diff options
| author |  caryclark <caryclark@google.com> | 2016-04-06 08:54:06 -0700 |
|---|---|---|
| committer |  Commit bot <commit-bot@chromium.org> | 2016-04-06 08:54:06 -0700 |
| commit | 4693a1748f19fa4ee83c6eee2333b39ffb3febd4 (patch) | |
| tree | edba3e060e46c29e8092521152af7109b51c8a6d /src/core | |
| parent | c416912da4840af0c49bd8cdcf00044ed39500f6 (diff) | |
cubic stroke fix
Normally parallel tangents means that the stroke can
be represented with a line. But looping cubics can
have parallel tangents if the loop is 180 degrees.
Check to see if the tangents direction is opposite
to subdivide further.
R=reed@google.com
BUG=skia:5099
GOLD_TRYBOT_URL= https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&issue=1862753002
Review URL: https://codereview.chromium.org/1862753002
Diffstat (limited to 'src/core')
| -rw-r--r-- | src/core/SkStroke.cpp | 10 |
1 files changed, 8 insertions, 2 deletions
diff --git a/src/core/SkStroke.cpp b/src/core/SkStroke.cpp index 0f1a15f0b6..20bd286316 100644 --- a/src/core/SkStroke.cpp +++ b/src/core/SkStroke.cpp @@ -85,6 +85,7 @@ struct SkQuadConstruct { // The state of the quad stroke under construction. SkScalar fEndT; // " bool fStartSet; // state to share common points across structs bool fEndSet; // " + bool fOppositeTangents; // set if coincident tangents have opposite directions // return false if start and end are too close to have a unique middle bool init(SkScalar start, SkScalar end) { @@ -861,8 +862,10 @@ SkPathStroker::ResultType SkPathStroker::intersectRay(SkQuadConstruct* quadPts, */ SkScalar denom = aLen.cross(bLen); if (denom == 0 || !SkScalarIsFinite(denom)) { + quadPts->fOppositeTangents = aLen.dot(bLen) < 0; return STROKER_RESULT(kDegenerate_ResultType, depth, quadPts, "denom == 0"); } + quadPts->fOppositeTangents = false; SkVector ab0 = start - end; SkScalar numerA = bLen.cross(ab0); SkScalar numerB = aLen.cross(ab0); @@ -893,6 +896,7 @@ SkPathStroker::ResultType SkPathStroker::intersectRay(SkQuadConstruct* quadPts, return STROKER_RESULT(kQuad_ResultType, depth, quadPts, "(numerA=%g >= 0) != (numerB=%g >= 0)", numerA, numerB); } + quadPts->fOppositeTangents = aLen.dot(bLen) < 0; // if the lines are parallel, straight line is good enough return STROKER_RESULT(kDegenerate_ResultType, depth, quadPts, "SkScalarNearlyZero(denom=%g)", denom); @@ -1116,8 +1120,10 @@ bool SkPathStroker::cubicStroke(const SkPoint cubic[4], SkQuadConstruct* quadPts return true; } if (kDegenerate_ResultType == resultType) { - addDegenerateLine(quadPts); - return true; + if (!quadPts->fOppositeTangents) { + addDegenerateLine(quadPts); + return true; + } } if (kNormalError_ResultType == resultType) { return false; |