Added Undo Redo to editor

OpenRA.Mods.Common/EditorBrushes/EditorActorBrush.cs

@@ -24,6 +24,7 @@ namespace OpenRA.Mods.Common.Widgets
 		readonly WorldRenderer worldRenderer;
 		readonly World world;
 		readonly EditorActorLayer editorLayer;
+		readonly EditorActionManager editorActionManager;
 		readonly EditorViewportControllerWidget editorWidget;
 		readonly ActorPreviewWidget preview;
 		readonly WVec centerOffset;
@@ -38,6 +39,7 @@ namespace OpenRA.Mods.Common.Widgets
 			worldRenderer = wr;
 			world = wr.World;
 			editorLayer = world.WorldActor.Trait<EditorActorLayer>();
+			editorActionManager = world.WorldActor.Trait<EditorActionManager>();
 
 			Actor = actor;
 			this.owner = owner;
@@ -101,33 +103,8 @@ namespace OpenRA.Mods.Common.Widgets
 					return true;
 
 				// Enforce first entry of ValidOwnerNames as owner if the actor has RequiresSpecificOwners
-				var ownerName = owner.Name;
+				var action = new AddActorAction(editorLayer, Actor, cell, owner, facing);
-				var specificOwnerInfo = Actor.TraitInfoOrDefault<RequiresSpecificOwnersInfo>();
+				editorActionManager.Add(action);
-				if (specificOwnerInfo != null && !specificOwnerInfo.ValidOwnerNames.Contains(ownerName))
-					ownerName = specificOwnerInfo.ValidOwnerNames.First();
-
-				var newActorReference = new ActorReference(Actor.Name);
-				newActorReference.Add(new OwnerInit(ownerName));
-
-				newActorReference.Add(new LocationInit(cell));
-
-				var ios = Actor.TraitInfoOrDefault<IOccupySpaceInfo>();
-				if (ios != null && ios.SharesCell)
-				{
-					var subcell = editorLayer.FreeSubCellAt(cell);
-					if (subcell != SubCell.Invalid)
-						newActorReference.Add(new SubCellInit(subcell));
-				}
-
-				var initDict = newActorReference.InitDict;
-
-				if (Actor.HasTraitInfo<IFacingInfo>())
-					initDict.Add(new FacingInit(facing));
-
-				if (Actor.HasTraitInfo<TurretedInfo>())
-					initDict.Add(new TurretFacingInit(facing));
-
-				editorLayer.Add(newActorReference);
 			}
 
 			return true;
@@ -151,4 +128,69 @@ namespace OpenRA.Mods.Common.Widgets
 
 		public void Dispose() { }
 	}
+
+	class AddActorAction : IEditorAction
+	{
+		public string Text { get; private set; }
+
+		readonly EditorActorLayer editorLayer;
+		readonly ActorInfo actor;
+		readonly CPos cell;
+		readonly PlayerReference owner;
+		readonly int facing;
+
+		EditorActorPreview editorActorPreview;
+
+		public AddActorAction(EditorActorLayer editorLayer, ActorInfo actor, CPos cell, PlayerReference owner, int facing)
+		{
+			this.editorLayer = editorLayer;
+			this.actor = actor;
+			this.cell = cell;
+			this.owner = owner;
+			this.facing = facing;
+		}
+
+		public void Execute()
+		{
+			Do();
+		}
+
+		public void Do()
+		{
+			var ownerName = owner.Name;
+			var specificOwnerInfo = actor.TraitInfoOrDefault<RequiresSpecificOwnersInfo>();
+			if (specificOwnerInfo != null && !specificOwnerInfo.ValidOwnerNames.Contains(ownerName))
+				ownerName = specificOwnerInfo.ValidOwnerNames.First();
+
+			var newActorReference = new ActorReference(actor.Name);
+			newActorReference.Add(new OwnerInit(ownerName));
+
+			newActorReference.Add(new LocationInit(cell));
+
+			var ios = actor.TraitInfoOrDefault<IOccupySpaceInfo>();
+			if (ios != null && ios.SharesCell)
+			{
+				var subcell = editorLayer.FreeSubCellAt(cell);
+				if (subcell != SubCell.Invalid)
+					newActorReference.Add(new SubCellInit(subcell));
+			}
+
+			var initDict = newActorReference.InitDict;
+
+			if (actor.HasTraitInfo<IFacingInfo>())
+				initDict.Add(new FacingInit(facing));
+
+			if (actor.HasTraitInfo<TurretedInfo>())
+				initDict.Add(new TurretFacingInit(facing));
+
+			editorActorPreview = editorLayer.Add(newActorReference);
+
+			Text = "Added {0} ({1})".F(editorActorPreview.Info.Name, editorActorPreview.ID);
+		}
+
+		public void Undo()
+		{
+			editorLayer.Remove(editorActorPreview);
+		}
+	}
 }

OpenRA.Mods.Common/EditorBrushes/EditorCopyPasteBrush.cs

@@ -36,6 +36,7 @@ namespace OpenRA.Mods.Common.Widgets
 		readonly EditorSelectionLayer selectionLayer;
 		readonly EditorActorLayer editorLayer;
 		readonly Func<MapCopyFilters> getCopyFilters;
+		readonly EditorActionManager editorActionManager;
 
 		State state;
 		CPos start;
@@ -46,6 +47,8 @@ namespace OpenRA.Mods.Common.Widgets
 			this.editorWidget = editorWidget;
 			worldRenderer = wr;
 
+			editorActionManager = wr.World.WorldActor.Trait<EditorActionManager>();
+
 			selectionLayer = wr.World.WorldActor.Trait<EditorSelectionLayer>();
 			editorLayer = wr.World.WorldActor.Trait<EditorActorLayer>();
 			this.getCopyFilters = getCopyFilters;
@@ -143,26 +146,8 @@ namespace OpenRA.Mods.Common.Widgets
 				}
 			}
 
-			foreach (var kv in tiles)
+			var action = new CopyPasteEditorAction(copyFilters, worldRenderer.World.Map, tiles, previews, editorLayer, dest);
-			{
+			editorActionManager.Add(action);
-				if (copyFilters.HasFlag(MapCopyFilters.Terrain))
-					mapTiles[kv.Key] = kv.Value.Item1;
-
-				if (copyFilters.HasFlag(MapCopyFilters.Resources))
-					mapResources[kv.Key] = kv.Value.Item2;
-
-				mapHeight[kv.Key] = kv.Value.Item3;
-			}
-
-			if (copyFilters.HasFlag(MapCopyFilters.Actors))
-			{
-				var removeActors = dest.SelectMany(editorLayer.PreviewsAt).Distinct().ToList();
-				foreach (var preview in removeActors)
-					editorLayer.Remove(preview);
-			}
-
-			foreach (var kv in previews)
-				editorLayer.Add(kv.Value);
 		}
 
