Resizing should now work

Also fixes cel replacing

src/Autoload/DrawingAlgos.gd

@@ -535,9 +535,11 @@ func center(indices: Array) -> void:
 			tmp_centered.blend_rect(cel.image, used_rect, offset)
 			var centered := ImageExtended.new()
 			centered.copy_from_custom(tmp_centered, cel_image.is_indexed)
+			if cel is CelTileMap:
+				(cel as CelTileMap).serialize_undo_data_source_image(centered, redo_data, undo_data)
 			centered.add_data_to_dictionary(redo_data, cel_image)
 			cel_image.add_data_to_dictionary(undo_data)
-	Global.undo_redo_compress_images(redo_data, undo_data)
+	project.deserialize_cel_undo_data(redo_data, undo_data)
 	project.undo_redo.add_undo_method(Global.undo_or_redo.bind(true))
 	project.undo_redo.add_do_method(Global.undo_or_redo.bind(false))
 	project.undo_redo.commit_action()
@@ -546,13 +548,13 @@ func center(indices: Array) -> void:
 func scale_project(width: int, height: int, interpolation: int) -> void:
 	var redo_data := {}
 	var undo_data := {}
-	for f in Global.current_project.frames:
+	for cel in Global.current_project.get_all_pixel_cels():
-		for i in range(f.cels.size() - 1, -1, -1):
-			var cel := f.cels[i]
 		if not cel is PixelCel:
 			continue
 		var cel_image := (cel as PixelCel).get_image()
 		var sprite := _resize_image(cel_image, width, height, interpolation) as ImageExtended
+		if cel is CelTileMap:
+			(cel as CelTileMap).serialize_undo_data_source_image(sprite, redo_data, undo_data)
 		sprite.add_data_to_dictionary(redo_data, cel_image)
 		cel_image.add_data_to_dictionary(undo_data)
 
@@ -596,9 +598,9 @@ func _resize_image(
 func crop_to_selection() -> void:
 	if not Global.current_project.has_selection:
 		return
+	Global.canvas.selection.transform_content_confirm()
 	var redo_data := {}
 	var undo_data := {}
-	Global.canvas.selection.transform_content_confirm()
 	var rect: Rect2i = Global.canvas.selection.big_bounding_rectangle
 	# Loop through all the cels to crop them
 	for cel in Global.current_project.get_all_pixel_cels():
@@ -606,6 +608,8 @@ func crop_to_selection() -> void:
 		var tmp_cropped := cel_image.get_region(rect)
 		var cropped := ImageExtended.new()
 		cropped.copy_from_custom(tmp_cropped, cel_image.is_indexed)
+		if cel is CelTileMap:
+			(cel as CelTileMap).serialize_undo_data_source_image(cropped, redo_data, undo_data)
 		cropped.add_data_to_dictionary(redo_data, cel_image)
 		cel_image.add_data_to_dictionary(undo_data)
 
@@ -617,8 +621,7 @@ func crop_to_selection() -> void:
 func crop_to_content() -> void:
 	Global.canvas.selection.transform_content_confirm()
 	var used_rect := Rect2i()
-	for f in Global.current_project.frames:
+	for cel in Global.current_project.get_all_pixel_cels():
-		for cel in f.cels:
 		if not cel is PixelCel:
 			continue
 		var cel_used_rect := cel.get_image().get_used_rect()
@@ -644,6 +647,8 @@ func crop_to_content() -> void:
 		var tmp_cropped := cel_image.get_region(used_rect)
 		var cropped := ImageExtended.new()
 		cropped.copy_from_custom(tmp_cropped, cel_image.is_indexed)
+		if cel is CelTileMap:
+			(cel as CelTileMap).serialize_undo_data_source_image(cropped, redo_data, undo_data)
 		cropped.add_data_to_dictionary(redo_data, cel_image)
 		cel_image.add_data_to_dictionary(undo_data)
 
