Rework chat line templates and logic

- Extract chat line templates and logic so they can be reused across widgets
- Make text notification styling entirely template driven (by removing chat color configuration and making color optional for `TextNotification`)
- Add a new TextNotificationsDisplay widget (based on and replacing ChatDisplayWidget)
- Add timestamp support to text notifications

OpenRA.Mods.Common/Widgets/TextNotificationsDisplayWidget.cs

@@ -0,0 +1,136 @@
+#region Copyright & License Information
+/*
+ * Copyright 2007-2021 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 OpenRA.Primitives;
+using OpenRA.Widgets;
+
+namespace OpenRA.Mods.Common.Widgets
+{
+	public class TextNotificationsDisplayWidget : Widget
+	{
+		public readonly int RemoveTime = 0;
+		public readonly int ItemSpacing = 4;
+		public readonly int BottomSpacing = 0;
+		public readonly int LogLength = 8;
+		public readonly bool HideOverflow = true;
+
+		public string ChatTemplate = "CHAT_LINE_TEMPLATE";
+		public string SystemTemplate = "SYSTEM_LINE_TEMPLATE";
+		public string MissionTemplate = "SYSTEM_LINE_TEMPLATE";
+		public string FeedbackTemplate = "SYSTEM_LINE_TEMPLATE";
+		readonly Dictionary<TextNotificationPool, Widget> templates = new Dictionary<TextNotificationPool, Widget>();
+
+		readonly List<int> expirations = new List<int>();
+
+		Rectangle overflowDrawBounds = Rectangle.Empty;
+		public override Rectangle EventBounds => Rectangle.Empty;
+
+		public override void Initialize(WidgetArgs args)
+		{
+			base.Initialize(args);
+
+			templates.Add(TextNotificationPool.Chat, Ui.LoadWidget(ChatTemplate, null, new WidgetArgs()));
+			templates.Add(TextNotificationPool.System, Ui.LoadWidget(SystemTemplate, null, new WidgetArgs()));
+			templates.Add(TextNotificationPool.Mission, Ui.LoadWidget(MissionTemplate, null, new WidgetArgs()));
+			templates.Add(TextNotificationPool.Feedback, Ui.LoadWidget(FeedbackTemplate, null, new WidgetArgs()));
+
+			// HACK: Assume that all templates use the same font
+			var lineHeight = Game.Renderer.Fonts[templates[TextNotificationPool.Chat].Get<LabelWidget>("TEXT").Font].Measure("").Y;
+			var wholeLines = (int)Math.Floor((double)((Bounds.Height - BottomSpacing) / lineHeight));
+			var visibleChildrenHeight = wholeLines * lineHeight;
+
+			overflowDrawBounds = new Rectangle(RenderOrigin.X, RenderOrigin.Y, Bounds.Width, Bounds.Height);
+			overflowDrawBounds.Y += Bounds.Height - visibleChildrenHeight;
+			overflowDrawBounds.Height = visibleChildrenHeight;
+		}
+
+		public override void DrawOuter()
+		{
+			if (!IsVisible() || Children.Count == 0)
+				return;
+
+			var mostRecentMessageOverflows = Bounds.Height < Children[Children.Count - 1].Bounds.Height;
+
+			if (mostRecentMessageOverflows && HideOverflow)
+				Game.Renderer.EnableScissor(overflowDrawBounds);
+
+			for (var i = Children.Count - 1; i >= 0; i--)
+			{
+				if (Bounds.Contains(Children[i].Bounds) || !HideOverflow || mostRecentMessageOverflows)
+					Children[i].DrawOuter();
+
+				if (mostRecentMessageOverflows)
+					break;
+			}
+
+			if (mostRecentMessageOverflows && HideOverflow)
+				Game.Renderer.DisableScissor();
+		}
+
+		public void AddNotification(TextNotification notification)
+		{
+			var notificationWidget = templates[notification.Pool].Clone();
+			WidgetUtils.SetupTextNotification(notificationWidget, notification, Bounds.Width, false);
+
+			if (Children.Count == 0)
+				notificationWidget.Bounds.Y = Bounds.Bottom - notificationWidget.Bounds.Height - BottomSpacing;
+			else
+			{
+				foreach (var line in Children)
+					line.Bounds.Y -= notificationWidget.Bounds.Height + ItemSpacing;
+
+				var lastLine = Children[Children.Count - 1];
+				notificationWidget.Bounds.Y = lastLine.Bounds.Bottom + ItemSpacing;
+			}
+
+			AddChild(notificationWidget);
+			expirations.Add(Game.LocalTick + RemoveTime);
+
+			while (Children.Count > LogLength)
+				RemoveNotification();
+		}
+
+		public void RemoveMostRecentNotification()
+		{
+			if (Children.Count == 0)
+				return;
+
+			var mostRecentChild = Children[Children.Count - 1];
+
+			RemoveChild(mostRecentChild);
+			expirations.RemoveAt(expirations.Count - 1);
+
+			for (var i = Children.Count - 1; i >= 0; i--)
+				Children[i].Bounds.Y += mostRecentChild.Bounds.Height + ItemSpacing;
+		}
+
+		private void RemoveNotification()
+		{
+			if (Children.Count == 0)
+				return;
+
+			RemoveChild(Children[0]);
+			expirations.RemoveAt(0);
+		}
+
+		public override void Tick()
+		{
+			if (RemoveTime == 0)
+				return;
+
+			// This takes advantage of the fact that recentLines is ordered by expiration, from sooner to later
+			while (Children.Count > 0 && Game.LocalTick >= expirations[0])
+				RemoveNotification();
+		}
+	}
+}