gfx/2d/PathAnalysis.h

   1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* vim: set ts=8 sts=2 et sw=2 tw=80: */
   3 /* This Source Code Form is subject to the terms of the Mozilla Public
   4  * License, v. 2.0. If a copy of the MPL was not distributed with this
   5  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   6
   7 #include "2D.h"
   8 #include <vector>
   9
  10 namespace mozilla {
  11 namespace gfx {
  12
  13 struct FlatPathOp {
  14   enum OpType {
  15     OP_MOVETO,
  16     OP_LINETO,
  17   };
  18
  19   OpType mType;
  20   Point mPoint;
  21 };
  22
  23 class FlattenedPath : public PathSink {
  24  public:
  25   MOZ_DECLARE_REFCOUNTED_VIRTUAL_TYPENAME(FlattenedPath, override)
  26
  27   virtual void MoveTo(const Point& aPoint) override;
  28   virtual void LineTo(const Point& aPoint) override;
  29   virtual void BezierTo(const Point& aCP1, const Point& aCP2,
  30                         const Point& aCP3) override;
  31   virtual void QuadraticBezierTo(const Point& aCP1, const Point& aCP2) override;
  32   virtual void Close() override;
  33   virtual void Arc(const Point& aOrigin, float aRadius, float aStartAngle,
  34                    float aEndAngle, bool aAntiClockwise = false) override;
  35
  36   virtual Point CurrentPoint() const override {
  37     return mPathOps.empty() ? Point() : mPathOps[mPathOps.size() - 1].mPoint;
  38   }
  39
  40   Float ComputeLength();
  41   Point ComputePointAtLength(Float aLength, Point* aTangent);
  42
  43  private:
  44   Float mCachedLength = 0.0f;
  45   bool mCalculatedLength = false;
  46
  47   std::vector<FlatPathOp> mPathOps;
  48
  49   // Used to accelerate ComputePointAtLength for the common case of iterating
  50   // forward along the path.
  51   struct {
  52     uint32_t mIndex = 0;
  53     Float mLength = 0.0f;
  54     Point mCurrentPoint;
  55     Point mLastPointSinceMove;
  56
  57     void Reset() {
  58       mIndex = 0;
  59       mLength = 0.0f;
  60       mCurrentPoint = Point();
  61       mLastPointSinceMove = Point();
  62     }
  63   } mCursor;
  64 };
  65
  66 }  // namespace gfx
  67 }  // namespace mozilla