 		public void Tick()
@@ -187,4 +172,114 @@ namespace OpenRA.Mods.Common.Widgets
 			selectionLayer.Clear();
 		}
 	}
+
+	class CopyPasteEditorAction : IEditorAction
+	{
+		public string Text { get; private set; }
+
+		readonly MapCopyFilters copyFilters;
+		readonly Dictionary<CPos, Tuple<TerrainTile, ResourceTile, byte>> tiles;
+		readonly Dictionary<string, ActorReference> previews;
+		readonly EditorActorLayer editorLayer;
+		readonly CellRegion dest;
+		readonly CellLayer<TerrainTile> mapTiles;
+		readonly CellLayer<byte> mapHeight;
+		readonly CellLayer<ResourceTile> mapResources;
+
+		readonly Queue<UndoCopyPaste> undoCopyPastes = new Queue<UndoCopyPaste>();
+		readonly Queue<EditorActorPreview> removedActors = new Queue<EditorActorPreview>();
+		readonly Queue<EditorActorPreview> addedActorPreviews = new Queue<EditorActorPreview>();
+
+		public CopyPasteEditorAction(MapCopyFilters copyFilters, Map map,
+			Dictionary<CPos, Tuple<TerrainTile, ResourceTile, byte>> tiles, Dictionary<string, ActorReference> previews,
+			EditorActorLayer editorLayer, CellRegion dest)
+		{
+			this.copyFilters = copyFilters;
+			this.tiles = tiles;
+			this.previews = previews;
+			this.editorLayer = editorLayer;
+			this.dest = dest;
+
+			mapTiles = map.Tiles;
+			mapHeight = map.Height;
+			mapResources = map.Resources;
+
+			Text = "Copied {0} tiles".F(tiles.Count);
+		}
+
+		public void Execute()
+		{
+			Do();
+		}
+
+		public void Do()
+		{
+			foreach (var kv in tiles)
+			{
+				undoCopyPastes.Enqueue(new UndoCopyPaste(kv.Key, mapTiles[kv.Key], mapResources[kv.Key], mapHeight[kv.Key]));
+
+				if (copyFilters.HasFlag(MapCopyFilters.Terrain))
+					mapTiles[kv.Key] = kv.Value.Item1;
+
+				if (copyFilters.HasFlag(MapCopyFilters.Resources))
+					mapResources[kv.Key] = kv.Value.Item2;
+
+				mapHeight[kv.Key] = kv.Value.Item3;
+			}
+
+			if (copyFilters.HasFlag(MapCopyFilters.Actors))
+			{
+				var removeActors = dest.SelectMany(editorLayer.PreviewsAt).Distinct().ToList();
+				foreach (var preview in removeActors)
+				{
+					removedActors.Enqueue(preview);
+					editorLayer.Remove(preview);
+				}
+			}
+
+			foreach (var kv in previews)
+				addedActorPreviews.Enqueue(editorLayer.Add(kv.Value));
+		}
+
+		public void Undo()
+		{
+			while (undoCopyPastes.Count > 0)
+			{
+				var undoCopyPaste = undoCopyPastes.Dequeue();
+
+				var cell = undoCopyPaste.Cell;
+
+				if (copyFilters.HasFlag(MapCopyFilters.Terrain))
+					mapTiles[cell] = undoCopyPaste.MapTile;
+
+				if (copyFilters.HasFlag(MapCopyFilters.Resources))
+					mapResources[cell] = undoCopyPaste.ResourceTile;
+
+				mapHeight[cell] = undoCopyPaste.Height;
+			}
+
+			while (addedActorPreviews.Count > 0)
+				editorLayer.Remove(addedActorPreviews.Dequeue());
+
+			if (copyFilters.HasFlag(MapCopyFilters.Actors))
+				while (removedActors.Count > 0)
+					editorLayer.Add(removedActors.Dequeue());
+		}
+	}
+
+	internal class UndoCopyPaste
+	{
+		public CPos Cell { get; private set; }
+		public TerrainTile MapTile { get; private set; }
+		public ResourceTile ResourceTile { get; private set; }
+		public byte Height { get; private set; }
+
+		public UndoCopyPaste(CPos cell, TerrainTile mapTile, ResourceTile resourceTile, byte height)
+		{
+			Cell = cell;
+			MapTile = mapTile;
+			ResourceTile = resourceTile;
+			Height = height;
+		}
+	}
 }

OpenRA.Mods.Common/EditorBrushes/EditorDefaultBrush.cs

@@ -33,6 +33,8 @@ namespace OpenRA.Mods.Common.Widgets
 		readonly EditorViewportControllerWidget editorWidget;
 		readonly EditorActorLayer editorLayer;
 		readonly Dictionary<int, ResourceType> resources;
+		readonly EditorActionManager editorActionManager;
+
 		public EditorActorPreview SelectedActor;
 		int2 worldPixel;
 
@@ -45,6 +47,8 @@ namespace OpenRA.Mods.Common.Widgets
 			editorLayer = world.WorldActor.Trait<EditorActorLayer>();
 			resources = world.WorldActor.TraitsImplementing<ResourceType>()
 				.ToDictionary(r => r.Info.ResourceType, r => r);
+
+			editorActionManager = world.WorldActor.Trait<EditorActionManager>();
 		}
 
 		long CalculateActorSelectionPriority(EditorActorPreview actor)
@@ -74,7 +78,7 @@ namespace OpenRA.Mods.Common.Widgets
 			var underCursor = editorLayer.PreviewsAt(worldPixel).MinByOrDefault(CalculateActorSelectionPriority);
 
 			var mapResources = world.Map.Resources;
-			ResourceType type;
+			ResourceType type = null;
 			if (underCursor != null)
 				editorWidget.SetTooltip(underCursor.Tooltip);
 			else if (mapResources.Contains(cell) && resources.TryGetValue(mapResources[cell].Type, out type))
@@ -97,10 +101,10 @@ namespace OpenRA.Mods.Common.Widgets
 				editorWidget.SetTooltip(null);
 
 				if (underCursor != null && underCursor != SelectedActor)
-					editorLayer.Remove(underCursor);
+					editorActionManager.Add(new RemoveActorAction(editorLayer, underCursor));
 
 				if (mapResources.Contains(cell) && mapResources[cell].Type != 0)
-					mapResources[cell] = default(ResourceTile);
+					editorActionManager.Add(new RemoveResourceAction(mapResources, cell, type));
 			}
 
 			return true;
@@ -109,4 +113,69 @@ namespace OpenRA.Mods.Common.Widgets
 		public void Tick() { }
 		public void Dispose() { }
 	}
+
+	class RemoveActorAction : IEditorAction
+	{
+		public string Text { get; private set; }
+
+		readonly EditorActorLayer editorActorLayer;
+		readonly EditorActorPreview actor;
+
+		public RemoveActorAction(EditorActorLayer editorActorLayer, EditorActorPreview actor)
+		{
+			this.editorActorLayer = editorActorLayer;
+			this.actor = actor;
+
+			Text = "Removed {0} ({1})".F(actor.Info.Name, actor.ID);
+		}
+
+		public void Execute()
+		{
+			Do();
+		}
+
+		public void Do()
+		{
+			editorActorLayer.Remove(actor);
+		}
+
+		public void Undo()
+		{
+			editorActorLayer.Add(actor);
+		}
+	}
+
+	class RemoveResourceAction : IEditorAction
+	{
+		public string Text { get; private set; }
+
+		readonly CellLayer<ResourceTile> mapResources;
+		readonly CPos cell;
+
+		ResourceTile resourceTile;
+
+		public RemoveResourceAction(CellLayer<ResourceTile> mapResources, CPos cell, ResourceType type)
+		{
+			this.mapResources = mapResources;
+			this.cell = cell;
+
+			Text = "Removed {0}".F(type.Info.TerrainType);
+		}
+
+		public void Execute()
+		{
+			Do();
+		}
+
+		public void Do()
+		{
+			resourceTile = mapResources[cell];
+			mapResources[cell] = default(ResourceTile);
+		}
+
+		public void Undo()
+		{
+			mapResources[cell] = resourceTile;
+		}
+	}
 }

OpenRA.Mods.Common/EditorBrushes/EditorResourceBrush.cs

@@ -9,6 +9,7 @@
  */
 #endregion
 
+using System.Collections.Generic;
 using System.Linq;
 using OpenRA.Graphics;
 using OpenRA.Mods.Common.Traits;
@@ -23,6 +24,10 @@ namespace OpenRA.Mods.Common.Widgets
 		readonly World world;
 		readonly EditorViewportControllerWidget editorWidget;
 		readonly SpriteWidget preview;
+		readonly EditorActionManager editorActionManager;
+
+		AddResourcesEditorAction action;
+		bool resourceAdded;
 
 		public EditorResourceBrush(EditorViewportControllerWidget editorWidget, ResourceTypeInfo resource, WorldRenderer wr)
 		{
@@ -30,6 +35,8 @@ namespace OpenRA.Mods.Common.Widgets
 			ResourceType = resource;
 			worldRenderer = wr;
 			world = wr.World;
+			editorActionManager = world.WorldActor.Trait<EditorActionManager>();
+			action = new AddResourcesEditorAction(world.Map, ResourceType);
 
 			preview = editorWidget.Get<SpriteWidget>("DRAG_LAYER_PREVIEW");
 			preview.Palette = resource.Palette;
@@ -65,11 +72,18 @@ namespace OpenRA.Mods.Common.Widgets
 
 			var cell = worldRenderer.Viewport.ViewToWorld(mi.Location);
 
