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 
15 class SkMaskFilter;
16 class 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 */
23 class SK_API SkBlurDrawLooper : public SkDrawLooper {
24 public:
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     static SkBlurDrawLooper* Create(SkColor color, SkScalar sigma, SkScalar dx, SkScalar dy,
39                                     uint32_t flags = kNone_BlurFlag) {
40         return SkNEW_ARGS(SkBlurDrawLooper, (color, sigma, dx, dy, flags));
41     }
42 
43     virtual ~SkBlurDrawLooper();
44 
45     SkDrawLooper::Context* createContext(SkCanvas*, void* storage) const override;
46 
contextSize()47     size_t contextSize() const override { return sizeof(BlurDrawLooperContext); }
48 
49     SK_TO_STRING_OVERRIDE()
50     SK_DECLARE_PUBLIC_FLATTENABLE_DESERIALIZATION_PROCS(SkBlurDrawLooper)
51 
52 protected:
53     SkBlurDrawLooper(SkColor color, SkScalar sigma, SkScalar dx, SkScalar dy,
54                      uint32_t flags);
55 
56     void flatten(SkWriteBuffer&) const override;
57 
58     bool asABlurShadow(BlurShadowRec*) const override;
59 
60 private:
61     SkMaskFilter*   fBlur;
62     SkColorFilter*  fColorFilter;
63     SkScalar        fDx, fDy, fSigma;
64     SkColor         fBlurColor;
65     uint32_t        fBlurFlags;
66 
67     enum State {
68         kBeforeEdge,
69         kAfterEdge,
70         kDone
71     };
72 
73     class BlurDrawLooperContext : public SkDrawLooper::Context {
74     public:
75         explicit BlurDrawLooperContext(const SkBlurDrawLooper* looper);
76 
77         bool next(SkCanvas* canvas, SkPaint* paint) override;
78 
79     private:
80         const SkBlurDrawLooper* fLooper;
81         State fState;
82     };
83 
84     void init(SkScalar sigma, SkScalar dx, SkScalar dy, SkColor color, uint32_t flags);
85     void initEffects();
86 
87     typedef SkDrawLooper INHERITED;
88 };
89 
90 #endif
91