From c144056ab08d8220365ac802635bc8bf75f8ac6a Mon Sep 17 00:00:00 2001
From: Dong Bin <popmessiah@hotmail.com>
Date: Sun, 8 Mar 2026 23:33:23 +0800
Subject: [PATCH] feat: add basic implementation of window decorations.

---
 .../Semi.Avalonia.Demo/Views/MainWindow.axaml |   6 +-
 .../Controls/WindowDrawnDecorations.axaml     | 217 ++++++++++++++----
 2 files changed, 182 insertions(+), 41 deletions(-)

diff --git a/demo/Semi.Avalonia.Demo/Views/MainWindow.axaml b/demo/Semi.Avalonia.Demo/Views/MainWindow.axaml
index 6df182c..87dc847 100644
--- a/demo/Semi.Avalonia.Demo/Views/MainWindow.axaml
+++ b/demo/Semi.Avalonia.Demo/Views/MainWindow.axaml
@@ -5,10 +5,12 @@
     xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
     xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
     xmlns:views="clr-namespace:Semi.Avalonia.Demo.Views"
-    Title="Semi.Avalonia.Demo"
+    Title="Semi Avalonia Demo"
     d:DesignHeight="450"
     d:DesignWidth="800"
+    ExtendClientAreaToDecorationsHint="True"
+    ExtendClientAreaTitleBarHeightHint="40"
     Icon="/Assets/irihi.ico"
     mc:Ignorable="d">
-    <views:MainView />
+    <views:MainView Margin="{Binding $parent[Window].WindowDecorationMargin}" />
 </Window>
\ No newline at end of file
diff --git a/src/Semi.Avalonia/Controls/WindowDrawnDecorations.axaml b/src/Semi.Avalonia/Controls/WindowDrawnDecorations.axaml
index 5caddf0..8b0ed6f 100644
--- a/src/Semi.Avalonia/Controls/WindowDrawnDecorations.axaml
+++ b/src/Semi.Avalonia/Controls/WindowDrawnDecorations.axaml
@@ -1,66 +1,205 @@
-<ResourceDictionary xmlns="https://github.com/avaloniaui"
-                    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
+<ResourceDictionary xmlns="https://github.com/avaloniaui" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
+
+    <ControlTheme x:Key="CaptionButton" TargetType="Button">
+        <Setter Property="Foreground" Value="{DynamicResource CaptionButtonForeground}" />
+        <Setter Property="Background" Value="Transparent" />
+        <Setter Property="CornerRadius" Value="{StaticResource CaptionButtonCornerRadius}" />
+        <Setter Property="Padding" Value="{StaticResource CaptionButtonPadding}" />
+        <Setter Property="Width" Value="{StaticResource CaptionButtonWidth}" />
+        <Setter Property="Height" Value="{StaticResource CaptionButtonHeight}" />
+        <Setter Property="Cursor" Value="Hand" />
+        <Setter Property="VerticalAlignment" Value="Stretch" />
+        <Setter Property="Template">
+            <ControlTemplate TargetType="Button">
+                <ContentPresenter
+                    Name="PART_ContentPresenter"
+                    Padding="{TemplateBinding Padding}"
+                    Background="{TemplateBinding Background}"
+                    BorderBrush="{TemplateBinding BorderBrush}"
+                    BorderThickness="{TemplateBinding BorderThickness}"
+                    Content="{TemplateBinding Content}"
+                    ContentTemplate="{TemplateBinding ContentTemplate}"
+                    CornerRadius="{TemplateBinding CornerRadius}"
+                    Foreground="{TemplateBinding Foreground}" />
+            </ControlTemplate>
+        </Setter>
+
+        <Style Selector="^:pointerover">
+            <Setter Property="Background" Value="{DynamicResource CaptionButtonPointeroverBackground}" />
+        </Style>
+
+        <Style Selector="^:pressed">
+            <Setter Property="Background" Value="{DynamicResource CaptionButtonPressedBackground}" />
+        </Style>
+    </ControlTheme>
+
     <ControlTheme x:Key="{x:Type WindowDrawnDecorations}" TargetType="WindowDrawnDecorations">
         <Setter Property="DefaultTitleBarHeight" Value="32" />
-        <Setter Property="DefaultFrameThickness" Value="0,0,0,0" />
+        <Setter Property="DefaultFrameThickness" Value="1" />
         <Setter Property="DefaultShadowThickness" Value="16" />
         <Setter Property="Template">
             <WindowDrawnDecorationsTemplate>
                 <WindowDrawnDecorationsContent>
-
                     <WindowDrawnDecorationsContent.Underlay>
-                        <!-- Full-size: covers shadow area + frame + behind client area -->
+                        <!--  Full-size: covers shadow area + frame + behind client area  -->
                         <Panel>
-                            <Border Margin="{TemplateBinding ShadowThickness}"
-                                    Background="{DynamicResource WindowBackground}"
-                                    BorderThickness="1"
-                                    BorderBrush="{DynamicResource WindowBorderBrush}"
-                                    BoxShadow="0 8 32 0 #40000000" />
+                            <Border
+                                x:Name="PART_WindowBorder"
+                                Margin="{TemplateBinding ShadowThickness}"
+                                Background="{DynamicResource WindowBackground}"
+                                BorderBrush="{DynamicResource WindowBorderBrush}"
+                                BorderThickness="1"
+                                BoxShadow="0 8 32 0 #40000000" />
+                            <!-- Titlebar: background, title text, and drag area live in underlay -->
+                            <Panel x:Name="PART_TitleBar" VerticalAlignment="Top"
+                                   Height="{TemplateBinding TitleBarHeight}"
