WIP

Toolkit.Avalonia/FrameHandler.cs

@@ -111,28 +111,30 @@ public class FrameHandler :
                 FrameNavigationOptions navigationOptions = new();
                 List<Action> postNavigateActions = [];
 
-                void CleanUp()
+                void CleanUp(int start, int end)
                 {
-                    foreach (PageStackEntry? entry in frame.BackStack)
+                    int startIndex = Math.Max(0, start - 1);
+                    int endIndex = Math.Min(frame.BackStack.Count - 1, end - 1);
+
+                    for (int i = endIndex; i >= startIndex; i--)
                     {
+                        PageStackEntry? entry = frame.BackStack[i];
                         if (entry.Context is Control control)
                         {
-                            if (control.DataContext is object content)
+                            if (control.DataContext is IDisposable disposable)
                             {
-                                if (content is IDisposable disposable)
+                                disposable.Dispose();
-                                {
-                                    disposable.Dispose();
-                                }
                             }
                         }
-                    }
 
-                    frame.BackStack.Clear();
+                        frame.BackStack.RemoveAt(i);
+                    }
                 }
 
                 if (args.Parameters is not null)
                 {
-                    if (args.Parameters.TryGetValue("Transition", out object? transition))
+                    if (args.Parameters.TryGetValue("Transition", 
+                        out object? transition))
                     {
                         switch ($"{transition}")
                         {
@@ -149,7 +151,8 @@ public class FrameHandler :
                         }
                     }
 
-                    if (args.Parameters.TryGetValue("IsBackStackEnabled", out object? isBackStackEnabled))
+                    if (args.Parameters.TryGetValue("IsBackStackEnabled", 
+                        out object? isBackStackEnabled))
                     {
                         if (isBackStackEnabled is bool value)
                         {
@@ -157,24 +160,49 @@ public class FrameHandler :
                         }
                     }
 
-                    if (args.Parameters.TryGetValue("ClearBackStack", out object? clearBackStack))
+                    if (args.Parameters.TryGetValue("ClearBackStack", 
+                        out object? clearBackStack))
                     {
-                        if (clearBackStack is bool value)
+                        if (clearBackStack is bool clearBool)
                         {
-                            if (value)
+                            if (clearBool)
                             {
-                                postNavigateActions.Add(() => CleanUp());
+                                postNavigateActions.Add(() => CleanUp(1, frame.BackStack.Count));
                             }
                         }
+
+                        if (clearBackStack is string clearString)
+                        {
+                            if (clearString.StartsWith('[') && clearString.EndsWith(']') && 
+                                clearString.Contains('-'))
+                            {
+                                string range = clearString.Trim('[', ']');
+                                string[] parts = range.Split('-');
+
+                                if (parts.Length == 2 && int.TryParse(parts[0], out int start) &&
+                                    int.TryParse(parts[1], out int end))
+                                {
+                                    postNavigateActions.Add(() => CleanUp(start, end));
+                                }
+                                else
+                                {
+                                    postNavigateActions.Add(() => CleanUp(1, frame.BackStack.Count));
+                                }
+                            }
+                            else
+                            {
+                                postNavigateActions.Add(() => CleanUp(1, frame.BackStack.Count));
+                            }
+                        } 
                     }
                 }
-                foreach (Action postAction in postNavigateActions)
-                {
-                    postAction.Invoke();
-                }
 
                 frame.NavigateFromObject(control, navigationOptions);
 
+                foreach (Action postAction in postNavigateActions)
+                {
+                    postAction.Invoke();
+                }
             }
         }
 

Toolkit.UI.Controls.Avalonia/PersonPicture/PersonPicture.cs

@@ -42,7 +42,7 @@ public class PersonPicture : TemplatedControl
     private TextBlock? badgeNumberTextBlock;
     private Ellipse? badgingBackgroundEllipse;
     private Ellipse? badgingEllipse;
-    private PersonPictureColourGenerator colourGenerator = new(hue: 210, saturation: 0.8f, lightness: 0.6f);
+    private PersonPictureColourGenerator colourGenerator = new();
     private string? displayNameInitials;
     private TextBlock? initialsTextBlock;
 
@@ -339,7 +339,7 @@ public class PersonPicture : TemplatedControl
 
         if (DisplayName is { Length: > 0 })
         {
-            Color rgb = colourGenerator.Create(DisplayName);
+            Color rgb = colourGenerator.GenerateColour(DisplayName);
             SetValue(BackgroundProperty, new SolidColorBrush(Color.FromArgb(rgb.A, rgb.R, rgb.G, rgb.B)));
         }
 

Toolkit.UI.Controls.Avalonia/PersonPicture/PersonPictureColourGenerator.cs

@@ -6,70 +6,39 @@ namespace Toolkit.UI.Controls.Avalonia;
 
 public class PersonPictureColourGenerator
 {
-    private readonly float hue;
+    private readonly string[] colours =
-    private readonly float saturation;
+    [
-    private readonly float lightness;
+        "#FFB900", "#E81123", "#0078D7", "#0099BC", "#7A7574",
-    private const float minLightness = 0.2f;
+        "#767676", "#FF8C00", "#E81123", "#0063B1", "#2D7D9A",
-    private const float maxLightness = 0.8f;
+        "#5D5A58", "#4C4A48", "#F7630C", "#EA005E", "#8E8CD8",
+        "#0078D7", "#68768A", "#69797E", "#CA5010", "#C30052",
+        "#6B69D6", "#038387", "#515C6B", "#4A5459", "#DA3B01",
+        "#E3008C", "#8764B8", "#00B294", "#567C73", "#647C64"
+    ];
 
-    public PersonPictureColourGenerator(float hue = 210, 
+    public Color GenerateColour(string input)
-        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);
+        int colourIndex = BitConverter.ToInt32(hashBytes, 0) % colours.Length;
+        colourIndex = Math.Abs(colourIndex);
 
-        float h = (hashBytes[0] + hue) % 360;
+        return HexToColour(colours[colourIndex]);
-        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) => 
+    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;
+        return SHA256.HashData(Encoding.UTF8.GetBytes(input));
-        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)
+    private Color HexToColour(string hex)
     {
-        if (t < 0) t += 1;
+        hex = hex.Replace("#", string.Empty);
-        if (t > 1) t -= 1;
+
-        if (t < 1.0f / 6.0f) return p + (q - p) * 6 * t;
+        byte a = 255;
-        if (t < 1.0f / 2.0f) return q;
+        byte r = byte.Parse(hex.Substring(0, 2), System.Globalization.NumberStyles.HexNumber);
-        if (t < 2.0f / 3.0f) return p + (q - p) * (2.0f / 3.0f - t) * 6;
+        byte g = byte.Parse(hex.Substring(2, 2), System.Globalization.NumberStyles.HexNumber);
-        return p;
+        byte b = byte.Parse(hex.Substring(4, 2), System.Globalization.NumberStyles.HexNumber);
+
+        return Color.FromArgb(a, r, g, b);
     }
 }