SkPixelXorXfermode.h revision 8a1c16ff38322f0210116fa7293eb8817c7e477e 
1/*
2 * Copyright (C) 2007 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 SkPixelXorXfermode_DEFINED
18#define SkPixelXorXfermode_DEFINED
19
20#include "SkXfermode.h"
21
22/** SkPixelXorXfermode implements a simple pixel xor (op ^ src ^ dst).
23    This transformation does not follow premultiplied conventions, therefore
24    this proc *always* returns an opaque color (alpha == 255). Thus it is
25    not really usefull for operating on blended colors.
26*/
27class SkPixelXorXfermode : public SkXfermode {
28public:
29    SkPixelXorXfermode(SkColor opColor) : fOpColor(opColor) {}
30
31    // override from SkFlattenable
32    virtual Factory getFactory();
33    virtual void flatten(SkFlattenableWriteBuffer&);
34
35protected:
36    // override from SkXfermode
37    virtual SkPMColor xferColor(SkPMColor src, SkPMColor dst);
38
39private:
40    SkColor fOpColor;
41
42    SkPixelXorXfermode(SkFlattenableReadBuffer& rb);
43    // our private factory
44    static SkFlattenable* Create(SkFlattenableReadBuffer&);
45
46    typedef SkXfermode INHERITED;
47};
48
49#endif
50
51