        bounds = clipIn.getConservativeBounds();
        if (!bounds.intersect(rtRect)) {
            bounds.setEmpty();
        }
    } else {
        bounds = rtRect;
    }

    bounds.roundOut(&scissorSettings->fScissorRect);
    if  (scissorSettings->fScissorRect.isEmpty()) {
        scissorSettings->fScissorRect.setLTRB(0,0,0,0);
        // TODO: I think we can do an early exit here - after refactoring try:
        //  set fEnableScissoring to true but leave fClipMaskInStencil false
        //  and return - everything is going to be scissored away anyway!
    }
    scissorSettings->fEnableScissoring = true;

    // use the stencil clip if we can't represent the clip as a rectangle.
    fClipMaskInStencil = !clipIn.isRect() && !clipIn.isEmpty() &&
                         !bounds.isEmpty();

    if (fClipMaskInStencil) {
        return this->createStencilClipMask(gpu, clipIn, bounds, scissorSettings);
    }

    return true;
}

////////////////////////////////////////////////////////////////////////////////
// Create a 8-bit clip mask in alpha
bool GrClipMaskManager::createAlphaClipMask(GrGpu* gpu,
                                            const GrClip& clipIn,
                                            GrTexture** result,
                                            GrIRect *resultBounds) {

    if (this->clipMaskPreamble(gpu, clipIn, result, resultBounds)) {
        return true;
    }

    GrTexture* accum = fAACache.getLastMask();
    if (NULL == accum) {
        fClipMaskInAlpha = false;
        fAACache.reset();
        return false;
    }

    GrDrawTarget::AutoStateRestore asr(gpu, GrDrawTarget::kReset_ASRInit);
    GrDrawState* drawState = gpu->drawState();

    GrDrawTarget::AutoGeometryPush agp(gpu);

    int count = clipIn.getElementCount();

    if (0 != resultBounds->fTop || 0 != resultBounds->fLeft) {
        // if we were able to trim down the size of the mask we need to 
        // offset the paths & rects that will be used to compute it
        GrMatrix m;

        m.setTranslate(SkIntToScalar(-resultBounds->fLeft), 
                       SkIntToScalar(-resultBounds->fTop));

        drawState->setViewMatrix(m);
    }

    bool clearToInside;
    SkRegion::Op startOp = SkRegion::kReplace_Op; // suppress warning
    int start = process_initial_clip_elements(clipIn,
                                              *resultBounds,
                                              &clearToInside,
                                              &startOp);

    clear(gpu, accum, clearToInside ? 0xffffffff : 0x00000000);

    GrAutoScratchTexture temp;

    // walk through each clip element and perform its set op
    for (int c = start; c < count; ++c) {

        SkRegion::Op op = (c == start) ? startOp : clipIn.getOp(c);

        if (SkRegion::kReplace_Op == op) {
            // TODO: replace is actually a lot faster then intersection
            // for this path - refactor the stencil path so it can handle
            // replace ops and alter GrClip to allow them through

            // clear the accumulator and draw the new object directly into it
            clear(gpu, accum, 0x00000000);

            setup_boolean_blendcoeffs(drawState, op);
            this->drawClipShape(gpu, accum, clipIn, c);

        } else if (SkRegion::kReverseDifference_Op == op ||
                   SkRegion::kIntersect_Op == op) {
            // there is no point in intersecting a screen filling rectangle.
            if (SkRegion::kIntersect_Op == op &&
                kRect_ClipType == clipIn.getElementType(c) &&
                contains(clipIn.getRect(c), *resultBounds)) {
                continue;
            }

            getTemp(*resultBounds, &temp);
            if (NULL == temp.texture()) {
                fClipMaskInAlpha = false;
                fAACache.reset();
                return false;
            }

            // clear the temp target & draw into it
            clear(gpu, temp.texture(), 0x00000000);

            setup_boolean_blendcoeffs(drawState, SkRegion::kReplace_Op);
            this->drawClipShape(gpu, temp.texture(), clipIn, c);

