C++ SkVector::isZero方法代码示例

// Use the intersection of the corners' diagonals with their ellipses to shrink
// the bounding rect
SkRect compute_central_occluder(const SkRRect& rr) {
    const SkRect r = rr.getBounds();

    SkScalar newL = r.fLeft, newT = r.fTop, newR = r.fRight, newB = r.fBottom;

    SkVector radii = rr.radii(SkRRect::kUpperLeft_Corner);
    if (!radii.isZero()) {
        SkPoint p = intersection(radii.fX, radii.fY);

        newL = SkTMax(newL, r.fLeft + radii.fX - p.fX);
        newT = SkTMax(newT, r.fTop + radii.fY - p.fY);
    }

    radii = rr.radii(SkRRect::kUpperRight_Corner);
    if (!radii.isZero()) {
        SkPoint p = intersection(radii.fX, radii.fY);

        newR = SkTMin(newR, r.fRight + p.fX - radii.fX);
        newT = SkTMax(newT, r.fTop + radii.fY - p.fY);
    }

    radii = rr.radii(SkRRect::kLowerRight_Corner);
    if (!radii.isZero()) {
        SkPoint p = intersection(radii.fX, radii.fY);

        newR = SkTMin(newR, r.fRight + p.fX - radii.fX);
        newB = SkTMin(newB, r.fBottom - radii.fY + p.fY);
    }

    radii = rr.radii(SkRRect::kLowerLeft_Corner);
    if (!radii.isZero()) {
        SkPoint p = intersection(radii.fX, radii.fY);

        newL = SkTMax(newL, r.fLeft + radii.fX - p.fX);
        newB = SkTMin(newB, r.fBottom - radii.fY + p.fY);
    }

    return SkRect::MakeLTRB(newL, newT, newR, newB);
}

// Currently asPoints is more restrictive then it needs to be. In the future
// we need to:
//      allow kRound_Cap capping (could allow rotations in the matrix with this)
//      allow paths to be returned
bool SkDashPathEffect::asPoints(PointData* results,
                                const SkPath& src,
                                const SkStrokeRec& rec,
                                const SkMatrix& matrix,
                                const SkRect* cullRect) const {
    // width < 0 -> fill && width == 0 -> hairline so requiring width > 0 rules both out
    if (fInitialDashLength < 0 || 0 >= rec.getWidth()) {
        return false;
    }

    // TODO: this next test could be eased up. We could allow any number of
    // intervals as long as all the ons match and all the offs match.
    // Additionally, they do not necessarily need to be integers.
    // We cannot allow arbitrary intervals since we want the returned points
    // to be uniformly sized.
    if (fCount != 2 ||
        !SkScalarNearlyEqual(fIntervals[0], fIntervals[1]) ||
        !SkScalarIsInt(fIntervals[0]) ||
        !SkScalarIsInt(fIntervals[1])) {
        return false;
    }

    SkPoint pts[2];

    if (!src.isLine(pts)) {
        return false;
    }

    // TODO: this test could be eased up to allow circles
    if (SkPaint::kButt_Cap != rec.getCap()) {
        return false;
    }

    // TODO: this test could be eased up for circles. Rotations could be allowed.
    if (!matrix.rectStaysRect()) {
        return false;
    }

    // See if the line can be limited to something plausible.
    if (!cull_line(pts, rec, matrix, cullRect, fIntervalLength)) {
        return false;
    }

    SkScalar length = SkPoint::Distance(pts[1], pts[0]);

    SkVector tangent = pts[1] - pts[0];
    if (tangent.isZero()) {
        return false;
    }

    tangent.scale(SkScalarInvert(length));

    // TODO: make this test for horizontal & vertical lines more robust
    bool isXAxis = true;
    if (SkScalarNearlyEqual(SK_Scalar1, tangent.fX) ||
        SkScalarNearlyEqual(-SK_Scalar1, tangent.fX)) {
        results->fSize.set(SkScalarHalf(fIntervals[0]), SkScalarHalf(rec.getWidth()));
    } else if (SkScalarNearlyEqual(SK_Scalar1, tangent.fY) ||
               SkScalarNearlyEqual(-SK_Scalar1, tangent.fY)) {
        results->fSize.set(SkScalarHalf(rec.getWidth()), SkScalarHalf(fIntervals[0]));
        isXAxis = false;
    } else if (SkPaint::kRound_Cap != rec.getCap()) {
        // Angled lines don't have axis-aligned boxes.
        return false;
    }

    if (results) {
        results->fFlags = 0;
        SkScalar clampedInitialDashLength = SkMinScalar(length, fInitialDashLength);

        if (SkPaint::kRound_Cap == rec.getCap()) {
            results->fFlags |= PointData::kCircles_PointFlag;
        }

        results->fNumPoints = 0;
        SkScalar len2 = length;
        if (clampedInitialDashLength > 0 || 0 == fInitialDashIndex) {
            SkASSERT(len2 >= clampedInitialDashLength);
            if (0 == fInitialDashIndex) {
                if (clampedInitialDashLength > 0) {
                    if (clampedInitialDashLength >= fIntervals[0]) {
                        ++results->fNumPoints;  // partial first dash
                    }
                    len2 -= clampedInitialDashLength;
                }
                len2 -= fIntervals[1];  // also skip first space
                if (len2 < 0) {
                    len2 = 0;
                }
            } else {
                len2 -= clampedInitialDashLength; // skip initial partial empty
            }
        }
        int numMidPoints = SkScalarFloorToInt(len2 / fIntervalLength);
        results->fNumPoints += numMidPoints;
        len2 -= numMidPoints * fIntervalLength;
//.........这里部分代码省略.........