| mike@reedtribe.org | e51755f | 2011-12-10 19:36:56 +0000 | [diff] [blame] | 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 | |
| tfarina@chromium.org | 6806fe8 | 2012-10-12 14:41:39 +0000 | [diff] [blame] | 13 | class SK_API SkArithmeticMode : public SkXfermode { |
| mike@reedtribe.org | e51755f | 2011-12-10 19:36:56 +0000 | [diff] [blame] | 14 | public: |
| 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 | |
| 29 | #endif |