Editor UI refactor with draggable selection box

OpenRA.Game/Map/CellCoordsRegion.cs

@@ -0,0 +1,90 @@
+#region Copyright & License Information
+/*
+ * Copyright (c) The OpenRA Developers and Contributors
+ * 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.Collections;
+using System.Collections.Generic;
+
+namespace OpenRA
+{
+	public readonly struct CellCoordsRegion : IEnumerable<CPos>
+	{
+		public struct CellCoordsEnumerator : IEnumerator<CPos>
+		{
+			readonly CellCoordsRegion r;
+
+			public CellCoordsEnumerator(CellCoordsRegion region)
+				: this()
+			{
+				r = region;
+				Reset();
+			}
+
+			public bool MoveNext()
+			{
+				var x = Current.X + 1;
+				var y = Current.Y;
+
+				// Check for column overflow.
+				if (x > r.BottomRight.X)
+				{
+					y++;
+					x = r.TopLeft.X;
+
+					// Check for row overflow.
+					if (y > r.BottomRight.Y)
+						return false;
+				}
+
+				Current = new CPos(x, y);
+				return true;
+			}
+
+			public void Reset()
+			{
+				Current = new CPos(r.TopLeft.X - 1, r.TopLeft.Y);
+			}
+
+			public CPos Current { get; private set; }
+
+			readonly object IEnumerator.Current => Current;
+			public readonly void Dispose() { }
+		}
+
+		public CellCoordsRegion(CPos topLeft, CPos bottomRight)
+		{
+			TopLeft = topLeft;
+			BottomRight = bottomRight;
+		}
+
+		public override string ToString()
+		{
+			return $"{TopLeft}->{BottomRight}";
+		}
+
+		public CellCoordsEnumerator GetEnumerator()
+		{
+			return new CellCoordsEnumerator(this);
+		}
+
+		IEnumerator<CPos> IEnumerable<CPos>.GetEnumerator()
+		{
+			return GetEnumerator();
+		}
+
+		IEnumerator IEnumerable.GetEnumerator()
+		{
+			return GetEnumerator();
+		}
+
+		public CPos TopLeft { get; }
+		public CPos BottomRight { get; }
+	}
+}

OpenRA.Game/Map/CellRegion.cs

@@ -102,6 +102,7 @@ public bool Contains(CPos cell)
 		}
 
 		public MapCoordsRegion MapCoords => new(mapTopLeft, mapBottomRight);
+		public CellCoordsRegion CellCoords => new(TopLeft, BottomRight);
 
 		public CellRegionEnumerator GetEnumerator()
 		{

OpenRA.Game/Traits/TraitsInterfaces.cs

@@ -296,6 +296,9 @@ public interface ISelectionDecorations
 		int2 GetDecorationOrigin(Actor self, WorldRenderer wr, string pos, int2 margin);
 	}
 
+	public interface IEditorSelectionLayer : ITraitInfoInterface { }
+	public interface IEditorPasteLayer : ITraitInfoInterface { }
+
 	public interface IMapPreviewSignatureInfo : ITraitInfoInterface
 	{
 		void PopulateMapPreviewSignatureCells(Map map, ActorInfo ai, ActorReference s, List<(MPos Uv, Color Color)> destinationBuffer);

OpenRA.Mods.Common/EditorBrushes/EditorClipboard.cs

@@ -0,0 +1,35 @@
+using System.Collections.Generic;
+using OpenRA.Mods.Common.Traits;
+
+namespace OpenRA.Mods.Common.EditorBrushes
+{
+	public readonly struct ClipboardTile
+	{
+		public readonly TerrainTile TerrainTile;
+		public readonly ResourceTile ResourceTile;
+		public readonly ResourceLayerContents ResourceLayerContents;
+		public readonly byte Height;
+
+		public ClipboardTile(TerrainTile terrainTile, ResourceTile resourceTile, ResourceLayerContents resourceLayerContents, byte height)
+		{
+			TerrainTile = terrainTile;
+			ResourceTile = resourceTile;
+			ResourceLayerContents = resourceLayerContents;
+			Height = height;
+		}
+	}
+
+	public readonly struct EditorClipboard
+	{
+		public readonly CellRegion CellRegion;
+		public readonly Dictionary<string, EditorActorPreview> Actors;
+		public readonly Dictionary<CPos, ClipboardTile> Tiles;
+
+		public EditorClipboard(CellRegion cellRegion, Dictionary<string, EditorActorPreview> actors, Dictionary<CPos, ClipboardTile> tiles)
+		{
+			CellRegion = cellRegion;
+			Actors = actors;
+			Tiles = tiles;
+		}
+	}
+}