feat: add more high contrast themes.

demo/Semi.Avalonia.Demo/Views/MainView.axaml.cs

@@ -1,8 +1,10 @@
 using System;
+using System.Collections.ObjectModel;
 using Avalonia;
 using Avalonia.Controls;
 using Avalonia.Interactivity;
 using Avalonia.Styling;
+using CommunityToolkit.Mvvm.ComponentModel;
 
 namespace Semi.Avalonia.Demo.Views;
 
@@ -11,6 +13,7 @@ public partial class MainView : UserControl
     public MainView()
     {
         InitializeComponent();
+        this.DataContext = new MainViewModel();
     }
 
     private void ToggleButton_OnIsCheckedChanged(object sender, RoutedEventArgs e)
@@ -38,4 +41,36 @@ public partial class MainView : UserControl
         var launcher = top.Launcher;
         await launcher.LaunchUriAsync(new Uri("https://docs.irihi.tech/semi"));
     }
+}
+
+public partial class MainViewModel: ObservableObject
+{
+    public ObservableCollection<ThemeItem> Themes { get; } = new()
+    {
+        new ThemeItem("Light", ThemeVariant.Light),
+        new ThemeItem("Dark", ThemeVariant.Dark),
+        new ThemeItem("Aquatic", SemiTheme.Aquatic),
+        new ThemeItem("Desert", SemiTheme.Desert),
+        new ThemeItem("Dust", SemiTheme.Dust),
+        new ThemeItem("NightSky", SemiTheme.NightSky),
+    };
+    
+    [ObservableProperty] private ThemeItem? _selectedTheme;
+    
+    partial void OnSelectedThemeChanged(ThemeItem? oldValue, ThemeItem? newValue)
+    {
+        if (newValue is null) return;
+        var app = Application.Current;
+        if (app is not null)
+        {
+            app.RequestedThemeVariant = newValue.Theme;
+        }
+    }
+    
+}
+
+public class ThemeItem(string name, ThemeVariant theme)
+{
+    public string Name { get; set; } = name;
+    public ThemeVariant Theme { get; set; } = theme;
 }