C++ GrStrokeInfo类代码示例

// Returns whether or not the gpu can fast path the dash line effect.
static bool can_fast_path_dash(const SkPoint pts[2], const GrStrokeInfo& strokeInfo,
                               const GrDrawTarget& target, const SkMatrix& viewMatrix) {
    if (target.getDrawState().getRenderTarget()->isMultisampled()) {
        return false;
    }

    // Pts must be either horizontal or vertical in src space
    if (pts[0].fX != pts[1].fX && pts[0].fY != pts[1].fY) {
        return false;
    }

    // May be able to relax this to include skew. As of now cannot do perspective
    // because of the non uniform scaling of bloating a rect
    if (!viewMatrix.preservesRightAngles()) {
        return false;
    }

    if (!strokeInfo.isDashed() || 2 != strokeInfo.dashCount()) {
        return false;
    }

    const SkPathEffect::DashInfo& info = strokeInfo.getDashInfo();
    if (0 == info.fIntervals[0] && 0 == info.fIntervals[1]) {
        return false;
    }

    SkPaint::Cap cap = strokeInfo.getStrokeRec().getCap();
    // Current we do don't handle Round or Square cap dashes
    if (SkPaint::kRound_Cap == cap && info.fIntervals[0] != 0.f) {
        return false;
    }

    return true;
}

 TessellatingPathBatch(const GrColor& color,
                       const SkPath& path,
                       const GrStrokeInfo& stroke,
                       const SkMatrix& viewMatrix,
                       const SkRect& clipBounds)
   : INHERITED(ClassID())
   , fColor(color)
   , fPath(path)
   , fStroke(stroke)
   , fViewMatrix(viewMatrix) {
     const SkRect& pathBounds = path.getBounds();
     fClipBounds = clipBounds;
     // Because the clip bounds are used to add a contour for inverse fills, they must also
     // include the path bounds.
     fClipBounds.join(pathBounds);
     if (path.isInverseFillType()) {
         fBounds = fClipBounds;
     } else {
         fBounds = path.getBounds();
     }
     if (!stroke.isFillStyle()) {
         SkScalar radius = SkScalarHalf(stroke.getWidth());
         if (stroke.getJoin() == SkPaint::kMiter_Join) {
             SkScalar scale = stroke.getMiter();
             if (scale > SK_Scalar1) {
                 radius = SkScalarMul(radius, scale);
             }
         }
         fBounds.outset(radius, radius);
     }
     viewMatrix.mapRect(&fBounds);
 }

bool GrStencilAndCoverPathRenderer::canDrawPath(const GrDrawTarget* target,
                                                const GrPipelineBuilder* pipelineBuilder,
                                                const SkMatrix& viewMatrix,
                                                const SkPath& path,
                                                const GrStrokeInfo& stroke,
                                                bool antiAlias) const {
    return !stroke.getStrokeRec().isHairlineStyle() &&
        !stroke.isDashed() &&
        !antiAlias && // doesn't do per-path AA, relies on the target having MSAA
        pipelineBuilder->getStencil().isDisabled();
}

bool GrAADistanceFieldPathRenderer::canDrawPath(const GrDrawTarget* target,
                                                const GrPipelineBuilder* pipelineBuilder,
                                                const SkMatrix& viewMatrix,
                                                const SkPath& path,
                                                const GrStrokeInfo& stroke,
                                                bool antiAlias) const {
    
    // TODO: Support inverse fill
    // TODO: Support strokes
    if (!target->caps()->shaderCaps()->shaderDerivativeSupport() || !antiAlias 
        || path.isInverseFillType() || path.isVolatile() || !stroke.isFillStyle()) {
        return false;
    }

    // currently don't support perspective
    if (viewMatrix.hasPerspective()) {
        return false;
    }
    
