michael@0: /*
michael@0:  * Copyright 2011 Google Inc.
michael@0:  *
michael@0:  * Use of this source code is governed by a BSD-style license that can be
michael@0:  * found in the LICENSE file.
michael@0:  */
michael@0: 
michael@0: #ifndef SkArithmeticMode_DEFINED
michael@0: #define SkArithmeticMode_DEFINED
michael@0: 
michael@0: #include "SkFlattenable.h"
michael@0: #include "SkScalar.h"
michael@0: 
michael@0: class SkXfermode;
michael@0: 
michael@0: class SK_API SkArithmeticMode {
michael@0: public:
michael@0:     /**
michael@0:      *  result = clamp[k1 * src * dst + k2 * src + k3 * dst + k4]
michael@0:      *
michael@0:      *  src and dst are treated as being [0.0 .. 1.0]. The polynomial is
michael@0:      *  evaluated on their unpremultiplied components.
michael@0:      *
michael@0:      *  k1=k2=k3=0, k4=1.0 results in returning opaque white
michael@0:      *  k1=k3=k4=0, k2=1.0 results in returning the src
michael@0:      *  k1=k2=k4=0, k3=1.0 results in returning the dst
michael@0:      */
michael@0:     static SkXfermode* Create(SkScalar k1, SkScalar k2,
michael@0:                               SkScalar k3, SkScalar k4);
michael@0: 
michael@0:     SK_DECLARE_FLATTENABLE_REGISTRAR_GROUP();
michael@0: 
michael@0: private:
michael@0:     SkArithmeticMode(); // can't be instantiated
michael@0: };
michael@0: 
michael@0: #endif