started moving Lobby/MapChooser to widgets

OpenRA.Game/Widgets/MapPreviewWidget.cs

@@ -0,0 +1,51 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using OpenRA.Graphics;
+using System.Drawing;
+using OpenRA.FileFormats;
+
+namespace OpenRA.Widgets
+{
+	class MapPreviewWidget : Widget
+	{
+		Sheet mapChooserSheet;
+		Sprite mapChooserSprite;
+		bool showMapChooser = false;
+		bool mapPreviewDirty = true;
+		MapStub lastMap;
+
+		public override void Draw( World world )
+		{
+			var map = Game.chrome.currentMap;
+			if( map == null ) return;
+
+			if (lastMap != map)
+			{
+				mapPreviewDirty = true;
+				lastMap = map;
+			}
+
+			var mapRect = map.PreviewBounds( new Rectangle( Bounds.X, Bounds.Y, Bounds.Width, Bounds.Height ) );
+
+			if( mapPreviewDirty )
+			{
+				if( mapChooserSheet == null || mapChooserSheet.Size.Width != map.Width || mapChooserSheet.Size.Height != map.Height )
+					mapChooserSheet = new Sheet( Game.renderer, new Size( map.Width, map.Height ) );
+
+				mapChooserSheet.Texture.SetData( map.Preview.Value );
+				mapChooserSprite = new Sprite( mapChooserSheet, new Rectangle( 0, 0, map.Width, map.Height ), TextureChannel.Alpha );
+				mapPreviewDirty = false;
+			}
+
+			Game.chrome.renderer.RgbaSpriteRenderer.DrawSprite( mapChooserSprite,
+				new float2( mapRect.Location ),
+				"chrome",
+				new float2( mapRect.Size ) );
+
+			Game.chrome.DrawSpawnPoints( map, Parent.Bounds );
+			base.Draw( world );
+		}
+	}
+}