| // Copyright 2013 The Flutter Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style license that can be |
| // found in the LICENSE file. |
| |
| // @dart = 2.6 |
| part of engine; |
| |
| /// A description of a color filter to apply when drawing a shape or compositing |
| /// a layer with a particular [Paint]. A color filter is a function that takes |
| /// two colors, and outputs one color. When applied during compositing, it is |
| /// independently applied to each pixel of the layer being drawn before the |
| /// entire layer is merged with the destination. |
| /// |
| /// Instances of this class are used with [Paint.colorFilter] on [Paint] |
| /// objects. |
| class EngineColorFilter implements ui.ColorFilter { |
| /// Creates a color filter that applies the blend mode given as the second |
| /// argument. The source color is the one given as the first argument, and the |
| /// destination color is the one from the layer being composited. |
| /// |
| /// The output of this filter is then composited into the background according |
| /// to the [Paint.blendMode], using the output of this filter as the source |
| /// and the background as the destination. |
| const EngineColorFilter.mode(ui.Color color, ui.BlendMode blendMode) |
| : _color = color, |
| _blendMode = blendMode, |
| _matrix = null, |
| _type = _TypeMode; |
| |
| /// Construct a color filter that transforms a color by a 5x5 matrix, where |
| /// the fifth row is implicitly added in an identity configuration. |
| /// |
| /// Every pixel's color value, repsented as an `[R, G, B, A]`, is matrix |
| /// multiplied to create a new color: |
| /// |
| /// ```text |
| /// | R' | | a00 a01 a02 a03 a04 | | R | |
| /// | G' | | a10 a11 a22 a33 a44 | | G | |
| /// | B' | = | a20 a21 a22 a33 a44 | * | B | |
| /// | A' | | a30 a31 a22 a33 a44 | | A | |
| /// | 1 | | 0 0 0 0 1 | | 1 | |
| /// ``` |
| /// |
| /// The matrix is in row-major order and the translation column is specified |
| /// in unnormalized, 0...255, space. For example, the identity matrix is: |
| /// |
| /// ``` |
| /// const ColorMatrix identity = ColorFilter.matrix(<double>[ |
| /// 1, 0, 0, 0, 0, |
| /// 0, 1, 0, 0, 0, |
| /// 0, 0, 1, 0, 0, |
| /// 0, 0, 0, 1, 0, |
| /// ]); |
| /// ``` |
| /// |
| /// ## Examples |
| /// |
| /// An inversion color matrix: |
| /// |
| /// ``` |
| /// const ColorFilter invert = ColorFilter.matrix(<double>[ |
| /// -1, 0, 0, 0, 255, |
| /// 0, -1, 0, 0, 255, |
| /// 0, 0, -1, 0, 255, |
| /// 0, 0, 0, 1, 0, |
| /// ]); |
| /// ``` |
| /// |
| /// A sepia-toned color matrix (values based on the [Filter Effects Spec](https://www.w3.org/TR/filter-effects-1/#sepiaEquivalent)): |
| /// |
| /// ``` |
| /// const ColorFilter sepia = ColorFilter.matrix(<double>[ |
| /// 0.393, 0.769, 0.189, 0, 0, |
| /// 0.349, 0.686, 0.168, 0, 0, |
| /// 0.272, 0.534, 0.131, 0, 0, |
| /// 0, 0, 0, 1, 0, |
| /// ]); |
| /// ``` |
| /// |
| /// A greyscale color filter (values based on the [Filter Effects Spec](https://www.w3.org/TR/filter-effects-1/#grayscaleEquivalent)): |
| /// |
| /// ``` |
| /// const ColorFilter greyscale = ColorFilter.matrix(<double>[ |
| /// 0.2126, 0.7152, 0.0722, 0, 0, |
| /// 0.2126, 0.7152, 0.0722, 0, 0, |
| /// 0.2126, 0.7152, 0.0722, 0, 0, |
| /// 0, 0, 0, 1, 0, |
| /// ]); |
| /// ``` |
| const EngineColorFilter.matrix(List<double> matrix) |
| : _color = null, |
| _blendMode = null, |
| _matrix = matrix, |
| _type = _TypeMatrix; |
| |
| /// Construct a color filter that applies the sRGB gamma curve to the RGB |
| /// channels. |
| const EngineColorFilter.linearToSrgbGamma() |
| : _color = null, |
| _blendMode = null, |
| _matrix = null, |
| _type = _TypeLinearToSrgbGamma; |
| |
| /// Creates a color filter that applies the inverse of the sRGB gamma curve |
| /// to the RGB channels. |
| const EngineColorFilter.srgbToLinearGamma() |
| : _color = null, |
| _blendMode = null, |
| _matrix = null, |
| _type = _TypeSrgbToLinearGamma; |
| |
| final ui.Color _color; |
| final ui.BlendMode _blendMode; |
| final List<double> _matrix; |
| final int _type; |
| |
| // The type of SkColorFilter class to create for Skia. |
| static const int _TypeMode = 1; // MakeModeFilter |
| static const int _TypeMatrix = 2; // MakeMatrixFilterRowMajor255 |
| static const int _TypeLinearToSrgbGamma = 3; // MakeLinearToSRGBGamma |
| static const int _TypeSrgbToLinearGamma = 4; // MakeSRGBToLinearGamma |
| |
| @override |
| bool operator ==(dynamic other) { |
| if (other is! EngineColorFilter) { |
| return false; |
| } |
| final EngineColorFilter typedOther = other; |
| |
| if (_type != typedOther._type) { |
| return false; |
| } |
| if (!_listEquals<double>(_matrix, typedOther._matrix)) { |
| return false; |
| } |
| |
| return _color == typedOther._color && _blendMode == typedOther._blendMode; |
| } |
| |
| SkColorFilter _toSkColorFilter() { |
| switch (_type) { |
| case _TypeMode: |
| if (_color == null || _blendMode == null) { |
| return null; |
| } |
| return SkColorFilter.mode(this); |
| case _TypeMatrix: |
| if (_matrix == null) { |
| return null; |
| } |
| assert(_matrix.length == 20, 'Color Matrix must have 20 entries.'); |
| return SkColorFilter.matrix(this); |
| case _TypeLinearToSrgbGamma: |
| return SkColorFilter.linearToSrgbGamma(this); |
| case _TypeSrgbToLinearGamma: |
| return SkColorFilter.srgbToLinearGamma(this); |
| default: |
| throw StateError('Unknown mode $_type for ColorFilter.'); |
| } |
| } |
| |
| @override |
| int get hashCode => ui.hashValues(_color, _blendMode, ui.hashList(_matrix), _type); |
| |
| @override |
| String toString() { |
| switch (_type) { |
| case _TypeMode: |
| return 'ColorFilter.mode($_color, $_blendMode)'; |
| case _TypeMatrix: |
| return 'ColorFilter.matrix($_matrix)'; |
| case _TypeLinearToSrgbGamma: |
| return 'ColorFilter.linearToSrgbGamma()'; |
| case _TypeSrgbToLinearGamma: |
| return 'ColorFilter.srgbToLinearGamma()'; |
| default: |
| return 'Unknown ColorFilter type. This is an error. If you\'re seeing this, please file an issue at https://github.com/flutter/flutter/issues/new.'; |
| } |
| } |
| |
| List<dynamic> webOnlySerializeToCssPaint() { |
| throw UnsupportedError('ColorFilter for CSS paint not yet supported'); |
| } |
| } |