feat: add placement.

demo/Ursa.Demo/Pages/IconButtonDemo.axaml

@@ -22,6 +22,14 @@
                     Data="{StaticResource iconGlyph}" />
             </u:IconButton.Icon>
         </u:IconButton>
+        <u:IconButton Content="GitHub" IsLoading="{Binding #loading.IsChecked}" IconPlacement="Right">
+            <u:IconButton.Icon>
+                <PathIcon
+                    Width="14"
+                    Height="14"
+                    Data="{StaticResource iconGlyph}" />
+            </u:IconButton.Icon>
+        </u:IconButton>
         <u:IconButton
             Width="150"
             Content="GitHub"

src/Ursa.Themes.Semi/Controls/IconButton.axaml

@@ -33,12 +33,13 @@
                         HorizontalAlignment="{TemplateBinding HorizontalContentAlignment}"
                         VerticalAlignment="{TemplateBinding VerticalContentAlignment}"
                         ColumnDefinitions="Auto, Auto">
-                        <Panel Grid.Column="0" Margin="0,0,4,0">
+                        <Panel
+                            Name="PART_IconRoot"
+                            Grid.Column="0"
+                            Margin="0,0,8,0">
                             <Panel.IsVisible>
                                 <MultiBinding Converter="{x:Static BoolConverters.Or}">
-                                    <Binding
+                                    <Binding Path="IsLoading" RelativeSource="{RelativeSource TemplatedParent}" />
-                                        Path="IsLoading"
-                                        RelativeSource="{RelativeSource TemplatedParent}" />
                                     <Binding
                                         Converter="{x:Static ObjectConverters.IsNotNull}"
                                         Path="Icon"
@@ -54,7 +55,10 @@
                                 Foreground="{TemplateBinding Foreground}"
                                 IsVisible="{TemplateBinding IsLoading}" />
                         </Panel>
-                        <ContentPresenter Grid.Column="1" Content="{TemplateBinding Content}" />
+                        <ContentPresenter
+                            Name="PART_ContentPresenter"
+                            Grid.Column="1"
+                            Content="{TemplateBinding Content}" />
                     </Grid>
                 </Border>
             </ControlTemplate>
@@ -99,6 +103,16 @@
             <Setter Property="Foreground" Value="{DynamicResource ButtonDefaultDisabledForeground}" />
         </Style>
 
+        <Style Selector="^:right">
+            <Style Selector="^ /template/ Panel#PART_IconRoot">
+                <Setter Property="Grid.Column" Value="1" />
+                <Setter Property="Margin" Value="8 0 0 0" />
+            </Style>
+            <Style Selector="^ /template/ ContentPresenter#PART_ContentPresenter">
+                <Setter Property="Grid.Column" Value="0" />
+            </Style>
+        </Style>
+
         <Style Selector="^.Large">
             <Setter Property="Padding" Value="{DynamicResource ButtonLargePadding}" />
         </Style>

src/Ursa/Common/IconPlacement.cs

@@ -0,0 +1,7 @@
+namespace Ursa.Common;
+
+public enum IconPlacement
+{
+    Left,
+    Right,
+}

src/Ursa/Controls/IconButton.cs

@@ -1,11 +1,17 @@
 using Avalonia;
 using Avalonia.Controls;
+using Avalonia.Controls.Metadata;
+using Avalonia.Controls.Primitives;
 using Avalonia.Controls.Templates;
+using Ursa.Common;
 
 namespace Ursa.Controls;
 
+[PseudoClasses(PC_Right)]
 public class IconButton: Button
 {
+    public const string PC_Right = ":right";
+    
     public static readonly StyledProperty<object?> IconProperty = AvaloniaProperty.Register<IconButton, object?>(
         nameof(Icon));
 
@@ -32,4 +38,32 @@ public class IconButton: Button
         get => GetValue(IsLoadingProperty);
         set => SetValue(IsLoadingProperty, value);
     }
+
+    public static readonly StyledProperty<IconPlacement> IconPlacementProperty = AvaloniaProperty.Register<IconButton, IconPlacement>(
+        nameof(IconPlacement), defaultValue: IconPlacement.Left);
+
+    public IconPlacement IconPlacement
+    {
+        get => GetValue(IconPlacementProperty);
+        set => SetValue(IconPlacementProperty, value);
+    }
+
+    static IconButton()
+    {
+        IconPlacementProperty.Changed.AddClassHandler<IconButton, IconPlacement>((o, e) =>
+        {
+            o.SetPlacement(e.NewValue.Value);
+        });
+    }
+
+    protected override void OnApplyTemplate(TemplateAppliedEventArgs e)
+    {
+        base.OnApplyTemplate(e);
+        SetPlacement(IconPlacement);
+    }
+
+    private void SetPlacement(IconPlacement placement)
+    {
+        PseudoClasses.Set(PC_Right, placement == IconPlacement.Right);
+    }
 }