1 /*
2  * Copyright 2016 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 SkArithmeticModePriv_DEFINED
9 #define SkArithmeticModePriv_DEFINED
10 
11 #include "SkScalar.h"
12 #include "SkXfermodePriv.h"
13 
14 class SkXfermode;
15 
16 struct SkArithmeticParams {
17     float fK[4];
18     bool fEnforcePMColor;
19 };
20 
21 // This only exists to unflatten instances that were serialized into old pictures as part of
22 // SkXfermodeImageFilter before the advent of SkBlendMode.
23 class SK_API SkArithmeticMode {
24 public:
25     /**
26      *  result = clamp[k1 * src * dst + k2 * src + k3 * dst + k4]
27      *
28      *  k1=k2=k3=0, k4=1.0 results in returning opaque white
29      *  k1=k3=k4=0, k2=1.0 results in returning the src
30      *  k1=k2=k4=0, k3=1.0 results in returning the dst
31      */
32     static sk_sp<SkXfermode> Make(SkScalar k1, SkScalar k2, SkScalar k3, SkScalar k4,
33                                   bool enforcePMColor = true);
34     SK_DECLARE_FLATTENABLE_REGISTRAR_GROUP();
35 
36 private:
37     SkArithmeticMode(); // can't be instantiated
38 };
39 
40 #endif
41