    // only support paths smaller than 64x64, scaled to less than 256x256
    // the goal is to accelerate rendering of lots of small paths that may be scaling
    SkScalar maxScale = viewMatrix.getMaxScale();
    const SkRect& bounds = path.getBounds();
    SkScalar maxDim = SkMaxScalar(bounds.width(), bounds.height());
    return maxDim < 64.f && maxDim * maxScale < 256.f;
}

bool GrAAConvexPathRenderer::canDrawPath(const GrDrawTarget* target,
                                         const GrPipelineBuilder*,
                                         const SkMatrix& viewMatrix,
                                         const SkPath& path,
                                         const GrStrokeInfo& stroke,
                                         bool antiAlias) const {
    return (target->caps()->shaderCaps()->shaderDerivativeSupport() && antiAlias &&
            stroke.isFillStyle() && !path.isInverseFillType() && path.isConvex());
}

void GrStencilAndCoverPathRenderer::onStencilPath(GrDrawTarget* target,
                                                  GrPipelineBuilder* pipelineBuilder,
                                                  const SkMatrix& viewMatrix,
                                                  const SkPath& path,
                                                  const GrStrokeInfo& stroke) {
    SkASSERT(!path.isInverseFillType());
    SkAutoTUnref<GrPathProcessor> pp(GrPathProcessor::Create(GrColor_WHITE, viewMatrix));
    SkAutoTUnref<GrPath> p(get_gr_path(fGpu, path, stroke.getStrokeRec()));
    target->stencilPath(pipelineBuilder, pp, p, convert_skpath_filltype(path.getFillType()));
}

bool GrDefaultPathRenderer::canDrawPath(const GrDrawTarget* target,
                                        const GrPipelineBuilder* pipelineBuilder,
                                        const SkMatrix& viewMatrix,
                                        const SkPath& path,
                                        const GrStrokeInfo& stroke,
                                        bool antiAlias) const {
    // this class can draw any path with any fill but doesn't do any anti-aliasing.
    return !antiAlias && (stroke.isFillStyle() || IsStrokeHairlineOrEquivalent(stroke,
                                                                               viewMatrix,
                                                                               NULL));
}

GrPathRenderer::StencilSupport
GrDefaultPathRenderer::onGetStencilSupport(const GrDrawTarget*,
                                           const GrPipelineBuilder*,
                                           const SkPath& path,
                                           const GrStrokeInfo& stroke) const {
    if (single_pass_path(path, stroke.getStrokeRec())) {
        return GrPathRenderer::kNoRestriction_StencilSupport;
    } else {
        return GrPathRenderer::kStencilOnly_StencilSupport;
    }
}

bool GrAALinearizingConvexPathRenderer::onDrawPath(GrDrawTarget* target,
                                                   GrPipelineBuilder* pipelineBuilder,
                                                   GrColor color,
                                                   const SkMatrix& vm,
                                                   const SkPath& path,
                                                   const GrStrokeInfo& stroke,
                                                   bool antiAlias) {
    if (path.isEmpty()) {
        return true;
    }
    AAFlatteningConvexPathBatch::Geometry geometry;
    geometry.fColor = color;
    geometry.fViewMatrix = vm;
    geometry.fPath = path;
    geometry.fStrokeWidth = stroke.isFillStyle() ? -1.0f : stroke.getWidth();
    geometry.fJoin = stroke.isFillStyle() ? SkPaint::Join::kMiter_Join : stroke.getJoin();
    geometry.fMiterLimit = stroke.getMiter();

    SkAutoTUnref<GrBatch> batch(AAFlatteningConvexPathBatch::Create(geometry));
    target->drawBatch(pipelineBuilder, batch);

    return true;
}

bool GrSoftwarePathRenderer::canDrawPath(const GrDrawTarget*,
                                         const GrPipelineBuilder*,
                                         const SkMatrix& viewMatrix,
                                         const SkPath&,
                                         const GrStrokeInfo& stroke,
                                         bool antiAlias) const {
    if (NULL == fContext) {
        return false;
    }
    if (stroke.isDashed()) {
        return false;
    }
    return true;
}

void GrGLPath::InitPathObjectStroke(GrGLGpu* gpu, GrGLuint pathID, const GrStrokeInfo& stroke) {
    SkASSERT(stroke.needToApply());
    SkASSERT(!stroke.isDashed());
    SkASSERT(!stroke.isHairlineStyle());
    GR_GL_CALL(gpu->glInterface(),
               PathParameterf(pathID, GR_GL_PATH_STROKE_WIDTH, SkScalarToFloat(stroke.getWidth())));
    GR_GL_CALL(gpu->glInterface(),
               PathParameterf(pathID, GR_GL_PATH_MITER_LIMIT, SkScalarToFloat(stroke.getMiter())));
    GrGLenum join = join_to_gl_join(stroke.getJoin());
    GR_GL_CALL(gpu->glInterface(), PathParameteri(pathID, GR_GL_PATH_JOIN_STYLE, join));
    GrGLenum cap = cap_to_gl_cap(stroke.getCap());
    GR_GL_CALL(gpu->glInterface(), PathParameteri(pathID, GR_GL_PATH_END_CAPS, cap));
    GR_GL_CALL(gpu->glInterface(), PathParameterf(pathID, GR_GL_PATH_STROKE_BOUND, 0.02f));
}

