feat: WIP dialog window.

src/Ursa/Controls/Dialog/OverlayDialogHost.cs

@@ -1,14 +1,26 @@
+using System.Collections.Specialized;
 using Avalonia;
 using Avalonia.Controls;
 using Avalonia.Controls.Primitives;
+using Avalonia.Controls.Shapes;
 using Avalonia.Input;
 using Avalonia.Media;
 using Avalonia.Utilities;
+using Avalonia.VisualTree;
 
-namespace Ursa.Controls;
+namespace Ursa.Controls; 
 
 public class OverlayDialogHost: Canvas
 {
+    private readonly List<DialogControl> _dialogs = new();
+    private readonly List<DialogControl> _modalDialogs = new();
+
+    private Rectangle _overlayMask = new()
+    {
+        Fill = new SolidColorBrush(new Color(1, 0, 0, 0)),
+        [Rectangle.ZIndexProperty] = 0,
+    };
+    
     public static readonly StyledProperty<string> HostIdProperty = AvaloniaProperty.Register<OverlayDialogHost, string>(
         nameof(HostId));
 
@@ -39,13 +51,18 @@ public class OverlayDialogHost: Canvas
         {
             if (e.GetCurrentPoint(this).Properties.IsLeftButtonPressed)
             {
+                var parent  = item.FindAncestorOfType<DialogControl>();
+                if (parent is null)
+                {
+                    return;
+                }
                 var p = e.GetPosition(this);
                 var left=  p.X - _lastPoint.X;
                 var top = p.Y - _lastPoint.Y;
-                left = MathUtilities.Clamp(left, 0, Bounds.Width - item.Bounds.Width);
-                top = MathUtilities.Clamp(top, 0, Bounds.Height - item.Bounds.Height);
-                Canvas.SetLeft(item, left);
-                Canvas.SetTop(item, top);
+                left = MathUtilities.Clamp(left, 0, Bounds.Width - parent.Bounds.Width);
+                top = MathUtilities.Clamp(top, 0, Bounds.Height - parent.Bounds.Height);
+                Canvas.SetLeft(parent, left);
+                Canvas.SetTop(parent, top);
             }
         }
     }
@@ -55,7 +72,22 @@ public class OverlayDialogHost: Canvas
         base.OnPointerPressed(e);
         if (e.Source is Control item)
         {
-            _lastPoint = e.GetPosition(item);
+            var parent  = item.FindAncestorOfType<DialogControl>();
+            if (parent is null)
+            {
+                return;
+            }
+            _lastPoint = e.GetPosition(parent);
         }
     }
+
+    public void AddDialog(DialogControl control)
+    {
+        this.Children.Add(control);
+    }
+
+    public void AddModalDialog(DialogControl control)
+    {
+        this.Children.Add(control);
+    }
 }