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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 
      8 #ifndef GrPathRendererChain_DEFINED
      9 #define GrPathRendererChain_DEFINED
     10 
     11 #include "SkRefCnt.h"
     12 #include "SkTArray.h"
     13 
     14 class GrContext;
     15 class GrDrawTarget;
     16 class GrPathRenderer;
     17 class SkPath;
     18 class SkStrokeRec;
     19 
     20 /**
     21  * Keeps track of an ordered list of path renderers. When a path needs to be
     22  * drawn this list is scanned to find the most preferred renderer. To add your
     23  * path renderer to the list implement the GrPathRenderer::AddPathRenderers
     24  * function.
     25  */
     26 class GrPathRendererChain : public SkRefCnt {
     27 public:
     28     // See comments in GrPathRenderer.h
     29     enum StencilSupport {
     30         kNoSupport_StencilSupport,
     31         kStencilOnly_StencilSupport,
     32         kNoRestriction_StencilSupport,
     33     };
     34 
     35     SK_DECLARE_INST_COUNT(GrPathRendererChain)
     36 
     37     GrPathRendererChain(GrContext* context);
     38 
     39     ~GrPathRendererChain();
     40 
     41     // takes a ref and unrefs in destructor
     42     GrPathRenderer* addPathRenderer(GrPathRenderer* pr);
     43 
     44     /** Documents how the caller plans to use a GrPathRenderer to draw a path. It affects the PR
     45         returned by getPathRenderer */
     46     enum DrawType {
     47         kColor_DrawType,                    // draw to the color buffer, no AA
     48         kColorAntiAlias_DrawType,           // draw to color buffer, with partial coverage AA
     49         kStencilOnly_DrawType,              // draw just to the stencil buffer
     50         kStencilAndColor_DrawType,          // draw the stencil and color buffer, no AA
     51         kStencilAndColorAntiAlias_DrawType  // draw the stencil and color buffer, with partial
     52                                             // coverage AA.
     53     };
     54     /** Returns a GrPathRenderer compatible with the request if one is available. If the caller
     55         is drawing the path to the stencil buffer then stencilSupport can be used to determine
     56         whether the path can be rendered with arbitrary stencil rules or not. See comments on
     57         StencilSupport in GrPathRenderer.h. */
     58     GrPathRenderer* getPathRenderer(const SkPath& path,
     59                                     const SkStrokeRec& rec,
     60                                     const GrDrawTarget* target,
     61                                     DrawType drawType,
     62                                     StencilSupport* stencilSupport);
     63 
     64 private:
     65     GrPathRendererChain();
     66 
     67     void init();
     68 
     69     enum {
     70         kPreAllocCount = 8,
     71     };
     72     bool fInit;
     73     GrContext*                                          fOwner;
     74     SkSTArray<kPreAllocCount, GrPathRenderer*, true>    fChain;
     75 
     76     typedef SkRefCnt INHERITED;
     77 };
     78 
     79 #endif
     80