| /* |
| * Copyright 2018 Google Inc. |
| * |
| * Use of this source code is governed by a BSD-style license that can be |
| * found in the LICENSE file. |
| */ |
| |
| #include "include/core/SkContourMeasure.h" |
| #include "include/core/SkPath.h" |
| #include "src/base/SkTSearch.h" |
| #include "src/core/SkGeometry.h" |
| #include "src/core/SkPathMeasurePriv.h" |
| #include "src/core/SkPathPriv.h" |
| |
| #define kMaxTValue 0x3FFFFFFF |
| |
| constexpr static inline SkScalar tValue2Scalar(int t) { |
| SkASSERT((unsigned)t <= kMaxTValue); |
| // 1/kMaxTValue can't be represented as a float, but it's close and the limits work fine. |
| const SkScalar kMaxTReciprocal = 1.0f / (SkScalar)kMaxTValue; |
| return t * kMaxTReciprocal; |
| } |
| |
| static_assert(0.0f == tValue2Scalar( 0), "Lower limit should be exact."); |
| static_assert(1.0f == tValue2Scalar(kMaxTValue), "Upper limit should be exact."); |
| |
| SkScalar SkContourMeasure::Segment::getScalarT() const { |
| return tValue2Scalar(fTValue); |
| } |
| |
| void SkContourMeasure_segTo(const SkPoint pts[], unsigned segType, |
| SkScalar startT, SkScalar stopT, SkPath* dst) { |
| SkASSERT(startT >= 0 && startT <= SK_Scalar1); |
| SkASSERT(stopT >= 0 && stopT <= SK_Scalar1); |
| SkASSERT(startT <= stopT); |
| |
| if (startT == stopT) { |
| if (!dst->isEmpty()) { |
| /* if the dash as a zero-length on segment, add a corresponding zero-length line. |
| The stroke code will add end caps to zero length lines as appropriate */ |
| SkPoint lastPt; |
| SkAssertResult(dst->getLastPt(&lastPt)); |
| dst->lineTo(lastPt); |
| } |
| return; |
| } |
| |
| SkPoint tmp0[7], tmp1[7]; |
| |
| switch (segType) { |
| case kLine_SegType: |
| if (SK_Scalar1 == stopT) { |
| dst->lineTo(pts[1]); |
| } else { |
| dst->lineTo(SkScalarInterp(pts[0].fX, pts[1].fX, stopT), |
| SkScalarInterp(pts[0].fY, pts[1].fY, stopT)); |
| } |
| break; |
| case kQuad_SegType: |
| if (0 == startT) { |
| if (SK_Scalar1 == stopT) { |
| dst->quadTo(pts[1], pts[2]); |
| } else { |
| SkChopQuadAt(pts, tmp0, stopT); |
| dst->quadTo(tmp0[1], tmp0[2]); |
| } |
| } else { |
| SkChopQuadAt(pts, tmp0, startT); |
| if (SK_Scalar1 == stopT) { |
| dst->quadTo(tmp0[3], tmp0[4]); |
| } else { |
| SkChopQuadAt(&tmp0[2], tmp1, (stopT - startT) / (1 - startT)); |
| dst->quadTo(tmp1[1], tmp1[2]); |
| } |
| } |
| break; |
| case kConic_SegType: { |
| SkConic conic(pts[0], pts[2], pts[3], pts[1].fX); |
| |
| if (0 == startT) { |
| if (SK_Scalar1 == stopT) { |
| dst->conicTo(conic.fPts[1], conic.fPts[2], conic.fW); |
| } else { |
| SkConic tmp[2]; |
| if (conic.chopAt(stopT, tmp)) { |
| dst->conicTo(tmp[0].fPts[1], tmp[0].fPts[2], tmp[0].fW); |
| } |
| } |
| } else { |
| if (SK_Scalar1 == stopT) { |
| SkConic tmp[2]; |
| if (conic.chopAt(startT, tmp)) { |
| dst->conicTo(tmp[1].fPts[1], tmp[1].fPts[2], tmp[1].fW); |
| } |
| } else { |
| SkConic tmp; |
| conic.chopAt(startT, stopT, &tmp); |