-			if (mi.Button == MouseButton.Left && AllowResourceAt(cell))
+			if (mi.Button == MouseButton.Left && mi.Event != MouseInputEvent.Up && AllowResourceAt(cell))
 			{
 				var type = (byte)ResourceType.ResourceType;
 				var index = (byte)ResourceType.MaxDensity;
-				world.Map.Resources[cell] = new ResourceTile(type, index);
+				action.Add(new CellResource(cell, world.Map.Resources[cell], new ResourceTile(type, index)));
+				resourceAdded = true;
+			}
+			else if (resourceAdded && mi.Button == MouseButton.Left && mi.Event == MouseInputEvent.Up)
+			{
+				editorActionManager.Add(action);
+				action = new AddResourcesEditorAction(world.Map, ResourceType);
+				resourceAdded = false;
 			}
 
 			return true;
@@ -112,4 +126,63 @@ namespace OpenRA.Mods.Common.Widgets
 
 		public void Dispose() { }
 	}
+
+	struct CellResource
+	{
+		public readonly CPos Cell;
+		public readonly ResourceTile ResourceTile;
+		public readonly ResourceTile NewResourceTile;
+
+		public CellResource(CPos cell, ResourceTile resourceTile, ResourceTile newResourceTile)
+		{
+			Cell = cell;
+			ResourceTile = resourceTile;
+			NewResourceTile = newResourceTile;
+		}
+	}
+
+	class AddResourcesEditorAction : IEditorAction
+	{
+		public string Text { get; private set; }
+
+		readonly Map map;
+		readonly ResourceTypeInfo resourceType;
+		readonly List<CellResource> cellResources = new List<CellResource>();
+
+		public AddResourcesEditorAction(Map map, ResourceTypeInfo resourceType)
+		{
+			this.map = map;
+			this.resourceType = resourceType;
+		}
+
+		public void Execute()
+		{
+		}
+
+		public void Do()
+		{
+			foreach (var resourceCell in cellResources)
+				SetTile(resourceCell.Cell, resourceCell.NewResourceTile);
+		}
+
+		void SetTile(CPos cell, ResourceTile tile)
+		{
+			map.Resources[cell] = tile;
+		}
+
+		public void Undo()
+		{
+			foreach (var resourceCell in cellResources)
+				SetTile(resourceCell.Cell, resourceCell.ResourceTile);
+		}
+
+		public void Add(CellResource cellResource)
+		{
+			SetTile(cellResource.Cell, cellResource.NewResourceTile);
+			cellResources.Add(cellResource);
+
+			var cellText = cellResources.Count != 1 ? "cells" : "cell";
+			Text = "Added {0} {1} of {2}".F(cellResources.Count, cellText, resourceType.TerrainType);
+		}
+	}
 }

OpenRA.Mods.Common/EditorBrushes/EditorTileBrush.cs

@@ -13,6 +13,7 @@ using System;
 using System.Collections.Generic;
 using System.Linq;
 using OpenRA.Graphics;
+using OpenRA.Mods.Common.Traits;
 using OpenRA.Primitives;
 
 namespace OpenRA.Mods.Common.Widgets
@@ -26,6 +27,7 @@ namespace OpenRA.Mods.Common.Widgets
 		readonly EditorViewportControllerWidget editorWidget;
 		readonly TerrainTemplatePreviewWidget preview;
 		readonly Rectangle bounds;
+		readonly EditorActionManager editorActionManager;
 
 		bool painting;
 
@@ -36,6 +38,8 @@ namespace OpenRA.Mods.Common.Widgets
 			worldRenderer = wr;
 			world = wr.World;
 
+			editorActionManager = world.WorldActor.Trait<EditorActionManager>();
+
 			preview = editorWidget.Get<TerrainTemplatePreviewWidget>("DRAG_TILE_PREVIEW");
 			preview.GetScale = () => worldRenderer.Viewport.Zoom;
 			preview.IsVisible = () => editorWidget.CurrentBrush == this;
@@ -97,33 +101,13 @@ namespace OpenRA.Mods.Common.Widgets
 		void PaintCell(CPos cell, bool isMoving)
 		{
 			var map = world.Map;
-			var mapTiles = map.Tiles;
-			var mapHeight = map.Height;
-
 			var tileset = map.Rules.TileSet;
 			var template = tileset.Templates[Template];
-			var baseHeight = mapHeight.Contains(cell) ? mapHeight[cell] : (byte)0;
 
 			if (isMoving && PlacementOverlapsSameTemplate(template, cell))
 				return;
 
-			var i = 0;
+			editorActionManager.Add(new PaintTileEditorAction(Template, map, cell));
-			for (var y = 0; y < template.Size.Y; y++)
-			{
-				for (var x = 0; x < template.Size.X; x++, i++)
-				{
-					if (template.Contains(i) && template[i] != null)
-					{
-						var index = template.PickAny ? (byte)Game.CosmeticRandom.Next(0, template.TilesCount) : (byte)i;
-						var c = cell + new CVec(x, y);
-						if (!mapTiles.Contains(c))
-							continue;
-
-						mapTiles[c] = new TerrainTile(Template, index);
-						mapHeight[c] = (byte)(baseHeight + template[index].Height).Clamp(0, map.Grid.MaximumTerrainHeight);
-					}
-				}
-			}
 		}
 
 		void FloodFillWithBrush(CPos cell, bool isMoving)
@@ -239,4 +223,87 @@ namespace OpenRA.Mods.Common.Widgets
 
 		public void Dispose() { }
 	}
+
+	class PaintTileEditorAction : IEditorAction
+	{
+		public string Text { get; private set; }
+
+		readonly ushort template;
+		readonly Map map;
+		readonly CPos cell;
+
+		readonly Queue<UndoTile> undoTiles = new Queue<UndoTile>();
+		readonly TerrainTemplateInfo terrainTemplate;
+
+		public PaintTileEditorAction(ushort template, Map map, CPos cell)
+		{
+			this.template = template;
+			this.map = map;
+			this.cell = cell;
+
+			var tileset = map.Rules.TileSet;
+			terrainTemplate = tileset.Templates[template];
+			Text = "Added tile {0}".F(terrainTemplate.Id);
+		}
+
+		public void Execute()
+		{
+			Do();
+		}
+
+		public void Do()
+		{
+			var mapTiles = map.Tiles;
+			var mapHeight = map.Height;
+			var baseHeight = mapHeight.Contains(cell) ? mapHeight[cell] : (byte)0;
+
+			var i = 0;
+			for (var y = 0; y < terrainTemplate.Size.Y; y++)
+			{
+				for (var x = 0; x < terrainTemplate.Size.X; x++, i++)
+				{
+					if (terrainTemplate.Contains(i) && terrainTemplate[i] != null)
+					{
+						var index = terrainTemplate.PickAny ? (byte)Game.CosmeticRandom.Next(0, terrainTemplate.TilesCount) : (byte)i;
+						var c = cell + new CVec(x, y);
+						if (!mapTiles.Contains(c))
+							continue;
+
+						undoTiles.Enqueue(new UndoTile(c, mapTiles[c], mapHeight[c]));
+
+						mapTiles[c] = new TerrainTile(template, index);
+						mapHeight[c] = (byte)(baseHeight + terrainTemplate[index].Height).Clamp(0, map.Grid.MaximumTerrainHeight);
+					}
+				}
+			}
+		}
+
+		public void Undo()
+		{
+			var mapTiles = map.Tiles;
+			var mapHeight = map.Height;
+
+			while (undoTiles.Count > 0)
+			{
+				var undoTile = undoTiles.Dequeue();
+
+				mapTiles[undoTile.Cell] = undoTile.MapTile;
+				mapHeight[undoTile.Cell] = undoTile.Height;
+			}
+		}
+	}
+
+	class UndoTile
+	{
+		public CPos Cell { get; private set; }
+		public TerrainTile MapTile { get; private set; }
+		public byte Height { get; private set; }
+
+		public UndoTile(CPos cell, TerrainTile mapTile, byte height)
+		{
+			Cell = cell;
+			MapTile = mapTile;
+			Height = height;
+		}
+	}
 }

