1 files changed, 67 insertions, 0 deletions
diff --git a/gfx/2d/PathAnalysis.h b/gfx/2d/PathAnalysis.h
new file mode 100644
index 0000000000..5821b8839e
--- /dev/null
+++ b/gfx/2d/PathAnalysis.h
@@ -0,0 +1,67 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "2D.h"
+#include <vector>
+
+namespace mozilla {
+namespace gfx {
+
+struct FlatPathOp {
+  enum OpType {
+    OP_MOVETO,
+    OP_LINETO,
+  };
+
+  OpType mType;
+  Point mPoint;
+};
+
+class FlattenedPath : public PathSink {
+ public:
+  MOZ_DECLARE_REFCOUNTED_VIRTUAL_TYPENAME(FlattenedPath, override)
+
+  virtual void MoveTo(const Point& aPoint) override;
+  virtual void LineTo(const Point& aPoint) override;
+  virtual void BezierTo(const Point& aCP1, const Point& aCP2,
+                        const Point& aCP3) override;
+  virtual void QuadraticBezierTo(const Point& aCP1, const Point& aCP2) override;
+  virtual void Close() override;
+  virtual void Arc(const Point& aOrigin, float aRadius, float aStartAngle,
+                   float aEndAngle, bool aAntiClockwise = false) override;
+
+  virtual Point CurrentPoint() const override {
+    return mPathOps.empty() ? Point() : mPathOps[mPathOps.size() - 1].mPoint;
+  }
+
+  Float ComputeLength();
+  Point ComputePointAtLength(Float aLength, Point* aTangent);
+
+ private:
+  Float mCachedLength = 0.0f;
+  bool mCalculatedLength = false;
+
+  std::vector<FlatPathOp> mPathOps;
+
+  // Used to accelerate ComputePointAtLength for the common case of iterating
+  // forward along the path.
+  struct {
+    uint32_t mIndex = 0;
+    Float mLength = 0.0f;
+    Point mCurrentPoint;
+    Point mLastPointSinceMove;
+
+    void Reset() {
+      mIndex = 0;
+      mLength = 0.0f;
+      mCurrentPoint = Point();
+      mLastPointSinceMove = Point();
+    }
+  } mCursor;
+};
+
+}  // namespace gfx
+}  // namespace mozilla