Jumar Macato
5 years ago
committed by
GitHub
GitHub
6 changed files with 1120 additions and 186 deletions
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// Color conversion portions of this source file are adapted from the Windows Community Toolkit project.
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// (https://github.com/CommunityToolkit/WindowsCommunityToolkit)
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//
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// Licensed to The Avalonia Project under MIT License, courtesy of The .NET Foundation.
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using System; |
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using System.Globalization; |
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using System.Text; |
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using Avalonia.Utilities; |
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namespace Avalonia.Media |
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{ |
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/// <summary>
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/// Defines a color using the hue/saturation/lightness (HSL) model.
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/// </summary>
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#if !BUILDTASK
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public |
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#endif
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readonly struct HslColor : IEquatable<HslColor> |
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{ |
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/// <summary>
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/// Initializes a new instance of the <see cref="HslColor"/> struct.
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/// </summary>
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/// <param name="alpha">The Alpha (transparency) component in the range from 0..1.</param>
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/// <param name="hue">The Hue component in the range from 0..360.
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/// Note that 360 is equivalent to 0 and will be adjusted automatically.</param>
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/// <param name="saturation">The Saturation component in the range from 0..1.</param>
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/// <param name="lightness">The Lightness component in the range from 0..1.</param>
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public HslColor( |
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double alpha, |
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double hue, |
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double saturation, |
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double lightness) |
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{ |
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A = MathUtilities.Clamp(alpha, 0.0, 1.0); |
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H = MathUtilities.Clamp(hue, 0.0, 360.0); |
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S = MathUtilities.Clamp(saturation, 0.0, 1.0); |
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L = MathUtilities.Clamp(lightness, 0.0, 1.0); |
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// The maximum value of Hue is technically 360 minus epsilon (just below 360).
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// This is because, in a color circle, 360 degrees is equivalent to 0 degrees.
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// However, that is too tricky to work with in code and isn't as intuitive.
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// Therefore, since 360 == 0, just wrap 360 if needed back to 0.
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H = (H == 360.0 ? 0 : H); |
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} |
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/// <summary>
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/// Initializes a new instance of the <see cref="HslColor"/> struct.
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/// </summary>
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/// <remarks>
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/// This constructor exists only for internal use where performance is critical.
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/// Whether or not the component values are in the correct ranges must be known.
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/// </remarks>
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/// <param name="alpha">The Alpha (transparency) component in the range from 0..1.</param>
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/// <param name="hue">The Hue component in the range from 0..360.
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/// Note that 360 is equivalent to 0 and will be adjusted automatically.</param>
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/// <param name="saturation">The Saturation component in the range from 0..1.</param>
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/// <param name="lightness">The Lightness component in the range from 0..1.</param>
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/// <param name="clampValues">Whether to clamp component values to their required ranges.</param>
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internal HslColor( |
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double alpha, |
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double hue, |
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double saturation, |
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double lightness, |
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bool clampValues) |
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{ |
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if (clampValues) |
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{ |
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A = MathUtilities.Clamp(alpha, 0.0, 1.0); |
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H = MathUtilities.Clamp(hue, 0.0, 360.0); |
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S = MathUtilities.Clamp(saturation, 0.0, 1.0); |
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L = MathUtilities.Clamp(lightness, 0.0, 1.0); |
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// See comments in constructor above
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H = (H == 360.0 ? 0 : H); |
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} |
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else |
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{ |
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A = alpha; |
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H = hue; |
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S = saturation; |
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L = lightness; |
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} |
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} |
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/// <summary>
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/// Initializes a new instance of the <see cref="HslColor"/> struct.
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/// </summary>
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/// <param name="color">The RGB color to convert to HSL.</param>
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public HslColor(Color color) |
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{ |
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var hsl = Color.ToHsl(color); |
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A = hsl.A; |
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H = hsl.H; |
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S = hsl.S; |
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L = hsl.L; |
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} |
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/// <summary>
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/// Gets the Alpha (transparency) component in the range from 0..1.
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/// </summary>
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public double A { get; } |
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/// <summary>
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/// Gets the Hue component in the range from 0..360.
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/// Note that 360 is equivalent to 0 and will be adjusted automatically.
