More UI improvements

2024-06-25 23:08:45 +01:00
parent 942331aa17
commit c646036b73
4 changed files with 96 additions and 11 deletions
@@ -0,0 +1,75 @@
+using Avalonia.Media;
+using System.Security.Cryptography;
+using System.Text;
+
+namespace Toolkit.UI.Controls.Avalonia;
+
+public class PersonPictureColourGenerator
+{
+    private readonly float hue;
+    private readonly float saturation;
+    private readonly float lightness;
+    private const float minLightness = 0.2f;
+    private const float maxLightness = 0.8f;
+
+    public PersonPictureColourGenerator(float hue = 210, 
+        float saturation = 0.8f,
+        float lightness = 0.6f)
+    {
+        this.hue = hue;
+        this.saturation = saturation;
+        this.lightness = lightness;
+    }
+
+    public Color Create(string input)
+    {
+        byte[] hashBytes = GetHash(input);
+
+        float h = (hashBytes[0] + hue) % 360;
+        float s = (hashBytes[1] / 255.0f) * saturation;
+        float l = EnsureNonExtremeLightness((hashBytes[2] / 255.0f) * lightness);
+
+        (byte r, byte g, byte b) = HslToRgb(h, s, l);
+
+        return Color.FromRgb(r, g, b);
+    }
+
+    private byte[] GetHash(string input) => 
+        SHA256.HashData(Encoding.UTF8.GetBytes(input));
+
+    private float EnsureNonExtremeLightness(float calculatedLightness) => 
+        calculatedLightness < minLightness ? minLightness : calculatedLightness > maxLightness ?
+        maxLightness : calculatedLightness;
+
+    private (byte r, byte g, byte b) HslToRgb(float h, float s, float l)
+    {
+        h /= 360;
+        float r, g, b;
+
+        if (s == 0)
+        {
+            r = g = b = l;
+        }
+        else
+        {
+            float q = l < 0.5f ? l * (1 + s) : l + s - l * s;
+            float p = 2 * l - q;
+
+            r = HueToRgb(p, q, h + 1.0f / 3.0f);
+            g = HueToRgb(p, q, h);
+            b = HueToRgb(p, q, h - 1.0f / 3.0f);
+        }
+
+        return ((byte)(r * 255), (byte)(g * 255), (byte)(b * 255));
+    }
+
+    private float HueToRgb(float p, float q, float t)
+    {
+        if (t < 0) t += 1;
+        if (t > 1) t -= 1;
+        if (t < 1.0f / 6.0f) return p + (q - p) * 6 * t;
+        if (t < 1.0f / 2.0f) return q;
+        if (t < 2.0f / 3.0f) return p + (q - p) * (2.0f / 3.0f - t) * 6;
+        return p;
+    }
+}