Inheritance #

UndoRedo #

is_instantiable, core, not_builtin_classes

Provides a high-level interface for implementing undo and redo operations.

UndoRedo works by registering methods and property changes inside "actions". You can create an action, then provide ways to do and undo this action using function calls and property changes, then commit the action.

When an action is committed, all of the do_* methods will run. If the undo method is used, the undo_* methods will run. If the redo method is used, once again, all of the do_* methods will run.

Here's an example on how to add an action:

GDScript

var undo_redo = UndoRedo.new()

func do_something():
    pass # Put your code here.

func undo_something():
    pass # Put here the code that reverts what's done by "do_something()".

func _on_my_button_pressed():
    var node = get_node("MyNode2D")
    undo_redo.create_action("Move the node")
    undo_redo.add_do_method(do_something)
    undo_redo.add_undo_method(undo_something)
    undo_redo.add_do_property(node, "position", Vector2(100,100))
    undo_redo.add_undo_property(node, "position", node.position)
    undo_redo.commit_action()

C#

private UndoRedo _undoRedo;

public override void _Ready()
{
    _undoRedo = new UndoRedo();
}

public void DoSomething()
{
    // Put your code here.
}

public void UndoSomething()
{
    // Put here the code that reverts what's done by "DoSomething()".
}

private void OnMyButtonPressed()
{
    var node = GetNode("MyNode2D");
    _undoRedo.CreateAction("Move the node");
    _undoRedo.AddDoMethod(new Callable(this, MethodName.DoSomething));
    _undoRedo.AddUndoMethod(new Callable(this, MethodName.UndoSomething));
    _undoRedo.AddDoProperty(node, "position", new Vector2(100, 100));
    _undoRedo.AddUndoProperty(node, "position", node.Position);
    _undoRedo.CommitAction();
}

Before calling any of the add_(un)do_* methods, you need to first call create_action. Afterwards you need to call commit_action.

If you don't need to register a method, you can leave add_do_method and add_undo_method out; the same goes for properties. You can also register more than one method/property.

If you are making an EditorPlugin and want to integrate into the editor's undo history, use EditorUndoRedoManager instead.

If you are registering multiple properties/method which depend on one another, be aware that by default undo operation are called in the same order they have been added. Therefore instead of grouping do operation with their undo operations it is better to group do on one side and undo on the other as shown below.

GDScript

undo_redo.create_action("Add object")

# DO
undo_redo.add_do_method(_create_object)
undo_redo.add_do_method(_add_object_to_singleton)

# UNDO
undo_redo.add_undo_method(_remove_object_from_singleton)
undo_redo.add_undo_method(_destroy_that_object)

undo_redo.commit_action()

C#

_undo_redo.CreateAction("Add object");

// DO
_undo_redo.AddDoMethod(new Callable(this, MethodName.CreateObject));
_undo_redo.AddDoMethod(new Callable(this, MethodName.AddObjectToSingleton));

// UNDO
_undo_redo.AddUndoMethod(new Callable(this, MethodName.RemoveObjectFromSingleton));
_undo_redo.AddUndoMethod(new Callable(this, MethodName.DestroyThatObject));

_undo_redo.CommitAction();

Members #

var max_steps: int = 0#

The maximum number of steps that can be stored in the undo/redo history. If the number of stored steps exceeds this limit, older steps are removed from history and can no longer be reached by calling undo. A value of 0 or lower means no limit.

Methods #

var node = Node2D.new()
undo_redo.create_action("Add node")
undo_redo.add_do_method(add_child.bind(node))
undo_redo.add_do_reference(node)
undo_redo.add_undo_method(remove_child.bind(node))
undo_redo.commit_action()

var node = $Node2D
undo_redo.create_action("Remove node")
undo_redo.add_do_method(remove_child.bind(node))
undo_redo.add_undo_method(add_child.bind(node))
undo_redo.add_undo_reference(node)
undo_redo.commit_action()

Annotations #

Constants #

const MERGE_DISABLE = 0 enum MergeMode#

Makes "do"/"undo" operations stay in separate actions.

const MERGE_ENDS = 1 enum MergeMode#

Merges this action with the previous one if they have the same name. Keeps only the first action's "undo" operations and the last action's "do" operations. Useful for sequential changes to a single value.

const MERGE_ALL = 2 enum MergeMode#

Merges this action with the previous one if they have the same name.

Constructors #

Enums #

MergeMode#

Operators #

Signals #

signal version_changed()#

Called when undo or redo was called.

Theme Items #

Tutorials #