            // TODO: rather than adding these two translations here
            // compute the bounding box needed to render the texture
            // into temp
            if (0 != resultBounds->fTop || 0 != resultBounds->fLeft) {
                GrMatrix m;

                m.setTranslate(SkIntToScalar(resultBounds->fLeft), 
                               SkIntToScalar(resultBounds->fTop));

                drawState->preConcatViewMatrix(m);
            }

            // Now draw into the accumulator using the real operation
            // and the temp buffer as a texture
            setup_boolean_blendcoeffs(drawState, op);
//.........这里部分代码省略.........

static void draw_path_with_mask_filter(GrContext* context,
                                       GrDrawContext* drawContext,
                                       const GrClip& clip,
                                       GrPaint* paint,
                                       const SkMatrix& viewMatrix,
                                       const SkMaskFilter* maskFilter,
                                       const GrStyle& style,
                                       const SkPath* path,
                                       bool pathIsMutable) {
    SkASSERT(maskFilter);

    SkIRect clipBounds;
    clip.getConservativeBounds(drawContext->width(), drawContext->height(), &clipBounds);
    SkTLazy<SkPath> tmpPath;
    SkStrokeRec::InitStyle fillOrHairline;

    // We just fully apply the style here.
    if (style.applies()) {
        if (!style.applyToPath(tmpPath.init(), &fillOrHairline, *path,
                                   GrStyle::MatrixToScaleFactor(viewMatrix))) {
            return;
        }
        pathIsMutable = true;
        path = tmpPath.get();
    } else if (style.isSimpleHairline()) {
        fillOrHairline = SkStrokeRec::kHairline_InitStyle;
    } else {
        SkASSERT(style.isSimpleFill());
        fillOrHairline = SkStrokeRec::kFill_InitStyle;
    }

    // transform the path into device space
    if (!viewMatrix.isIdentity()) {
        SkPath* result;
        if (pathIsMutable) {
            result = const_cast<SkPath*>(path);
        } else {
            if (!tmpPath.isValid()) {
                tmpPath.init();
            }
            result = tmpPath.get();
        }
        path->transform(viewMatrix, result);
        path = result;
        result->setIsVolatile(true);
        pathIsMutable = true;
    }

    SkRect maskRect;
    if (maskFilter->canFilterMaskGPU(SkRRect::MakeRect(path->getBounds()),
                                     clipBounds,
                                     viewMatrix,
                                     &maskRect)) {
        // This mask will ultimately be drawn as a non-AA rect (see draw_mask).
        // Non-AA rects have a bad habit of snapping arbitrarily. Integerize here
        // so the mask draws in a reproducible manner.
        SkIRect finalIRect;
        maskRect.roundOut(&finalIRect);
        if (clip_bounds_quick_reject(clipBounds, finalIRect)) {
            // clipped out
            return;
        }

        if (maskFilter->directFilterMaskGPU(context->textureProvider(),
                                            drawContext,
                                            paint,
                                            clip,
                                            viewMatrix,
                                            SkStrokeRec(fillOrHairline),
                                            *path)) {
            // the mask filter was able to draw itself directly, so there's nothing
            // left to do.
            return;
        }

        sk_sp<GrTexture> mask(create_mask_GPU(context,
                                              finalIRect,
                                              *path,
                                              fillOrHairline,
                                              paint->isAntiAlias(),
                                              drawContext->numColorSamples()));
        if (mask) {
            GrTexture* filtered;

            if (maskFilter->filterMaskGPU(mask.get(), viewMatrix, finalIRect, &filtered, true)) {
                // filterMaskGPU gives us ownership of a ref to the result
                SkAutoTUnref<GrTexture> atu(filtered);
                if (draw_mask(drawContext, clip, viewMatrix, finalIRect, paint, filtered)) {
                    // This path is completely drawn
                    return;
                }
            }
        }
    }

    sw_draw_with_mask_filter(drawContext, context->textureProvider(),
                             clip, viewMatrix, *path,
                             maskFilter, clipBounds, paint, fillOrHairline);
}

void GrDrawTarget::drawBatch(const GrPipelineBuilder& pipelineBuilder,
                             GrDrawContext* drawContext,
                             const GrClip& clip,
                             GrDrawBatch* batch) {
    // Setup clip
    GrAppliedClip appliedClip;
    if (!clip.apply(fContext, pipelineBuilder, drawContext, &batch->bounds(), &appliedClip)) {
        return;
    }

