C++ SkVector::negate方法代码示例

void SkOffsetImageFilter::onFilterNodeBounds(const SkIRect& src, const SkMatrix& ctm,
                                             SkIRect* dst, MapDirection direction) const {
    SkVector vec;
    ctm.mapVectors(&vec, &fOffset, 1);
    if (kReverse_MapDirection == direction) {
        vec.negate();
    }

    *dst = src;
    dst->offset(SkScalarCeilToInt(vec.fX), SkScalarCeilToInt(vec.fY));
}

static void RoundJoiner(SkPath* outer, SkPath* inner, const SkVector& beforeUnitNormal,
                        const SkPoint& pivot, const SkVector& afterUnitNormal,
                        SkScalar radius, SkScalar invMiterLimit, bool, bool)
{
    SkScalar    dotProd = SkPoint::DotProduct(beforeUnitNormal, afterUnitNormal);
    AngleType   angleType = Dot2AngleType(dotProd);

    if (angleType == kNearlyLine_AngleType)
        return;

    SkVector            before = beforeUnitNormal;
    SkVector            after = afterUnitNormal;
    SkRotationDirection dir = kCW_SkRotationDirection;

    if (!is_clockwise(before, after))
    {
        SkTSwap<SkPath*>(outer, inner);
        before.negate();
        after.negate();
        dir = kCCW_SkRotationDirection;
    }

    SkPoint     pts[kSkBuildQuadArcStorage];
    SkMatrix    matrix;
    matrix.setScale(radius, radius);
    matrix.postTranslate(pivot.fX, pivot.fY);
    int count = SkBuildQuadArc(before, after, dir, &matrix, pts);
    SkASSERT((count & 1) == 1);

    if (count > 1)
    {
        for (int i = 1; i < count; i += 2)
            outer->quadTo(pts[i].fX, pts[i].fY, pts[i+1].fX, pts[i+1].fY);

        after.scale(radius);
        HandleInnerJoin(inner, pivot, after);
    }
}

void SkOffsetImageFilter::onFilterNodeBounds(const SkIRect& src, const SkMatrix& ctm,
                                             SkIRect* dst, MapDirection direction) const {
    SkVector vec;
    ctm.mapVectors(&vec, &fOffset, 1);
    if (kReverse_MapDirection == direction) {
        vec.negate();
    }

    *dst = src;
    dst->offset(SkScalarCeilToInt(vec.fX), SkScalarCeilToInt(vec.fY));
#ifdef SK_SUPPORT_SRC_BOUNDS_BLOAT_FOR_IMAGEFILTERS
    dst->join(src);
#endif
}

static void BluntJoiner(SkPath* outer, SkPath* inner, const SkVector& beforeUnitNormal,
                        const SkPoint& pivot, const SkVector& afterUnitNormal,
                        SkScalar radius, SkScalar invMiterLimit, bool, bool)
{
    SkVector    after;
    afterUnitNormal.scale(radius, &after);

    if (!is_clockwise(beforeUnitNormal, afterUnitNormal))
    {
        SkTSwap<SkPath*>(outer, inner);
        after.negate();
    }

    outer->lineTo(pivot.fX + after.fX, pivot.fY + after.fY);
    HandleInnerJoin(inner, pivot, after);
}

void SkDropShadowImageFilter::onFilterNodeBounds(const SkIRect& src, const SkMatrix& ctm,
                                                 SkIRect* dst, MapDirection direction) const {
    *dst = src;
    SkVector offsetVec = SkVector::Make(fDx, fDy);
    if (kReverse_MapDirection == direction) {
        offsetVec.negate();
    }
    ctm.mapVectors(&offsetVec, 1);
    dst->offset(SkScalarCeilToInt(offsetVec.x()),
                SkScalarCeilToInt(offsetVec.y()));
    SkVector sigma = SkVector::Make(fSigmaX, fSigmaY);
    ctm.mapVectors(&sigma, 1);
    dst->outset(SkScalarCeilToInt(SkScalarMul(sigma.x(), SkIntToScalar(3))),
                SkScalarCeilToInt(SkScalarMul(sigma.y(), SkIntToScalar(3))));
    if (fShadowMode == kDrawShadowAndForeground_ShadowMode) {
        dst->join(src);
    }
}

