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Merge pull request #7894 from robloo/hsvcolor-strings 

Add HsvColor.ToString() and TryParse()
pull/7921/head
Max Katz 5 years ago
committed by GitHub
parent
df9a221ab1 ec1a393295
commit
69b462b0f9
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2 changed files with 140 additions and 3 deletions
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  1. 2
      src/Avalonia.Visuals/Media/Color.cs
  2. 141
      src/Avalonia.Visuals/Media/HsvColor.cs

2
src/Avalonia.Visuals/Media/Color.cs
View File

@ -258,7 +258,7 @@ namespace Avalonia.Media
public override string ToString()
{
uint rgb = ToUint32();
return KnownColors.GetKnownColorName(rgb) ?? $"#{rgb:x8}";
return KnownColors.GetKnownColorName(rgb) ?? $"#{rgb.ToString("x8", CultureInfo.InvariantCulture)}";
}
/// <summary>

141
src/Avalonia.Visuals/Media/HsvColor.cs
View File

@ -4,6 +4,8 @@
// Licensed to The Avalonia Project under MIT License, courtesy of The .NET Foundation.
using System;
using System.Globalization;
using System.Text;
using Avalonia.Utilities;
namespace Avalonia.Media
@ -20,7 +22,8 @@ namespace Avalonia.Media
/// Initializes a new instance of the <see cref="HsvColor"/> struct.
/// </summary>
/// <param name="alpha">The Alpha (transparency) channel value in the range from 0..1.</param>
/// <param name="hue">The Hue channel value in the range from 0..360.</param>
/// <param name="hue">The Hue channel value in the range from 0..360.
/// Note that 360 is equivalent to 0 and will be adjusted automatically.</param>
/// <param name="saturation">The Saturation channel value in the range from 0..1.</param>
/// <param name="value">The Value channel value in the range from 0..1.</param>
public HsvColor(
@ -33,6 +36,12 @@ namespace Avalonia.Media
H = MathUtilities.Clamp(hue, 0.0, 360.0);
S = MathUtilities.Clamp(saturation, 0.0, 1.0);
V = MathUtilities.Clamp(value, 0.0, 1.0);
// The maximum value of Hue is technically 360 minus epsilon (just below 360).
// This is because, in a color circle, 360 degrees is equivalent to 0 degrees.
// However, that is too tricky to work with in code and isn't as intuitive.
// Therefore, since 360 == 0, just wrap 360 if needed back to 0.
H = (H == 360.0 ? 0 : H);
}
/// <summary>
@ -43,7 +52,8 @@ namespace Avalonia.Media
/// Whether or not the channel values are in the correct ranges must be known.
/// </remarks>
/// <param name="alpha">The Alpha (transparency) channel value in the range from 0..1.</param>
/// <param name="hue">The Hue channel value in the range from 0..360.</param>
/// <param name="hue">The Hue channel value in the range from 0..360.
/// Note that 360 is equivalent to 0 and will be adjusted automatically.</param>
/// <param name="saturation">The Saturation channel value in the range from 0..1.</param>
/// <param name="value">The Value channel value in the range from 0..1.</param>
/// <param name="clampValues">Whether to clamp channel values to their required ranges.</param>
@ -60,6 +70,9 @@ namespace Avalonia.Media
H = MathUtilities.Clamp(hue, 0.0, 360.0);
S = MathUtilities.Clamp(saturation, 0.0, 1.0);
V = MathUtilities.Clamp(value, 0.0, 1.0);
// See comments in constructor above
H = (H == 360.0 ? 0 : H);
}
else
{
@ -91,6 +104,7 @@ namespace Avalonia.Media
/// <summary>
/// Gets the Hue channel value in the range from 0..360.
/// Note that 360 is equivalent to 0 and will be adjusted automatically.
/// </summary>
public double H { get; }
@ -155,6 +169,129 @@ namespace Avalonia.Media
return HsvColor.ToRgb(H, S, V, A);
