[GTK] Another fix for label alignment

Testing/Tests/LabelTests.cs

@@ -51,7 +51,7 @@ namespace Xwt
 			var la = new Label ("Some text here");
 			la.TextAlignment = Alignment.Center;
 			la.BackgroundColor = Xwt.Drawing.Colors.LightGray;
-			CheckWidgetRender ("Label.AlignCenter", la);
+			CheckWidgetRender ("Label.AlignCenter.png", la);
 		}
 
 		[Test]
@@ -62,7 +62,25 @@ namespace Xwt
 			la.Wrap = WrapMode.Word;
 			la.WidthRequest = 200;
 			la.BackgroundColor = Xwt.Drawing.Colors.LightGray;
-			CheckWidgetRender ("Label.AlignCenterWrapped", la);
+			CheckWidgetRender ("Label.AlignCenterWrapped.png", la);
+		}
+
+		[Test]
+		public void AlignCenterWrappedChangeText ()
+		{
+			var la = new Label ("Some text here");
+			la.TextAlignment = Alignment.Center;
+			la.Wrap = WrapMode.Word;
+			la.WidthRequest = 200;
+
+			using (var win = new Window { Width = 200, Height = 100 }) {
+				win.Content = la;
+				ShowWindow (win);
+				la.Text = "Some text here Some text here";
+				WaitForEvents ();
+				var img = Toolkit.CurrentEngine.RenderWidget (la);
+				ReferenceImageManager.CheckImage ("Label.AlignCenterWrappedChangeText.png", img);
+			}
 		}
 
 		[Test]
@@ -71,7 +89,7 @@ namespace Xwt
 			var la = new Label ("Some text here");
 			la.TextAlignment = Alignment.Start;
 			la.BackgroundColor = Xwt.Drawing.Colors.LightGray;
-			CheckWidgetRender ("Label.AlignLeft", la);
+			CheckWidgetRender ("Label.AlignLeft.png", la);
 		}
 
 		[Test]
@@ -82,7 +100,7 @@ namespace Xwt
 			la.Wrap = WrapMode.Word;
 			la.WidthRequest = 200;
 			la.BackgroundColor = Xwt.Drawing.Colors.LightGray;
-			CheckWidgetRender ("Label.AlignLeftWrapped", la);
+			CheckWidgetRender ("Label.AlignLeftWrapped.png", la);
 		}
 
 		[Test]
@@ -91,7 +109,7 @@ namespace Xwt
 			var la = new Label ("Some text here");
 			la.TextAlignment = Alignment.End;
 			la.BackgroundColor = Xwt.Drawing.Colors.LightGray;
-			CheckWidgetRender ("Label.AlignRight", la);
+			CheckWidgetRender ("Label.AlignRight.png", la);
 		}
 
 		[Test]
@@ -102,7 +120,7 @@ namespace Xwt
 			la.Wrap = WrapMode.Word;
 			la.WidthRequest = 200;
 			la.BackgroundColor = Xwt.Drawing.Colors.LightGray;
-			CheckWidgetRender ("Label.AlignRightWrapped", la);
+			CheckWidgetRender ("Label.AlignRightWrapped.png", la);
 		}
 	}
 }

Testing/Tests/ReferenceImageVerifierDialog.cs

@@ -55,13 +55,28 @@ namespace Xwt
 			nameLabel.Font = nameLabel.Font.WithWeight (Xwt.Drawing.FontWeight.Bold);
 
 			img1 = new ImageView ();
-			table.Add (img1, 0, 2, hexpand:true, vexpand:true);
+			var frame = new FrameBox {
+				Content = img1,
+				BorderColor = Xwt.Drawing.Colors.Gray,
+				BorderWidth = 1
+			};
+			table.Add (frame, 0, 2, hexpand:true, vexpand:true, hpos:WidgetPlacement.Center, vpos:WidgetPlacement.Center);
 			
 			imgDiff = new ImageView ();
-			table.Add (imgDiff, 1, 2, hexpand:true, vexpand:true);
+			frame = new FrameBox {
+				Content = imgDiff,
+				BorderColor = Xwt.Drawing.Colors.Gray,
+				BorderWidth = 1
+			};
+			table.Add (frame, 1, 2, hexpand:true, vexpand:true, hpos:WidgetPlacement.Center, vpos:WidgetPlacement.Center);
 
 			img2 = new ImageView ();
-			table.Add (img2, 2, 2, hexpand:true, vexpand:true);
+			frame = new FrameBox {
+				Content = img2,
+				BorderColor = Xwt.Drawing.Colors.Gray,
+				BorderWidth = 1
+			};
+			table.Add (frame, 2, 2, hexpand:true, vexpand:true, hpos:WidgetPlacement.Center, vpos:WidgetPlacement.Center);
 
 			var buttonBox = new HBox ();
 			table.Add (buttonBox, 0, 3, colspan:2, hexpand:true);

Xwt.Gtk/Xwt.GtkBackend/LabelBackend.cs

@@ -175,15 +175,20 @@ namespace Xwt.GtkBackend
 			Label.Layout.GetPixelSize (out unused, out wrapHeight);
 			if (wrapWidth != args.Allocation.Width || oldHeight != wrapHeight) {
 				wrapWidth = args.Allocation.Width;
-				// GTK renders the text using the calculated pixel width, not the allocated width.
-				// If the calculated width is smaller and text is not left aligned, then a gap is
-				// shown at the right of the label. We then have the adjust the allocation.
-				if (Label.Justify == Gtk.Justification.Right)
-					Label.Xpad = wrapWidth - unused;
-				else if (Label.Justify == Gtk.Justification.Center)
-					Label.Xpad = (wrapWidth - unused) / 2;
 				Label.QueueResize ();
 			}
+			// GTK renders the text using the calculated pixel width, not the allocated width.
+			// If the calculated width is smaller and text is not left aligned, then a gap is
+			// shown at the right of the label. We then have the adjust the allocation.
+			if (Label.Justify == Gtk.Justification.Right) {
+				var w = wrapWidth - unused;
+				if (w != Label.Xpad)
+					Label.Xpad = w;
+			} else if (Label.Justify == Gtk.Justification.Center) {
+				var w = (wrapWidth - unused) / 2;
+				if (w != Label.Xpad)
+					Label.Xpad = w;
+			}
 		}
 
 		void HandleLabelDynamicSizeRequest (object o, Gtk.SizeRequestedArgs args)