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
14class GrContext;
15class GrDrawTarget;
16class GrPathRenderer;
17class SkPath;
18class 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 */
26class GrPathRendererChain : public SkRefCnt {
27public:
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
64private:
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