Move highlighting logic into a dedicated widget.

OpenRA.Mods.Common/Widgets/LabelWithHighlightWidget.cs

@@ -0,0 +1,90 @@
+#region Copyright & License Information
+/*
+ * Copyright 2007-2020 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 System.Collections.Generic;
+using System.Linq;
+using OpenRA.Graphics;
+using OpenRA.Primitives;
+using OpenRA.Widgets;
+
+namespace OpenRA.Mods.Common.Widgets
+{
+	public class LabelWithHighlightWidget : LabelWidget
+	{
+		public Color HighlightColor = ChromeMetrics.Get<Color>("TextHighlightColor");
+		readonly CachedTransform<string, Pair<string, bool>[]> textComponents;
+
+		[ObjectCreator.UseCtor]
+		public LabelWithHighlightWidget()
+			: base()
+		{
+			textComponents = new CachedTransform<string, Pair<string, bool>[]>(MakeComponents);
+		}
+
+		protected LabelWithHighlightWidget(LabelWithHighlightWidget other)
+			: base(other)
+		{
+			HighlightColor = other.HighlightColor;
+			textComponents = new CachedTransform<string, Pair<string, bool>[]>(MakeComponents);
+		}
+
+		Pair<string, bool>[] MakeComponents(string text)
+		{
+			List<Pair<string, bool>> components = new List<Pair<string, bool>>();
+			foreach (var l in text.Split(new[] { "\\n" }, StringSplitOptions.None))
+			{
+				var line = l;
+
+				while (line.Length > 0)
+				{
+					var highlightStart = line.IndexOf('{');
+					var highlightEnd = line.IndexOf('}', 0);
+
+					if (highlightStart > 0 && highlightEnd > highlightStart)
+					{
+						if (highlightStart > 0)
+						{
+							// Normal line segment before highlight
+							var lineNormal = line.Substring(0, highlightStart);
+							components.Add(Pair.New(lineNormal, false));
+						}
+
+						// Highlight line segment
+						var lineHighlight = line.Substring(highlightStart + 1, highlightEnd - highlightStart - 1);
+						components.Add(Pair.New(lineHighlight, true));
+						line = line.Substring(highlightEnd + 1);
+					}
+					else
+					{
+						// Final normal line segment
+						components.Add(Pair.New(line, false));
+						break;
+					}
+				}
+			}
+
+			return components.ToArray();
+		}
+
+		protected override void DrawInner(string text, SpriteFont font, Color color, int2 position)
+		{
+			var advance = 0;
+			foreach (var c in textComponents.Update(text))
+			{
+				base.DrawInner(c.First, font, c.Second ? HighlightColor : color, position + new int2(advance, 0));
+				advance += font.Measure(c.First).X;
+			}
+		}
+
+		public override Widget Clone() { return new LabelWithHighlightWidget(this); }
+	}
+}