diff options
Diffstat (limited to 'src/core/SkPath.cpp')
| -rw-r--r-- | src/core/SkPath.cpp | 26 |
1 files changed, 26 insertions, 0 deletions
diff --git a/src/core/SkPath.cpp b/src/core/SkPath.cpp index c433424635..422c2b911d 100644 --- a/src/core/SkPath.cpp +++ b/src/core/SkPath.cpp @@ -1417,7 +1417,12 @@ void SkPath::arcTo(SkScalar rx, SkScalar ry, SkScalar angle, SkPath::ArcSize arc pointTransform.setRotate(angle); pointTransform.preScale(rx, ry); +#ifdef SK_SUPPORT_LEGACY_SVG_ARC_TO int segments = SkScalarCeilToInt(SkScalarAbs(thetaArc / (SK_ScalarPI / 2))); +#else + // the arc may be slightly bigger than 1/4 circle, so allow up to 1/3rd + int segments = SkScalarCeilToInt(SkScalarAbs(thetaArc / (2 * SK_ScalarPI / 3))); +#endif SkScalar thetaWidth = thetaArc / segments; SkScalar t = SkScalarTan(0.5f * thetaWidth); if (!SkScalarIsFinite(t)) { @@ -1425,6 +1430,14 @@ void SkPath::arcTo(SkScalar rx, SkScalar ry, SkScalar angle, SkPath::ArcSize arc } SkScalar startTheta = theta1; SkScalar w = SkScalarSqrt(SK_ScalarHalf + SkScalarCos(thetaWidth) * SK_ScalarHalf); +#ifndef SK_SUPPORT_LEGACY_SVG_ARC_TO + auto scalar_is_integer = [](SkScalar scalar) -> bool { + return scalar == SkScalarFloorToScalar(scalar); + }; + bool expectIntegers = SkScalarNearlyZero(SK_ScalarPI/2 - SkScalarAbs(thetaWidth)) && + scalar_is_integer(rx) && scalar_is_integer(ry) && + scalar_is_integer(x) && scalar_is_integer(y); +#endif for (int i = 0; i < segments; ++i) { SkScalar endTheta = startTheta + thetaWidth; SkScalar cosEndTheta, sinEndTheta = SkScalarSinCos(endTheta, &cosEndTheta); @@ -1435,6 +1448,19 @@ void SkPath::arcTo(SkScalar rx, SkScalar ry, SkScalar angle, SkPath::ArcSize arc unitPts[0].offset(t * sinEndTheta, -t * cosEndTheta); SkPoint mapped[2]; pointTransform.mapPoints(mapped, unitPts, (int) SK_ARRAY_COUNT(unitPts)); + /* + Computing the arc width introduces rounding errors that cause arcs to start + outside their marks. A round rect may lose convexity as a result. If the input + values are on integers, place the conic on integers as well. + */ +#ifndef SK_SUPPORT_LEGACY_SVG_ARC_TO + if (expectIntegers) { + SkScalar* mappedScalars = &mapped[0].fX; + for (unsigned index = 0; index < sizeof(mapped) / sizeof(SkScalar); ++index) { + mappedScalars[index] = SkScalarRoundToScalar(mappedScalars[index]); + } + } +#endif this->conicTo(mapped[0], mapped[1], w); startTheta = endTheta; } |