    // TODO: this is the only remaining usage of the AutoRestoreFragmentProcessorState - remove it
    GrPipelineBuilder::AutoRestoreFragmentProcessorState arfps;
    if (appliedClip.getClipCoverageFragmentProcessor()) {
        arfps.set(&pipelineBuilder);
        arfps.addCoverageFragmentProcessor(sk_ref_sp(appliedClip.getClipCoverageFragmentProcessor()));
    }

    GrPipeline::CreateArgs args;
    args.fPipelineBuilder = &pipelineBuilder;
    args.fDrawContext = drawContext;
    args.fCaps = this->caps();
    args.fScissor = &appliedClip.scissorState();
    args.fHasStencilClip = appliedClip.hasStencilClip();
    if (pipelineBuilder.hasUserStencilSettings() || appliedClip.hasStencilClip()) {
        if (!fResourceProvider->attachStencilAttachment(drawContext->accessRenderTarget())) {
            SkDebugf("ERROR creating stencil attachment. Draw skipped.\n");
            return;
        }
    }
    batch->getPipelineOptimizations(&args.fOpts);
    GrScissorState finalScissor;
    if (args.fOpts.fOverrides.fUsePLSDstRead || fClipBatchToBounds) {
        GrGLIRect viewport;
        viewport.fLeft = 0;
        viewport.fBottom = 0;
        viewport.fWidth = drawContext->width();
        viewport.fHeight = drawContext->height();
        SkIRect ibounds;
        ibounds.fLeft = SkTPin(SkScalarFloorToInt(batch->bounds().fLeft), viewport.fLeft,
                              viewport.fWidth);
        ibounds.fTop = SkTPin(SkScalarFloorToInt(batch->bounds().fTop), viewport.fBottom,
                             viewport.fHeight);
        ibounds.fRight = SkTPin(SkScalarCeilToInt(batch->bounds().fRight), viewport.fLeft,
                               viewport.fWidth);
        ibounds.fBottom = SkTPin(SkScalarCeilToInt(batch->bounds().fBottom), viewport.fBottom,
                                viewport.fHeight);
        if (appliedClip.scissorState().enabled()) {
            const SkIRect& scissorRect = appliedClip.scissorState().rect();
            if (!ibounds.intersect(scissorRect)) {
                return;
            }
        }
        finalScissor.set(ibounds);
        args.fScissor = &finalScissor;
    }
    args.fOpts.fColorPOI.completeCalculations(
        sk_sp_address_as_pointer_address(pipelineBuilder.fColorFragmentProcessors.begin()),
        pipelineBuilder.numColorFragmentProcessors());
    args.fOpts.fCoveragePOI.completeCalculations(
        sk_sp_address_as_pointer_address(pipelineBuilder.fCoverageFragmentProcessors.begin()),
        pipelineBuilder.numCoverageFragmentProcessors());
    if (!this->setupDstReadIfNecessary(pipelineBuilder, drawContext->accessRenderTarget(),
                                       clip, args.fOpts,
                                       &args.fDstTexture, batch->bounds())) {
        return;
    }

    if (!batch->installPipeline(args)) {
        return;
    }

#ifdef ENABLE_MDB
    SkASSERT(fRenderTarget);
    batch->pipeline()->addDependenciesTo(fRenderTarget);
#endif

    this->recordBatch(batch);
}

bool GrDrawTarget::setupDstReadIfNecessary(const GrPipelineBuilder& pipelineBuilder,
                                           GrRenderTarget* rt,
                                           const GrClip& clip,
                                           const GrPipelineOptimizations& optimizations,
                                           GrXferProcessor::DstTexture* dstTexture,
                                           const SkRect& batchBounds) {
    SkRect bounds = batchBounds;
    bounds.outset(0.5f, 0.5f);

    if (!pipelineBuilder.willXPNeedDstTexture(*this->caps(), optimizations)) {
        return true;
    }

    if (this->caps()->textureBarrierSupport()) {
        if (GrTexture* rtTex = rt->asTexture()) {
            // The render target is a texture, so we can read from it directly in the shader. The XP
            // will be responsible to detect this situation and request a texture barrier.
            dstTexture->setTexture(rtTex);
            dstTexture->setOffset(0, 0);
            return true;
        }
    }