OpenRA.Mods.Common/Traits/World/EditorActionManager.cs

@@ -0,0 +1,172 @@
+#region Copyright & License Information
+/*
+ * Copyright 2007-2019 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.Graphics;
+using OpenRA.Traits;
+
+namespace OpenRA.Mods.Common.Traits
+{
+	public class EditorActionManagerInfo : TraitInfo<EditorActionManager> { }
+
+	public class EditorActionManager : IWorldLoaded
+	{
+		readonly Stack<EditorActionContainer> undoStack = new Stack<EditorActionContainer>();
+		readonly Stack<EditorActionContainer> redoStack = new Stack<EditorActionContainer>();
+
+		public event Action<EditorActionContainer> ItemAdded;
+		public event Action<EditorActionContainer> ItemRemoved;
+		public event Action OnChange;
+
+		int nextId;
+
+		public void WorldLoaded(World w, WorldRenderer wr)
+		{
+			Add(new OpenMapAction());
+		}
+
+		public void Add(IEditorAction editorAction)
+		{
+			editorAction.Execute();
+
+			if (undoStack.Count > 0)
+				undoStack.Peek().Status = EditorActionStatus.History;
+
+			var actionContainer = new EditorActionContainer(nextId++, editorAction);
+
+			ClearRedo();
+			undoStack.Push(actionContainer);
+
+			if (ItemAdded != null)
+				ItemAdded(actionContainer);
+		}
+
+		public void Undo()
+		{
+			if (!HasUndos())
+				return;
+
+			var editorAction = undoStack.Pop();
+			undoStack.Peek().Status = EditorActionStatus.Active;
+			editorAction.Action.Undo();
+			editorAction.Status = EditorActionStatus.Future;
+			redoStack.Push(editorAction);
+
+			if (OnChange != null)
+				OnChange();
+		}
+
+		void ClearRedo()
+		{
+			while (HasRedos())
+			{
+				var item = redoStack.Pop();
+
+				if (ItemRemoved != null)
+					ItemRemoved(item);
+			}
+		}
+
+		public void Redo()
+		{
+			if (!HasRedos())
+				return;
+
+			var editorAction = redoStack.Pop();
+
+			editorAction.Status = EditorActionStatus.Active;
+			editorAction.Action.Do();
+			undoStack.Peek().Status = EditorActionStatus.History;
+			undoStack.Push(editorAction);
+
+			if (OnChange != null)
+				OnChange();
+		}
+
+		public bool HasUndos()
+		{
+			// Preserve the initial OpenMapAction.
+			return undoStack.Count > 1;
+		}
+
+		public bool HasRedos()
+		{
+			return redoStack.Count > 0;
+		}
+
+		public void Rewind(int id)
+		{
+			while (undoStack.Peek().Id != id)
+				Undo();
+		}
+
+		public void Forward(int id)
+		{
+			while (undoStack.Peek().Id != id)
+				Redo();
+		}
+	}
+
+	public enum EditorActionStatus
+	{
+		History,
+		Active,
+		Future,
+	}
+
+	public interface IEditorAction
+	{
+		void Execute();
+		void Do();
+		void Undo();
+
+		string Text { get; }
+	}
+
+	class OpenMapAction : IEditorAction
+	{
+		public OpenMapAction()
+		{
+			Text = "Opened";
+		}
+
+		public void Execute()
+		{
+		}
+
+		public void Do()
+		{
+		}
+
+		public void Undo()
+		{
+		}
+
+		public string Text { get; private set; }
+
+		public EditorActionStatus Status { get; set; }
+	}
+
+	public class EditorActionContainer
+	{
+		public int Id { get; private set; }
+		public IEditorAction Action { get; private set; }
+		public EditorActionStatus Status { get; set; }
+
+		public EditorActionContainer(int id, IEditorAction action)
+		{
+			Id = id;
+			Action = action;
+			Status = EditorActionStatus.Active;
+		}
+	}
+}

OpenRA.Mods.Common/Traits/World/EditorActorLayer.cs

@@ -110,8 +110,15 @@ namespace OpenRA.Mods.Common.Traits
 			var owner = Players.Players[reference.InitDict.Get<OwnerInit>().PlayerName];
 
 			var preview = new EditorActorPreview(worldRenderer, id, reference, owner);
-			previews.Add(preview);
 
+			Add(preview, initialSetup);
+
+			return preview;
+		}
+
+		public void Add(EditorActorPreview preview, bool initialSetup = false)
+		{
+			previews.Add(preview);
 			if (!preview.Bounds.IsEmpty)
 				screenMap.Add(preview, preview.Bounds);
 
@@ -126,11 +133,9 @@ namespace OpenRA.Mods.Common.Traits
 			{
 				UpdateNeighbours(preview.Footprint);
 
-				if (reference.Type == "mpspawn")
+				if (preview.Actor.Type == "mpspawn")
 					SyncMultiplayerCount();
 			}
-
-			return preview;
 		}
 
 		public void Remove(EditorActorPreview preview)
@@ -262,7 +267,7 @@ namespace OpenRA.Mods.Common.Traits
 
 		string NextActorName()
 		{
-			var id = previews.Count();
+			var id = previews.Count;
 			var possibleName = "Actor" + id.ToString();
 
 			while (previews.Any(p => p.ID == possibleName))

OpenRA.Mods.Common/Traits/World/EditorActorPreview.cs

@@ -20,7 +20,7 @@ using OpenRA.Traits;
 
 namespace OpenRA.Mods.Common.Traits
 {
-	public class EditorActorPreview
+	public class EditorActorPreview : IEquatable<EditorActorPreview>
 	{
 		public readonly string DescriptiveName;
 		public readonly ActorInfo Info;
@@ -28,6 +28,7 @@ namespace OpenRA.Mods.Common.Traits
 		public readonly IReadOnlyDictionary<CPos, SubCell> Footprint;
 		public readonly Rectangle Bounds;
 		public readonly SelectionBoxRenderable SelectionBox;
+		public readonly ActorReference Actor;
 
 		public string Tooltip
 		{
@@ -43,7 +44,6 @@ namespace OpenRA.Mods.Common.Traits
 		public SubCell SubCell { get; private set; }
 		public bool Selected { get; set; }
 
-		readonly ActorReference actor;
 		readonly WorldRenderer worldRenderer;
 		readonly TooltipInfoBase tooltip;
 		IActorPreview[] previews;
@@ -51,7 +51,7 @@ namespace OpenRA.Mods.Common.Traits
 		public EditorActorPreview(WorldRenderer worldRenderer, string id, ActorReference actor, PlayerReference owner)
 		{
 			ID = id;
-			this.actor = actor;
+			Actor = actor;
 			Owner = owner;
 			this.worldRenderer = worldRenderer;
 
@@ -120,25 +120,25 @@ namespace OpenRA.Mods.Common.Traits
 
 		public void ReplaceInit<T>(T init)
 		{
-			var original = actor.InitDict.GetOrDefault<T>();
+			var original = Actor.InitDict.GetOrDefault<T>();
 			if (original != null)
-				actor.InitDict.Remove(original);
+				Actor.InitDict.Remove(original);
 
-			actor.InitDict.Add(init);
+			Actor.InitDict.Add(init);
 			GeneratePreviews();
 		}
 
 		public void RemoveInit<T>()
 		{
-			var original = actor.InitDict.GetOrDefault<T>();
+			var original = Actor.InitDict.GetOrDefault<T>();
 			if (original != null)
-				actor.InitDict.Remove(original);
+				Actor.InitDict.Remove(original);
 			GeneratePreviews();
 		}
 
 		public T Init<T>()
 		{
-			return actor.InitDict.GetOrDefault<T>();
+			return Actor.InitDict.GetOrDefault<T>();
 		}
 
 		public MiniYaml Save()
@@ -154,7 +154,7 @@ namespace OpenRA.Mods.Common.Traits
 				return true;
 			};
 
-			return actor.Save(saveInit);
+			return Actor.Save(saveInit);
 		}
 
 		WPos PreviewPosition(World world, TypeDictionary init)
@@ -167,7 +167,7 @@ namespace OpenRA.Mods.Common.Traits
 				var cell = init.Get<LocationInit>().Value(world);
 				var offset = WVec.Zero;
 
-				var subCellInit = actor.InitDict.GetOrDefault<SubCellInit>();
+				var subCellInit = Actor.InitDict.GetOrDefault<SubCellInit>();
 				var subCell = subCellInit != null ? subCellInit.Value(worldRenderer.World) : SubCell.Any;
 
 				var buildingInfo = Info.TraitInfoOrDefault<BuildingInfo>();
@@ -182,7 +182,7 @@ namespace OpenRA.Mods.Common.Traits
 
 		void GeneratePreviews()
 		{
-			var init = new ActorPreviewInitializer(Info, worldRenderer, actor.InitDict);
+			var init = new ActorPreviewInitializer(Info, worldRenderer, Actor.InitDict);
 			previews = Info.TraitInfos<IRenderActorPreviewInfo>()
 				.SelectMany(rpi => rpi.RenderPreview(init))
 				.ToArray();
@@ -190,12 +190,39 @@ namespace OpenRA.Mods.Common.Traits
 
 		public ActorReference Export()
 		{
-			return new ActorReference(actor.Type, actor.Save().ToDictionary());
+			return new ActorReference(Actor.Type, Actor.Save().ToDictionary());
 		}
 
 		public override string ToString()
 		{
 			return "{0} {1}".F(Info.Name, ID);
 		}
+
+		public bool Equals(EditorActorPreview other)
+		{
+			if (ReferenceEquals(null, other))
+				return false;
+			if (ReferenceEquals(this, other))
+				return true;
+
+			return string.Equals(ID, other.ID, StringComparison.OrdinalIgnoreCase);
+		}
+
+		public override bool Equals(object obj)
+		{
+			if (ReferenceEquals(null, obj))
+				return false;
+			if (ReferenceEquals(this, obj))
+				return true;
+			if (obj.GetType() != GetType())
+				return false;
+
+			return Equals((EditorActorPreview)obj);
+		}
+
+		public override int GetHashCode()
+		{
+			return ID != null ? StringComparer.OrdinalIgnoreCase.GetHashCode(ID) : 0;
+		}
 	}
 }

