| /* |
| * Copyright 2017 Google Inc. |
| * |
| * Use of this source code is governed by a BSD-style license that can be |
| * found in the LICENSE file. |
| */ |
| |
| #ifndef SkHighContrastFilter_DEFINED |
| #define SkHighContrastFilter_DEFINED |
| |
| #include "include/core/SkRefCnt.h" |
| #include "include/core/SkScalar.h" |
| #include "include/core/SkTypes.h" |
| |
| class SkColorFilter; |
| |
| /** |
| * Configuration struct for SkHighContrastFilter. |
| * |
| * Provides transformations to improve contrast for users with low vision. |
| */ |
| struct SkHighContrastConfig { |
| enum class InvertStyle { |
| kNoInvert, |
| kInvertBrightness, |
| kInvertLightness, |
| |
| kLast = kInvertLightness |
| }; |
| |
| SkHighContrastConfig() { |
| fGrayscale = false; |
| fInvertStyle = InvertStyle::kNoInvert; |
| fContrast = 0.0f; |
| } |
| |
| SkHighContrastConfig(bool grayscale, |
| InvertStyle invertStyle, |
| SkScalar contrast) |
| : fGrayscale(grayscale), |
| fInvertStyle(invertStyle), |
| fContrast(contrast) {} |
| |
| // Returns true if all of the fields are set within the valid range. |
| bool isValid() const { |
| return fInvertStyle >= InvertStyle::kNoInvert && |
| fInvertStyle <= InvertStyle::kInvertLightness && |
| fContrast >= -1.0 && |
| fContrast <= 1.0; |
| } |
| |
| // If true, the color will be converted to grayscale. |
| bool fGrayscale; |
| |
| // Whether to invert brightness, lightness, or neither. |
| InvertStyle fInvertStyle; |
| |
| // After grayscale and inverting, the contrast can be adjusted linearly. |
| // The valid range is -1.0 through 1.0, where 0.0 is no adjustment. |
| SkScalar fContrast; |
| }; |
| |
| /** |
| * Color filter that provides transformations to improve contrast |
| * for users with low vision. |
| * |
| * Applies the following transformations in this order. Each of these |
| * can be configured using SkHighContrastConfig. |
| * |
| * - Conversion to grayscale |
| * - Color inversion (either in RGB or HSL space) |
| * - Increasing the resulting contrast. |
| * |
| * Calling SkHighContrastFilter::Make will return nullptr if the config is |
| * not valid, e.g. if you try to call it with a contrast outside the range of |
| * -1.0 to 1.0. |
| */ |
| |
| struct SK_API SkHighContrastFilter { |
| // Returns the filter, or nullptr if the config is invalid. |
| static sk_sp<SkColorFilter> Make(const SkHighContrastConfig& config); |
| }; |
| |
| #endif |