    SkIRect copyRect;
    clip.getConservativeBounds(rt->width(), rt->height(), &copyRect);

    SkIRect drawIBounds;
    bounds.roundOut(&drawIBounds);
    if (!copyRect.intersect(drawIBounds)) {
#ifdef SK_DEBUG
        GrCapsDebugf(this->caps(), "Missed an early reject. "
                                   "Bailing on draw from setupDstReadIfNecessary.\n");
#endif
        return false;
    }

    // MSAA consideration: When there is support for reading MSAA samples in the shader we could
    // have per-sample dst values by making the copy multisampled.
    GrSurfaceDesc desc;
    if (!fGpu->initCopySurfaceDstDesc(rt, &desc)) {
        desc.fOrigin = kDefault_GrSurfaceOrigin;
        desc.fFlags = kRenderTarget_GrSurfaceFlag;
        desc.fConfig = rt->config();
    }

    desc.fWidth = copyRect.width();
    desc.fHeight = copyRect.height();

    static const uint32_t kFlags = 0;
    SkAutoTUnref<GrTexture> copy(fResourceProvider->createApproxTexture(desc, kFlags));

    if (!copy) {
        SkDebugf("Failed to create temporary copy of destination texture.\n");
        return false;
    }
    SkIPoint dstPoint = {0, 0};
    this->copySurface(copy, rt, copyRect, dstPoint);
    dstTexture->setTexture(copy);
    dstTexture->setOffset(copyRect.fLeft, copyRect.fTop);
    return true;
}

static void draw_path_with_mask_filter(GrContext* context,
                                       GrDrawContext* drawContext,
                                       const GrClip& clip,
                                       GrPaint* paint,
                                       const SkMatrix& viewMatrix,
                                       const SkMaskFilter* maskFilter,
                                       const SkPathEffect* pathEffect,
                                       const GrStrokeInfo& origStrokeInfo,
                                       SkPath* pathPtr,
                                       bool pathIsMutable) {
    SkASSERT(maskFilter);

    SkIRect clipBounds;
    clip.getConservativeBounds(drawContext->width(), drawContext->height(), &clipBounds);
    SkTLazy<SkPath> tmpPath;
    GrStrokeInfo strokeInfo(origStrokeInfo);

    static const SkRect* cullRect = nullptr;  // TODO: what is our bounds?

    SkASSERT(strokeInfo.isDashed() || !pathEffect);

    if (!strokeInfo.isHairlineStyle()) {
        SkPath* strokedPath = pathIsMutable ? pathPtr : tmpPath.init();
        if (strokeInfo.isDashed()) {
            if (pathEffect->filterPath(strokedPath, *pathPtr, &strokeInfo, cullRect)) {
                pathPtr = strokedPath;
                pathPtr->setIsVolatile(true);
                pathIsMutable = true;
            }
            strokeInfo.removeDash();
        }
        if (strokeInfo.applyToPath(strokedPath, *pathPtr)) {
            // Apply the stroke to the path if there is one
            pathPtr = strokedPath;
            pathPtr->setIsVolatile(true);
            pathIsMutable = true;
            strokeInfo.setFillStyle();
        }
    }

    // avoid possibly allocating a new path in transform if we can
    SkPath* devPathPtr = pathIsMutable ? pathPtr : tmpPath.init();
    if (!pathIsMutable) {
        devPathPtr->setIsVolatile(true);
    }

    // transform the path into device space
    pathPtr->transform(viewMatrix, devPathPtr);

