SkLerpXfermode.h revision b83cb9bf89d26b40e4db83db1b9782437d2adba7 
1/*
2 * Copyright 2013 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 SkLerpXfermode_DEFINED
9#define SkLerpXfermode_DEFINED
10
11#include "SkXfermode.h"
12
13class SK_API SkLerpXfermode : public SkXfermode {
14public:
15    /**
16     *  result = scale * src + (1 - scale) * dst
17     *
18     *  When scale == 1, this is the same as kSrc_Mode
19     *  When scale == 0, this is the same as kDst_Mode
20     */
21    static SkXfermode* Create(SkScalar scale);
22
23    // overrides from SkXfermode
24    virtual void xfer32(SkPMColor dst[], const SkPMColor src[], int count,
25                        const SkAlpha aa[]) const SK_OVERRIDE;
26    virtual void xfer16(uint16_t dst[], const SkPMColor src[], int count,
27                        const SkAlpha aa[]) const SK_OVERRIDE;
28    virtual void xferA8(SkAlpha dst[], const SkPMColor src[], int count,
29                        const SkAlpha aa[]) const SK_OVERRIDE;
30
31    SK_DEVELOPER_TO_STRING()
32    SK_DECLARE_PUBLIC_FLATTENABLE_DESERIALIZATION_PROCS(SkLerpXfermode)
33
34protected:
35    SkLerpXfermode(SkFlattenableReadBuffer&);
36    virtual void flatten(SkFlattenableWriteBuffer&) const SK_OVERRIDE;
37
38private:
39    SkLerpXfermode(unsigned scale256);
40
41    unsigned fScale256;  // 0..256
42
43    typedef SkXfermode INHERITED;
44};
45
46#endif
47