Fix mac os Editor transparent color handling (#3218)

Xamarin.Forms.Controls.Issues/Xamarin.Forms.Controls.Issues.Shared/GitHub3216.cs

@@ -0,0 +1,35 @@
+using Xamarin.Forms.CustomAttributes;
+using Xamarin.Forms.Internals;
+
+namespace Xamarin.Forms.Controls.Issues
+{
+	[Preserve(AllMembers = true)]
+	[Issue(IssueTracker.Github, 3216, "[macOS] Editor still displays white background when BackgroundColor set to Transparent", PlatformAffected.macOS)]
+	public class GitHub3216 : TestContentPage
+	{
+		protected override void Init()
+		{
+			var grid = new Grid
+			{
+				BackgroundColor = Color.BurlyWood
+			};
+
+			var defaultEditor = new Editor
+			{
+				Text = "I'm a default Editor!"
+			};
+
+			var transparentEditor = new Editor
+			{
+				Text = "I'm a transparent Editor!",
+				BackgroundColor = Color.Transparent
+			};
+			Grid.SetRow(transparentEditor, 1);
+
+			grid.Children.Add(defaultEditor);
+			grid.Children.Add(transparentEditor);
+
+			Content = grid;
+		}
+	}
+}

Xamarin.Forms.Controls.Issues/Xamarin.Forms.Controls.Issues.Shared/Xamarin.Forms.Controls.Issues.Shared.projitems

@@ -766,6 +766,7 @@
     <Compile Include="$(MSBuildThisFileDirectory)Issue2728.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Issue1667.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Issue3012.cs" />
+    <Compile Include="$(MSBuildThisFileDirectory)GitHub3216.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)GitHub1776.cs" />
   </ItemGroup>
   <ItemGroup>

Xamarin.Forms.Platform.MacOS/Renderers/EditorRenderer.cs

@@ -71,6 +71,17 @@ namespace Xamarin.Forms.Platform.MacOS
 
 			Control.BackgroundColor = color == Color.Default ? NSColor.Clear : color.ToNSColor();
 
+			if (color == Color.Transparent)
+			{
+				Control.DrawsBackground = false;
+				Control.Bezeled = false;
+			}
+			else
+			{
+				Control.DrawsBackground = true;
+				Control.Bezeled = true;
+			}
+
 			base.SetBackgroundColor(color);
 		}
 
@@ -92,14 +103,14 @@ namespace Xamarin.Forms.Platform.MacOS
 		void HandleChanged(object sender, EventArgs e)
 		{
 			UpdateMaxLength();
-			
+
 			ElementController.SetValueFromRenderer(Editor.TextProperty, Control.StringValue);
 		}
 
 		void OnEditingEnded(object sender, EventArgs eventArgs)
 		{
 			Element.SetValue(VisualElement.IsFocusedPropertyKey, false);
-            ElementController.SendCompleted();
+			ElementController.SendCompleted();
 		}
 
 		void OnEditingBegan(object sender, EventArgs eventArgs)