OpenRA.Mods.Common/Widgets/EditorViewportControllerWidget.cs

@@ -11,6 +11,7 @@
 
 using System;
 using OpenRA.Graphics;
+using OpenRA.Mods.Common.Traits;
 using OpenRA.Widgets;
 
 namespace OpenRA.Mods.Common.Widgets
@@ -25,6 +26,7 @@ namespace OpenRA.Mods.Common.Widgets
 
 		readonly Lazy<TooltipContainerWidget> tooltipContainer;
 		readonly WorldRenderer worldRenderer;
+		readonly EditorActionManager editorActionManager;
 
 		bool enableTooltips;
 
@@ -34,6 +36,14 @@ namespace OpenRA.Mods.Common.Widgets
 			this.worldRenderer = worldRenderer;
 			tooltipContainer = Exts.Lazy(() => Ui.Root.Get<TooltipContainerWidget>(TooltipContainer));
 			CurrentBrush = DefaultBrush = new EditorDefaultBrush(this, worldRenderer);
+			editorActionManager = world.WorldActor.Trait<EditorActionManager>();
+
+			editorActionManager.OnChange += EditorActionManagerOnChange;
+		}
+
+		void EditorActionManagerOnChange()
+		{
+			DefaultBrush.SelectedActor = null;
 		}
 
 		public void ClearBrush() { SetBrush(null); }
@@ -109,5 +119,11 @@ namespace OpenRA.Mods.Common.Widgets
 			cachedViewportPosition = worldRenderer.Viewport.CenterPosition;
 			CurrentBrush.Tick();
 		}
+
+		public override void Removed()
+		{
+			base.Removed();
+			editorActionManager.OnChange -= EditorActionManagerOnChange;
+		}
 	}
 }

OpenRA.Mods.Common/Widgets/Logic/Editor/ActorEditLogic.cs

@@ -26,6 +26,7 @@ namespace OpenRA.Mods.Common.Widgets.Logic
 
 		readonly WorldRenderer worldRenderer;
 		readonly EditorActorLayer editorActorLayer;
+		readonly EditorActionManager editorActionManager;
 		readonly EditorViewportControllerWidget editor;
 		readonly BackgroundWidget actorEditPanel;
 		readonly LabelWidget typeLabel;
@@ -48,6 +49,8 @@ namespace OpenRA.Mods.Common.Widgets.Logic
 		string initialActorID;
 
 		EditorActorPreview currentActorInner;
+		EditActorPreview editActorPreview;
+
 		EditorActorPreview CurrentActor
 		{
 			get
@@ -61,7 +64,10 @@ namespace OpenRA.Mods.Common.Widgets.Logic
 					return;
 
 				if (currentActorInner != null)
+				{
+					Reset();
 					currentActorInner.Selected = false;
+				}
 
 				currentActorInner = value;
 				if (currentActorInner != null)
@@ -74,6 +80,8 @@ namespace OpenRA.Mods.Common.Widgets.Logic
 		{
 			this.worldRenderer = worldRenderer;
 			editorActorLayer = world.WorldActor.Trait<EditorActorLayer>();
+			editorActionManager = world.WorldActor.Trait<EditorActionManager>();
+
 			editor = widget.Parent.Get<EditorViewportControllerWidget>("MAP_EDITOR");
 			actorEditPanel = editor.Get<BackgroundWidget>("ACTOR_EDIT_PANEL");
 
@@ -88,7 +96,8 @@ namespace OpenRA.Mods.Common.Widgets.Logic
 			initContainer.RemoveChildren();
 
 			var deleteButton = actorEditPanel.Get<ButtonWidget>("DELETE_BUTTON");
-			var closeButton = actorEditPanel.Get<ButtonWidget>("CLOSE_BUTTON");
+			var cancelButton = actorEditPanel.Get<ButtonWidget>("CANCEL_BUTTON");
+			var okButton = actorEditPanel.Get<ButtonWidget>("OK_BUTTON");
 
 			actorIDErrorLabel = actorEditPanel.Get<LabelWidget>("ACTOR_ID_ERROR_LABEL");
 			actorIDErrorLabel.IsVisible = () => actorIDStatus != ActorIDStatus.Normal;
@@ -99,7 +108,9 @@ namespace OpenRA.Mods.Common.Widgets.Logic
 			if (logicArgs.TryGetValue("EditPanelPadding", out yaml))
 				editPanelPadding = FieldLoader.GetValue<int>("EditPanelPadding", yaml.Value);
 
-			closeButton.OnClick = Close;
+			okButton.IsDisabled = () => !IsValid() || !editActorPreview.IsDirty;
+			okButton.OnClick = Save;
+			cancelButton.OnClick = Cancel;
 			deleteButton.OnClick = Delete;
 			actorEditPanel.IsVisible = () => CurrentActor != null
 				&& editor.CurrentBrush == editor.DefaultBrush
@@ -113,15 +124,15 @@ namespace OpenRA.Mods.Common.Widgets.Logic
 
 			actorIDField.OnTextEdited = () =>
 			{
-				if (string.IsNullOrWhiteSpace(actorIDField.Text))
+				var actorId = actorIDField.Text.Trim();
+				if (string.IsNullOrWhiteSpace(actorId))
 				{
 					nextActorIDStatus = ActorIDStatus.Empty;
 					return;
 				}
 
 				// Check for duplicate actor ID
-				var actorId = actorIDField.Text.ToLowerInvariant();
+				if (CurrentActor.ID.Equals(actorId, StringComparison.OrdinalIgnoreCase))
-				if (CurrentActor.ID.ToLowerInvariant() != actorId)
 				{
 					if (editorActorLayer[actorId] != null)
 					{
@@ -130,23 +141,30 @@ namespace OpenRA.Mods.Common.Widgets.Logic
 					}
 				}
 
-				SetActorID(world, actorId);
+				SetActorID(actorId);
+				nextActorIDStatus = ActorIDStatus.Normal;
 			};
 
 			actorIDField.OnLoseFocus = () =>
 			{
 				// Reset invalid IDs back to their starting value
 				if (actorIDStatus != ActorIDStatus.Normal)
-					SetActorID(world, initialActorID);
+					SetActorID(initialActorID);
 			};
 		}
 
-		void SetActorID(World world, string actorId)
+		void SetActorID(string actorId)
 		{
-			CurrentActor.ID = actorId;
+			editActorPreview.SetActorID(actorId);
+
 			nextActorIDStatus = ActorIDStatus.Normal;
 		}
 
+		bool IsValid()
+		{
+			return nextActorIDStatus == ActorIDStatus.Normal;
+		}
+
 		public override void Tick()
 		{
 			if (actorIDStatus != nextActorIDStatus)
@@ -183,6 +201,8 @@ namespace OpenRA.Mods.Common.Widgets.Logic
 					lastScrollTime = 0; // Ensure visible
 					CurrentActor = actor;
 
+					editActorPreview = new EditActorPreview(CurrentActor);
+
 					initialActorID = actorIDField.Text = actor.ID;
 
 					var font = Game.Renderer.Fonts[typeLabel.Font];
@@ -203,13 +223,22 @@ namespace OpenRA.Mods.Common.Widgets.Logic
 					var ownerDropdown = ownerContainer.Get<DropDownButtonWidget>("OPTION");
 					var selectedOwner = actor.Owner;
 
+					Action<EditorActorPreview, PlayerReference> updateOwner = (preview, reference) =>
+					{
+						preview.Owner = reference;
+						preview.ReplaceInit(new OwnerInit(reference.Name));
+					};
+
+					var ownerHandler = new EditorActorOptionActionHandle<PlayerReference>(updateOwner, actor.Owner);
+					editActorPreview.Add(ownerHandler);
+
 					Func<PlayerReference, ScrollItemWidget, ScrollItemWidget> setupItem = (option, template) =>
 					{
 						var item = ScrollItemWidget.Setup(template, () => selectedOwner == option, () =>
 						{
 							selectedOwner = option;
-							CurrentActor.Owner = selectedOwner;
+							updateOwner(CurrentActor, selectedOwner);
-							CurrentActor.ReplaceInit(new OwnerInit(selectedOwner.Name));
+							ownerHandler.OnChange(option);
 						});
 
 						item.Get<LabelWidget>("LABEL").GetText = () => option.Name;
@@ -248,8 +277,12 @@ namespace OpenRA.Mods.Common.Widgets.Logic
 							slider.MaximumValue = so.MaxValue;
 							slider.Ticks = so.Ticks;
 
