Fix macOS label renderer Italic Font attributes (#2729) fixes #2728

Xamarin.Forms.Controls.Issues/Xamarin.Forms.Controls.Issues.Shared/Issue2728.cs

@@ -0,0 +1,38 @@
+using Xamarin.Forms.CustomAttributes;
+using Xamarin.Forms.Internals;
+
+#if UITEST
+using NUnit.Framework;
+using Xamarin.UITest;
+#endif
+
+namespace Xamarin.Forms.Controls.Issues
+{
+	[Preserve(AllMembers = true)]
+	[Issue(IssueTracker.Github, 2728, "[macOS] Label FontAttributes Italic is not working")]
+	public class Issue2728 : TestContentPage
+	{
+		protected override void Init()
+		{
+			var label = new Label { Text = "Hello Label", FontAttributes = FontAttributes.Italic };
+
+			Content = new StackLayout
+			{
+				Children = {
+					label
+				}
+			};
+		}
+
+
+#if UITEST
+		[Test]
+		public void Issue2728TestsItalicLabel ()
+		{
+			RunningApp.WaitForElement(q => q.Text("Home"));
+			RunningApp.Screenshot ("Label rendererd with italic font");
+		}
+#endif
+
+	}
+}

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

@@ -732,6 +732,7 @@
     <Compile Include="$(MSBuildThisFileDirectory)Issue1323.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Issue2399.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Issue1729.cs" />
+    <Compile Include="$(MSBuildThisFileDirectory)Issue2728.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Issue1667.cs" />
   </ItemGroup>
   <ItemGroup>

Xamarin.Forms.Platform.iOS/Renderers/FontExtensions.cs

@@ -231,8 +231,9 @@ namespace Xamarin.Forms.Platform.MacOS
 			}
 			if (italic)
 			{
-				Debug.WriteLine("Italic font requested, passing regular one");
-				return NSFont.UserFontOfSize(size);
+				var defaultFont = UIFont.SystemFontOfSize(size);
+				var descriptor = defaultFont.FontDescriptor.FontDescriptorWithSymbolicTraits(NSFontSymbolicTraits.ItalicTrait);
+				return NSFont.FromDescription(descriptor, 0);
 			}
 #endif
 			if (bold)