| dst->conicTo(tmp.fPts[1], tmp.fPts[2], tmp.fW); |
| } |
| } |
| } break; |
| case kCubic_SegType: |
| if (0 == startT) { |
| if (SK_Scalar1 == stopT) { |
| dst->cubicTo(pts[1], pts[2], pts[3]); |
| } else { |
| SkChopCubicAt(pts, tmp0, stopT); |
| dst->cubicTo(tmp0[1], tmp0[2], tmp0[3]); |
| } |
| } else { |
| SkChopCubicAt(pts, tmp0, startT); |
| if (SK_Scalar1 == stopT) { |
| dst->cubicTo(tmp0[4], tmp0[5], tmp0[6]); |
| } else { |
| SkChopCubicAt(&tmp0[3], tmp1, (stopT - startT) / (1 - startT)); |
| dst->cubicTo(tmp1[1], tmp1[2], tmp1[3]); |
| } |
| } |
| break; |
| default: |
| SK_ABORT("unknown segType"); |
| } |
| } |
| |
| /////////////////////////////////////////////////////////////////////////////// |
| |
| static inline int tspan_big_enough(int tspan) { |
| SkASSERT((unsigned)tspan <= kMaxTValue); |
| return tspan >> 10; |
| } |
| |
| // can't use tangents, since we need [0..1..................2] to be seen |
| // as definitely not a line (it is when drawn, but not parametrically) |
| // so we compare midpoints |
| #define CHEAP_DIST_LIMIT (SK_Scalar1/2) // just made this value up |
| |
| static bool quad_too_curvy(const SkPoint pts[3], SkScalar tolerance) { |
| // diff = (a/4 + b/2 + c/4) - (a/2 + c/2) |
| // diff = -a/4 + b/2 - c/4 |
| SkScalar dx = SkScalarHalf(pts[1].fX) - |
| SkScalarHalf(SkScalarHalf(pts[0].fX + pts[2].fX)); |
| SkScalar dy = SkScalarHalf(pts[1].fY) - |
| SkScalarHalf(SkScalarHalf(pts[0].fY + pts[2].fY)); |
| |
| SkScalar dist = std::max(SkScalarAbs(dx), SkScalarAbs(dy)); |
| return dist > tolerance; |
| } |
| |
| static bool conic_too_curvy(const SkPoint& firstPt, const SkPoint& midTPt, |
| const SkPoint& lastPt, SkScalar tolerance) { |
| SkPoint midEnds = firstPt + lastPt; |
| midEnds *= 0.5f; |
| SkVector dxy = midTPt - midEnds; |
| SkScalar dist = std::max(SkScalarAbs(dxy.fX), SkScalarAbs(dxy.fY)); |
| return dist > tolerance; |
| } |
| |
| static bool cheap_dist_exceeds_limit(const SkPoint& pt, SkScalar x, SkScalar y, |
| SkScalar tolerance) { |
| SkScalar dist = std::max(SkScalarAbs(x - pt.fX), SkScalarAbs(y - pt.fY)); |
| // just made up the 1/2 |
| return dist > tolerance; |
| } |
| |
| static bool cubic_too_curvy(const SkPoint pts[4], SkScalar tolerance) { |
| return cheap_dist_exceeds_limit(pts[1], |
| SkScalarInterp(pts[0].fX, pts[3].fX, SK_Scalar1/3), |
| SkScalarInterp(pts[0].fY, pts[3].fY, SK_Scalar1/3), tolerance) |
| || |
| cheap_dist_exceeds_limit(pts[2], |
| SkScalarInterp(pts[0].fX, pts[3].fX, SK_Scalar1*2/3), |
| SkScalarInterp(pts[0].fY, pts[3].fY, SK_Scalar1*2/3), tolerance); |
| } |
| |
| class SkContourMeasureIter::Impl { |
| public: |
| Impl(const SkPath& path, bool forceClosed, SkScalar resScale) |
| : fPath(path) |
| , fIter(SkPathPriv::Iterate(fPath).begin()) |
| , fTolerance(CHEAP_DIST_LIMIT * SkScalarInvert(resScale)) |
| , fForceClosed(forceClosed) {} |
| |
