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
16class GrContext;
17class GrDrawTarget;
18class GrPathRenderer;
19class SkPath;
20class 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 */
28class GrPathRendererChain : public SkRefCnt {
29public:
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
66private:
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