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/// </summary>
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public double H { get; } |
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/// <summary>
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/// Gets the Saturation component in the range from 0..1.
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/// </summary>
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public double S { get; } |
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/// <summary>
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/// Gets the Lightness component in the range from 0..1.
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/// </summary>
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public double L { get; } |
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/// <inheritdoc/>
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public bool Equals(HslColor other) |
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{ |
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return other.A == A && |
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other.H == H && |
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other.S == S && |
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other.L == L; |
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} |
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/// <inheritdoc/>
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public override bool Equals(object? obj) |
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{ |
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if (obj is HslColor hslColor) |
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{ |
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return Equals(hslColor); |
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} |
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else |
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{ |
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return false; |
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} |
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} |
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/// <summary>
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/// Gets a hashcode for this object.
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/// Hashcode is not guaranteed to be unique.
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/// </summary>
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/// <returns>The hashcode for this object.</returns>
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public override int GetHashCode() |
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{ |
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// Same algorithm as Color
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// This is used instead of HashCode.Combine() due to .NET Standard 2.0 requirements
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unchecked |
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{ |
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int hashCode = A.GetHashCode(); |
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hashCode = (hashCode * 397) ^ H.GetHashCode(); |
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hashCode = (hashCode * 397) ^ S.GetHashCode(); |
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hashCode = (hashCode * 397) ^ L.GetHashCode(); |
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return hashCode; |
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} |
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} |
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/// <summary>
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/// Returns the RGB color model equivalent of this HSL color.
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/// </summary>
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/// <returns>The RGB equivalent color.</returns>
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public Color ToRgb() |
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{ |
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// Use the by-component conversion method directly for performance
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return HslColor.ToRgb(H, S, L, A); |
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} |
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/// <inheritdoc/>
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public override string ToString() |
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{ |
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var sb = new StringBuilder(); |
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// Use a format similar to CSS. However:
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// - To ensure precision is never lost, allow decimal places.
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// This is especially important for round-trip serialization.
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// - To maintain numerical consistency, do not use percent.
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//
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// Example:
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//
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// hsla(hue, saturation, lightness, alpha)
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// hsla(230, 1.0, 0.5, 1.0)
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//
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sb.Append("hsva("); |
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sb.Append(H.ToString(CultureInfo.InvariantCulture)); |
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sb.Append(", "); |
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sb.Append(S.ToString(CultureInfo.InvariantCulture)); |
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sb.Append(", "); |
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sb.Append(L.ToString(CultureInfo.InvariantCulture)); |
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sb.Append(", "); |
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sb.Append(A.ToString(CultureInfo.InvariantCulture)); |
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sb.Append(')'); |
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return sb.ToString(); |
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} |
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/// <summary>
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/// Parses an HSL color string.
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/// </summary>
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/// <param name="s">The HSL color string to parse.</param>
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/// <returns>The parsed <see cref="HslColor"/>.</returns>
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public static HslColor Parse(string s) |
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{ |
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if (s is null) |
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{ |
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throw new ArgumentNullException(nameof(s)); |
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} |
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if (TryParse(s, out HslColor hslColor)) |
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{ |
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return hslColor; |
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} |
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throw new FormatException($"Invalid HSL color string: '{s}'."); |
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} |
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/// <summary>
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/// Parses an HSL color string.