    SkRect maskRect;
    if (maskFilter->canFilterMaskGPU(SkRRect::MakeRect(devPathPtr->getBounds()),
                                     clipBounds,
                                     viewMatrix,
                                     &maskRect)) {
        SkIRect finalIRect;
        maskRect.roundOut(&finalIRect);
        if (clip_bounds_quick_reject(clipBounds, finalIRect)) {
            // clipped out
            return;
        }

        if (maskFilter->directFilterMaskGPU(context->textureProvider(),
                                            drawContext,
                                            paint,
                                            clip,
                                            viewMatrix,
                                            strokeInfo,
                                            *devPathPtr)) {
            // the mask filter was able to draw itself directly, so there's nothing
            // left to do.
            return;
        }

        SkAutoTUnref<GrTexture> mask(create_mask_GPU(context,
                                                     &maskRect,
                                                     *devPathPtr,
                                                     strokeInfo,
                                                     paint->isAntiAlias(),
                                                     drawContext->numColorSamples()));
        if (mask) {
            GrTexture* filtered;

            if (maskFilter->filterMaskGPU(mask, viewMatrix, maskRect, &filtered, true)) {
                // filterMaskGPU gives us ownership of a ref to the result
                SkAutoTUnref<GrTexture> atu(filtered);
                if (draw_mask(drawContext, clip, viewMatrix, maskRect, paint, filtered)) {
                    // This path is completely drawn
                    return;
                }
            }
        }
    }

    // draw the mask on the CPU - this is a fallthrough path in case the
    // GPU path fails
    SkPaint::Style style = strokeInfo.isHairlineStyle() ? SkPaint::kStroke_Style :
                                                          SkPaint::kFill_Style;
    sw_draw_with_mask_filter(drawContext, context->textureProvider(),
                             clip, viewMatrix, *devPathPtr,
                             maskFilter, clipBounds, paint, style);
//.........这里部分代码省略.........

void GrTextBlob::flush(GrTextTarget* target, const SkSurfaceProps& props,
                       const GrDistanceFieldAdjustTable* distanceAdjustTable,
                       const SkPaint& paint, GrColor filteredColor, const GrClip& clip,
                       const SkMatrix& viewMatrix, SkScalar x, SkScalar y) {

    // GrTextBlob::makeOp only takes uint16_t values for run and subRun indices.
    // Encountering something larger than this is highly unlikely, so we'll just not draw it.
    int lastRun = SkTMin(fRunCount, (1 << 16)) - 1;
    // For each run in the GrTextBlob we're going to churn through all the glyphs.
    // Each run is broken into a path part and a Mask / DFT / ARGB part.
    for (int runIndex = 0; runIndex <= lastRun; runIndex++) {

        Run& run = fRuns[runIndex];

        // first flush any path glyphs
        if (run.fPathGlyphs.count()) {
            SkPaint runPaint{paint};
            runPaint.setFlags((runPaint.getFlags() & ~Run::kPaintFlagsMask) | run.fPaintFlags);

            for (int i = 0; i < run.fPathGlyphs.count(); i++) {
                GrTextBlob::Run::PathGlyph& pathGlyph = run.fPathGlyphs[i];

                SkMatrix ctm;
                const SkPath* path = &pathGlyph.fPath;

                // TmpPath must be in the same scope as GrShape shape below.
                SkTLazy<SkPath> tmpPath;

                // The glyph positions and glyph outlines are either in device space or in source
                // space based on fPreTransformed.
                if (!pathGlyph.fPreTransformed) {
                    // Positions and outlines are in source space.

                    ctm = viewMatrix;

                    SkMatrix pathMatrix = SkMatrix::MakeScale(pathGlyph.fScale, pathGlyph.fScale);

                    // The origin for the blob may have changed, so figure out the delta.
                    SkVector originShift = SkPoint{x, y} - SkPoint{fInitialX, fInitialY};

                    // Shift the original glyph location in source space to the position of the new
                    // blob.
                    pathMatrix.postTranslate(originShift.x() + pathGlyph.fX,
                                             originShift.y() + pathGlyph.fY);

                    // If there are shaders, blurs or styles, the path must be scaled into source
                    // space independently of the CTM. This allows the CTM to be correct for the
                    // different effects.
                    GrStyle style(runPaint);
                    bool scalePath = runPaint.getShader()
                                     || style.applies()
                                     || runPaint.getMaskFilter();
                    if (!scalePath) {
                        // Scale can be applied to CTM -- no effects.