+							var editorActionHandle = new EditorActorOptionActionHandle<float>(so.OnChange, so.GetValue(actor));
+							editActorPreview.Add(editorActionHandle);
+
 							slider.GetValue = () => so.GetValue(actor);
 							slider.OnChange += value => so.OnChange(actor, value);
+							slider.OnChange += value => editorActionHandle.OnChange(value);
 
 							initContainer.AddChild(sliderContainer);
 						}
@@ -261,12 +294,19 @@ namespace OpenRA.Mods.Common.Widgets.Logic
 							initContainer.Bounds.Height += dropdownContainer.Bounds.Height;
 							dropdownContainer.Get<LabelWidget>("LABEL").GetText = () => ddo.Name;
 
+							var editorActionHandle = new EditorActorOptionActionHandle<string>(ddo.OnChange, ddo.GetValue(actor));
+							editActorPreview.Add(editorActionHandle);
+
 							var dropdown = dropdownContainer.Get<DropDownButtonWidget>("OPTION");
 							Func<KeyValuePair<string, string>, ScrollItemWidget, ScrollItemWidget> dropdownSetup = (option, template) =>
 							{
 								var item = ScrollItemWidget.Setup(template,
 									() => ddo.GetValue(actor) == option.Key,
-									() => ddo.OnChange(actor, option.Key));
+									() =>
+									{
+										ddo.OnChange(actor, option.Key);
+										editorActionHandle.OnChange(option.Key);
+									});
 
 								item.Get<LabelWidget>("LABEL").GetText = () => option.Value;
 								return item;
@@ -298,16 +338,180 @@ namespace OpenRA.Mods.Common.Widgets.Logic
 		void Delete()
 		{
 			if (CurrentActor != null)
-				editorActorLayer.Remove(CurrentActor);
+				editorActionManager.Add(new RemoveActorAction(editorActorLayer, CurrentActor));
 
 			Close();
 		}
 
+		void Cancel()
+		{
+			Reset();
+			Close();
+		}
+
+		void Reset()
+		{
+			if (editActorPreview != null)
+				editActorPreview.Reset();
+		}
+
 		void Close()
 		{
 			actorIDField.YieldKeyboardFocus();
 			editor.DefaultBrush.SelectedActor = null;
 			CurrentActor = null;
 		}
+
+		void Save()
+		{
+			editorActionManager.Add(new EditActorEditorAction(editorActorLayer, CurrentActor, editActorPreview.GetDirtyHandles()));
+			editActorPreview = null;
+			Close();
+		}
+	}
+
+	public class EditorActorOptionActionHandle<T> : IEditActorHandle
+	{
+		readonly Action<EditorActorPreview, T> change;
+		T value;
+		readonly T initialValue;
+
+		public EditorActorOptionActionHandle(Action<EditorActorPreview, T> change, T value)
+		{
+			this.change = change;
+			this.value = value;
+			initialValue = value;
+		}
+
+		public void OnChange(T value)
+		{
+			IsDirty = !EqualityComparer<T>.Default.Equals(initialValue, value);
+
+			this.value = value;
+		}
+
+		public void Do(EditorActorPreview actor)
+		{
+			change(actor, value);
+		}
+
+		public void Undo(EditorActorPreview actor)
+		{
+			change(actor, initialValue);
+		}
+
+		public bool IsDirty { get; private set; }
+	}
+
+	public interface IEditActorHandle
+	{
+		void Do(EditorActorPreview actor);
+		void Undo(EditorActorPreview actor);
+		bool IsDirty { get; }
+	}
+
+	class EditActorEditorAction : IEditorAction
+	{
+		public string Text { get; private set; }
+
+		readonly IEnumerable<IEditActorHandle> handles;
+		readonly EditorActorLayer editorActorLayer;
+		EditorActorPreview actor;
+		readonly string actorId;
+
+		public EditActorEditorAction(EditorActorLayer editorActorLayer, EditorActorPreview actor, IEnumerable<IEditActorHandle> handles)
+		{
+			this.editorActorLayer = editorActorLayer;
+			actorId = actor.ID;
+			this.actor = actor;
+			this.handles = handles;
+			Text = "Edited {0} ({1})".F(actor.Info.Name, actor.ID);
+		}
+
+		public void Execute()
+		{
+		}
+
+		public void Do()
+		{
+			actor = editorActorLayer[actorId.ToLowerInvariant()];
+			foreach (var editorActionHandle in handles)
+				editorActionHandle.Do(actor);
+		}
+
+		public void Undo()
+		{
+			foreach (var editorActionHandle in handles)
+				editorActionHandle.Undo(actor);
+		}
+	}
+
+	class EditActorPreview
+	{
+		readonly EditorActorPreview actor;
+		readonly SetActorIdAction setActorIdAction;
+		readonly List<IEditActorHandle> handles = new List<IEditActorHandle>();
+
+		public EditActorPreview(EditorActorPreview actor)
+		{
+			this.actor = actor;
+			setActorIdAction = new SetActorIdAction(actor.ID);
+			handles.Add(setActorIdAction);
+		}
+
+		public bool IsDirty
+		{
+			get { return handles.Any(h => h.IsDirty); }
+		}
+
+		public void SetActorID(string actorID)
+		{
+			setActorIdAction.Set(actorID);
+		}
+
+		public void Add(IEditActorHandle editActor)
+		{
+			handles.Add(editActor);
+		}
+
+		public IEnumerable<IEditActorHandle> GetDirtyHandles()
+		{
+			return handles.Where(h => h.IsDirty);
+		}
+
+		public void Reset()
+		{
+			foreach (var handle in handles.Where(h => h.IsDirty))
+				handle.Undo(actor);
+		}
+	}
+
+	public class SetActorIdAction : IEditActorHandle
+	{
+		readonly string initial;
+		string newID;
+
+		public void Set(string actorId)
+		{
+			IsDirty = initial != actorId;
+			newID = actorId;
+		}
+
+		public SetActorIdAction(string initial)
+		{
+			this.initial = initial;
+		}
+
+		public void Do(EditorActorPreview actor)
+		{
+			actor.ID = newID;
+		}
+
+		public void Undo(EditorActorPreview actor)
+		{
+			actor.ID = initial;
+		}
+
+		public bool IsDirty { get; private set; }
 	}
 }

OpenRA.Mods.Common/Widgets/Logic/Editor/HistoryLogLogic.cs

@@ -0,0 +1,71 @@
+#region Copyright & License Information
+/*
+ * Copyright 2007-2019 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.Collections.Generic;
+using OpenRA.Graphics;
+using OpenRA.Mods.Common.Traits;
+using OpenRA.Primitives;
+using OpenRA.Widgets;
+
+namespace OpenRA.Mods.Common.Widgets.Logic
+{
+	public class HistoryLogLogic : ChromeLogic
+	{
+		readonly ScrollPanelWidget panel;
+		readonly EditorActionManager editorActionManager;
+		readonly ScrollItemWidget template;
+
+		readonly Dictionary<EditorActionContainer, ScrollItemWidget> states = new Dictionary<EditorActionContainer, ScrollItemWidget>();
+
+		[ObjectCreator.UseCtor]
+		public HistoryLogLogic(Widget widget, World world, WorldRenderer worldRenderer, Dictionary<string, MiniYaml> logicArgs)
+		{
+			panel = widget.Get<ScrollPanelWidget>("HISTORY_LIST");
+			template = panel.Get<ScrollItemWidget>("HISTORY_TEMPLATE");
+			editorActionManager = world.WorldActor.Trait<EditorActionManager>();
+
+			editorActionManager.ItemAdded += ItemAdded;
+			editorActionManager.ItemRemoved += ItemRemoved;
+		}
+
+		void ItemAdded(EditorActionContainer editorAction)
+		{
+			var item = ScrollItemWidget.Setup(template, () => false, () =>
+			{
+				if (editorAction.Status == EditorActionStatus.History)
+					editorActionManager.Rewind(editorAction.Id);
+				else if (editorAction.Status == EditorActionStatus.Future)
+					editorActionManager.Forward(editorAction.Id);
+			});
+
+			var titleLabel = item.Get<LabelWidget>("TITLE");
+			var textColor = template.TextColor;
+			var futureTextColor = template.TextColorDisabled;
+
+			titleLabel.GetText = () => editorAction.Action.Text;
+			titleLabel.GetColor = () => editorAction.Status == EditorActionStatus.Future ? futureTextColor : textColor;
+
+			item.IsSelected = () => editorAction.Status == EditorActionStatus.Active;
+			panel.AddChild(item);
+
+			states[editorAction] = item;
+		}
+
+		void ItemRemoved(EditorActionContainer editorAction)
+		{
+			var widget = states[editorAction];
+
+			panel.RemoveChild(widget);
+
+			states.Remove(editorAction);
+		}
+	}
+}