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/// </summary>
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/// <param name="s">The HSL color string to parse.</param>
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/// <param name="hslColor">The parsed <see cref="HslColor"/>.</param>
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/// <returns>True if parsing was successful; otherwise, false.</returns>
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public static bool TryParse(string s, out HslColor hslColor) |
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{ |
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hslColor = default; |
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if (s is null) |
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{ |
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return false; |
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} |
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string workingString = s.Trim(); |
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if (workingString.Length == 0 || |
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workingString.IndexOf(",", StringComparison.Ordinal) < 0) |
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{ |
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return false; |
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} |
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if (workingString.Length > 6 && |
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workingString.StartsWith("hsla(", StringComparison.OrdinalIgnoreCase) && |
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workingString.EndsWith(")", StringComparison.Ordinal)) |
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{ |
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workingString = workingString.Substring(5, workingString.Length - 6); |
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} |
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if (workingString.Length > 5 && |
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workingString.StartsWith("hsl(", StringComparison.OrdinalIgnoreCase) && |
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workingString.EndsWith(")", StringComparison.Ordinal)) |
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{ |
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workingString = workingString.Substring(4, workingString.Length - 5); |
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} |
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string[] components = workingString.Split(','); |
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if (components.Length == 3) // HSL
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{ |
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if (double.TryParse(components[0], NumberStyles.Number, CultureInfo.InvariantCulture, out double hue) && |
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TryInternalParse(components[1], out double saturation) && |
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TryInternalParse(components[2], out double lightness)) |
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{ |
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hslColor = new HslColor(1.0, hue, saturation, lightness); |
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return true; |
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} |
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} |
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else if (components.Length == 4) // HSLA
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{ |
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if (double.TryParse(components[0], NumberStyles.Number, CultureInfo.InvariantCulture, out double hue) && |
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TryInternalParse(components[1], out double saturation) && |
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TryInternalParse(components[2], out double lightness) && |
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TryInternalParse(components[3], out double alpha)) |
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{ |
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hslColor = new HslColor(alpha, hue, saturation, lightness); |
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return true; |
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} |
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} |
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// Local function to specially parse a double value with an optional percentage sign
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bool TryInternalParse(string inString, out double outDouble) |
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{ |
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// The percent sign, if it exists, must be at the end of the number
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int percentIndex = inString.IndexOf("%", StringComparison.Ordinal); |
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if (percentIndex >= 0) |
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{ |
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var result = double.TryParse( |
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inString.Substring(0, percentIndex), |
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NumberStyles.Number, |
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CultureInfo.InvariantCulture, |
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out double percentage); |
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outDouble = percentage / 100.0; |
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return result; |
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} |
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else |
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{ |
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return double.TryParse( |
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inString, |
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NumberStyles.Number, |
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CultureInfo.InvariantCulture, |
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out outDouble); |
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} |
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} |
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return false; |
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} |
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/// <summary>
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/// Creates a new <see cref="HslColor"/> from individual color component values.
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/// </summary>
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/// <remarks>
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/// This exists for symmetry with the <see cref="Color"/> struct; however, the
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/// appropriate constructor should commonly be used instead.
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/// </remarks>
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/// <param name="a">The Alpha (transparency) component in the range from 0..1.</param>
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/// <param name="h">The Hue component in the range from 0..360.</param>
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/// <param name="s">The Saturation component in the range from 0..1.</param>
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/// <param name="l">The Lightness component in the range from 0..1.</param>
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/// <returns>A new <see cref="HslColor"/> built from the individual color component values.</returns>
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public static HslColor FromAhsl(double a, double h, double s, double l) |
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{ |
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return new HslColor(a, h, s, l); |
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} |
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/// <summary>
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/// Creates a new <see cref="HslColor"/> from individual color component values.
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/// </summary>
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/// <remarks>
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/// This exists for symmetry with the <see cref="Color"/> struct; however, the
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/// appropriate constructor should commonly be used instead.
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/// </remarks>
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/// <param name="h">The Hue component in the range from 0..360.</param>
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/// <param name="s">The Saturation component in the range from 0..1.</param>
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/// <param name="l">The Lightness component in the range from 0..1.</param>
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/// <returns>A new <see cref="HslColor"/> built from the individual color component values.</returns>
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public static HslColor FromHsl(double h, double s, double l) |
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{ |
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return new HslColor(1.0, h, s, l); |
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} |
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/// <summary>
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/// Converts the given HSL color to its RGB color equivalent.
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/// </summary>
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/// <param name="hslColor">The color in the HSL color model.</param>
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/// <returns>A new RGB <see cref="Color"/> equivalent to the given HSLA values.</returns>
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public static Color ToRgb(HslColor hslColor) |
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{ |
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return HslColor.ToRgb(hslColor.H, hslColor.S, hslColor.L, hslColor.A); |
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} |
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/// <summary>
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/// Converts the given HSLA color component values to their RGB color equivalent.