bool GrAALinearizingConvexPathRenderer::canDrawPath(const GrDrawTarget* target,
                                                    const GrPipelineBuilder*,
                                                    const SkMatrix& viewMatrix,
                                                    const SkPath& path,
                                                    const GrStrokeInfo& stroke,
                                                    bool antiAlias) const {
    if (!antiAlias) {
        return false;
    }
    if (path.isInverseFillType()) {
        return false;
    }
    if (!path.isConvex()) {
        return false;
    }
    if (stroke.getStyle() == SkStrokeRec::kStroke_Style) {
        return viewMatrix.isSimilarity() && stroke.getWidth() >= 1.0f && 
                stroke.getWidth() <= kMaxStrokeWidth && !stroke.isDashed() && 
                SkPathPriv::LastVerbIsClose(path) && stroke.getJoin() != SkPaint::Join::kRound_Join;
    }
    return stroke.getStyle() == SkStrokeRec::kFill_Style;
}

bool GrStencilAndCoverPathRenderer::onDrawPath(GrDrawTarget* target,
                                               GrPipelineBuilder* pipelineBuilder,
                                               GrColor color,
                                               const SkMatrix& viewMatrix,
                                               const SkPath& path,
                                               const GrStrokeInfo& stroke,
                                               bool antiAlias) {
    SkASSERT(!antiAlias);
    SkASSERT(!stroke.getStrokeRec().isHairlineStyle());
    SkASSERT(!stroke.isDashed());
    SkASSERT(pipelineBuilder->getStencil().isDisabled());

    SkAutoTUnref<GrPath> p(get_gr_path(fGpu, path, stroke.getStrokeRec()));

    if (path.isInverseFillType()) {
        GR_STATIC_CONST_SAME_STENCIL(kInvertedStencilPass,
            kZero_StencilOp,
            kZero_StencilOp,
            // We know our rect will hit pixels outside the clip and the user bits will be 0
            // outside the clip. So we can't just fill where the user bits are 0. We also need to
            // check that the clip bit is set.
            kEqualIfInClip_StencilFunc,
            0xffff,
            0x0000,
            0xffff);

        pipelineBuilder->setStencil(kInvertedStencilPass);

        // fake inverse with a stencil and cover
        SkAutoTUnref<GrPathProcessor> pp(GrPathProcessor::Create(GrColor_WHITE, viewMatrix));
        target->stencilPath(pipelineBuilder, pp, p, convert_skpath_filltype(path.getFillType()));

        SkMatrix invert = SkMatrix::I();
        SkRect bounds =
            SkRect::MakeLTRB(0, 0, SkIntToScalar(pipelineBuilder->getRenderTarget()->width()),
                             SkIntToScalar(pipelineBuilder->getRenderTarget()->height()));
        SkMatrix vmi;
        // mapRect through persp matrix may not be correct
        if (!viewMatrix.hasPerspective() && viewMatrix.invert(&vmi)) {
            vmi.mapRect(&bounds);
            // theoretically could set bloat = 0, instead leave it because of matrix inversion
            // precision.
            SkScalar bloat = viewMatrix.getMaxScale() * SK_ScalarHalf;
            bounds.outset(bloat, bloat);
        } else {
            if (!viewMatrix.invert(&invert)) {
                return false;
            }
        }
        const SkMatrix& viewM = viewMatrix.hasPerspective() ? SkMatrix::I() : viewMatrix;
        target->drawRect(pipelineBuilder, color, viewM, bounds, NULL, &invert);
    } else {
        GR_STATIC_CONST_SAME_STENCIL(kStencilPass,
            kZero_StencilOp,
            kZero_StencilOp,
            kNotEqual_StencilFunc,
            0xffff,
            0x0000,
            0xffff);

        pipelineBuilder->setStencil(kStencilPass);
        SkAutoTUnref<GrPathProcessor> pp(GrPathProcessor::Create(color, viewMatrix));
        target->drawPath(pipelineBuilder, pp, p, convert_skpath_filltype(path.getFillType()));
    }

    pipelineBuilder->stencil()->setDisabled();
    return true;
}

bool GrDashingEffect::DrawDashLine(const SkPoint pts[2], const GrPaint& paint,
                                   const GrStrokeInfo& strokeInfo, GrGpu* gpu,
                                   GrDrawTarget* target, const SkMatrix& vm) {

    if (!can_fast_path_dash(pts, strokeInfo, *target, vm)) {
        return false;
    }

    const SkPathEffect::DashInfo& info = strokeInfo.getDashInfo();