SkIRect SkDropShadowImageFilter::onFilterNodeBounds(const SkIRect& src, const SkMatrix& ctm,
                                                    MapDirection direction) const {
    SkVector offsetVec = SkVector::Make(fDx, fDy);
    if (kReverse_MapDirection == direction) {
        offsetVec.negate();
    }
    ctm.mapVectors(&offsetVec, 1);
    SkIRect dst = src.makeOffset(SkScalarCeilToInt(offsetVec.x()),
                                 SkScalarCeilToInt(offsetVec.y()));
    SkVector sigma = SkVector::Make(fSigmaX, fSigmaY);
    ctm.mapVectors(&sigma, 1);
    dst.outset(
        SkScalarCeilToInt(SkScalarAbs(sigma.x() * 3)),
        SkScalarCeilToInt(SkScalarAbs(sigma.y() * 3)));
    if (fShadowMode == kDrawShadowAndForeground_ShadowMode) {
        dst.join(src);
    }
    return dst;
}

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);
    }
}

static void MiterJoiner(SkPath* outer, SkPath* inner, const SkVector& beforeUnitNormal,
                        const SkPoint& pivot, const SkVector& afterUnitNormal,
                        SkScalar radius, SkScalar invMiterLimit,
                        bool prevIsLine, bool currIsLine)
{
    // negate the dot since we're using normals instead of tangents
    SkScalar    dotProd = SkPoint::DotProduct(beforeUnitNormal, afterUnitNormal);
    AngleType   angleType = Dot2AngleType(dotProd);
    SkVector    before = beforeUnitNormal;
    SkVector    after = afterUnitNormal;
    SkVector    mid;
    SkScalar    sinHalfAngle;
    bool        ccw;

    if (angleType == kNearlyLine_AngleType)
        return;
    if (angleType == kNearly180_AngleType)
    {
        currIsLine = false;
        goto DO_BLUNT;
    }

    ccw = !is_clockwise(before, after);
    if (ccw)
    {
        SkTSwap<SkPath*>(outer, inner);
        before.negate();
        after.negate();
    }

    /*  Before we enter the world of square-roots and divides,
        check if we're trying to join an upright right angle
        (common case for stroking rectangles). If so, special case
        that (for speed an accuracy).
        Note: we only need to check one normal if dot==0
    */
    if (0 == dotProd && invMiterLimit <= kOneOverSqrt2)
    {
        mid.set(SkScalarMul(before.fX + after.fX, radius),
                SkScalarMul(before.fY + after.fY, radius));
        goto DO_MITER;
    }

    /*  midLength = radius / sinHalfAngle
        if (midLength > miterLimit * radius) abort
        if (radius / sinHalf > miterLimit * radius) abort
        if (1 / sinHalf > miterLimit) abort
        if (1 / miterLimit > sinHalf) abort
        My dotProd is opposite sign, since it is built from normals and not tangents
        hence 1 + dot instead of 1 - dot in the formula
    */
    sinHalfAngle = SkScalarSqrt(SkScalarHalf(SK_Scalar1 + dotProd));
    if (sinHalfAngle < invMiterLimit)
    {
        currIsLine = false;
        goto DO_BLUNT;
    }

    // choose the most accurate way to form the initial mid-vector
    if (angleType == kSharp_AngleType)
    {
        mid.set(after.fY - before.fY, before.fX - after.fX);
        if (ccw)
            mid.negate();
    }
    else
        mid.set(before.fX + after.fX, before.fY + after.fY);

    mid.setLength(SkScalarDiv(radius, sinHalfAngle));
DO_MITER:
    if (prevIsLine)
        outer->setLastPt(pivot.fX + mid.fX, pivot.fY + mid.fY);
    else
        outer->lineTo(pivot.fX + mid.fX, pivot.fY + mid.fY);

DO_BLUNT:
    after.scale(radius);
    if (!currIsLine)
        outer->lineTo(pivot.fX + after.fX, pivot.fY + after.fY);
    HandleInnerJoin(inner, pivot, after);
}