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      1 
      2 /*
      3  * Copyright 2011 Google Inc.
      4  *
      5  * Use of this source code is governed by a BSD-style license that can be
      6  * found in the LICENSE file.
      7  */
      8 
      9 
     10 #ifndef GrPathRendererChain_DEFINED
     11 #define GrPathRendererChain_DEFINED
     12 
     13 #include "GrRefCnt.h"
     14 #include "SkTArray.h"
     15 
     16 class GrContext;
     17 class GrDrawTarget;
     18 class GrPathRenderer;
     19 class SkPath;
     20 class SkStrokeRec;
     21 
     22 /**
     23  * Keeps track of an ordered list of path renderers. When a path needs to be
     24  * drawn this list is scanned to find the most preferred renderer. To add your
     25  * path renderer to the list implement the GrPathRenderer::AddPathRenderers
     26  * function.
     27  */
     28 class GrPathRendererChain : public SkRefCnt {
     29 public:
     30     // See comments in GrPathRenderer.h
     31     enum StencilSupport {
     32         kNoSupport_StencilSupport,
     33         kStencilOnly_StencilSupport,
     34         kNoRestriction_StencilSupport,
     35     };
     36 
     37     SK_DECLARE_INST_COUNT(GrPathRendererChain)
     38 
     39     GrPathRendererChain(GrContext* context);
     40 
     41     ~GrPathRendererChain();
     42 
     43     // takes a ref and unrefs in destructor
     44     GrPathRenderer* addPathRenderer(GrPathRenderer* pr);
     45 
     46     /** Documents how the caller plans to use a GrPathRenderer to draw a path. It affects the PR
     47         returned by getPathRenderer */
     48     enum DrawType {
     49         kColor_DrawType,                    // draw to the color buffer, no AA
     50         kColorAntiAlias_DrawType,           // draw to color buffer, with partial coverage AA
     51         kStencilOnly_DrawType,              // draw just to the stencil buffer
     52         kStencilAndColor_DrawType,          // draw the stencil and color buffer, no AA
     53         kStencilAndColorAntiAlias_DrawType  // draw the stencil and color buffer, with partial
     54                                             // coverage AA.
     55     };
     56     /** Returns a GrPathRenderer compatible with the request if one is available. If the caller
     57         is drawing the path to the stencil buffer then stencilSupport can be used to determine
     58         whether the path can be rendered with arbitrary stencil rules or not. See comments on
     59         StencilSupport in GrPathRenderer.h. */
     60     GrPathRenderer* getPathRenderer(const SkPath& path,
     61                                     const SkStrokeRec& rec,
     62                                     const GrDrawTarget* target,
     63                                     DrawType drawType,
     64                                     StencilSupport* stencilSupport);
     65 
     66 private:
     67 
     68     GrPathRendererChain();
     69 
     70     void init();
     71 
     72     enum {
     73         kPreAllocCount = 8,
     74     };
     75     bool fInit;
     76     GrContext*                                          fOwner;
     77     SkSTArray<kPreAllocCount, GrPathRenderer*, true>    fChain;
     78 
     79     typedef SkRefCnt INHERITED;
     80 };
     81 
     82 
     83 #endif
     84