[New Control] Descriptions (#791)

* feat: add ColumnWrapPanel.

* feat: add Descriptions and DescriptionsItem controls

* WIP: extract a LabeledContentControl for this particular need.

* wip.

* feat: setup demo. fix various initial status issue.

* fix: fix a layout issue.

* feat: improve demo.

* feat: update demo.

* fix: remove a redundant calculation.

* feat: update per copilot feedback.

* feat: add tests, fix a calculation issue.

* feat: refactor to change the default label and value binding assignment logic.

* feat: introduce orientation.

* misc: format codes.

* feat: clarify LabelPosition property.

* feat: extract Font resources.

* revert AvatarDemo.

* feat: assign specific value to Font resources for testing.

* misc: resolve copilot comment.

---------

Co-authored-by: Zhang Dian <54255897+zdpcdt@users.noreply.github.com>

tests/HeadlessTest.Ursa/Controls/DescriptionTests/Test.cs

@@ -0,0 +1,183 @@
+using Avalonia.Controls;
+using Avalonia.Data;
+using Avalonia.Headless.XUnit;
+using Avalonia.LogicalTree;
+using Ursa.Common;
+using Ursa.Controls;
+
+namespace HeadlessTest.Ursa.Controls.DescriptionTests;
+
+public class Test
+{
+    [AvaloniaFact]
+    public void Descriptions_LabelPosition_Propagates_To_DescriptionItems()
+    {
+        var descriptions = new Descriptions
+        {
+            LabelPosition = Position.Left,
+            ItemsSource = new[]
+            {
+                new { Label = "Name", Content = "John Doe" },
+                new { Label = "Age", Content = "30" }
+            },
+            LabelMemberBinding = new Binding("Label"),
+        };
+        var window = new Window
+        {
+            Content = descriptions
+        };
+
+        window.Show();
+
+        var items = descriptions.GetLogicalChildren().OfType<DescriptionsItem>().ToList();
+        foreach (var item in items)
+        {
+            Assert.Equal(Position.Left, item.LabelPosition);
+        }
+
+        descriptions.LabelPosition = Position.Top;
+        foreach (var item in items)
+        {
+            Assert.Equal(Position.Top, item.LabelPosition);
+        }
+    }
+
+    [AvaloniaFact]
+    public void Inline_Descriptions_LabelPosition_Overrides_Parent_Descriptions()
+    {
+        var descriptions = new Descriptions
+        {
+            LabelPosition = Position.Left,
+            Items =
+            {
+                new DescriptionsItem()
+                {
+                    Label = "Name",
+                    Content = "John Doe",
+                    LabelPosition = Position.Top
+                },
+                new DescriptionsItem()
+                {
+                    Label = "Age",
+                    Content = "30",
+                }
+            }
+        };
+        var window = new Window
+        {
+            Content = descriptions
+        };
+
+        window.Show();
+
+        var items = descriptions.GetLogicalChildren().OfType<DescriptionsItem>().ToList();
+        Assert.Equal(Position.Top, items[0].LabelPosition);
+        Assert.Equal(Position.Left, items[1].LabelPosition);
+
+        descriptions.LabelPosition = Position.Top;
+        Assert.Equal(Position.Top, items[0].LabelPosition);
+        Assert.Equal(Position.Top, items[1].LabelPosition);
+    }
+
+    [AvaloniaFact]
+    public void Descriptions_ItemAlignment_Propagates_To_DescriptionItems()
+    {
+        var descriptions = new Descriptions
+        {
+            LabelPosition = Position.Left,
+            ItemsSource = new[]
+            {
+                new { Label = "Name", Content = "John Doe" },
+                new { Label = "Age", Content = "30" }
+            },
+            ItemAlignment = ItemAlignment.Center,
+            LabelMemberBinding = new Binding("Label"),
+        };
+        var window = new Window
+        {
+            Content = descriptions
+        };
+
+        window.Show();
+
+        var items = descriptions.GetLogicalChildren().OfType<DescriptionsItem>().ToList();
+        foreach (var item in items)
+        {
+            Assert.Equal(ItemAlignment.Center, item.ItemAlignment);
+        }
+
+        descriptions.ItemAlignment = ItemAlignment.Justify;
+        foreach (var item in items)
+        {
+            Assert.Equal(ItemAlignment.Justify, item.ItemAlignment);
+        }
+    }
+
+    [AvaloniaFact]
+    public void Inline_Descriptions_ItemAlignment_Overrides_Parent_Descriptions()
+    {
+        var descriptions = new Descriptions
+        {
+            ItemAlignment = ItemAlignment.Center,
+            Items =
+            {
+                new DescriptionsItem()
+                {
+                    Label = "Name",
+                    Content = "John Doe",
+                    ItemAlignment = ItemAlignment.Justify
+                },
+                new DescriptionsItem()
+                {
+                    Label = "Age",
+                    Content = "30",
+                }
+            }
+        };
+        var window = new Window
+        {
+            Content = descriptions
+        };
+
+        window.Show();
+
+        var items = descriptions.GetLogicalChildren().OfType<DescriptionsItem>().ToList();
+        Assert.Equal(ItemAlignment.Justify, items[0].ItemAlignment);
+        Assert.Equal(ItemAlignment.Center, items[1].ItemAlignment);
+
+        descriptions.ItemAlignment = ItemAlignment.Left;
+        Assert.Equal(ItemAlignment.Justify, items[0].ItemAlignment);
+        Assert.Equal(ItemAlignment.Left, items[1].ItemAlignment);
+    }
+
+    [AvaloniaFact]
+    public void Descriptions_LabelWidth_Propagates_To_DescriptionItems()
+    {
+        var descriptions = new Descriptions
+        {
+            LabelWidth = new GridLength(100),
+            ItemsSource = new[]
+            {
+                new { Label = "Name", Content = "John Doe" },
+                new { Label = "Age", Content = "30" }
+            },
+            LabelMemberBinding = new Binding("Label"),
+        };
+        var window = new Window
+        {
+            Content = descriptions
+        };
+        window.Show();
+        var items = descriptions.GetLogicalChildren().OfType<DescriptionsItem>().ToList();
+        foreach (var item in items)
+        {
+            Assert.Equal(100, item.LabelWidth);
+        }
+
+        descriptions.LabelWidth = new GridLength(150);
+        foreach (var item in items)
+        {
+            Assert.Equal(150, item.LabelWidth);
+        }
+    }
+}