}
/// <inheritdoc/>
public override string ToString()
{
var sb = new StringBuilder();
// Use a format similar to HSL in HTML/CSS "hsla(0, 100%, 50%, 0.5)"
//
// However:
// - To ensure precision is never lost, allow decimal places
// - To maintain numerical consistency do not use percent
//
// Example:
//
// hsva(hue, saturation, value, alpha)
// hsva(230, 1.0, 0.5, 1.0)
//
// Where:
//
// hue : double from 0 to 360
// saturation : double from 0 to 1
// (HTML uses a percentage)
// value : double from 0 to 1
// (HTML uses a percentage)
// alpha : double from 0 to 1
// (HTML does not use a percentage for alpha)
sb.Append("hsva(");
sb.Append(H.ToString(CultureInfo.InvariantCulture));
sb.Append(", ");
sb.Append(S.ToString(CultureInfo.InvariantCulture));
sb.Append(", ");
sb.Append(V.ToString(CultureInfo.InvariantCulture));
sb.Append(", ");
sb.Append(A.ToString(CultureInfo.InvariantCulture));
sb.Append(')');
return sb.ToString();
}
/// <summary>
/// Parses an HSV color string.
/// </summary>
/// <param name="s">The HSV color string to parse.</param>
/// <returns>The parsed <see cref="HsvColor"/>.</returns>
public static HsvColor Parse(string s)
{
if (s is null)
{
throw new ArgumentNullException(nameof(s));
}
if (TryParse(s, out HsvColor hsvColor))
{
return hsvColor;
}
throw new FormatException($"Invalid HSV color string: '{s}'.");
}
/// <summary>
/// Parses an HSV color string.
/// </summary>
/// <param name="s">The HSV color string to parse.</param>
/// <param name="hsvColor">The parsed <see cref="HsvColor"/>.</param>
/// <returns>True if parsing was successful; otherwise, false.</returns>
public static bool TryParse(string s, out HsvColor hsvColor)
{
hsvColor = default;
if (s is null)
{
return false;
}
string workingString = s.Trim();
if (workingString.Length == 0 ||
workingString.IndexOf(",", StringComparison.Ordinal) < 0)
{
return false;
}
if (workingString.Length > 6 &&
workingString.StartsWith("hsva(", StringComparison.OrdinalIgnoreCase) &&
workingString.EndsWith(")", StringComparison.Ordinal))
{
workingString = workingString.Substring(5, workingString.Length - 6);
}
if (workingString.Length > 5 &&
workingString.StartsWith("hsv(", StringComparison.OrdinalIgnoreCase) &&
workingString.EndsWith(")", StringComparison.Ordinal))
{
workingString = workingString.Substring(4, workingString.Length - 5);
}
string[] components = workingString.Split(',');
if (components.Length == 3) // HSV
{
if (double.TryParse(components[0], NumberStyles.Number, CultureInfo.InvariantCulture, out double hue) &&
double.TryParse(components[1], NumberStyles.Number, CultureInfo.InvariantCulture, out double saturation) &&
double.TryParse(components[2], NumberStyles.Number, CultureInfo.InvariantCulture, out double value))
{
hsvColor = new HsvColor(1.0, hue, saturation, value);
return true;
}
}
else if (components.Length == 4) // HSVA
{
if (double.TryParse(components[0], NumberStyles.Number, CultureInfo.InvariantCulture, out double hue) &&
double.TryParse(components[1], NumberStyles.Number, CultureInfo.InvariantCulture, out double saturation) &&
double.TryParse(components[2], NumberStyles.Number, CultureInfo.InvariantCulture, out double value) &&
double.TryParse(components[3], NumberStyles.Number, CultureInfo.InvariantCulture, out double alpha))
{
hsvColor = new HsvColor(alpha, hue, saturation, value);
return true;
}
}
return false;
}
/// <summary>
/// Creates a new <see cref="HsvColor"/> from individual color channel values.
/// </summary>

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