+                                   Background="{DynamicResource SystemControlBackgroundAltHighBrush}"
+                                   IsVisible="{TemplateBinding HasTitleBar}"
+                                   WindowDecorationProperties.ElementRole="TitleBar" />
                         </Panel>
                     </WindowDrawnDecorationsContent.Underlay>
 
                     <WindowDrawnDecorationsContent.Overlay>
-                        <!-- Positioned over the titlebar area -->
-                        <DockPanel Height="{TemplateBinding TitleBarHeight}"
-                                   VerticalAlignment="Top"
-                                   Margin="{TemplateBinding ShadowThickness}">
-                            <StackPanel DockPanel.Dock="Right" Orientation="Horizontal">
-                                <Button x:Name="PART_MinimizeButton" Content="─" />
-                                <Button x:Name="PART_MaximizeButton" Content="□" />
-                                <Button x:Name="PART_CloseButton" Content="✕" />
+                        <!--  Positioned over the titlebar area  -->
+                        <Panel x:Name="PART_OverlayWrapper">
+                            <!--  Title text lives in overlay so it renders above client content  -->
+                            <Panel
+                                x:Name="PART_TitleTextPanel"
+                                Height="{TemplateBinding TitleBarHeight}"
+                                VerticalAlignment="Top"
+                                IsHitTestVisible="False"
+                                IsVisible="{TemplateBinding HasTitleBar}">
+                                <TextBlock
+                                    Margin="12,0,0,0"
+                                    VerticalAlignment="Center"
+                                    FontSize="12"
+                                    Text="{TemplateBinding Title}" />
+                            </Panel>
+                            <StackPanel
+                                x:Name="PART_OverlayPanel"
+                                Height="{TemplateBinding TitleBarHeight}"
+                                HorizontalAlignment="Right"
+                                VerticalAlignment="Top"
+                                IsVisible="{TemplateBinding HasTitleBar}"
+                                Orientation="Horizontal"
+                                Spacing="2"
+                                TextElement.FontSize="10">
+                                <Button
+                                    Name="PART_FullScreenButton"
+                                    Theme="{StaticResource CaptionButton}"
+                                    WindowDecorationProperties.ElementRole="FullScreenButton">
+                                    <PathIcon
+                                        Name="PART_FullScreenButtonIcon"
+                                        Data="{StaticResource WindowExpandGlyph}"
+                                        Foreground="{Binding $parent[Button].Foreground}"
+                                        Theme="{StaticResource InnerPathIcon}" />
+                                </Button>
+                                <Button
+                                    Name="PART_MinimizeButton"
+                                    AutomationProperties.Name="Minimize"
+                                    Theme="{StaticResource CaptionButton}"
+                                    WindowDecorationProperties.ElementRole="MinimizeButton">
+                                    <PathIcon
+                                        Name="PART_MinimizeButtonIcon"
+                                        Data="{StaticResource WindowMinimizeGlyph}"
+                                        Foreground="{Binding $parent[Button].Foreground}"
+                                        Theme="{StaticResource InnerPathIcon}" />
+                                </Button>
+                                <Button
+                                    Name="PART_MaximizeButton"
+                                    AutomationProperties.Name="Maximize"
+                                    Theme="{StaticResource CaptionButton}"
+                                    WindowDecorationProperties.ElementRole="MaximizeButton">
+                                    <PathIcon
+                                        Name="PART_MaximizeButtonIcon"
+                                        Data="{StaticResource WindowMaximizeGlyph}"
+                                        Foreground="{Binding $parent[Button].Foreground}"
+                                        Theme="{StaticResource InnerPathIcon}" />
+                                </Button>
+                                <Button
+                                    Name="PART_CloseButton"
+                                    AutomationProperties.Name="Close"
+                                    Theme="{StaticResource CaptionButton}"
+                                    WindowDecorationProperties.ElementRole="CloseButton">
+                                    <PathIcon
+                                        Name="PART_CloseButtonIcon"
+                                        Data="{StaticResource WindowCloseIconGlyph}"
+                                        Foreground="{Binding $parent[Button].Foreground}"
+                                        Theme="{StaticResource InnerPathIcon}" />
+                                </Button>