    SkPaint::Cap cap = strokeInfo.getStrokeRec().getCap();

    SkScalar srcStrokeWidth = strokeInfo.getStrokeRec().getWidth();

    // the phase should be normalized to be [0, sum of all intervals)
    SkASSERT(info.fPhase >= 0 && info.fPhase < info.fIntervals[0] + info.fIntervals[1]);

    SkScalar srcPhase = info.fPhase;

    // Rotate the src pts so they are aligned horizontally with pts[0].fX < pts[1].fX
    SkMatrix srcRotInv;
    SkPoint ptsRot[2];
    if (pts[0].fY != pts[1].fY || pts[0].fX > pts[1].fX) {
        SkMatrix rotMatrix;
        align_to_x_axis(pts, &rotMatrix, ptsRot);
        if(!rotMatrix.invert(&srcRotInv)) {
            GrPrintf("Failed to create invertible rotation matrix!\n");
            return false;
        }
    } else {
        srcRotInv.reset();
        memcpy(ptsRot, pts, 2 * sizeof(SkPoint));
    }

    bool useAA = paint.isAntiAlias();

    // Scale corrections of intervals and stroke from view matrix
    SkScalar parallelScale;
    SkScalar perpScale;
    calc_dash_scaling(&parallelScale, &perpScale, vm, ptsRot);

    bool hasCap = SkPaint::kButt_Cap != cap && 0 != srcStrokeWidth;

    // We always want to at least stroke out half a pixel on each side in device space
    // so 0.5f / perpScale gives us this min in src space
    SkScalar halfSrcStroke = SkMaxScalar(srcStrokeWidth * 0.5f, 0.5f / perpScale);

    SkScalar strokeAdj;
    if (!hasCap) {
        strokeAdj = 0.f;
    } else {
        strokeAdj = halfSrcStroke;
    }

    SkScalar startAdj = 0;

    SkMatrix combinedMatrix = srcRotInv;
    combinedMatrix.postConcat(vm);

    bool lineDone = false;
    SkRect startRect;
    bool hasStartRect = false;
    // If we are using AA, check to see if we are drawing a partial dash at the start. If so
    // draw it separately here and adjust our start point accordingly
    if (useAA) {
        if (srcPhase > 0 && srcPhase < info.fIntervals[0]) {
            SkPoint startPts[2];
            startPts[0] = ptsRot[0];
            startPts[1].fY = startPts[0].fY;
            startPts[1].fX = SkMinScalar(startPts[0].fX + info.fIntervals[0] - srcPhase,
                                         ptsRot[1].fX);
            startRect.set(startPts, 2);
            startRect.outset(strokeAdj, halfSrcStroke);

            hasStartRect = true;
            startAdj = info.fIntervals[0] + info.fIntervals[1] - srcPhase;
        }
    }

    // adjustments for start and end of bounding rect so we only draw dash intervals
    // contained in the original line segment.
    startAdj += calc_start_adjustment(info);
    if (startAdj != 0) {
        ptsRot[0].fX += startAdj;
        srcPhase = 0;
    }
    SkScalar endingInterval = 0;
    SkScalar endAdj = calc_end_adjustment(info, ptsRot, srcPhase, &endingInterval);
    ptsRot[1].fX -= endAdj;
    if (ptsRot[0].fX >= ptsRot[1].fX) {
        lineDone = true;
    }

    SkRect endRect;
    bool hasEndRect = false;
    // If we are using AA, check to see if we are drawing a partial dash at then end. If so
    // draw it separately here and adjust our end point accordingly
    if (useAA && !lineDone) {
        // If we adjusted the end then we will not be drawing a partial dash at the end.
        // If we didn't adjust the end point then we just need to make sure the ending
//.........这里部分代码省略.........

void GrGLPath::InitPathObject(GrGLGpu* gpu,
                              GrGLuint pathID,
                              const SkPath& skPath,
                              const GrStrokeInfo& stroke) {
    SkASSERT(!stroke.isDashed());
    if (!skPath.isEmpty()) {
        int verbCnt = skPath.countVerbs();
        int pointCnt = skPath.countPoints();
        int minCoordCnt = pointCnt * 2;

