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      1 /*
      2  * Copyright 2011 Google Inc.
      3  *
      4  * Use of this source code is governed by a BSD-style license that can be
      5  * found in the LICENSE file.
      6  */
      7 #ifndef SkEdgeBuilder_DEFINED
      8 #define SkEdgeBuilder_DEFINED
      9 
     10 #include "SkAnalyticEdge.h"
     11 #include "SkArenaAlloc.h"
     12 #include "SkEdge.h"
     13 #include "SkRect.h"
     14 #include "SkTDArray.h"
     15 
     16 class SkPath;
     17 
     18 class SkEdgeBuilder {
     19 public:
     20     int buildEdges(const SkPath& path,
     21                    const SkIRect* shiftedClip);
     22 
     23 protected:
     24     SkEdgeBuilder() = default;
     25     virtual ~SkEdgeBuilder() = default;
     26 
     27     // In general mode we allocate pointers in fList and fEdgeList points to its head.
     28     // In polygon mode we preallocated edges contiguously in fAlloc and fEdgeList points there.
     29     void**              fEdgeList = nullptr;
     30     SkTDArray<void*>    fList;
     31     SkSTArenaAlloc<512> fAlloc;
     32 
     33     enum Combine {
     34         kNo_Combine,
     35         kPartial_Combine,
     36         kTotal_Combine
     37     };
     38 
     39 private:
     40     int build    (const SkPath& path, const SkIRect* clip, bool clipToTheRight);
     41     int buildPoly(const SkPath& path, const SkIRect* clip, bool clipToTheRight);
     42 
     43     virtual char* allocEdges(size_t n, size_t* sizeof_edge) = 0;
     44     virtual SkRect recoverClip(const SkIRect&) const = 0;
     45     virtual bool chopCubics() const = 0;
     46 
     47     virtual void addLine (const SkPoint pts[]) = 0;
     48     virtual void addQuad (const SkPoint pts[]) = 0;
     49     virtual void addCubic(const SkPoint pts[]) = 0;
     50     virtual Combine addPolyLine(SkPoint pts[], char* edge, char** edgePtr) = 0;
     51 };
     52 
     53 class SkBasicEdgeBuilder final : public SkEdgeBuilder {
     54 public:
     55     explicit SkBasicEdgeBuilder(int clipShift) : fClipShift(clipShift) {}
     56 
     57     SkEdge** edgeList() { return (SkEdge**)fEdgeList; }
     58 
     59 private:
     60     Combine combineVertical(const SkEdge* edge, SkEdge* last);
     61 
     62     char* allocEdges(size_t, size_t*) override;
     63     SkRect recoverClip(const SkIRect&) const override;
     64     bool chopCubics() const override { return true; }
     65 
     66     void addLine (const SkPoint pts[]) override;
     67     void addQuad (const SkPoint pts[]) override;
     68     void addCubic(const SkPoint pts[]) override;
     69     Combine addPolyLine(SkPoint pts[], char* edge, char** edgePtr) override;
     70 
     71     const int fClipShift;
     72 };
     73 
     74 class SkAnalyticEdgeBuilder final : public SkEdgeBuilder {
     75 public:
     76     SkAnalyticEdgeBuilder() {}
     77 
     78     SkAnalyticEdge** analyticEdgeList() { return (SkAnalyticEdge**)fEdgeList; }
     79 
     80 private:
     81     Combine combineVertical(const SkAnalyticEdge* edge, SkAnalyticEdge* last);
     82 
     83     char* allocEdges(size_t, size_t*) override;
     84     SkRect recoverClip(const SkIRect&) const override;
     85     bool chopCubics() const override { return true; }
     86 
     87     void addLine (const SkPoint pts[]) override;
     88     void addQuad (const SkPoint pts[]) override;
     89     void addCubic(const SkPoint pts[]) override;
     90     Combine addPolyLine(SkPoint pts[], char* edge, char** edgePtr) override;
     91 };
     92 
     93 class SkBezierEdgeBuilder final : public SkEdgeBuilder {
     94 public:
     95     SkBezierEdgeBuilder() {}
     96 
     97     SkBezier** bezierList() { return (SkBezier**)fEdgeList; }
     98 
     99 private:
    100     char* allocEdges(size_t, size_t*) override;
    101     SkRect recoverClip(const SkIRect&) const override;
    102     bool chopCubics() const override { return false; }
    103 
    104     void addLine (const SkPoint pts[]) override;
    105     void addQuad (const SkPoint pts[]) override;
    106     void addCubic(const SkPoint pts[]) override;
    107     Combine addPolyLine(SkPoint pts[], char* edge, char** edgePtr) override;
    108 };
    109 
    110 #endif
    111