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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 "GrPathRenderer.h"
     12 
     13 #include "SkTypes.h"
     14 #include "SkTArray.h"
     15 
     16 class GrContext;
     17 
     18 /**
     19  * Keeps track of an ordered list of path renderers. When a path needs to be
     20  * drawn this list is scanned to find the most preferred renderer. To add your
     21  * path renderer to the list implement the GrPathRenderer::AddPathRenderers
     22  * function.
     23  */
     24 class GrPathRendererChain : public SkNoncopyable {
     25 public:
     26     GrPathRendererChain(GrContext* context);
     27 
     28     ~GrPathRendererChain();
     29 
     30     /** Documents how the caller plans to use a GrPathRenderer to draw a path. It affects the PR
     31         returned by getPathRenderer */
     32     enum DrawType {
     33         kColor_DrawType,                    // draw to the color buffer, no AA
     34         kColorAntiAlias_DrawType,           // draw to color buffer, with partial coverage AA
     35         kStencilOnly_DrawType,              // draw just to the stencil buffer
     36         kStencilAndColor_DrawType,          // draw the stencil and color buffer, no AA
     37         kStencilAndColorAntiAlias_DrawType  // draw the stencil and color buffer, with partial
     38                                             // coverage AA.
     39     };
     40 
     41     /** Returns a GrPathRenderer compatible with the request if one is available. If the caller
     42         is drawing the path to the stencil buffer then stencilSupport can be used to determine
     43         whether the path can be rendered with arbitrary stencil rules or not. See comments on
     44         StencilSupport in GrPathRenderer.h. */
     45     GrPathRenderer* getPathRenderer(const GrPathRenderer::CanDrawPathArgs& args,
     46                                     DrawType drawType,
     47                                     GrPathRenderer::StencilSupport* stencilSupport);
     48 
     49 private:
     50     // takes a ref and unrefs in destructor
     51     GrPathRenderer* addPathRenderer(GrPathRenderer* pr);
     52 
     53     enum {
     54         kPreAllocCount = 8,
     55     };
     56     SkSTArray<kPreAllocCount, GrPathRenderer*, true>    fChain;
     57 };
     58 
     59 #endif
     60