        SkSTArray<16, GrGLubyte, true> pathCommands(verbCnt);
        SkSTArray<16, GrGLfloat, true> pathCoords(minCoordCnt);

        SkDEBUGCODE(int numCoords = 0);

        if ((skPath.getSegmentMasks() & SkPath::kConic_SegmentMask) == 0) {
            // This branch does type punning, converting SkPoint* to GrGLfloat*.
            SK_COMPILE_ASSERT(sizeof(SkPoint) == sizeof(GrGLfloat) * 2, sk_point_not_two_floats);
            // This branch does not convert with SkScalarToFloat.
#ifndef SK_SCALAR_IS_FLOAT
#error Need SK_SCALAR_IS_FLOAT.
#endif
            pathCommands.resize_back(verbCnt);
            pathCoords.resize_back(minCoordCnt);
            skPath.getPoints(reinterpret_cast<SkPoint*>(&pathCoords[0]), pointCnt);
            skPath.getVerbs(&pathCommands[0], verbCnt);
            for (int i = 0; i < verbCnt; ++i) {
                SkPath::Verb v = static_cast<SkPath::Verb>(pathCommands[i]);
                pathCommands[i] = verb_to_gl_path_cmd(v);
                SkDEBUGCODE(numCoords += num_coords(v));
            }
        } else {
            SkPoint points[4];
            SkPath::RawIter iter(skPath);
            SkPath::Verb verb;
            while ((verb = iter.next(points)) != SkPath::kDone_Verb) {
                pathCommands.push_back(verb_to_gl_path_cmd(verb));
                GrGLfloat coords[6];
                int coordsForVerb;
                switch (verb) {
                    case SkPath::kMove_Verb:
                        points_to_coords(points, 0, 1, coords);
                        coordsForVerb = 2;
                        break;
                    case SkPath::kLine_Verb:
                        points_to_coords(points, 1, 1, coords);
                        coordsForVerb = 2;
                        break;
                    case SkPath::kConic_Verb:
                        points_to_coords(points, 1, 2, coords);
                        coords[4] = SkScalarToFloat(iter.conicWeight());
                        coordsForVerb = 5;
                        break;
                    case SkPath::kQuad_Verb:
                        points_to_coords(points, 1, 2, coords);
                        coordsForVerb = 4;
                        break;
                    case SkPath::kCubic_Verb:
                        points_to_coords(points, 1, 3, coords);
                        coordsForVerb = 6;
                        break;
                    case SkPath::kClose_Verb:
                        continue;
                    default:
                        SkASSERT(false);  // Not reached.
                        continue;
                }
                SkDEBUGCODE(numCoords += num_coords(verb));
                pathCoords.push_back_n(coordsForVerb, coords);
            }
        }

        SkASSERT(verbCnt == pathCommands.count());
        SkASSERT(numCoords == pathCoords.count());

        GR_GL_CALL(gpu->glInterface(), PathCommands(pathID, pathCommands.count(), &pathCommands[0],
                   pathCoords.count(), GR_GL_FLOAT, &pathCoords[0]));
    } else {
        GR_GL_CALL(gpu->glInterface(), PathCommands(pathID, 0, NULL, 0, GR_GL_FLOAT, NULL));
    }

    if (stroke.needToApply()) {
        SkASSERT(!stroke.isHairlineStyle());
        GR_GL_CALL(gpu->glInterface(),
            PathParameterf(pathID, GR_GL_PATH_STROKE_WIDTH, SkScalarToFloat(stroke.getWidth())));
        GR_GL_CALL(gpu->glInterface(),
            PathParameterf(pathID, GR_GL_PATH_MITER_LIMIT, SkScalarToFloat(stroke.getMiter())));
        GrGLenum join = join_to_gl_join(stroke.getJoin());
        GR_GL_CALL(gpu->glInterface(), PathParameteri(pathID, GR_GL_PATH_JOIN_STYLE, join));
        GrGLenum cap = cap_to_gl_cap(stroke.getCap());
        GR_GL_CALL(gpu->glInterface(), PathParameteri(pathID, GR_GL_PATH_END_CAPS, cap));
        GR_GL_CALL(gpu->glInterface(), PathParameterf(pathID, GR_GL_PATH_STROKE_BOUND, 0.02f));
    }
}