C++ SkStrokeRec::getMiter方法代码示例

uint64_t GrPath::ComputeStrokeKey(const SkStrokeRec& stroke) {
    enum {
        kStyleBits = 2,
        kJoinBits = 2,
        kCapBits = 2,
        kWidthBits = 29,
        kMiterBits = 29,

        kJoinShift = kStyleBits,
        kCapShift = kJoinShift + kJoinBits,
        kWidthShift = kCapShift + kCapBits,
        kMiterShift = kWidthShift + kWidthBits,

        kBitCount = kMiterShift + kMiterBits
    };

    SK_COMPILE_ASSERT(SkStrokeRec::kStyleCount <= (1 << kStyleBits), style_shift_will_be_wrong);
    SK_COMPILE_ASSERT(SkPaint::kJoinCount <= (1 << kJoinBits), cap_shift_will_be_wrong);
    SK_COMPILE_ASSERT(SkPaint::kCapCount <= (1 << kCapBits), miter_shift_will_be_wrong);
    SK_COMPILE_ASSERT(kBitCount == 64, wrong_stroke_key_size);

    if (!stroke.needToApply()) {
        return SkStrokeRec::kFill_Style;
    }

    uint64_t key = stroke.getStyle();
    key |= stroke.getJoin() << kJoinShift;
    key |= stroke.getCap() << kCapShift;
    key |= get_top_n_float_bits<kWidthBits>(stroke.getWidth()) << kWidthShift;
    key |= get_top_n_float_bits<kMiterBits>(stroke.getMiter()) << kMiterShift;

    return key;
}

inline static bool is_miter(const SkStrokeRec& stroke) {
    // For hairlines, make bevel and round joins appear the same as mitered ones.
    // small miter limit means right angles show bevel...
    if ((stroke.getWidth() > 0) && (stroke.getJoin() != SkPaint::kMiter_Join ||
                                    stroke.getMiter() < SK_ScalarSqrt2)) {
        return false;
    }
    return true;
}

static void outset_for_stroke(SkRect* rect, const SkStrokeRec& rec) {
    SkScalar radius = SkScalarHalf(rec.getWidth());
    if (0 == radius) {
        radius = SK_Scalar1;    // hairlines
    }
    if (SkPaint::kMiter_Join == rec.getJoin()) {
        radius = SkScalarMul(radius, rec.getMiter());
    }
    rect->outset(radius, radius);
}

// Allow all hairlines and all miters, so long as the miter limit doesn't produce beveled corners.
inline static bool allowed_stroke(const SkStrokeRec& stroke) {
    SkASSERT(stroke.getStyle() == SkStrokeRec::kStroke_Style ||
             stroke.getStyle() == SkStrokeRec::kHairline_Style);
    return !stroke.getWidth() ||
           (stroke.getJoin() == SkPaint::kMiter_Join && stroke.getMiter() > SK_ScalarSqrt2);
}

void GrAARectRenderer::strokeAARect(GrDrawTarget* target,
                                    GrDrawState* drawState,
                                    GrColor color,
                                    const SkRect& rect,
                                    const SkMatrix& combinedMatrix,
                                    const SkRect& devRect,
                                    const SkStrokeRec& stroke) {
    SkVector devStrokeSize;
    SkScalar width = stroke.getWidth();
    if (width > 0) {
        devStrokeSize.set(width, width);
        combinedMatrix.mapVectors(&devStrokeSize, 1);
        devStrokeSize.setAbs(devStrokeSize);
    } else {
        devStrokeSize.set(SK_Scalar1, SK_Scalar1);
    }

    const SkScalar dx = devStrokeSize.fX;
    const SkScalar dy = devStrokeSize.fY;
    const SkScalar rx = SkScalarMul(dx, SK_ScalarHalf);
    const SkScalar ry = SkScalarMul(dy, SK_ScalarHalf);

    // Temporarily #if'ed out. We don't want to pass in the devRect but
    // right now it is computed in GrContext::apply_aa_to_rect and we don't
    // want to throw away the work
#if 0
    SkRect devRect;
    combinedMatrix.mapRect(&devRect, rect);
#endif

    SkScalar spare;
    {
        SkScalar w = devRect.width() - dx;
        SkScalar h = devRect.height() - dy;
        spare = SkTMin(w, h);
    }

