Change color of labels that correspond to disabled inputs

- Add a new widget type for input and extend it from other input widgets
- Add a new label type that can be linked to an input widget
- Change the label color when the input's disabled state changes

OpenRA.Mods.Common/Widgets/LabelForInputWidget.cs

@@ -0,0 +1,48 @@
+#region Copyright & License Information
+/*
+ * Copyright 2007-2022 The OpenRA Developers (see AUTHORS)
+ * This file is part of OpenRA, which is free software. It is made
+ * available to you under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, either version 3 of
+ * the License, or (at your option) any later version. For more
+ * information, see COPYING.
+ */
+#endregion
+
+using System;
+using OpenRA.Graphics;
+using OpenRA.Primitives;
+using OpenRA.Widgets;
+
+namespace OpenRA.Mods.Common.Widgets
+{
+	public class LabelForInputWidget : LabelWidget
+	{
+		public string For = null;
+		public readonly Color TextDisabledColor = ChromeMetrics.Get<Color>("TextDisabledColor");
+		readonly Lazy<InputWidget> inputWidget;
+		readonly CachedTransform<bool, Color> textColor;
+
+		[ObjectCreator.UseCtor]
+		public LabelForInputWidget()
+			: base()
+		{
+			inputWidget = Exts.Lazy(() => Parent.Get<InputWidget>(For));
+			textColor = new CachedTransform<bool, Color>(disabled => disabled ? TextDisabledColor : TextColor);
+		}
+
+		protected LabelForInputWidget(LabelForInputWidget other)
+			: base(other)
+		{
+			inputWidget = Exts.Lazy(() => Parent.Get<InputWidget>(other.For));
+			textColor = new CachedTransform<bool, Color>(disabled => disabled ? TextDisabledColor : TextColor);
+		}
+
+		protected override void DrawInner(string text, SpriteFont font, Color color, int2 position)
+		{
+			font.DrawText(text, position, textColor.Update(inputWidget.Value.IsDisabled()));
+		}
+
+		public override Widget Clone() { return new LabelForInputWidget(this); }
+	}
+}