@@ -662,6 +667,8 @@ func resize_canvas(width: int, height: int, offset_x: int, offset_y: int) -> voi
 			cel_image, Rect2i(Vector2i.ZERO, cel_image.get_size()), Vector2i(offset_x, offset_y)
 		)
 		resized.convert_rgb_to_indexed()
+		if cel is CelTileMap:
+			(cel as CelTileMap).serialize_undo_data_source_image(resized, redo_data, undo_data)
 		resized.add_data_to_dictionary(redo_data, cel_image)
 		cel_image.add_data_to_dictionary(undo_data)
 
@@ -698,7 +705,7 @@ func general_do_and_undo_scale(
 	project.undo_redo.add_do_property(project, "y_symmetry_point", new_y_symmetry_point)
 	project.undo_redo.add_do_property(project.x_symmetry_axis, "points", new_x_symmetry_axis_points)
 	project.undo_redo.add_do_property(project.y_symmetry_axis, "points", new_y_symmetry_axis_points)
-	Global.undo_redo_compress_images(redo_data, undo_data)
+	project.deserialize_cel_undo_data(redo_data, undo_data)
 	project.undo_redo.add_undo_property(project, "size", project.size)
 	project.undo_redo.add_undo_property(project, "x_symmetry_point", project.x_symmetry_point)
 	project.undo_redo.add_undo_property(project, "y_symmetry_point", project.y_symmetry_point)

src/Classes/Cels/CelTileMap.gd

@@ -156,13 +156,14 @@ func transform_tile(
 	return transformed_tile
 
 
-func update_tileset() -> void:
+func update_tileset(
+	tile_editing_mode := TileSetPanel.tile_editing_mode, source_image := image
+) -> void:
 	editing_images.clear()
-	var tile_editing_mode := TileSetPanel.tile_editing_mode
 	for i in cells.size():
 		var coords := get_cell_coords_in_image(i)
 		var rect := Rect2i(coords, tileset.tile_size)
-		var image_portion := image.get_region(rect)
+		var image_portion := source_image.get_region(rect)
 		var index := cells[i].index
 		if index >= tileset.tiles.size():
 			printerr("Cell at position ", i + 1, ", mapped to ", index, " is out of bounds!")
@@ -416,11 +417,6 @@ func update_texture(undo := false) -> void:
 	super.update_texture(undo)
 
 
-func size_changed(new_size: Vector2i) -> void:
-	_resize_cells(new_size)
-	_re_index_all_cells()
-
-
 func serialize_undo_data() -> Dictionary:
 	var dict := {}
 	var cell_indices := []
@@ -432,22 +428,39 @@ func serialize_undo_data() -> Dictionary:
 	return dict
 
 
+func serialize_undo_data_source_image(
+	source_image: ImageExtended, redo_data: Dictionary, undo_data: Dictionary
+) -> void:
+	undo_data[self] = serialize_undo_data()
+	if source_image.get_size() != image.get_size():
+		_resize_cells(source_image.get_size())
+		tileset.clear_tileset(self)
+	var tile_editing_mode := TileSetPanel.tile_editing_mode
+	if tile_editing_mode == TileSetPanel.TileEditingMode.MANUAL:
+		tile_editing_mode = TileSetPanel.TileEditingMode.AUTO
+	update_tileset(tile_editing_mode, source_image)
+	redo_data[self] = serialize_undo_data()
+
+
 func deserialize_undo_data(dict: Dictionary, undo_redo: UndoRedo, undo: bool) -> void:
 	var cell_indices = dict["cell_indices"]
 	if undo:
-		for i in cell_indices.size():
+		undo_redo.add_undo_method(deserialize_cell_data.bind(cell_indices))
-			var cell_data: Dictionary = cell_indices[i]
-			undo_redo.add_undo_method(cells[i].deserialize.bind(cell_data))
 		if dict.has("tileset"):
 			undo_redo.add_undo_method(tileset.deserialize_undo_data.bind(dict.tileset, self))
 	else:
-		for i in cell_indices.size():
+		undo_redo.add_do_method(deserialize_cell_data.bind(cell_indices))
-			var cell_data: Dictionary = cell_indices[i]
-			undo_redo.add_do_method(cells[i].deserialize.bind(cell_data))
 		if dict.has("tileset"):
 			undo_redo.add_do_method(tileset.deserialize_undo_data.bind(dict.tileset, self))
 