                             </StackPanel>
-                            <TextBlock Text="{TemplateBinding Title}"
-                                       VerticalAlignment="Center"
-                                       Margin="12,0"
-                                       WindowDecorationProperties.ElementRole="TitleBar" />
-                        </DockPanel>
+                        </Panel>
                     </WindowDrawnDecorationsContent.Overlay>
 
                     <WindowDrawnDecorationsContent.FullscreenPopover>
-                        <!-- Shown on hover at top edge in fullscreen -->
-                        <DockPanel Height="{TemplateBinding TitleBarHeight}"
-                                   Background="#E0000000">
+                        <!--  Shown on hover at top edge in fullscreen  -->
+                        <DockPanel Height="{TemplateBinding TitleBarHeight}" Background="#E0000000">
                             <StackPanel DockPanel.Dock="Right" Orientation="Horizontal">
-                                <Button x:Name="PART_MinimizeButton" Content="─" />
-                                <Button x:Name="PART_MaximizeButton" Content="□" />
-                                <Button x:Name="PART_CloseButton" Content="✕" />
+                                <Button
+                                    x:Name="PART_PopoverFullScreenButton"
+                                    Theme="{StaticResource CaptionButton}"
+                                    WindowDecorationProperties.ElementRole="FullScreenButton">
+                                    <PathIcon
+                                        Data="{StaticResource WindowCollapseGlyph}"
+                                        Foreground="{Binding $parent[Button].Foreground}"
+                                        Theme="{StaticResource InnerPathIcon}" />
+                                </Button>
                             </StackPanel>
-                            <TextBlock Text="{TemplateBinding Title}"
-                                       Foreground="White"
-                                       VerticalAlignment="Center"
-                                       Margin="12,0" />
+                            <TextBlock
+                                Margin="12,0"
+                                VerticalAlignment="Center"
+                                Foreground="White"
+                                Text="{TemplateBinding Title}" />
                         </DockPanel>
                     </WindowDrawnDecorationsContent.FullscreenPopover>
-
                 </WindowDrawnDecorationsContent>
             </WindowDrawnDecorationsTemplate>
         </Setter>
-
-        <!-- Pseudoclass styling -->
-        <Style Selector="^:maximized /template/ Border">
-            <Setter Property="BorderThickness" Value="0" />
+        
+        <Style Selector="^ /template/ Button#PART_CloseButton:pointerover">
+            <Setter Property="Foreground" Value="{DynamicResource CaptionButtonCloseForeground}" />
+            <Setter Property="Background" Value="{DynamicResource CaptionButtonClosePointeroverBackground}" />
         </Style>
-        <Style Selector="^:fullscreen /template/ DockPanel">
+        <Style Selector="^ /template/ Button#PART_CloseButton:pressed">
+            <Setter Property="Foreground" Value="{DynamicResource CaptionButtonCloseForeground}" />
+            <Setter Property="Background" Value="{DynamicResource CaptionButtonClosePressedBackground}" />
+        </Style>
+        
+        <!--  Shadow: inset border and add drop shadow  -->
+        <Style Selector="^:has-shadow /template/ Panel#PART_UnderlayWrapper">
+            <Setter Property="Margin" Value="{TemplateBinding ShadowThickness}" />
+        </Style>
+        <Style Selector="^:has-shadow /template/ Border#PART_WindowBorder">
+            <Setter Property="BoxShadow" Value="0 2 10 2 #80000000" />
+        </Style>
+        <Style Selector="^:has-shadow /template/ Panel#PART_OverlayWrapper">
+            <Setter Property="Margin" Value="{TemplateBinding ShadowThickness}" />
+        </Style>
+        
+        <!-- Maximized: restore button path changes -->
+        <Style Selector="^:maximized /template/ Path#PART_MaximizeButtonIcon">
+            <Setter Property="Data" Value="{StaticResource WindowRestoreGlyph}" />
+        </Style>
+
+        <!--  Border: inset titlebar and buttons inside frame  -->
+        <Style Selector="^:has-border /template/ Panel#PART_TitleTextPanel">
+            <Setter Property="Margin" Value="1,1,1,0" />
+        </Style>
+        <Style Selector="^:has-border /template/ Panel#PART_TitleBar">
+            <Setter Property="Margin" Value="1,1,1,0" />
+        </Style>
+        <Style Selector="^:has-border /template/ StackPanel#PART_OverlayPanel">
+            <Setter Property="Margin" Value="0,1,1,0" />
+        </Style>
+        
+        <!--  Fullscreen: hide overlay and titlebar (popover takes over)  -->
+        <Style Selector="^:fullscreen /template/ Panel#PART_TitleTextPanel">
+            <Setter Property="IsVisible" Value="False" />
+        </Style>
+        <Style Selector="^:fullscreen /template/ StackPanel#PART_OverlayPanel">
+            <Setter Property="IsVisible" Value="False" />
+        </Style>
+        <Style Selector="^:fullscreen /template/ Panel#PART_TitleBar">
             <Setter Property="IsVisible" Value="False" />
         </Style>
     </ControlTheme>