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 GrPipelineBuilder;
18 class GrStrokeInfo;
19 class SkMatrix;
20 class SkPath;
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 GrDrawTarget* target,
61                                     const GrPipelineBuilder*,
62                                     const SkMatrix& viewMatrix,
63                                     const SkPath& path,
64                                     const GrStrokeInfo& stroke,
65                                     DrawType drawType,
66                                     StencilSupport* stencilSupport);
67 
68 private:
69     GrPathRendererChain();
70 
71     void init();
72 
73     enum {
74         kPreAllocCount = 8,
75     };
76     bool fInit;
77     GrContext*                                          fOwner;
78     SkSTArray<kPreAllocCount, GrPathRenderer*, true>    fChain;
79 
80     typedef SkRefCnt INHERITED;
81 };
82 
83 #endif
84