 
+func deserialize_cell_data(cell_indices: Array) -> void:
+	_resize_cells(image.get_size())
+	for i in cell_indices.size():
+		var cell_data: Dictionary = cell_indices[i]
+		cells[i].deserialize(cell_data)
+
+
 func serialize() -> Dictionary:
 	var dict := super.serialize()
 	var cell_indices := []

src/Classes/TileSetCustom.gd

@@ -2,8 +2,8 @@ class_name TileSetCustom
 extends RefCounted
 
 ## A Tileset is a collection of tiles, used by [LayerTileMap]s and [CelTileMap]s.
-## The tileset contains the [Project] that it is being used by, its [member name].
+## The tileset contains its [member name], the size of each individual tile,
-## the size of each individual tile, and the collection of [TileSetCustom.Tile]s itself.
+## and the collection of [TileSetCustom.Tile]s itself.
 ## Not to be confused with [TileSet], which is a Godot class.
 
 ## Emitted every time the tileset changes, such as when a tile is added, removed or replaced.
@@ -16,6 +16,11 @@ var name := ""
 var tile_size: Vector2i
 ## The collection of tiles in the form of an [Array] of type [TileSetCustom.Tile].
 var tiles: Array[Tile] = []
+## If [code]true[/code], the code in [method clear_tileset] does not execute.
+## This variable is used to prevent multiple cels from clearing the tileset at the same time.
+## In [method clear_tileset], the variable is set to [code]true[/code], and then
+## immediately set to [code]false[/code] in the next frame using [method Object.set_deferred].
+var _tileset_has_been_cleared := false
 
 
 ## An internal class of [TileSetCustom], which contains data used by individual tiles of a tileset.
@@ -109,6 +114,19 @@ func remove_unused_tiles(cel: CelTileMap) -> bool:
 	return tile_removed
 
 
+## Clears the tileset. Usually called when the project gets resized,
+## and tilemap cels are updating their size and clearing the tileset to re-create it.
+func clear_tileset(cel: CelTileMap) -> void:
+	if _tileset_has_been_cleared:
+		return
+	tiles.clear()
+	var empty_image := Image.create_empty(tile_size.x, tile_size.y, false, Image.FORMAT_RGBA8)
+	tiles.append(Tile.new(empty_image))
+	updated.emit(cel)
+	_tileset_has_been_cleared = true
+	set_deferred("_tileset_has_been_cleared", false)
+
+
 ## Serializes the data of this class into the form of a [Dictionary],
 ## which is used so the data can be stored in pxo files.
 func serialize() -> Dictionary:

src/UI/Timeline/AnimationTimeline.gd

@@ -1107,9 +1107,9 @@ func _on_MergeDownLayer_pressed() -> void:
 			var undo_data := {}
 			var redo_data := {}
 			if bottom_cel is CelTileMap:
-				undo_data[bottom_cel] = (bottom_cel as CelTileMap).serialize_undo_data()
+				(bottom_cel as CelTileMap).serialize_undo_data_source_image(
-				(bottom_cel as CelTileMap).update_tileset(new_bottom_image)
+					new_bottom_image, redo_data, undo_data
-				redo_data[bottom_cel] = (bottom_cel as CelTileMap).serialize_undo_data()
+				)
 			new_bottom_image.add_data_to_dictionary(redo_data, bottom_image)
 			bottom_image.add_data_to_dictionary(undo_data)
 			project.deserialize_cel_undo_data(redo_data, undo_data)