SkBlurDrawLooper.h revision 4e2b3d3fb1288c6dc0f3ea1c0aa4a0d7c603bd7b 
1/*
2 * Copyright (C) 2008 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17#ifndef SkBlurDrawLooper_DEFINED
18#define SkBlurDrawLooper_DEFINED
19
20#include "SkDrawLooper.h"
21#include "SkColor.h"
22
23class SkMaskFilter;
24class SkColorFilter;
25
26/** \class SkBlurDrawLooper
27    This class draws a shadow of the object (possibly offset), and then draws
28    the original object in its original position.
29    should there be an option to just draw the shadow/blur layer? webkit?
30*/
31class SK_API SkBlurDrawLooper : public SkDrawLooper {
32public:
33    enum BlurFlags {
34        kNone_BlurFlag = 0x00,
35        /**
36            The blur layer's dx/dy/radius aren't affected by the canvas
37            transform.
38        */
39        kIgnoreTransform_BlurFlag   = 0x01,
40        kOverrideColor_BlurFlag     = 0x02,
41        kHighQuality_BlurFlag       = 0x04,
42        /** mask for all blur flags */
43        kAll_BlurFlag = 0x07
44    };
45
46    SkBlurDrawLooper(SkScalar radius, SkScalar dx, SkScalar dy, SkColor color,
47                     uint32_t flags = kNone_BlurFlag);
48    virtual ~SkBlurDrawLooper();
49
50    // overrides from SkDrawLooper
51    virtual void init(SkCanvas*);
52    virtual bool next(SkCanvas*, SkPaint* paint);
53
54    static SkFlattenable* CreateProc(SkFlattenableReadBuffer& buffer) {
55        return SkNEW_ARGS(SkBlurDrawLooper, (buffer));
56    }
57
58
59protected:
60    SkBlurDrawLooper(SkFlattenableReadBuffer&);
61    // overrides from SkFlattenable
62    virtual void flatten(SkFlattenableWriteBuffer& );
63    virtual Factory getFactory() { return CreateProc; }
64
65private:
66    SkMaskFilter*   fBlur;
67    SkColorFilter*  fColorFilter;
68    SkScalar        fDx, fDy;
69    SkColor         fBlurColor;
70    uint32_t        fBlurFlags;
71
72    enum State {
73        kBeforeEdge,
74        kAfterEdge,
75        kDone
76    };
77    State   fState;
78
79    typedef SkDrawLooper INHERITED;
80};
81
82#endif
83