| bool hasNextSegments() const { return fIter != SkPathPriv::Iterate(fPath).end(); } |
| SkContourMeasure* buildSegments(); |
| |
| private: |
| SkPath fPath; |
| SkPathPriv::RangeIter fIter; |
| SkScalar fTolerance; |
| bool fForceClosed; |
| |
| // temporary |
| SkTDArray<SkContourMeasure::Segment> fSegments; |
| SkTDArray<SkPoint> fPts; // Points used to define the segments |
| |
| SkDEBUGCODE(void validate() const;) |
| SkScalar compute_line_seg(SkPoint p0, SkPoint p1, SkScalar distance, unsigned ptIndex); |
| SkScalar compute_quad_segs(const SkPoint pts[3], SkScalar distance, |
| int mint, int maxt, unsigned ptIndex); |
| SkScalar compute_conic_segs(const SkConic& conic, SkScalar distance, |
| int mint, const SkPoint& minPt, |
| int maxt, const SkPoint& maxPt, |
| unsigned ptIndex); |
| SkScalar compute_cubic_segs(const SkPoint pts[4], SkScalar distance, |
| int mint, int maxt, unsigned ptIndex); |
| }; |
| |
| SkScalar SkContourMeasureIter::Impl::compute_quad_segs(const SkPoint pts[3], SkScalar distance, |
| int mint, int maxt, unsigned ptIndex) { |
| if (tspan_big_enough(maxt - mint) && quad_too_curvy(pts, fTolerance)) { |
| SkPoint tmp[5]; |
| int halft = (mint + maxt) >> 1; |
| |
| SkChopQuadAtHalf(pts, tmp); |
| distance = this->compute_quad_segs(tmp, distance, mint, halft, ptIndex); |
| distance = this->compute_quad_segs(&tmp[2], distance, halft, maxt, ptIndex); |
| } else { |
| SkScalar d = SkPoint::Distance(pts[0], pts[2]); |
| SkScalar prevD = distance; |
| distance += d; |
| if (distance > prevD) { |
| SkASSERT(ptIndex < (unsigned)fPts.size()); |
| SkContourMeasure::Segment* seg = fSegments.append(); |
| seg->fDistance = distance; |
| seg->fPtIndex = ptIndex; |
| seg->fType = kQuad_SegType; |
| seg->fTValue = maxt; |
| } |
| } |
| return distance; |
| } |
| |
| SkScalar SkContourMeasureIter::Impl::compute_conic_segs(const SkConic& conic, SkScalar distance, |
| int mint, const SkPoint& minPt, |
| int maxt, const SkPoint& maxPt, |
| unsigned ptIndex) { |
| int halft = (mint + maxt) >> 1; |
| SkPoint halfPt = conic.evalAt(tValue2Scalar(halft)); |
| if (!halfPt.isFinite()) { |
| return distance; |
| } |
| if (tspan_big_enough(maxt - mint) && conic_too_curvy(minPt, halfPt, maxPt, fTolerance)) { |
| distance = this->compute_conic_segs(conic, distance, mint, minPt, halft, halfPt, ptIndex); |
| distance = this->compute_conic_segs(conic, distance, halft, halfPt, maxt, maxPt, ptIndex); |
| } else { |
| SkScalar d = SkPoint::Distance(minPt, maxPt); |
| SkScalar prevD = distance; |
| distance += d; |
| if (distance > prevD) { |
| SkASSERT(ptIndex < (unsigned)fPts.size()); |
| SkContourMeasure::Segment* seg = fSegments.append(); |
| seg->fDistance = distance; |
| seg->fPtIndex = ptIndex; |
| seg->fType = kConic_SegType; |
| seg->fTValue = maxt; |
| } |
| } |
| return distance; |
| } |
| |
| SkScalar SkContourMeasureIter::Impl::compute_cubic_segs(const SkPoint pts[4], SkScalar distance, |