                        ctm.preConcat(pathMatrix);
                    } else {
                        // Scale the outline into source space.

                        // Transform the path form the normalized outline to source space. This
                        // way the CTM will remain the same so it can be used by the effects.
                        SkPath* sourceOutline = tmpPath.init();
                        path->transform(pathMatrix, sourceOutline);
                        sourceOutline->setIsVolatile(true);
                        path = sourceOutline;
                    }


                } else {
                    // Positions and outlines are in device space.

                    SkPoint originalOrigin = {fInitialX, fInitialY};
                    fInitialViewMatrix.mapPoints(&originalOrigin, 1);

                    SkPoint newOrigin = {x, y};
                    viewMatrix.mapPoints(&newOrigin, 1);

                    // The origin shift in device space.
                    SkPoint originShift = newOrigin - originalOrigin;

                    // Shift the original glyph location in device space to the position of the
                    // new blob.
                    ctm = SkMatrix::MakeTrans(originShift.x() + pathGlyph.fX,
                                              originShift.y() + pathGlyph.fY);
                }

                // TODO: we are losing the mutability of the path here
                GrShape shape(*path, paint);

                target->drawShape(clip, runPaint, ctm, shape);
            }
        }

        // then flush each subrun, if any
        if (!run.fInitialized) {
            continue;
        }

        int lastSubRun = SkTMin(run.fSubRunInfo.count(), 1 << 16) - 1;
        for (int subRun = 0; subRun <= lastSubRun; subRun++) {
//.........这里部分代码省略.........

/*
 * This method traverses the clip stack to see if the GrSoftwarePathRenderer
 * will be used on any element. If so, it returns true to indicate that the
 * entire clip should be rendered in SW and then uploaded en masse to the gpu.
 */
bool GrClipMaskManager::useSWOnlyPath(GrGpu* gpu, const GrClip& clipIn) {

    if (!clipIn.requiresAA()) {
        // The stencil buffer can handle this case
        return false;
    }

    // TODO: generalize this test so that when
    // a clip gets complex enough it can just be done in SW regardless
    // of whether it would invoke the GrSoftwarePathRenderer.
    bool useSW = false;

    for (int i = 0; i < clipIn.getElementCount(); ++i) {

        if (SkRegion::kReplace_Op == clipIn.getOp(i)) {
            // Everything before a replace op can be ignored so start
            // afresh w.r.t. determining if any element uses the SW path
            useSW = false;
        }

        if (!clipIn.getDoAA(i)) {
            // non-anti-aliased rects and paths can always be drawn either
            // directly or by the GrDefaultPathRenderer
            continue;
        }

        if (kRect_ClipType == clipIn.getElementType(i)) {
            // Antialiased rects are converted to paths and then drawn with
            // kEvenOdd_PathFill. 
            if (!GrAAConvexPathRenderer::staticCanDrawPath(
                                                    true,     // always convex
                                                    kEvenOdd_PathFill,
                                                    gpu, 
                                                    true)) {  // anti-aliased
                // if the GrAAConvexPathRenderer can't render this rect (due
                // to lack of derivative support in the shaders) then 
                // the GrSoftwarePathRenderer will be used
                useSW = true;
            }

            continue;
        }

        // only paths need to be considered in the rest of the loop body

        if (GrAAHairLinePathRenderer::staticCanDrawPath(clipIn.getPath(i),
                                                        clipIn.getPathFill(i),
                                                        gpu,
                                                        clipIn.getDoAA(i))) {
            // the hair line path renderer can handle this one
            continue;
        }

        if (GrAAConvexPathRenderer::staticCanDrawPath(
                                                clipIn.getPath(i).isConvex(),
                                                clipIn.getPathFill(i),
                                                gpu,
                                                clipIn.getDoAA(i))) {
            // the convex path renderer can handle this one
            continue;
        }