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/// </summary>
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/// <param name="hue">The Hue component in the HSL color model in the range from 0..360.</param>
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/// <param name="saturation">The Saturation component in the HSL color model in the range from 0..1.</param>
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/// <param name="lightness">The Lightness component in the HSL color model in the range from 0..1.</param>
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/// <param name="alpha">The Alpha component in the range from 0..1.</param>
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/// <returns>A new RGB <see cref="Color"/> equivalent to the given HSLA values.</returns>
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public static Color ToRgb( |
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double hue, |
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double saturation, |
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double lightness, |
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double alpha = 1.0) |
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{ |
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// Note: Conversion code is originally based on ColorHelper in the Windows Community Toolkit (licensed MIT)
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// https://github.com/CommunityToolkit/WindowsCommunityToolkit/blob/main/Microsoft.Toolkit.Uwp/Helpers/ColorHelper.cs
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// It has been modified to ensure input ranges and not throw exceptions.
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// We want the hue to be between 0 and 359,
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// so we first ensure that that's the case.
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while (hue >= 360.0) |
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{ |
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hue -= 360.0; |
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} |
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while (hue < 0.0) |
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{ |
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hue += 360.0; |
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} |
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// We similarly clamp saturation, lightness and alpha between 0 and 1.
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saturation = saturation < 0.0 ? 0.0 : saturation; |
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saturation = saturation > 1.0 ? 1.0 : saturation; |
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lightness = lightness < 0.0 ? 0.0 : lightness; |
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lightness = lightness > 1.0 ? 1.0 : lightness; |
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alpha = alpha < 0.0 ? 0.0 : alpha; |
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alpha = alpha > 1.0 ? 1.0 : alpha; |
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double chroma = (1 - Math.Abs((2 * lightness) - 1)) * saturation; |
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double h1 = hue / 60; |
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double x = chroma * (1 - Math.Abs((h1 % 2) - 1)); |
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double m = lightness - (0.5 * chroma); |
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double r1, g1, b1; |
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if (h1 < 1) |
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{ |
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r1 = chroma; |
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g1 = x; |
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b1 = 0; |
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} |
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else if (h1 < 2) |
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{ |
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r1 = x; |
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g1 = chroma; |
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b1 = 0; |
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} |
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else if (h1 < 3) |
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{ |
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r1 = 0; |
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g1 = chroma; |
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b1 = x; |
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} |
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else if (h1 < 4) |
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{ |
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r1 = 0; |
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g1 = x; |
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b1 = chroma; |
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} |
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else if (h1 < 5) |
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{ |
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r1 = x; |
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g1 = 0; |
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b1 = chroma; |
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} |
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else |
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{ |
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r1 = chroma; |
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g1 = 0; |
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b1 = x; |
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} |
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return Color.FromArgb( |
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(byte)Math.Round(255 * alpha), |
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(byte)Math.Round(255 * (r1 + m)), |
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(byte)Math.Round(255 * (g1 + m)), |
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(byte)Math.Round(255 * (b1 + m))); |
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} |
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/// <summary>
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/// Indicates whether the values of two specified <see cref="HslColor"/> objects are equal.
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/// </summary>
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/// <param name="left">The first object to compare.</param>
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/// <param name="right">The second object to compare.</param>
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/// <returns>True if left and right are equal; otherwise, false.</returns>
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public static bool operator ==(HslColor left, HslColor right) |
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{ |
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return left.Equals(right); |
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} |
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/// <summary>
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/// Indicates whether the values of two specified <see cref="HslColor"/> objects are not equal.
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/// </summary>
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/// <param name="left">The first object to compare.</param>
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/// <param name="right">The second object to compare.</param>
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/// <returns>True if left and right are not equal; otherwise, false.</returns>
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public static bool operator !=(HslColor left, HslColor right) |
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{ |
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return !(left == right); |
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} |
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/// <summary>
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/// Explicit conversion from an <see cref="HslColor"/> to a <see cref="Color"/>.
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/// </summary>
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/// <param name="hslColor">The <see cref="HslColor"/> to convert.</param>
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public static explicit operator Color(HslColor hslColor) |
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{ |
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return hslColor.ToRgb(); |
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} |
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} |
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} |
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