OpenRA.Mods.Common/Widgets/Logic/Editor/MapEditorLogic.cs

@@ -128,6 +128,21 @@ namespace OpenRA.Mods.Common.Widgets.Logic
 				if (reslayer != null)
 					cashLabel.GetText = () => "$ {0}".F(reslayer.NetWorth);
 			}
+
+			var actionManager = world.WorldActor.Trait<EditorActionManager>();
+			var undoButton = widget.GetOrNull<ButtonWidget>("UNDO_BUTTON");
+			if (undoButton != null)
+			{
+				undoButton.IsDisabled = () => !actionManager.HasUndos();
+				undoButton.OnClick = () => actionManager.Undo();
+			}
+
+			var redoButton = widget.GetOrNull<ButtonWidget>("REDO_BUTTON");
+			if (redoButton != null)
+			{
+				redoButton.IsDisabled = () => !actionManager.HasRedos();
+				redoButton.OnClick = () => actionManager.Redo();
+			}
 		}
 
 		Widget CreateCategoriesPanel()

OpenRA.Mods.Common/Widgets/Logic/Editor/MapEditorTabsLogic.cs

@@ -18,7 +18,7 @@ namespace OpenRA.Mods.Common.Widgets.Logic
 	{
 		readonly Widget widget;
 
-		protected enum MenuType { Tiles, Layers, Actors }
+		protected enum MenuType { Tiles, Layers, Actors, History }
 		protected MenuType menuType = MenuType.Tiles;
 		readonly Widget tabContainer;
 
@@ -31,6 +31,7 @@ namespace OpenRA.Mods.Common.Widgets.Logic
 			SetupTab("TILES_TAB", "TILE_WIDGETS", MenuType.Tiles);
 			SetupTab("OVERLAYS_TAB", "LAYER_WIDGETS", MenuType.Layers);
 			SetupTab("ACTORS_TAB", "ACTOR_WIDGETS", MenuType.Actors);
+			SetupTab("HISTORY_TAB", "HISTORY_WIDGETS", MenuType.History);
 		}
 
 		void SetupTab(string buttonId, string tabId, MenuType tabType)

mods/cnc/chrome/editor.yaml

@@ -292,15 +292,21 @@ Container@EDITOR_WORLD_ROOT:
 							Children:
 								Button@DELETE_BUTTON:
 									X: 4
-									Width: 85
+									Width: 75
 									Height: 25
 									Text: Delete
 									Font: Bold
-								Button@CLOSE_BUTTON:
+								Button@CANCEL_BUTTON:
-									X: 180
+									X: 110
-									Width: 85
+									Width: 75
 									Height: 25
-									Text: Close
+									Text: Cancel
+									Font: Bold
+								Button@OK_BUTTON:
+									X: 190
+									Width: 75
+									Height: 25
+									Text: OK
 									Font: Bold
 		ViewportController:
 			Width: WINDOW_RIGHT
@@ -318,10 +324,10 @@ Container@EDITOR_WORLD_ROOT:
 			BookmarkRestoreKeyPrefix: MapBookmarkRestore
 			BookmarkKeyCount: 4
 		Background@RADAR_BG:
-			X: WINDOW_RIGHT - 255
+			X: WINDOW_RIGHT - 295
 			Y: 5
-			Width: 250
+			Width: 290
-			Height: 250
+			Height: 290
 			Background: panel-gray
 			Children:
 				Radar@INGAME_RADAR:
@@ -332,7 +338,7 @@ Container@EDITOR_WORLD_ROOT:
 		MenuButton@OPTIONS_BUTTON:
 			Logic: MenuButtonsChromeLogic
 			Key: escape
-			X: WINDOW_RIGHT - 254 - WIDTH
+			X: WINDOW_RIGHT - 294 - WIDTH
 			Y: 5
 			Width: 30
 			Height: 25
@@ -346,10 +352,10 @@ Container@EDITOR_WORLD_ROOT:
 					ImageName: options
 		Container@TILE_WIDGETS:
 			Logic: TileSelectorLogic
-			X: WINDOW_RIGHT - 255
+			X: WINDOW_RIGHT - 295
-			Y: 278
+			Y: 318
-			Width: 250
+			Width: 290
-			Height: WINDOW_BOTTOM - 370
+			Height: WINDOW_BOTTOM - 410
 			ClickThrough: false
 			Children:
 				Container@TILES_BG:
@@ -402,10 +408,10 @@ Container@EDITOR_WORLD_ROOT:
 											Y: 4
 		Container@LAYER_WIDGETS:
 			Logic: LayerSelectorLogic
-			X: WINDOW_RIGHT - 255
+			X: WINDOW_RIGHT - 295
-			Y: 278
+			Y: 318
-			Width: 250
+			Width: 290
-			Height: WINDOW_BOTTOM - 370
+			Height: WINDOW_BOTTOM - 410
 			ClickThrough: false
 			Children:
 				Container@LAYERS_BG:
@@ -429,10 +435,10 @@ Container@EDITOR_WORLD_ROOT:
 											Visible: false
 		Container@ACTOR_WIDGETS:
 			Logic: ActorSelectorLogic
-			X: WINDOW_RIGHT - 255
+			X: WINDOW_RIGHT - 295
-			Y: 278
+			Y: 318
-			Width: 250
+			Width: 290
-			Height: WINDOW_BOTTOM - 370
+			Height: WINDOW_BOTTOM - 410
 			ClickThrough: false
 			Children:
 				Container@ACTORS_BG:
@@ -499,33 +505,72 @@ Container@EDITOR_WORLD_ROOT:
 											X: 4
 											Y: 4
 											Visible: true
+		Container@HISTORY_WIDGETS:
+			Logic: HistoryLogLogic
+			X: WINDOW_RIGHT - 295
+			Y: 318
+			Width: 290
+			Height: WINDOW_BOTTOM - 410
+			ClickThrough: false
+			Children:
+				Container@HISTORY_BG:
+					Width: PARENT_RIGHT
+					Height: PARENT_BOTTOM
+					Children:
+						ScrollPanel@HISTORY_LIST:
+							Width: PARENT_RIGHT
+							Height: PARENT_BOTTOM
+							CollapseHiddenChildren: True
+							TopBottomSpacing: 4
+							ItemSpacing: 4
+							Children:
+								ScrollItem@HISTORY_TEMPLATE:
+									X: 4
+									Visible: false
+									Width: PARENT_RIGHT - 31
+									Height: 25
+									IgnoreChildMouseOver: true
+									TextColor: ffffff
+									TextColorDisabled: 8f8f8f
+									Children:
+										Label@TITLE:
+											X: 5
+											Width: PARENT_RIGHT
+											Height: 25
+											Align: Left
 		Container@MAP_EDITOR_TAB_CONTAINER:
 			Logic: MapEditorTabsLogic
-			X: WINDOW_RIGHT - 255
+			X: WINDOW_RIGHT - 295
-			Y: 254
+			Y: 294
-			Width: 250
+			Width: 290
 			Height: 25
 			ClickThrough: false
 			Children:
 				Button@TILES_TAB:
-					Width: 81
+					Width: 71
 					Height: 25
 					Text: Tiles
 					Font: Bold
 				Button@OVERLAYS_TAB:
-					X: 80
+					X: 70
-					Width: 90
+					Width: 80
 					Height: 25
 					Text: Overlays
 					Font: Bold
 				Button@ACTORS_TAB:
-					X: 169
+					X: 149
-					Width: 81
+					Width: 71
 					Height: 25
 					Text: Actors
 					Font: Bold
+				Button@HISTORY_TAB:
+					X: 219
+					Width: 71
+					Height: 25
+					Text: History
+					Font: Bold
 		Button@GRID_BUTTON:
-			X: WINDOW_RIGHT - 650
+			X: WINDOW_RIGHT - 690
 			Y: 5
 			Width: 100
 			Height: 25
@@ -536,7 +581,7 @@ Container@EDITOR_WORLD_ROOT:
 			TooltipText: Toggle the terrain grid
 			TooltipContainer: TOOLTIP_CONTAINER
 		Label@ZOOM_LABEL:
-			X: WINDOW_RIGHT - 730 - 55
+			X: WINDOW_RIGHT - 770 - 55
 			Y: 5
 			Width: 50
 			Height: 25
@@ -545,7 +590,7 @@ Container@EDITOR_WORLD_ROOT:
 			Font: Bold
 			Contrast: true
 		DropDownButton@ZOOM_BUTTON:
-			X: WINDOW_RIGHT - 730
+			X: WINDOW_RIGHT - 770
 			Y: 5
 			Width: 70
 			Height: 25
@@ -555,7 +600,7 @@ Container@EDITOR_WORLD_ROOT:
 			TooltipText: Zoom
 			TooltipContainer: TOOLTIP_CONTAINER
 		Button@COPYPASTE_BUTTON:
-			X: WINDOW_RIGHT - 540
+			X: WINDOW_RIGHT - 580
 			Y: 5
 			Width: 96
 			Height: 25
@@ -565,7 +610,7 @@ Container@EDITOR_WORLD_ROOT:
 			TooltipText: Copy
 			TooltipContainer: TOOLTIP_CONTAINER
 		DropDownButton@COPYFILTER_BUTTON:
-			X: WINDOW_RIGHT - 435
+			X: WINDOW_RIGHT - 475
 			Y: 5
 			Width: 140
 			Height: 25
@@ -585,6 +630,26 @@ Container@EDITOR_WORLD_ROOT:
 			Align: Left
 			Font: Bold
 			Contrast: true
+		Button@UNDO_BUTTON:
+			X: 200
+			Height: 25
+			Width: 100
+			Text: Undo
+			Font: Bold
+			Key: z ctrl
+			TooltipTemplate: BUTTON_TOOLTIP
+			TooltipText: Undo last step
+			TooltipContainer: TOOLTIP_CONTAINER
+		Button@REDO_BUTTON:
+			X: 305
+			Height: 25
+			Width: 100
+			Text: Redo
+			Font: Bold
+			Key: y ctrl
+			TooltipTemplate: BUTTON_TOOLTIP
+			TooltipText: Redo last step
+			TooltipContainer: TOOLTIP_CONTAINER
 