    SkRect devOutside(devRect);
    devOutside.outset(rx, ry);

    bool miterStroke = true;
    // For hairlines, make bevel and round joins appear the same as mitered ones.
    // small miter limit means right angles show bevel...
    if ((width > 0) && (stroke.getJoin() != SkPaint::kMiter_Join ||
                        stroke.getMiter() < SK_ScalarSqrt2)) {
        miterStroke = false;
    }

    if (spare <= 0 && miterStroke) {
        this->fillAARect(target, drawState, color, devOutside, SkMatrix::I(), devOutside);
        return;
    }

    SkRect devInside(devRect);
    devInside.inset(rx, ry);

    SkRect devOutsideAssist(devRect);

    // For bevel-stroke, use 2 SkRect instances(devOutside and devOutsideAssist)
    // to draw the outer of the rect. Because there are 8 vertices on the outer
    // edge, while vertex number of inner edge is 4, the same as miter-stroke.
    if (!miterStroke) {
        devOutside.inset(0, ry);
        devOutsideAssist.outset(0, ry);
    }

    this->geometryStrokeAARect(target, drawState, color, devOutside, devOutsideAssist, devInside,
                               miterStroke);
}

bool GrStrokePathRenderer::onDrawPath(const SkPath& origPath,
                                      const SkStrokeRec& stroke,
                                      GrDrawTarget* target,
                                      bool antiAlias) {
    if (origPath.isEmpty()) {
        return true;
    }

    SkScalar width = stroke.getWidth();
    if (width <= 0) {
        return false;
    }

    // Get the join type
    SkPaint::Join join = stroke.getJoin();
    SkScalar miterLimit = stroke.getMiter();
    SkScalar sqMiterLimit = SkScalarMul(miterLimit, miterLimit);
    if ((join == SkPaint::kMiter_Join) && (miterLimit <= SK_Scalar1)) {
        // If the miter limit is small, treat it as a bevel join
        join = SkPaint::kBevel_Join;
    }
    const bool isMiter       = (join == SkPaint::kMiter_Join);
    const bool isBevel       = (join == SkPaint::kBevel_Join);
    SkScalar invMiterLimit   = isMiter ? SK_Scalar1 / miterLimit : 0;
    SkScalar invMiterLimitSq = SkScalarMul(invMiterLimit, invMiterLimit);

    // Allocate vertices
    const int nbQuads     = origPath.countPoints() + 1; // Could be "-1" if path is not closed
    const int extraVerts  = isMiter || isBevel ? 1 : 0;
    const int maxVertexCount = nbQuads * (4 + extraVerts);
    const int maxIndexCount  = nbQuads * (6 + extraVerts * 3); // Each extra vert adds a triangle
    target->drawState()->setDefaultVertexAttribs();
    GrDrawTarget::AutoReleaseGeometry arg(target, maxVertexCount, maxIndexCount);
    if (!arg.succeeded()) {
        return false;
    }
    SkPoint* verts = reinterpret_cast<SkPoint*>(arg.vertices());
    uint16_t* idxs = reinterpret_cast<uint16_t*>(arg.indices());
    int vCount = 0, iCount = 0;

    // Transform the path into a list of triangles
    SkPath::Iter iter(origPath, false);
    SkPoint pts[4];
    const SkScalar radius = SkScalarMul(width, 0.5f);
    SkPoint *firstPt = verts, *lastPt = NULL;
    SkVector firstDir, dir;
    firstDir.set(0, 0);
    dir.set(0, 0);
    bool isOpen = true;
    for(SkPath::Verb v = iter.next(pts); v != SkPath::kDone_Verb; v = iter.next(pts)) {
        switch(v) {
            case SkPath::kMove_Verb:
                // This will already be handled as pts[0] of the 1st line
                break;
            case SkPath::kClose_Verb:
                isOpen = (lastPt == NULL);
                break;
            case SkPath::kLine_Verb:
            {
                SkVector v0 = dir;
                dir = pts[1] - pts[0];
                if (dir.setLength(radius)) {
                    SkVector dirT;
                    dirT.set(dir.fY, -dir.fX); // Get perpendicular direction
                    SkPoint l1a = pts[0]+dirT, l1b = pts[1]+dirT,
                            l2a = pts[0]-dirT, l2b = pts[1]-dirT;
                    SkPoint miterPt[2];
                    bool useMiterPoint = false;
                    int idx0(-1), idx1(-1);
                    if (NULL == lastPt) {
                        firstDir = dir;
                    } else {
                        SkVector v1 = dir;
                        if (v0.normalize() && v1.normalize()) {
                            SkScalar dotProd = v0.dot(v1);
                            // No need for bevel or miter join if the angle
                            // is either 0 or 180 degrees
                            if (!SkScalarNearlyZero(dotProd + SK_Scalar1) &&
                                !SkScalarNearlyZero(dotProd - SK_Scalar1)) {
                                bool ccw = !is_clockwise(v0, v1);
                                int offset = ccw ? 1 : 0;
                                idx0 = vCount-2+offset;
                                idx1 = vCount+offset;
                                const SkPoint* pt0 = &(lastPt[offset]);
                                const SkPoint* pt1 = ccw ? &l2a : &l1a;
                                switch(join) {
                                    case SkPaint::kMiter_Join:
                                    {
                                        // *Note : Logic is from MiterJoiner

                                        // FIXME : Special case if we have a right angle ?
                                        // if (SkScalarNearlyZero(dotProd)) {...}

                                        SkScalar sinHalfAngleSq =
                                                SkScalarHalf(SK_Scalar1 + dotProd);
                                        if (sinHalfAngleSq >= invMiterLimitSq) {
                                            // Find the miter point (or points if it is further
                                            // than the miter limit)
                                            const SkPoint pt2 = *pt0+v0, pt3 = *pt1+v1;
                                            if (intersection(*pt0, pt2, *pt1, pt3, miterPt[0]) !=
//.........这里部分代码省略.........

void GrAARectRenderer::StrokeAARect(GrDrawTarget* target,
                                    const GrPipelineBuilder& pipelineBuilder,
                                    GrColor color,
                                    const SkMatrix& viewMatrix,
                                    const SkRect& rect,
                                    const SkRect& devRect,
                                    const SkStrokeRec& stroke) {
    SkVector devStrokeSize;
    SkScalar width = stroke.getWidth();
    if (width > 0) {
        devStrokeSize.set(width, width);
        viewMatrix.mapVectors(&devStrokeSize, 1);
        devStrokeSize.setAbs(devStrokeSize);
    } else {
        devStrokeSize.set(SK_Scalar1, SK_Scalar1);
    }

    const SkScalar dx = devStrokeSize.fX;
    const SkScalar dy = devStrokeSize.fY;
    const SkScalar rx = SkScalarMul(dx, SK_ScalarHalf);
    const SkScalar ry = SkScalarMul(dy, SK_ScalarHalf);

    SkScalar spare;
    {
        SkScalar w = devRect.width() - dx;
        SkScalar h = devRect.height() - dy;
        spare = SkTMin(w, h);
    }

    SkRect devOutside(devRect);
    devOutside.outset(rx, ry);

    bool miterStroke = true;
    // For hairlines, make bevel and round joins appear the same as mitered ones.
    // small miter limit means right angles show bevel...
    if ((width > 0) && (stroke.getJoin() != SkPaint::kMiter_Join ||
                        stroke.getMiter() < SK_ScalarSqrt2)) {
        miterStroke = false;
    }

    if (spare <= 0 && miterStroke) {
        FillAARect(target, pipelineBuilder, color, viewMatrix, devOutside, devOutside);
        return;
    }

    SkRect devInside(devRect);
    devInside.inset(rx, ry);

    SkRect devOutsideAssist(devRect);

    // For bevel-stroke, use 2 SkRect instances(devOutside and devOutsideAssist)
    // to draw the outer of the rect. Because there are 8 vertices on the outer
    // edge, while vertex number of inner edge is 4, the same as miter-stroke.
    if (!miterStroke) {
        devOutside.inset(0, ry);
        devOutsideAssist.outset(0, ry);
    }

    GeometryStrokeAARect(target, pipelineBuilder, color, viewMatrix, devOutside,
                         devOutsideAssist, devInside, miterStroke);
}