SkBlurDrawLooper.h revision 0f10f7bf1fb43ca6346dc220a076773b1f19a367 
1/*
2 * Copyright 2008 The Android Open Source Project
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
9#ifndef SkBlurDrawLooper_DEFINED
10#define SkBlurDrawLooper_DEFINED
11
12#include "SkDrawLooper.h"
13#include "SkColor.h"
14
15class SkMaskFilter;
16class SkColorFilter;
17
18/** \class SkBlurDrawLooper
19    This class draws a shadow of the object (possibly offset), and then draws
20    the original object in its original position.
21    should there be an option to just draw the shadow/blur layer? webkit?
22*/
23class SK_API SkBlurDrawLooper : public SkDrawLooper {
24public:
25    enum BlurFlags {
26        kNone_BlurFlag = 0x00,
27        /**
28            The blur layer's dx/dy/radius aren't affected by the canvas
29            transform.
30        */
31        kIgnoreTransform_BlurFlag   = 0x01,
32        kOverrideColor_BlurFlag     = 0x02,
33        kHighQuality_BlurFlag       = 0x04,
34        /** mask for all blur flags */
35        kAll_BlurFlag               = 0x07
36    };
37
38    SkBlurDrawLooper(SkColor color, SkScalar sigma, SkScalar dx, SkScalar dy,
39                     uint32_t flags = kNone_BlurFlag);
40
41//    SK_ATTR_DEPRECATED("use sigma version")
42    SkBlurDrawLooper(SkScalar radius, SkScalar dx, SkScalar dy, SkColor color,
43                     uint32_t flags = kNone_BlurFlag);
44    virtual ~SkBlurDrawLooper();
45
46    virtual SkDrawLooper::Context* createContext(SkCanvas*, void* storage) const SK_OVERRIDE;
47
48    virtual size_t contextSize() const SK_OVERRIDE { return sizeof(BlurDrawLooperContext); }
49
50    SK_TO_STRING_OVERRIDE()
51    SK_DECLARE_PUBLIC_FLATTENABLE_DESERIALIZATION_PROCS(SkBlurDrawLooper)
52
53protected:
54    SkBlurDrawLooper(SkReadBuffer&);
55    virtual void flatten(SkWriteBuffer&) const SK_OVERRIDE;
56
57private:
58    SkMaskFilter*   fBlur;
59    SkColorFilter*  fColorFilter;
60    SkScalar        fDx, fDy;
61    SkColor         fBlurColor;
62    uint32_t        fBlurFlags;
63
64    enum State {
65        kBeforeEdge,
66        kAfterEdge,
67        kDone
68    };
69
70    class BlurDrawLooperContext : public SkDrawLooper::Context {
71    public:
72        explicit BlurDrawLooperContext(const SkBlurDrawLooper* looper);
73
74        virtual bool next(SkCanvas* canvas, SkPaint* paint) SK_OVERRIDE;
75
76    private:
77        const SkBlurDrawLooper* fLooper;
78        State fState;
79    };
80
81    void init(SkScalar sigma, SkScalar dx, SkScalar dy, SkColor color, uint32_t flags);
82
83    typedef SkDrawLooper INHERITED;
84};
85
86#endif
87