 ScrollPanel@CATEGORY_FILTER_PANEL:
 	Width: 190

mods/cnc/rules/world.yaml

@@ -268,3 +268,4 @@ EditorWorld:
 	EditorResourceLayer:
 	EditorSelectionLayer:
 	LoadWidgetAtGameStart:
+	EditorActionManager:

mods/common/chrome/editor.yaml

@@ -287,15 +287,21 @@ Container@EDITOR_WORLD_ROOT:
 							Children:
 								Button@DELETE_BUTTON:
 									X: 15
-									Width: 85
+									Width: 75
 									Height: 25
 									Text: Delete
 									Font: Bold
-								Button@CLOSE_BUTTON:
+								Button@CANCEL_BUTTON:
-									X: 195
+									X: 125
-									Width: 85
+									Width: 75
 									Height: 25
-									Text: Close
+									Text: Cancel
+									Font: Bold
+								Button@OK_BUTTON:
+									X: 205
+									Width: 75
+									Height: 25
+									Text: OK
 									Font: Bold
 		ViewportController:
 			Width: WINDOW_RIGHT
@@ -313,10 +319,10 @@ Container@EDITOR_WORLD_ROOT:
 			BookmarkRestoreKeyPrefix: MapBookmarkRestore
 			BookmarkKeyCount: 4
 		Background@RADAR_BG:
-			X: WINDOW_RIGHT - 255
+			X: WINDOW_RIGHT - 325
 			Y: 5
-			Width: 250
+			Width: 320
-			Height: 250
+			Height: 320
 			Children:
 				Radar@INGAME_RADAR:
 					X: 10
@@ -327,10 +333,10 @@ Container@EDITOR_WORLD_ROOT:
 			Logic: TileSelectorLogic
 			Children:
 				Background@TILES_BG:
-					X: WINDOW_RIGHT - 250
+					X: WINDOW_RIGHT - 320
-					Y: 290
+					Y: 360
-					Width: 240
+					Width: 310
-					Height: WINDOW_BOTTOM - 382
+					Height: WINDOW_BOTTOM - 452
 					Children:
 						Label@SEARCH_LABEL:
 							Y: 12
@@ -378,10 +384,10 @@ Container@EDITOR_WORLD_ROOT:
 			Logic: LayerSelectorLogic
 			Children:
 				Background@LAYERS_BG:
-					X: WINDOW_RIGHT - 250
+					X: WINDOW_RIGHT - 320
-					Y: 290
+					Y: 360
-					Width: 240
+					Width: 310
-					Height: WINDOW_BOTTOM - 382
+					Height: WINDOW_BOTTOM - 452
 					Children:
 						ScrollPanel@LAYERTEMPLATE_LIST:
 							X: 10
@@ -405,10 +411,10 @@ Container@EDITOR_WORLD_ROOT:
 			Logic: ActorSelectorLogic
 			Children:
 				Background@ACTORS_BG:
-					X: WINDOW_RIGHT - 250
+					X: WINDOW_RIGHT - 320
-					Y: 290
+					Y: 360
-					Width: 240
+					Width: 310
-					Height: WINDOW_BOTTOM - 382
+					Height: WINDOW_BOTTOM - 452
 					Children:
 						Label@SEARCH_LABEL:
 							Y: 12
@@ -467,11 +473,44 @@ Container@EDITOR_WORLD_ROOT:
 											X: 4
 											Y: 4
 											Visible: true
+		Container@HISTORY_WIDGETS:
+			Logic: HistoryLogLogic
+			Visible: false
+			Children:
+				Background@HISTORY_BG:
+					X: WINDOW_RIGHT - 320
+					Y: 360
+					Width: 310
+					Height: WINDOW_BOTTOM - 452
+					Children:
+						ScrollPanel@HISTORY_LIST:
+							X: 10
+							Y: 10
+							Width: PARENT_RIGHT - 20
+							Height: PARENT_BOTTOM - 20
+							CollapseHiddenChildren: True
+							TopBottomSpacing: 4
+							ItemSpacing: 4
+							Children:
+								ScrollItem@HISTORY_TEMPLATE:
+									X: 4
+									Visible: false
+									Width: PARENT_RIGHT - 31
+									Height: 25
+									IgnoreChildMouseOver: true
+									TextColor: ffffff
+									TextColorDisabled: 8f8f8f
+									Children:
+										Label@TITLE:
+											X: 5
+											Width: PARENT_RIGHT
+											Height: 25
+											Align: Left
 		Container@MAP_EDITOR_TAB_CONTAINER:
 			Logic: MapEditorTabsLogic
-			X: WINDOW_RIGHT - 245
+			X: WINDOW_RIGHT - 315
-			Y: 260
+			Y: 330
-			Width: 240
+			Width: 310
 			Height: 25
 			Children:
 				Button@TILES_TAB:
@@ -492,6 +531,12 @@ Container@EDITOR_WORLD_ROOT:
 					Height: 25
 					Text: Actors
 					Font: Bold
+				Button@HISTORY_TAB:
+					X: 230
+					Width: 70
+					Height: 25
+					Text: History
+					Font: Bold
 		MenuButton@OPTIONS_BUTTON:
 			Logic: MenuButtonsChromeLogic
 			MenuContainer: INGAME_MENU
@@ -547,15 +592,35 @@ Container@EDITOR_WORLD_ROOT:
 			TooltipTemplate: BUTTON_TOOLTIP
 			TooltipText: Zoom
 			TooltipContainer: TOOLTIP_CONTAINER
+		Button@UNDO_BUTTON:
+			X: 630
+			Height: 25
+			Width: 90
+			Text: Undo
+			Font: Bold
+			Key: z ctrl
+			TooltipTemplate: BUTTON_TOOLTIP
+			TooltipText: Undo last step
+			TooltipContainer: TOOLTIP_CONTAINER
+		Button@REDO_BUTTON:
+			X: 730
+			Height: 25
+			Width: 90
+			Text: Redo
+			Font: Bold
+			Key: y ctrl
+			TooltipTemplate: BUTTON_TOOLTIP
+			TooltipText: Redo last step
+			TooltipContainer: TOOLTIP_CONTAINER
 		Label@COORDINATE_LABEL:
-			X: 635
+			X: 835
 			Width: 50
 			Height: 25
 			Align: Left
 			Font: Bold
 			Contrast: true
 		Label@CASH_LABEL:
-			X: 750
+			X: 950
 			Width: 50
 			Height: 25
 			Align: Left

mods/d2k/rules/world.yaml

@@ -243,3 +243,4 @@ EditorWorld:
 	D2kEditorResourceLayer:
 	EditorSelectionLayer:
 	LoadWidgetAtGameStart:
+	EditorActionManager:

mods/ra/rules/world.yaml

@@ -284,3 +284,4 @@ EditorWorld:
 	EditorResourceLayer:
 	EditorSelectionLayer:
 	LoadWidgetAtGameStart:
+	EditorActionManager:

mods/ts/rules/world.yaml

@@ -379,3 +379,4 @@ EditorWorld:
 	EditorSelectionLayer:
 		Palette: placefootprint
 	LoadWidgetAtGameStart:
+	EditorActionManager: