C++ SkVector::normalize方法代码示例

GrFragmentProcessor* GrConvexPolyEffect::Create(GrPrimitiveEdgeType type, const SkPath& path,
                                                const SkVector* offset) {
    if (kHairlineAA_GrProcessorEdgeType == type) {
        return NULL;
    }
    if (path.getSegmentMasks() != SkPath::kLine_SegmentMask ||
        !path.isConvex()) {
        return NULL;
    }

    if (path.countPoints() > kMaxEdges) {
        return NULL;
    }

    SkPoint pts[kMaxEdges];
    SkScalar edges[3 * kMaxEdges];

    SkPath::Direction dir;
    SkAssertResult(path.cheapComputeDirection(&dir));

    SkVector t;
    if (NULL == offset) {
        t.set(0, 0);
    } else {
        t = *offset;
    }

    int count = path.getPoints(pts, kMaxEdges);
    int n = 0;
    for (int lastPt = count - 1, i = 0; i < count; lastPt = i++) {
        if (pts[lastPt] != pts[i]) {
            SkVector v = pts[i] - pts[lastPt];
            v.normalize();
            if (SkPath::kCCW_Direction == dir) {
                edges[3 * n] = v.fY;
                edges[3 * n + 1] = -v.fX;
            } else {
                edges[3 * n] = -v.fY;
                edges[3 * n + 1] = v.fX;
            }
            SkPoint p = pts[i] + t;
            edges[3 * n + 2] = -(edges[3 * n] * p.fX + edges[3 * n + 1] * p.fY);
            ++n;
        }
    }
    if (path.isInverseFillType()) {
        type = GrInvertProcessorEdgeType(type);
    }
    return Create(type, n, edges);
}

static void bloat_quad(const SkPoint qpts[3], const SkMatrix* toDevice,
                       const SkMatrix* toSrc, BezierVertex verts[kQuadNumVertices]) {
    SkASSERT(!toDevice == !toSrc);
    // original quad is specified by tri a,b,c
    SkPoint a = qpts[0];
    SkPoint b = qpts[1];
    SkPoint c = qpts[2];

    if (toDevice) {
        toDevice->mapPoints(&a, 1);
        toDevice->mapPoints(&b, 1);
        toDevice->mapPoints(&c, 1);
    }
    // make a new poly where we replace a and c by a 1-pixel wide edges orthog
    // to edges ab and bc:
    //
    //   before       |        after
    //                |              b0
    //         b      |
    //                |
    //                |     a0            c0
    // a         c    |        a1       c1
    //
    // edges a0->b0 and b0->c0 are parallel to original edges a->b and b->c,
    // respectively.
    BezierVertex& a0 = verts[0];
    BezierVertex& a1 = verts[1];
    BezierVertex& b0 = verts[2];
    BezierVertex& c0 = verts[3];
    BezierVertex& c1 = verts[4];

    SkVector ab = b;
    ab -= a;
    SkVector ac = c;
    ac -= a;
    SkVector cb = b;
    cb -= c;

    // We should have already handled degenerates
    SkASSERT(ab.length() > 0 && cb.length() > 0);

    ab.normalize();
    SkVector abN;
    abN.setOrthog(ab, SkVector::kLeft_Side);
    if (abN.dot(ac) > 0) {
        abN.negate();
    }

    cb.normalize();
    SkVector cbN;
    cbN.setOrthog(cb, SkVector::kLeft_Side);
    if (cbN.dot(ac) < 0) {
        cbN.negate();
    }

    a0.fPos = a;
    a0.fPos += abN;
    a1.fPos = a;
    a1.fPos -= abN;

    c0.fPos = c;
    c0.fPos += cbN;
    c1.fPos = c;
    c1.fPos -= cbN;

    intersect_lines(a0.fPos, abN, c0.fPos, cbN, &b0.fPos);

    if (toSrc) {
        toSrc->mapPointsWithStride(&verts[0].fPos, sizeof(BezierVertex), kQuadNumVertices);
    }
}

void SkPathStroker::cubic_to(const SkPoint pts[4],
                      const SkVector& normalAB, const SkVector& unitNormalAB,
                      SkVector* normalCD, SkVector* unitNormalCD,
                      int subDivide) {
    SkVector    ab = pts[1] - pts[0];
    SkVector    cd = pts[3] - pts[2];
    SkVector    normalBC, unitNormalBC;

    bool    degenerateAB = degenerate_vector(ab);
    bool    degenerateCD = degenerate_vector(cd);

    if (degenerateAB && degenerateCD) {
DRAW_LINE:
        this->line_to(pts[3], normalAB);
        *normalCD = normalAB;
        *unitNormalCD = unitNormalAB;
        return;
    }

    if (degenerateAB) {
        ab = pts[2] - pts[0];
        degenerateAB = degenerate_vector(ab);
    }
    if (degenerateCD) {
        cd = pts[3] - pts[1];
        degenerateCD = degenerate_vector(cd);
    }
    if (degenerateAB || degenerateCD) {
        goto DRAW_LINE;
    }
    SkAssertResult(set_normal_unitnormal(cd, fRadius, normalCD, unitNormalCD));
    bool degenerateBC = !set_normal_unitnormal(pts[1], pts[2], fRadius,
                                               &normalBC, &unitNormalBC);

    if (degenerateBC || normals_too_curvy(unitNormalAB, unitNormalBC) ||
             normals_too_curvy(unitNormalBC, *unitNormalCD)) {
        // subdivide if we can
        if (--subDivide < 0) {
            goto DRAW_LINE;
        }
        SkPoint     tmp[7];
        SkVector    norm, unit, dummy, unitDummy;

        SkChopCubicAtHalf(pts, tmp);
        this->cubic_to(&tmp[0], normalAB, unitNormalAB, &norm, &unit,
                       subDivide);
        // we use dummys since we already have a valid (and more accurate)
        // normals for CD
        this->cubic_to(&tmp[3], norm, unit, &dummy, &unitDummy, subDivide);
    } else {
        SkVector    normalB, normalC;
        
        // need normals to inset/outset the off-curve pts B and C

        if (0) {    // this is normal to the line between our adjacent pts
            normalB = pts[2] - pts[0];
            normalB.rotateCCW();
            SkAssertResult(normalB.setLength(fRadius));

            normalC = pts[3] - pts[1];
            normalC.rotateCCW();
            SkAssertResult(normalC.setLength(fRadius));
        } else {    // miter-join
            SkVector    unitBC = pts[2] - pts[1];
            unitBC.normalize();
            unitBC.rotateCCW();

            normalB = unitNormalAB + unitBC;
            normalC = *unitNormalCD + unitBC;

            SkScalar dot = SkPoint::DotProduct(unitNormalAB, unitBC);
            SkAssertResult(normalB.setLength(SkScalarDiv(fRadius,
                                        SkScalarSqrt((SK_Scalar1 + dot)/2))));
            dot = SkPoint::DotProduct(*unitNormalCD, unitBC);
            SkAssertResult(normalC.setLength(SkScalarDiv(fRadius,
                                        SkScalarSqrt((SK_Scalar1 + dot)/2))));
        }

        fOuter.cubicTo( pts[1].fX + normalB.fX, pts[1].fY + normalB.fY,
                        pts[2].fX + normalC.fX, pts[2].fY + normalC.fY,
                        pts[3].fX + normalCD->fX, pts[3].fY + normalCD->fY);

        fInner.cubicTo( pts[1].fX - normalB.fX, pts[1].fY - normalB.fY,
                        pts[2].fX - normalC.fX, pts[2].fY - normalC.fY,
                        pts[3].fX - normalCD->fX, pts[3].fY - normalCD->fY);
    }
}

static void create_vertices(const SegmentArray&  segments,
                            const SkPoint& fanPt,
                            DrawArray*     draws,
                            QuadVertex*    verts,
                            uint16_t*      idxs) {
    Draw* draw = &draws->push_back();
    // alias just to make vert/index assignments easier to read.
    int* v = &draw->fVertexCnt;
    int* i = &draw->fIndexCnt;

    int count = segments.count();
    for (int a = 0; a < count; ++a) {
        const Segment& sega = segments[a];
        int b = (a + 1) % count;
        const Segment& segb = segments[b];

        // Check whether adding the verts for this segment to the current draw would cause index
        // values to overflow.
        int vCount = 4;
        if (Segment::kLine == segb.fType) {
            vCount += 5;
        } else {
            vCount += 6;
        }
        if (draw->fVertexCnt + vCount > (1 << 16)) {
            verts += *v;
            idxs += *i;
            draw = &draws->push_back();
            v = &draw->fVertexCnt;
            i = &draw->fIndexCnt;
        }

        // FIXME: These tris are inset in the 1 unit arc around the corner
        verts[*v + 0].fPos = sega.endPt();
        verts[*v + 1].fPos = verts[*v + 0].fPos + sega.endNorm();
        verts[*v + 2].fPos = verts[*v + 0].fPos + segb.fMid;
        verts[*v + 3].fPos = verts[*v + 0].fPos + segb.fNorms[0];
        verts[*v + 0].fUV.set(0,0);
        verts[*v + 1].fUV.set(0,-SK_Scalar1);
        verts[*v + 2].fUV.set(0,-SK_Scalar1);
        verts[*v + 3].fUV.set(0,-SK_Scalar1);
        verts[*v + 0].fD0 = verts[*v + 0].fD1 = -SK_Scalar1;
        verts[*v + 1].fD0 = verts[*v + 1].fD1 = -SK_Scalar1;
        verts[*v + 2].fD0 = verts[*v + 2].fD1 = -SK_Scalar1;
        verts[*v + 3].fD0 = verts[*v + 3].fD1 = -SK_Scalar1;

        idxs[*i + 0] = *v + 0;
        idxs[*i + 1] = *v + 2;
        idxs[*i + 2] = *v + 1;
        idxs[*i + 3] = *v + 0;
        idxs[*i + 4] = *v + 3;
        idxs[*i + 5] = *v + 2;

        *v += 4;
        *i += 6;

        if (Segment::kLine == segb.fType) {
            verts[*v + 0].fPos = fanPt;
            verts[*v + 1].fPos = sega.endPt();
            verts[*v + 2].fPos = segb.fPts[0];

            verts[*v + 3].fPos = verts[*v + 1].fPos + segb.fNorms[0];
            verts[*v + 4].fPos = verts[*v + 2].fPos + segb.fNorms[0];

            // we draw the line edge as a degenerate quad (u is 0, v is the
            // signed distance to the edge)
            SkScalar dist = fanPt.distanceToLineBetween(verts[*v + 1].fPos,
                                                        verts[*v + 2].fPos);
            verts[*v + 0].fUV.set(0, dist);
            verts[*v + 1].fUV.set(0, 0);
            verts[*v + 2].fUV.set(0, 0);
            verts[*v + 3].fUV.set(0, -SK_Scalar1);
            verts[*v + 4].fUV.set(0, -SK_Scalar1);

            verts[*v + 0].fD0 = verts[*v + 0].fD1 = -SK_Scalar1;
            verts[*v + 1].fD0 = verts[*v + 1].fD1 = -SK_Scalar1;
            verts[*v + 2].fD0 = verts[*v + 2].fD1 = -SK_Scalar1;
            verts[*v + 3].fD0 = verts[*v + 3].fD1 = -SK_Scalar1;
            verts[*v + 4].fD0 = verts[*v + 4].fD1 = -SK_Scalar1;

            idxs[*i + 0] = *v + 0;
            idxs[*i + 1] = *v + 2;
            idxs[*i + 2] = *v + 1;

            idxs[*i + 3] = *v + 3;
            idxs[*i + 4] = *v + 1;
            idxs[*i + 5] = *v + 2;

            idxs[*i + 6] = *v + 4;
            idxs[*i + 7] = *v + 3;
            idxs[*i + 8] = *v + 2;

            *v += 5;
            *i += 9;
        } else {
            SkPoint qpts[] = {sega.endPt(), segb.fPts[0], segb.fPts[1]};

            SkVector midVec = segb.fNorms[0] + segb.fNorms[1];
            midVec.normalize();

//.........这里部分代码省略.........

GrFragmentProcessor* GrConvexPolyEffect::Create(GrPrimitiveEdgeType type, const SkPath& path,
                                                const SkVector* offset) {
    if (kHairlineAA_GrProcessorEdgeType == type) {
        return nullptr;
    }
    if (path.getSegmentMasks() != SkPath::kLine_SegmentMask ||
        !path.isConvex()) {
        return nullptr;
    }

    SkPathPriv::FirstDirection dir;
    // The only way this should fail is if the clip is effectively a infinitely thin line. In that
    // case nothing is inside the clip. It'd be nice to detect this at a higher level and either
    // skip the draw or omit the clip element.
    if (!SkPathPriv::CheapComputeFirstDirection(path, &dir)) {
        if (GrProcessorEdgeTypeIsInverseFill(type)) {
            return GrConstColorProcessor::Create(0xFFFFFFFF,
                                                 GrConstColorProcessor::kModulateRGBA_InputMode);
        }
        return GrConstColorProcessor::Create(0, GrConstColorProcessor::kIgnore_InputMode);
    }

    SkVector t;
    if (nullptr == offset) {
        t.set(0, 0);
    } else {
        t = *offset;
    }

    SkScalar        edges[3 * kMaxEdges];
    SkPoint         pts[4];
    SkPath::Verb    verb;
    SkPath::Iter    iter(path, true);

    // SkPath considers itself convex so long as there is a convex contour within it,
    // regardless of any degenerate contours such as a string of moveTos before it.
    // Iterate here to consume any degenerate contours and only process the points
    // on the actual convex contour.
    int n = 0;
    while ((verb = iter.next(pts, true, true)) != SkPath::kDone_Verb) {
        switch (verb) {
            case SkPath::kMove_Verb:
                SkASSERT(n == 0);
            case SkPath::kClose_Verb:
                break;
            case SkPath::kLine_Verb: {
                if (n >= kMaxEdges) {
                    return nullptr;
                }
                SkVector v = pts[1] - pts[0];
                v.normalize();
                if (SkPathPriv::kCCW_FirstDirection == dir) {
                    edges[3 * n] = v.fY;
                    edges[3 * n + 1] = -v.fX;
                } else {
                    edges[3 * n] = -v.fY;
                    edges[3 * n + 1] = v.fX;
                }
                SkPoint p = pts[1] + t;
                edges[3 * n + 2] = -(edges[3 * n] * p.fX + edges[3 * n + 1] * p.fY);
                ++n;
                break;
            }
            default:
                return nullptr;
        }
    }

    if (path.isInverseFillType()) {
        type = GrInvertProcessorEdgeType(type);
    }
    return Create(type, n, edges);
}