feat: cross platform projects.

demo/Ursa.Demo.Desktop/Program.cs

@@ -0,0 +1,34 @@
+using System;
+using Avalonia;
+using Avalonia.Dialogs;
+using Avalonia.Media;
+
+namespace Ursa.Demo.Desktop;
+
+class Program
+{
+    // Initialization code. Don't use any Avalonia, third-party APIs or any
+    // SynchronizationContext-reliant code before AppMain is called: things aren't initialized
+    // yet and stuff might break.
+    [STAThread]
+    public static void Main(string[] args) => BuildAvaloniaApp()
+        .With(new FontManagerOptions
+        {
+            FontFallbacks = new[]
+            {
+                new FontFallback
+                {
+                    FontFamily = new FontFamily("Microsoft YaHei")
+                }
+            }
+        })
+        .StartWithClassicDesktopLifetime(args);
+
+    // Avalonia configuration, don't remove; also used by visual designer.
+    public static AppBuilder BuildAvaloniaApp()
+        => AppBuilder.Configure<App>()
+            .UseManagedSystemDialogs()
+            .UsePlatformDetect()
+            .With(new Win32PlatformOptions())
+            .LogToTrace();
+}