SkArithmeticMode.h revision 6b6c1dc34c299be87a3ff3ab41d3d4fd0f96a846 
1/*
2 * Copyright 2011 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 SkArithmeticMode_DEFINED
9#define SkArithmeticMode_DEFINED
10
11#include "SkXfermode.h"
12
13class SK_API SkArithmeticMode : public SkXfermode {
14public:
15    /**
16     *  result = clamp[k1 * src * dst + k2 * src + k3 * dst + k4]
17     *
18     *  src and dst are treated as being [0.0 .. 1.0]. The polynomial is
19     *  evaluated on their unpremultiplied components.
20     *
21     *  k1=k2=k3=0, k4=1.0 results in returning opaque white
22     *  k1=k3=k4=0, k2=1.0 results in returning the src
23     *  k1=k2=k4=0, k3=1.0 results in returning the dst
24     */
25    static SkXfermode* Create(SkScalar k1, SkScalar k2,
26                              SkScalar k3, SkScalar k4);
27
28    SK_DECLARE_FLATTENABLE_REGISTRAR_GROUP();
29
30private:
31    typedef SkXfermode INHERITED;
32};
33
34#endif
35