| int mint, int maxt, unsigned ptIndex) { |
| if (tspan_big_enough(maxt - mint) && cubic_too_curvy(pts, fTolerance)) { |
| SkPoint tmp[7]; |
| int halft = (mint + maxt) >> 1; |
| |
| SkChopCubicAtHalf(pts, tmp); |
| distance = this->compute_cubic_segs(tmp, distance, mint, halft, ptIndex); |
| distance = this->compute_cubic_segs(&tmp[3], distance, halft, maxt, ptIndex); |
| } else { |
| SkScalar d = SkPoint::Distance(pts[0], pts[3]); |
| SkScalar prevD = distance; |
| distance += d; |
| if (distance > prevD) { |
| SkASSERT(ptIndex < (unsigned)fPts.size()); |
| SkContourMeasure::Segment* seg = fSegments.append(); |
| seg->fDistance = distance; |
| seg->fPtIndex = ptIndex; |
| seg->fType = kCubic_SegType; |
| seg->fTValue = maxt; |
| } |
| } |
| return distance; |
| } |
| |
| SkScalar SkContourMeasureIter::Impl::compute_line_seg(SkPoint p0, SkPoint p1, SkScalar distance, |
| unsigned ptIndex) { |
| SkScalar d = SkPoint::Distance(p0, p1); |
| SkASSERT(d >= 0); |
| SkScalar prevD = distance; |
| distance += d; |
| if (distance > prevD) { |
| SkASSERT((unsigned)ptIndex < (unsigned)fPts.size()); |
| SkContourMeasure::Segment* seg = fSegments.append(); |
| seg->fDistance = distance; |
| seg->fPtIndex = ptIndex; |
| seg->fType = kLine_SegType; |
| seg->fTValue = kMaxTValue; |
| } |
| return distance; |
| } |
| |
| #ifdef SK_DEBUG |
| void SkContourMeasureIter::Impl::validate() const { |
| const SkContourMeasure::Segment* seg = fSegments.begin(); |
| const SkContourMeasure::Segment* stop = fSegments.end(); |
| unsigned ptIndex = 0; |
| SkScalar distance = 0; |
| // limit the loop to a reasonable number; pathological cases can run for minutes |
| int maxChecks = 10000000; // set to INT_MAX to defeat the check |
| while (seg < stop) { |
| SkASSERT(seg->fDistance > distance); |
| SkASSERT(seg->fPtIndex >= ptIndex); |
| SkASSERT(seg->fTValue > 0); |
| |
| const SkContourMeasure::Segment* s = seg; |
| while (s < stop - 1 && s[0].fPtIndex == s[1].fPtIndex && --maxChecks > 0) { |
| SkASSERT(s[0].fType == s[1].fType); |
| SkASSERT(s[0].fTValue < s[1].fTValue); |
| s += 1; |
| } |
| |
| distance = seg->fDistance; |
| ptIndex = seg->fPtIndex; |
| seg += 1; |
| } |
| } |
| #endif |
| |
| SkContourMeasure* SkContourMeasureIter::Impl::buildSegments() { |
| int ptIndex = -1; |
| SkScalar distance = 0; |
| bool haveSeenClose = fForceClosed; |
| bool haveSeenMoveTo = false; |
| |
| /* Note: |
| * as we accumulate distance, we have to check that the result of += |
| * actually made it larger, since a very small delta might be > 0, but |
| * still have no effect on distance (if distance >>> delta). |
| * |
| * We do this check below, and in compute_quad_segs and compute_cubic_segs |
| */ |
| |
| fSegments.reset(); |
| fPts.reset(); |
| |
| auto end = SkPathPriv::Iterate(fPath).end(); |
| for (; fIter != end; ++fIter) { |
| auto [verb, pts, w] = *fIter; |
| if (haveSeenMoveTo && verb == SkPathVerb::kMove) { |
