| /* |
| * Copyright 2022 Google LLC |
| * |
| * Use of this source code is governed by a BSD-style license that can be |
| * found in the LICENSE file. |
| */ |
| |
| #ifndef SkAlphaType_DEFINED |
| #define SkAlphaType_DEFINED |
| |
| /** \enum SkAlphaType |
| Describes how to interpret the alpha component of a pixel. A pixel may |
| be opaque, or alpha, describing multiple levels of transparency. |
| |
| In simple blending, alpha weights the draw color and the destination |
| color to create a new color. If alpha describes a weight from zero to one: |
| |
| new color = draw color * alpha + destination color * (1 - alpha) |
| |
| In practice alpha is encoded in two or more bits, where 1.0 equals all bits set. |
| |
| RGB may have alpha included in each component value; the stored |
| value is the original RGB multiplied by alpha. Premultiplied color |
| components improve performance. |
| */ |
| enum SkAlphaType : int { |
| kUnknown_SkAlphaType, //!< uninitialized |
| kOpaque_SkAlphaType, //!< pixel is opaque |
| kPremul_SkAlphaType, //!< pixel components are premultiplied by alpha |
| kUnpremul_SkAlphaType, //!< pixel components are independent of alpha |
| kLastEnum_SkAlphaType = kUnpremul_SkAlphaType, //!< last valid value |
| }; |
| |
| /** Returns true if SkAlphaType equals kOpaque_SkAlphaType. |
| |
| kOpaque_SkAlphaType is a hint that the SkColorType is opaque, or that all |
| alpha values are set to their 1.0 equivalent. If SkAlphaType is |
| kOpaque_SkAlphaType, and SkColorType is not opaque, then the result of |
| drawing any pixel with a alpha value less than 1.0 is undefined. |
| */ |
| static inline bool SkAlphaTypeIsOpaque(SkAlphaType at) { |
| return kOpaque_SkAlphaType == at; |
| } |
| |
| #endif |
