1 /* 2 * Copyright 2018 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 SkCoverageMode_DEFINED 9 #define SkCoverageMode_DEFINED 10 11 /** 12 * Describes geometric operations (ala SkRegion::Op) that can be applied to coverage bytes. 13 * These can be thought of as variants of porter-duff (SkBlendMode) modes, but only applied 14 * to the alpha channel. 15 * 16 * See SkMaskFilter for ways to use these when combining two different masks. 17 */ 18 enum class SkCoverageMode { 19 kUnion, // A ∪ B A+B-A*B 20 kIntersect, // A ∩ B A*B 21 kDifference, // A - B A*(1-B) 22 kReverseDifference, // B - A B*(1-A) 23 kXor, // A ⊕ B A+B-2*A*B 24 25 kLast = kXor, 26 }; 27 28 #endif 29