| break; |
| } |
| switch (verb) { |
| case SkPathVerb::kMove: |
| ptIndex += 1; |
| fPts.append(1, pts); |
| SkASSERT(!haveSeenMoveTo); |
| haveSeenMoveTo = true; |
| break; |
| |
| case SkPathVerb::kLine: { |
| SkASSERT(haveSeenMoveTo); |
| SkScalar prevD = distance; |
| distance = this->compute_line_seg(pts[0], pts[1], distance, ptIndex); |
| if (distance > prevD) { |
| fPts.append(1, pts + 1); |
| ptIndex++; |
| } |
| } break; |
| |
| case SkPathVerb::kQuad: { |
| SkASSERT(haveSeenMoveTo); |
| SkScalar prevD = distance; |
| distance = this->compute_quad_segs(pts, distance, 0, kMaxTValue, ptIndex); |
| if (distance > prevD) { |
| fPts.append(2, pts + 1); |
| ptIndex += 2; |
| } |
| } break; |
| |
| case SkPathVerb::kConic: { |
| SkASSERT(haveSeenMoveTo); |
| const SkConic conic(pts, *w); |
| SkScalar prevD = distance; |
| distance = this->compute_conic_segs(conic, distance, 0, conic.fPts[0], |
| kMaxTValue, conic.fPts[2], ptIndex); |
| if (distance > prevD) { |
| // we store the conic weight in our next point, followed by the last 2 pts |
| // thus to reconstitue a conic, you'd need to say |
| // SkConic(pts[0], pts[2], pts[3], weight = pts[1].fX) |
| fPts.append()->set(conic.fW, 0); |
| fPts.append(2, pts + 1); |
| ptIndex += 3; |
| } |
| } break; |
| |
| case SkPathVerb::kCubic: { |
| SkASSERT(haveSeenMoveTo); |
| SkScalar prevD = distance; |
| distance = this->compute_cubic_segs(pts, distance, 0, kMaxTValue, ptIndex); |
| if (distance > prevD) { |
| fPts.append(3, pts + 1); |
| ptIndex += 3; |
| } |
| } break; |
| |
| case SkPathVerb::kClose: |
| haveSeenClose = true; |
| break; |
| } |
| |
| } |
| |
| if (!SkScalarIsFinite(distance)) { |
| return nullptr; |
| } |
| if (fSegments.empty()) { |
| return nullptr; |
| } |
| |
| if (haveSeenClose) { |
| SkScalar prevD = distance; |
| SkPoint firstPt = fPts[0]; |
| distance = this->compute_line_seg(fPts[ptIndex], firstPt, distance, ptIndex); |
| if (distance > prevD) { |
| *fPts.append() = firstPt; |
| } |
| } |
| |
| SkDEBUGCODE(this->validate();) |
| |
| return new SkContourMeasure(std::move(fSegments), std::move(fPts), distance, haveSeenClose); |
| } |
| |
| static void compute_pos_tan(const SkPoint pts[], unsigned segType, |
| SkScalar t, SkPoint* pos, SkVector* tangent) { |
| switch (segType) { |
| case kLine_SegType: |
| if (pos) { |
| pos->set(SkScalarInterp(pts[0].fX, pts[1].fX, t), |
| SkScalarInterp(pts[0].fY, pts[1].fY, t)); |
| } |
| if (tangent) { |
| tangent->setNormalize(pts[1].fX - pts[0].fX, pts[1].fY - pts[0].fY); |
| } |
| break; |
| case kQuad_SegType: |
| SkEvalQuadAt(pts, t, pos, tangent); |
| if (tangent) { |
| tangent->normalize(); |
| } |
| break; |
| case kConic_SegType: { |
| SkConic(pts[0], pts[2], pts[3], pts[1].fX).evalAt(t, pos, tangent); |
| if (tangent) { |
| tangent->normalize(); |
| } |
| } break; |
| case kCubic_SegType: |
| SkEvalCubicAt(pts, t, pos, tangent, nullptr); |
