SkLayerRasterizer.h revision 65044bfe021e9c0023d78080583e9acb3bdb5ce7 
1
2/*
3 * Copyright 2006 The Android Open Source Project
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 SkLayerRasterizer_DEFINED
11#define SkLayerRasterizer_DEFINED
12
13#include "SkRasterizer.h"
14#include "SkDeque.h"
15#include "SkScalar.h"
16
17class SkPaint;
18
19class SK_API SkLayerRasterizer : public SkRasterizer {
20public:
21    virtual ~SkLayerRasterizer();
22
23    class SK_API Builder {
24    public:
25        Builder();
26        ~Builder();
27
28        void addLayer(const SkPaint& paint) {
29            this->addLayer(paint, 0, 0);
30        }
31
32        /**
33          *  Add a new layer (above any previous layers) to the rasterizer.
34          *  The layer will extract those fields that affect the mask from
35          *  the specified paint, but will not retain a reference to the paint
36          *  object itself, so it may be reused without danger of side-effects.
37          */
38        void addLayer(const SkPaint& paint, SkScalar dx, SkScalar dy);
39
40        /**
41          *  Pass queue of layers on to newly created layer rasterizer and return it. The builder
42          *  *cannot* be used any more after calling this function. If no layers have been added,
43          *  returns NULL.
44          *
45          *  The caller is responsible for calling unref() on the returned object, if non NULL.
46          */
47        SkLayerRasterizer* detachRasterizer();
48
49        /**
50          *  Create and return a new immutable SkLayerRasterizer that contains a shapshot of the
51          *  layers that were added to the Builder, without modifying the Builder. The Builder
52          *  *may* be used after calling this function. It will continue to hold any layers
53          *  previously added, so consecutive calls to this function will return identical objects,
54          *  and objects returned by future calls to this function contain all the layers in
55          *  previously returned objects. If no layers have been added, returns NULL.
56          *
57          *  Future calls to addLayer will not affect rasterizers previously returned by this call.
58          *
59          *  The caller is responsible for calling unref() on the returned object, if non NULL.
60          */
61        SkLayerRasterizer* snapshotRasterizer() const;
62
63    private:
64        SkDeque* fLayers;
65    };
66
67#ifdef SK_SUPPORT_LEGACY_LAYERRASTERIZER_API
68    void addLayer(const SkPaint& paint) {
69        this->addLayer(paint, 0, 0);
70    }
71
72    /**    Add a new layer (above any previous layers) to the rasterizer.
73        The layer will extract those fields that affect the mask from
74        the specified paint, but will not retain a reference to the paint
75        object itself, so it may be reused without danger of side-effects.
76    */
77    void addLayer(const SkPaint& paint, SkScalar dx, SkScalar dy);
78#endif
79
80    SK_DECLARE_PUBLIC_FLATTENABLE_DESERIALIZATION_PROCS(SkLayerRasterizer)
81
82protected:
83    SkLayerRasterizer(SkDeque* layers);
84    SkLayerRasterizer(SkReadBuffer&);
85    virtual void flatten(SkWriteBuffer&) const SK_OVERRIDE;
86
87    // override from SkRasterizer
88    virtual bool onRasterize(const SkPath& path, const SkMatrix& matrix,
89                             const SkIRect* clipBounds,
90                             SkMask* mask, SkMask::CreateMode mode) const;
91
92#ifdef SK_SUPPORT_LEGACY_LAYERRASTERIZER_API
93public:
94#endif
95    SkLayerRasterizer();
96
97private:
98#ifdef SK_SUPPORT_LEGACY_LAYERRASTERIZER_API
99    SkDeque* fLayers;
100#else
101    const SkDeque* const fLayers;
102#endif
103
104    static SkDeque* ReadLayers(SkReadBuffer& buffer);
105
106    friend class LayerRasterizerTester;
107
108    typedef SkRasterizer INHERITED;
109};
110
111#endif
112