TheXamlGuy
76 lines
2.1 KiB
C#
76 lines
2.1 KiB
C#
using Avalonia.Media;
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using System.Security.Cryptography;
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using System.Text;
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namespace Toolkit.UI.Controls.Avalonia;
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public class PersonPictureColourGenerator
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{
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private readonly float hue;
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private readonly float saturation;
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private readonly float lightness;
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private const float minLightness = 0.2f;
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private const float maxLightness = 0.8f;
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public PersonPictureColourGenerator(float hue = 210,
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float saturation = 0.8f,
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float lightness = 0.6f)
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{
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this.hue = hue;
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this.saturation = saturation;
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this.lightness = lightness;
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}
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public Color Create(string input)
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{
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byte[] hashBytes = GetHash(input);
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float h = (hashBytes[0] + hue) % 360;
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float s = (hashBytes[1] / 255.0f) * saturation;
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float l = EnsureNonExtremeLightness((hashBytes[2] / 255.0f) * lightness);
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(byte r, byte g, byte b) = HslToRgb(h, s, l);
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return Color.FromRgb(r, g, b);
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}
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private byte[] GetHash(string input) =>
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SHA256.HashData(Encoding.UTF8.GetBytes(input));
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private float EnsureNonExtremeLightness(float calculatedLightness) =>
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calculatedLightness < minLightness ? minLightness : calculatedLightness > maxLightness ?
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maxLightness : calculatedLightness;
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private (byte r, byte g, byte b) HslToRgb(float h, float s, float l)
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{
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h /= 360;
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float r, g, b;
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if (s == 0)
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{
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r = g = b = l;
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}
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else
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{
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float q = l < 0.5f ? l * (1 + s) : l + s - l * s;
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float p = 2 * l - q;
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r = HueToRgb(p, q, h + 1.0f / 3.0f);
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g = HueToRgb(p, q, h);
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b = HueToRgb(p, q, h - 1.0f / 3.0f);
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}
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return ((byte)(r * 255), (byte)(g * 255), (byte)(b * 255));
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}
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private float HueToRgb(float p, float q, float t)
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{
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if (t < 0) t += 1;
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if (t > 1) t -= 1;
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if (t < 1.0f / 6.0f) return p + (q - p) * 6 * t;
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if (t < 1.0f / 2.0f) return q;
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if (t < 2.0f / 3.0f) return p + (q - p) * (2.0f / 3.0f - t) * 6;
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return p;
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}
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}
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