| if (tangent) { |
| tangent->normalize(); |
| } |
| break; |
| default: |
| SkDEBUGFAIL("unknown segType"); |
| } |
| } |
| |
| |
| //////////////////////////////////////////////////////////////////////////////// |
| //////////////////////////////////////////////////////////////////////////////// |
| |
| SkContourMeasureIter::SkContourMeasureIter() { |
| } |
| |
| SkContourMeasureIter::SkContourMeasureIter(const SkPath& path, bool forceClosed, |
| SkScalar resScale) { |
| this->reset(path, forceClosed, resScale); |
| } |
| |
| SkContourMeasureIter::~SkContourMeasureIter() {} |
| |
| /** Assign a new path, or null to have none. |
| */ |
| void SkContourMeasureIter::reset(const SkPath& path, bool forceClosed, SkScalar resScale) { |
| if (path.isFinite()) { |
| fImpl = std::make_unique<Impl>(path, forceClosed, resScale); |
| } else { |
| fImpl.reset(); |
| } |
| } |
| |
| sk_sp<SkContourMeasure> SkContourMeasureIter::next() { |
| if (!fImpl) { |
| return nullptr; |
| } |
| while (fImpl->hasNextSegments()) { |
| auto cm = fImpl->buildSegments(); |
| if (cm) { |
| return sk_sp<SkContourMeasure>(cm); |
| } |
| } |
| return nullptr; |
| } |
| |
| /////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// |
| |
| SkContourMeasure::SkContourMeasure(SkTDArray<Segment>&& segs, SkTDArray<SkPoint>&& pts, SkScalar length, bool isClosed) |
| : fSegments(std::move(segs)) |
| , fPts(std::move(pts)) |
| , fLength(length) |
| , fIsClosed(isClosed) |
| {} |
| |
| template <typename T, typename K> |
| int SkTKSearch(const T base[], int count, const K& key) { |
| SkASSERT(count >= 0); |
| if (count <= 0) { |
| return ~0; |
| } |
| |
| SkASSERT(base != nullptr); // base may be nullptr if count is zero |
| |
| unsigned lo = 0; |
| unsigned hi = count - 1; |
| |
| while (lo < hi) { |
| unsigned mid = (hi + lo) >> 1; |
| if (base[mid].fDistance < key) { |
| lo = mid + 1; |
| } else { |
| hi = mid; |
| } |
| } |
| |
| if (base[hi].fDistance < key) { |
| hi += 1; |
| hi = ~hi; |
| } else if (key < base[hi].fDistance) { |
| hi = ~hi; |
| } |
| return hi; |
| } |
| |
| const SkContourMeasure::Segment* SkContourMeasure::distanceToSegment( SkScalar distance, |
| SkScalar* t) const { |
| SkDEBUGCODE(SkScalar length = ) this->length(); |
| SkASSERT(distance >= 0 && distance <= length); |
| |
| const Segment* seg = fSegments.begin(); |
| int count = fSegments.size(); |
| |
| int index = SkTKSearch<Segment, SkScalar>(seg, count, distance); |
| // don't care if we hit an exact match or not, so we xor index if it is negative |
| index ^= (index >> 31); |
| seg = &seg[index]; |
| |
| // now interpolate t-values with the prev segment (if possible) |
| SkScalar startT = 0, startD = 0; |
| // check if the prev segment is legal, and references the same set of points |
| if (index > 0) { |
| startD = seg[-1].fDistance; |
| if (seg[-1].fPtIndex == seg->fPtIndex) { |
| SkASSERT(seg[-1].fType == seg->fType); |