        // otherwise the GrSoftwarePathRenderer is going to be invoked
        useSW = true;
    }

    return useSW;
}

////////////////////////////////////////////////////////////////////////////////
// sort out what kind of clip mask needs to be created: alpha, stencil,
// scissor, or entirely software
bool GrClipMaskManager::createClipMask(GrGpu* gpu, 
                                       const GrClip& clipIn,
                                       ScissoringSettings* scissorSettings) {

    GrAssert(scissorSettings);

    scissorSettings->fEnableScissoring = false;
    fClipMaskInStencil = false;
    fClipMaskInAlpha = false;

    GrDrawState* drawState = gpu->drawState();
    if (!drawState->isClipState()) {
        return true;
    }

    GrRenderTarget* rt = drawState->getRenderTarget();

    // GrDrawTarget should have filtered this for us
    GrAssert(NULL != rt);

#if GR_SW_CLIP
    // If MSAA is enabled we can do everything in the stencil buffer.
    // Otherwise check if we should just create the entire clip mask 
    // in software (this will only happen if the clip mask is anti-aliased
    // and too complex for the gpu to handle in its entirety)
    if (0 == rt->numSamples() && useSWOnlyPath(gpu, clipIn)) {
        // The clip geometry is complex enough that it will be more
        // efficient to create it entirely in software
        GrTexture* result = NULL;
        GrIRect bound;
        if (this->createSoftwareClipMask(gpu, clipIn, &result, &bound)) {
            fClipMaskInAlpha = true;

            setup_drawstate_aaclip(gpu, result, bound);
            return true;
        }

        // if SW clip mask creation fails fall through to the other
        // two possible methods (bottoming out at stencil clipping)
    }
#endif // GR_SW_CLIP

#if GR_AA_CLIP
    // If MSAA is enabled use the (faster) stencil path for AA clipping
    // otherwise the alpha clip mask is our only option
    if (0 == rt->numSamples() && clipIn.requiresAA()) {
        // Since we are going to create a destination texture of the correct
        // size for the mask (rather than being bound by the size of the
        // render target) we aren't going to use scissoring like the stencil
        // path does (see scissorSettings below)
        GrTexture* result = NULL;
        GrIRect bound;
        if (this->createAlphaClipMask(gpu, clipIn, &result, &bound)) {
            fClipMaskInAlpha = true;

            setup_drawstate_aaclip(gpu, result, bound);
            return true;
        }

        // if alpha clip mask creation fails fall through to the stencil
        // buffer method
    }
#endif // GR_AA_CLIP

    // Either a hard (stencil buffer) clip was explicitly requested or 
    // an antialiased clip couldn't be created. In either case, free up
    // the texture in the antialiased mask cache.
    // TODO: this may require more investigation. Ganesh performs a lot of
    // utility draws (e.g., clears, InOrderDrawBuffer playbacks) that hit
    // the stencil buffer path. These may be "incorrectly" clearing the 
    // AA cache.
    fAACache.reset();

    GrRect bounds;
    GrRect rtRect;
    rtRect.setLTRB(0, 0,
                   GrIntToScalar(rt->width()), GrIntToScalar(rt->height()));
    if (clipIn.hasConservativeBounds()) {
        bounds = clipIn.getConservativeBounds();
        if (!bounds.intersect(rtRect)) {
            bounds.setEmpty();
        }
    } else {
        bounds = rtRect;
    }

    bounds.roundOut(&scissorSettings->fScissorRect);
    if  (scissorSettings->fScissorRect.isEmpty()) {
        scissorSettings->fScissorRect.setLTRB(0,0,0,0);
        // TODO: I think we can do an early exit here - after refactoring try:
        //  set fEnableScissoring to true but leave fClipMaskInStencil false
        //  and return - everything is going to be scissored away anyway!
    }
    scissorSettings->fEnableScissoring = true;

    // use the stencil clip if we can't represent the clip as a rectangle.
    fClipMaskInStencil = !clipIn.isRect() && !clipIn.isEmpty() &&
//.........这里部分代码省略.........