factor out layout policy for ScrollPanelWidget; add GridLayout option.

OpenRA.Game/OpenRA.Game.csproj

@@ -1,4 +1,4 @@
-<?xml version="1.0" encoding="utf-8"?>
+<?xml version="1.0" encoding="utf-8"?>
 <Project DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003" ToolsVersion="3.5">
   <PropertyGroup>
     <Configuration Condition=" '$(Configuration)' == '' ">Debug</Configuration>
@@ -202,6 +202,8 @@
     <Compile Include="Widgets\WorldInteractionControllerWidget.cs" />
     <Compile Include="World.cs" />
     <Compile Include="WorldUtils.cs" />
+    <Compile Include="Widgets\ListLayout.cs" />
+    <Compile Include="Widgets\GridLayout.cs" />
   </ItemGroup>
   <ItemGroup>
     <ProjectReference Include="..\OpenRA.FileFormats\OpenRA.FileFormats.csproj">

OpenRA.Game/Widgets/GridLayout.cs

@@ -0,0 +1,46 @@
+#region Copyright & License Information
+/*
+ * Copyright 2007-2011 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. For more information,
+ * see COPYING.
+ */
+#endregion
+
+using System;
+
+namespace OpenRA.Widgets
+{
+	public class GridLayout : ILayout
+	{
+		ScrollPanelWidget widget;
+		int2 pos;
+
+		public GridLayout(ScrollPanelWidget w) { widget = w; }
+
+		public void AdjustChild(Widget w)
+		{
+			if (widget.Children.Count == 0)
+			{
+				widget.ContentHeight = widget.ItemSpacing;
+				pos = new int2(widget.ItemSpacing, widget.ItemSpacing);
+			}
+			
+			if (pos.X + widget.ItemSpacing + w.Bounds.Width > widget.Bounds.Width - widget.ScrollbarWidth)
+			{
+				/* start a new row */
+				pos.X = widget.ItemSpacing;
+				pos.Y = widget.ContentHeight;
+			}
+			
+			w.Bounds.X += pos.X;
+			w.Bounds.Y += pos.Y;
+			
+			pos.X += widget.Bounds.Width + widget.ItemSpacing;
+
+			widget.ContentHeight = Math.Max(widget.ContentHeight, pos.Y + widget.ItemSpacing + w.Bounds.Height);
+		}
+	}
+}
+

OpenRA.Game/Widgets/ListLayout.cs

@@ -0,0 +1,28 @@
+#region Copyright & License Information
+/*
+ * Copyright 2007-2011 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. For more information,
+ * see COPYING.
+ */
+#endregion
+
+namespace OpenRA.Widgets
+{
+	public class ListLayout : ILayout
+	{
+		ScrollPanelWidget widget;
+
+		public ListLayout(ScrollPanelWidget w) { widget = w; }
+
+		public void AdjustChild(Widget w)
+		{
+			if (widget.Children.Count == 0)
+				widget.ContentHeight = widget.ItemSpacing;
+
+			w.Bounds.Y += widget.ContentHeight;
+			widget.ContentHeight += w.Bounds.Height + widget.ItemSpacing;
+		}
+	}
+}

OpenRA.Game/Widgets/ScrollPanelWidget.cs

@@ -14,6 +14,8 @@ using OpenRA.Graphics;
 
 namespace OpenRA.Widgets
 {
+	public interface ILayout { void AdjustChild(Widget w); }
+
 	public class ScrollPanelWidget : Widget
 	{
 		public int ScrollbarWidth = 24;
@@ -22,6 +24,7 @@ namespace OpenRA.Widgets
 		public int ButtonDepth = ChromeMetrics.Get<int>("ButtonDepth");
 		public string Background = "scrollpanel-bg";
 		public int ContentHeight = 0;
+		public ILayout Layout;
 		protected float ListOffset = 0;
 		protected bool UpPressed = false;
 		protected bool DownPressed = false;
@@ -32,12 +35,7 @@ namespace OpenRA.Widgets
 		protected Rectangle scrollbarRect;
 		protected Rectangle thumbRect;
 
-		public ScrollPanelWidget() : base() {}
-		protected ScrollPanelWidget(ScrollPanelWidget other)
-			: base(other)
-		{
-			throw new NotImplementedException();
-		}
+		public ScrollPanelWidget() : base() { Layout = new ListLayout(this); }
 
 		public override void RemoveChildren()
 		{
@@ -48,11 +46,7 @@ namespace OpenRA.Widgets
 		public override void AddChild(Widget child)
 		{
 			// Initial setup of margins/height
-			if (Children.Count == 0)
-				ContentHeight = ItemSpacing;
-
-			child.Bounds.Y += ContentHeight;
-			ContentHeight += child.Bounds.Height + ItemSpacing;
+			Layout.AdjustChild(child);
 			base.AddChild(child);
 		}
 
@@ -192,7 +186,5 @@ namespace OpenRA.Widgets
 
 			return (UpPressed || DownPressed || ThumbPressed);
 		}
-
-		public override Widget Clone() { return new ScrollPanelWidget(this); }
 	}
 }

OpenRA.Game/Widgets/Widget.cs

@@ -134,7 +134,7 @@ namespace OpenRA.Widgets
         public Widget Parent = null;
 		public Func<bool> IsVisible;
         public Widget() { IsVisible = () => Visible; }
-        protected readonly List<Widget> Children = new List<Widget>();
+        public readonly List<Widget> Children = new List<Widget>();
 
         public Widget(Widget widget)
         {
@@ -283,6 +283,7 @@ namespace OpenRA.Widgets
 		public virtual void MouseEntered() {}
 		public virtual void MouseExited() {}
 		public virtual bool HandleMouseInput(MouseInput mi) { return false; }
+
         public bool HandleMouseInputOuter(MouseInput mi)
         {
 			// Are we able to handle this event?
@@ -305,6 +306,7 @@ namespace OpenRA.Widgets
         }
 
         public virtual bool HandleKeyPress(KeyInput e) { return false; }
+
         public virtual bool HandleKeyPressOuter(KeyInput e)
         {
             if (!IsVisible())
@@ -322,6 +324,7 @@ namespace OpenRA.Widgets
         }
 
         public virtual void Draw() {}
+
         public virtual void DrawOuter()
         {
             if (IsVisible())
@@ -333,6 +336,7 @@ namespace OpenRA.Widgets
         }
 
 		public virtual void Tick() {}
+
         public virtual void TickOuter()
         {
             if (IsVisible())