| startT = seg[-1].getScalarT(); |
| } |
| } |
| |
| SkASSERT(seg->getScalarT() > startT); |
| SkASSERT(distance >= startD); |
| SkASSERT(seg->fDistance > startD); |
| |
| *t = startT + (seg->getScalarT() - startT) * (distance - startD) / (seg->fDistance - startD); |
| return seg; |
| } |
| |
| bool SkContourMeasure::getPosTan(SkScalar distance, SkPoint* pos, SkVector* tangent) const { |
| if (SkScalarIsNaN(distance)) { |
| return false; |
| } |
| |
| const SkScalar length = this->length(); |
| SkASSERT(length > 0 && !fSegments.empty()); |
| |
| // pin the distance to a legal range |
| if (distance < 0) { |
| distance = 0; |
| } else if (distance > length) { |
| distance = length; |
| } |
| |
| SkScalar t; |
| const Segment* seg = this->distanceToSegment(distance, &t); |
| if (SkScalarIsNaN(t)) { |
| return false; |
| } |
| |
| SkASSERT((unsigned)seg->fPtIndex < (unsigned)fPts.size()); |
| compute_pos_tan(&fPts[seg->fPtIndex], seg->fType, t, pos, tangent); |
| return true; |
| } |
| |
| bool SkContourMeasure::getMatrix(SkScalar distance, SkMatrix* matrix, MatrixFlags flags) const { |
| SkPoint position; |
| SkVector tangent; |
| |
| if (this->getPosTan(distance, &position, &tangent)) { |
| if (matrix) { |
| if (flags & kGetTangent_MatrixFlag) { |
| matrix->setSinCos(tangent.fY, tangent.fX, 0, 0); |
| } else { |
| matrix->reset(); |
| } |
| if (flags & kGetPosition_MatrixFlag) { |
| matrix->postTranslate(position.fX, position.fY); |
| } |
| } |
| return true; |
| } |
| return false; |
| } |
| |
| bool SkContourMeasure::getSegment(SkScalar startD, SkScalar stopD, SkPath* dst, |
| bool startWithMoveTo) const { |
| SkASSERT(dst); |
| |
| SkScalar length = this->length(); // ensure we have built our segments |
| |
| if (startD < 0) { |
| startD = 0; |
| } |
| if (stopD > length) { |
| stopD = length; |
| } |
| if (!(startD <= stopD)) { // catch NaN values as well |
| return false; |
| } |
| if (fSegments.empty()) { |
| return false; |
| } |
| |
| SkPoint p; |
| SkScalar startT, stopT; |
| const Segment* seg = this->distanceToSegment(startD, &startT); |
| if (!SkScalarIsFinite(startT)) { |
| return false; |
| } |
| const Segment* stopSeg = this->distanceToSegment(stopD, &stopT); |
| if (!SkScalarIsFinite(stopT)) { |
| return false; |
| } |
| SkASSERT(seg <= stopSeg); |
| if (startWithMoveTo) { |
| compute_pos_tan(&fPts[seg->fPtIndex], seg->fType, startT, &p, nullptr); |
| dst->moveTo(p); |
| } |
| |
| if (seg->fPtIndex == stopSeg->fPtIndex) { |
| SkContourMeasure_segTo(&fPts[seg->fPtIndex], seg->fType, startT, stopT, dst); |
| } else { |
| do { |
| SkContourMeasure_segTo(&fPts[seg->fPtIndex], seg->fType, startT, SK_Scalar1, dst); |
| seg = SkContourMeasure::Segment::Next(seg); |
| startT = 0; |
| } while (seg->fPtIndex < stopSeg->fPtIndex); |
| SkContourMeasure_segTo(&fPts[seg->fPtIndex], seg->fType, 0, stopT, dst); |
| } |
| |
| return true; |
| } |
