Controls.Hosting(GTK): mappings for Frame (lytico#11)

Add mappers for BorderColor and CornerRadius for Frame elements
so they can now have borders.

src/Controls/src/Xaml/Hosting/AppHostBuilderExtensions.cs

@@ -26,6 +26,7 @@
 #elif GTK
 using Microsoft.Maui.Controls.Handlers.Compatibility;
 using Microsoft.Maui.Controls.Compatibility.Platform.Gtk;
+using Microsoft.Maui.Graphics.Platform.Gtk;
 #endif
 
 namespace Microsoft.Maui.Controls.Hosting
@@ -181,6 +182,7 @@ static MauiAppBuilder SetupDefaults(this MauiAppBuilder builder)
  builder.Services.TryAddEnumerable(ServiceDescriptor.Transient<IMauiInitializeService, MauiControlsInitializer>());
 #endif
  builder.RemapForControls();
+ AddDefaultMappings();
 
  return builder;
  }
@@ -249,5 +251,34 @@ internal static MauiAppBuilder RemapForControls(this MauiAppBuilder builder)
 
  return builder;
  }
+
+ internal static void AddDefaultMappings()
+ {
+#if GTK
+ ContentViewHandler.Mapper.AppendToMapping(
+ "BorderColor",
+ (IContentViewHandler handler, IContentView view) =>
+ {
+ if (view is Frame frame)
+ {
+ Microsoft.Maui.Platform.ContentView contentView = (Microsoft.Maui.Platform.ContentView)handler.PlatformView;
+ contentView.SetStyleValueNode($"1px solid {frame.BorderColor.ToGdkRgba().ToString()}", contentView.CssMainNode(), "border");
+ }
+ }
+ );
+
+ ContentViewHandler.Mapper.AppendToMapping(
+ "CornerRadius",
+ (IContentViewHandler handler, IContentView view) =>
+ {
+ if (view is Frame frame)
+ {
+ Microsoft.Maui.Platform.ContentView contentView = (Microsoft.Maui.Platform.ContentView)handler.PlatformView;
+ contentView.SetStyleValueNode($"{frame.CornerRadius:f}px", contentView.CssMainNode(), "border-radius");
+ }
+ }
+ );
+#endif
+ }
  }
 }