diff options
Diffstat (limited to 'libs/hwui/PathTessellator.cpp')
| -rw-r--r-- | libs/hwui/PathTessellator.cpp | 53 |
1 files changed, 51 insertions, 2 deletions
diff --git a/libs/hwui/PathTessellator.cpp b/libs/hwui/PathTessellator.cpp index c1f61d6..e7c6c05 100644 --- a/libs/hwui/PathTessellator.cpp +++ b/libs/hwui/PathTessellator.cpp @@ -37,6 +37,7 @@ #include <SkPath.h> #include <SkPaint.h> +#include <SkPoint.h> #include <SkGeometry.h> // WARNING: Internal Skia Header #include <stdlib.h> @@ -912,6 +913,39 @@ void pushToVector(Vector<Vertex>& vertices, float x, float y) { Vertex::set(newVertex, x, y); } +class ClockwiseEnforcer { +public: + void addPoint(const SkPoint& point) { + double x = point.x(); + double y = point.y(); + + if (initialized) { + sum += (x + lastX) * (y - lastY); + } else { + initialized = true; + } + + lastX = x; + lastY = y; + } + void reverseVectorIfNotClockwise(Vector<Vertex>& vertices) { + if (sum < 0) { + // negative sum implies CounterClockwise + const int size = vertices.size(); + for (int i = 0; i < size / 2; i++) { + Vertex tmp = vertices[i]; + int k = size - 1 - i; + vertices.replaceAt(vertices[k], i); + vertices.replaceAt(tmp, k); + } + } + } +private: + bool initialized = false; + double lastX, lastY; + double sum = 0; +}; + bool PathTessellator::approximatePathOutlineVertices(const SkPath& path, bool forceClose, float sqrInvScaleX, float sqrInvScaleY, float thresholdSquared, Vector<Vertex>& outputVertices) { @@ -922,18 +956,22 @@ bool PathTessellator::approximatePathOutlineVertices(const SkPath& path, bool fo SkPath::Iter iter(path, forceClose); SkPoint pts[4]; SkPath::Verb v; + ClockwiseEnforcer clockwiseEnforcer; while (SkPath::kDone_Verb != (v = iter.next(pts))) { switch (v) { case SkPath::kMove_Verb: pushToVector(outputVertices, pts[0].x(), pts[0].y()); ALOGV("Move to pos %f %f", pts[0].x(), pts[0].y()); + clockwiseEnforcer.addPoint(pts[0]); break; case SkPath::kClose_Verb: ALOGV("Close at pos %f %f", pts[0].x(), pts[0].y()); + clockwiseEnforcer.addPoint(pts[0]); break; case SkPath::kLine_Verb: ALOGV("kLine_Verb %f %f -> %f %f", pts[0].x(), pts[0].y(), pts[1].x(), pts[1].y()); pushToVector(outputVertices, pts[1].x(), pts[1].y()); + clockwiseEnforcer.addPoint(pts[1]); break; case SkPath::kQuad_Verb: ALOGV("kQuad_Verb"); @@ -942,6 +980,8 @@ bool PathTessellator::approximatePathOutlineVertices(const SkPath& path, bool fo pts[2].x(), pts[2].y(), pts[1].x(), pts[1].y(), sqrInvScaleX, sqrInvScaleY, thresholdSquared, outputVertices); + clockwiseEnforcer.addPoint(pts[1]); + clockwiseEnforcer.addPoint(pts[2]); break; case SkPath::kCubic_Verb: ALOGV("kCubic_Verb"); @@ -951,6 +991,9 @@ bool PathTessellator::approximatePathOutlineVertices(const SkPath& path, bool fo pts[3].x(), pts[3].y(), pts[2].x(), pts[2].y(), sqrInvScaleX, sqrInvScaleY, thresholdSquared, outputVertices); + clockwiseEnforcer.addPoint(pts[1]); + clockwiseEnforcer.addPoint(pts[2]); + clockwiseEnforcer.addPoint(pts[3]); break; case SkPath::kConic_Verb: { ALOGV("kConic_Verb"); @@ -965,6 +1008,8 @@ bool PathTessellator::approximatePathOutlineVertices(const SkPath& path, bool fo quads[offset+1].x(), quads[offset+1].y(), sqrInvScaleX, sqrInvScaleY, thresholdSquared, outputVertices); } + clockwiseEnforcer.addPoint(pts[1]); + clockwiseEnforcer.addPoint(pts[2]); break; } default: @@ -972,13 +1017,17 @@ bool PathTessellator::approximatePathOutlineVertices(const SkPath& path, bool fo } } + bool wasClosed = false; int size = outputVertices.size(); if (size >= 2 && outputVertices[0].x == outputVertices[size - 1].x && outputVertices[0].y == outputVertices[size - 1].y) { outputVertices.pop(); - return true; + wasClosed = true; } - return false; + + // ensure output vector is clockwise + clockwiseEnforcer.reverseVectorIfNotClockwise(outputVertices); + return wasClosed; } /////////////////////////////////////////////////////////////////////////////// |