Beispiel #1
0
// 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;
        bool partialLast = false;
        if (len2 > 0) {
            if (len2 < fIntervals[0]) {
                partialLast = true;
            } else {
                ++numMidPoints;
                ++results->fNumPoints;
            }
        }

        results->fPoints = new SkPoint[results->fNumPoints];

        SkScalar    distance = 0;
        int         curPt = 0;

        if (clampedInitialDashLength > 0 || 0 == fInitialDashIndex) {
            SkASSERT(clampedInitialDashLength <= length);

            if (0 == fInitialDashIndex) {
                if (clampedInitialDashLength > 0) {
                    // partial first block
                    SkASSERT(SkPaint::kRound_Cap != rec.getCap()); // can't handle partial circles
                    SkScalar x = pts[0].fX + SkScalarMul(tangent.fX, SkScalarHalf(clampedInitialDashLength));
                    SkScalar y = pts[0].fY + SkScalarMul(tangent.fY, SkScalarHalf(clampedInitialDashLength));
                    SkScalar halfWidth, halfHeight;
                    if (isXAxis) {
                        halfWidth = SkScalarHalf(clampedInitialDashLength);
                        halfHeight = SkScalarHalf(rec.getWidth());
                    } else {
                        halfWidth = SkScalarHalf(rec.getWidth());
                        halfHeight = SkScalarHalf(clampedInitialDashLength);
                    }
                    if (clampedInitialDashLength < fIntervals[0]) {
                        // This one will not be like the others
                        results->fFirst.addRect(x - halfWidth, y - halfHeight,
                                                x + halfWidth, y + halfHeight);
                    } else {
                        SkASSERT(curPt < results->fNumPoints);
                        results->fPoints[curPt].set(x, y);
                        ++curPt;
                    }

                    distance += clampedInitialDashLength;
                }

                distance += fIntervals[1];  // skip over the next blank block too
            } else {
                distance += clampedInitialDashLength;
            }
        }

        if (0 != numMidPoints) {
            distance += SkScalarHalf(fIntervals[0]);

            for (int i = 0; i < numMidPoints; ++i) {
                SkScalar x = pts[0].fX + SkScalarMul(tangent.fX, distance);
                SkScalar y = pts[0].fY + SkScalarMul(tangent.fY, distance);

                SkASSERT(curPt < results->fNumPoints);
                results->fPoints[curPt].set(x, y);
                ++curPt;

                distance += fIntervalLength;
            }

            distance -= SkScalarHalf(fIntervals[0]);
        }

        if (partialLast) {
            // partial final block
            SkASSERT(SkPaint::kRound_Cap != rec.getCap()); // can't handle partial circles
            SkScalar temp = length - distance;
            SkASSERT(temp < fIntervals[0]);
            SkScalar x = pts[0].fX + SkScalarMul(tangent.fX, distance + SkScalarHalf(temp));
            SkScalar y = pts[0].fY + SkScalarMul(tangent.fY, distance + SkScalarHalf(temp));
            SkScalar halfWidth, halfHeight;
            if (isXAxis) {
                halfWidth = SkScalarHalf(temp);
                halfHeight = SkScalarHalf(rec.getWidth());
            } else {
                halfWidth = SkScalarHalf(rec.getWidth());
                halfHeight = SkScalarHalf(temp);
            }
            results->fLast.addRect(x - halfWidth, y - halfHeight,
                                   x + halfWidth, y + halfHeight);
        }

        SkASSERT(curPt == results->fNumPoints);
    }

    return true;
}