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      1 
      2 /*
      3  * Copyright 2012 Google Inc.
      4  *
      5  * Use of this source code is governed by a BSD-style license that can be
      6  * found in the LICENSE file.
      7  */
      8 
      9 
     10 #include "GrStencilAndCoverPathRenderer.h"
     11 #include "GrContext.h"
     12 #include "GrDrawTargetCaps.h"
     13 #include "GrGpu.h"
     14 #include "GrPath.h"
     15 #include "SkStrokeRec.h"
     16 
     17 GrPathRenderer* GrStencilAndCoverPathRenderer::Create(GrContext* context) {
     18     SkASSERT(context);
     19     SkASSERT(context->getGpu());
     20     if (context->getGpu()->caps()->pathRenderingSupport()) {
     21         return SkNEW_ARGS(GrStencilAndCoverPathRenderer, (context->getGpu()));
     22     } else {
     23         return NULL;
     24     }
     25 }
     26 
     27 GrStencilAndCoverPathRenderer::GrStencilAndCoverPathRenderer(GrGpu* gpu) {
     28     SkASSERT(gpu->caps()->pathRenderingSupport());
     29     fGpu = gpu;
     30     gpu->ref();
     31 }
     32 
     33 GrStencilAndCoverPathRenderer::~GrStencilAndCoverPathRenderer() {
     34     fGpu->unref();
     35 }
     36 
     37 bool GrStencilAndCoverPathRenderer::canDrawPath(const SkPath& path,
     38                                                 const SkStrokeRec& stroke,
     39                                                 const GrDrawTarget* target,
     40                                                 bool antiAlias) const {
     41     return !stroke.isHairlineStyle() &&
     42            !antiAlias && // doesn't do per-path AA, relies on the target having MSAA
     43            target->getDrawState().getRenderTarget()->getStencilBuffer() &&
     44            target->getDrawState().getStencil().isDisabled();
     45 }
     46 
     47 GrPathRenderer::StencilSupport GrStencilAndCoverPathRenderer::onGetStencilSupport(
     48                                                         const SkPath&,
     49                                                         const SkStrokeRec& ,
     50                                                         const GrDrawTarget*) const {
     51     return GrPathRenderer::kStencilOnly_StencilSupport;
     52 }
     53 
     54 static GrPath* get_gr_path(GrGpu* gpu, const SkPath& skPath, const SkStrokeRec& stroke) {
     55     GrContext* ctx = gpu->getContext();
     56     GrResourceKey resourceKey = GrPath::ComputeKey(skPath, stroke);
     57     SkAutoTUnref<GrPath> path(static_cast<GrPath*>(ctx->findAndRefCachedResource(resourceKey)));
     58     if (NULL == path || !path->isEqualTo(skPath, stroke)) {
     59         path.reset(gpu->pathRendering()->createPath(skPath, stroke));
     60         ctx->addResourceToCache(resourceKey, path);
     61     }
     62     return path.detach();
     63 }
     64 
     65 void GrStencilAndCoverPathRenderer::onStencilPath(const SkPath& path,
     66                                                   const SkStrokeRec& stroke,
     67                                                   GrDrawTarget* target) {
     68     SkASSERT(!path.isInverseFillType());
     69     SkAutoTUnref<GrPath> p(get_gr_path(fGpu, path, stroke));
     70     target->stencilPath(p, path.getFillType());
     71 }
     72 
     73 bool GrStencilAndCoverPathRenderer::onDrawPath(const SkPath& path,
     74                                                const SkStrokeRec& stroke,
     75                                                GrDrawTarget* target,
     76                                                bool antiAlias) {
     77     SkASSERT(!antiAlias);
     78     SkASSERT(!stroke.isHairlineStyle());
     79 
     80     GrDrawState* drawState = target->drawState();
     81     SkASSERT(drawState->getStencil().isDisabled());
     82 
     83     SkAutoTUnref<GrPath> p(get_gr_path(fGpu, path, stroke));
     84 
     85     if (path.isInverseFillType()) {
     86         GR_STATIC_CONST_SAME_STENCIL(kInvertedStencilPass,
     87             kZero_StencilOp,
     88             kZero_StencilOp,
     89             // We know our rect will hit pixels outside the clip and the user bits will be 0
     90             // outside the clip. So we can't just fill where the user bits are 0. We also need to
     91             // check that the clip bit is set.
     92             kEqualIfInClip_StencilFunc,
     93             0xffff,
     94             0x0000,
     95             0xffff);
     96 
     97         *drawState->stencil() = kInvertedStencilPass;
     98     } else {
     99         GR_STATIC_CONST_SAME_STENCIL(kStencilPass,
    100             kZero_StencilOp,
    101             kZero_StencilOp,
    102             kNotEqual_StencilFunc,
    103             0xffff,
    104             0x0000,
    105             0xffff);
    106 
    107         *drawState->stencil() = kStencilPass;
    108     }
    109 
    110     target->drawPath(p, path.getFillType());
    111 
    112     target->drawState()->stencil()->setDisabled();
    113     return true;
    114 }
    115