diff options
Diffstat (limited to 'src')
| -rw-r--r-- | src/core/SkPath.cpp | 139 |
1 files changed, 134 insertions, 5 deletions
diff --git a/src/core/SkPath.cpp b/src/core/SkPath.cpp index 704863cc87..fa6b3b9f66 100644 --- a/src/core/SkPath.cpp +++ b/src/core/SkPath.cpp @@ -97,7 +97,7 @@ static void compute_pt_bounds(SkRect* bounds, const SkTDArray<SkPoint>& pts) { //////////////////////////////////////////////////////////////////////////// SkPath::SkPath() : fBoundsIsDirty(true), fFillType(kWinding_FillType) { - fIsConvex = false; // really should be kUnknown + fConvexity = kUnknown_Convexity; #ifdef ANDROID fGenerationID = 0; #endif @@ -125,7 +125,7 @@ SkPath& SkPath::operator=(const SkPath& src) { fVerbs = src.fVerbs; fFillType = src.fFillType; fBoundsIsDirty = src.fBoundsIsDirty; - fIsConvex = src.fIsConvex; + fConvexity = src.fConvexity; GEN_ID_INC; } SkDEBUGCODE(this->validate();) @@ -148,7 +148,7 @@ void SkPath::swap(SkPath& other) { fVerbs.swap(other.fVerbs); SkTSwap<uint8_t>(fFillType, other.fFillType); SkTSwap<uint8_t>(fBoundsIsDirty, other.fBoundsIsDirty); - SkTSwap<uint8_t>(fIsConvex, other.fIsConvex); + SkTSwap<uint8_t>(fConvexity, other.fConvexity); GEN_ID_INC; } } @@ -166,7 +166,7 @@ void SkPath::reset() { fVerbs.reset(); GEN_ID_INC; fBoundsIsDirty = true; - fIsConvex = false; // really should be kUnknown + fConvexity = kUnknown_Convexity; } void SkPath::rewind() { @@ -176,7 +176,7 @@ void SkPath::rewind() { fVerbs.rewind(); GEN_ID_INC; fBoundsIsDirty = true; - fIsConvex = false; // really should be kUnknown + fConvexity = kUnknown_Convexity; } bool SkPath::isEmpty() const { @@ -244,6 +244,13 @@ void SkPath::computeBounds() const { compute_pt_bounds(&fBounds, fPts); } +void SkPath::setConvexity(Convexity c) { + if (fConvexity != c) { + fConvexity = c; + GEN_ID_INC; + } +} + ////////////////////////////////////////////////////////////////////////////// // Construction methods @@ -1382,3 +1389,125 @@ void SkPath::validate() const { } #endif +/////////////////////////////////////////////////////////////////////////////// + +/** + * Returns -1 || 0 || 1 depending on the sign of value: + * -1 if value < 0 + * 0 if vlaue == 0 + * 1 if value > 0 + */ +static int SkScalarSign(SkScalar value) { + return value < 0 ? -1 : (value > 0); +} + +static int CrossProductSign(const SkVector& a, const SkVector& b) { + return SkScalarSign(SkPoint::CrossProduct(a, b)); +} + +// only valid for a single contour +struct Convexicator { + Convexicator() : fPtCount(0), fConvexity(SkPath::kUnknown_Convexity) { + fSign = 0; + // warnings + fCurrPt.set(0, 0); + fVec0.set(0, 0); + fVec1.set(0, 0); + fFirstVec.set(0, 0); + } + + SkPath::Convexity getConvexity() const { return fConvexity; } + + void addPt(const SkPoint& pt) { + if (SkPath::kConcave_Convexity == fConvexity) { + return; + } + + if (0 == fPtCount) { + fCurrPt = pt; + ++fPtCount; + } else { + SkVector vec = pt - fCurrPt; + if (vec.fX || vec.fY) { + fCurrPt = pt; + if (++fPtCount == 2) { + fFirstVec = fVec1 = vec; + } else { + SkASSERT(fPtCount > 2); + this->addVec(vec); + } + } + } + } + + void close() { + if (fPtCount > 2) { + this->addVec(fFirstVec); + } + } + +private: + void addVec(const SkVector& vec) { + SkASSERT(vec.fX || vec.fY); + fVec0 = fVec1; + fVec1 = vec; + int sign = CrossProductSign(fVec0, fVec1); + if (0 == fSign) { + fSign = sign; + } else if (sign) { + if (fSign == sign) { + fConvexity = SkPath::kConvex_Convexity; + } else { + fConvexity = SkPath::kConcave_Convexity; + } + } + } + + SkPoint fCurrPt; + SkVector fVec0, fVec1, fFirstVec; + int fPtCount; // non-degenerate points + int fSign; + SkPath::Convexity fConvexity; +}; + +SkPath::Convexity SkPath::ComputeConvexity(const SkPath& path) { + SkPoint pts[4]; + SkPath::Verb verb; + SkPath::Iter iter(path, true); + + int contourCount = 0; + int count; + Convexicator state; + + while ((verb = iter.next(pts)) != SkPath::kDone_Verb) { + switch (verb) { + case kMove_Verb: + if (++contourCount > 1) { + return kConcave_Convexity; + } + pts[1] = pts[0]; + count = 1; + break; + case kLine_Verb: count = 1; break; + case kQuad_Verb: count = 2; break; + case kCubic_Verb: count = 3; break; + case kClose_Verb: + state.close(); + count = 0; + break; + default: + SkASSERT(!"bad verb"); + return kConcave_Convexity; + } + + for (int i = 1; i <= count; i++) { + state.addPt(pts[i]); + } + // early exit + if (kConcave_Convexity == state.getConvexity()) { + return kConcave_Convexity; + } + } + return state.getConvexity(); +} + |