Attention: Here be dragons

This is the latest (unstable) version of this documentation, which may document features not available in or compatible with released stable versions of Godot.

Checking the stable version of the documentation...

UndoRedo¶

Inherits: Object

Helper to manage undo/redo operations in the editor or custom tools.

Description¶

Helper to manage undo/redo operations in the editor or custom tools. It works by registering methods and property changes inside "actions".

Common behavior is to create an action, then add do/undo calls to functions or property changes, then committing the action.

Here's an example on how to add an action to the Godot editor's own UndoRedo, from a plugin:

var undo_redo = get_undo_redo() # Method of EditorPlugin.

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(self, "do_something")
    undo_redo.add_undo_method(self, "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()

private UndoRedo _undoRedo;

public override void _Ready()
{
    _undoRedo = GetUndoRedo(); // Method of EditorPlugin.
}

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<Node2D>("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();
}

create_action, add_do_method, add_undo_method, add_do_property, add_undo_property, and commit_action should be called one after the other, like in the example. Not doing so could lead to crashes.

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.

Methods¶

void	add_do_method ( Callable callable )
void	add_do_property ( Object object, StringName property, Variant value )
void	add_do_reference ( Object object )
void	add_undo_method ( Callable callable )
void	add_undo_property ( Object object, StringName property, Variant value )
void	add_undo_reference ( Object object )
void	clear_history ( bool increase_version=true )
void	commit_action ( bool execute=true )
void	create_action ( String name, MergeMode merge_mode=0 )
void	end_force_keep_in_merge_ends ( )
String	get_action_name ( int id )
int	get_current_action ( )
String	get_current_action_name ( ) const
int	get_history_count ( )
int	get_version ( ) const
bool	has_redo ( ) const
bool	has_undo ( ) const
bool	is_committing_action ( ) const
bool	redo ( )
void	start_force_keep_in_merge_ends ( )
bool	undo ( )

Signals¶

version_changed ( )

Called when undo or redo was called.

Enumerations¶

enum MergeMode:

MergeMode MERGE_DISABLE = 0

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

MergeMode MERGE_ENDS = 1

Makes so that the action's "undo" operations are from the first action created and the "do" operations are from the last subsequent action with the same name.

MergeMode MERGE_ALL = 2

Makes subsequent actions with the same name be merged into one.

Method Descriptions¶

void add_do_method ( Callable callable )

Register a Callable that will be called when the action is committed.

void add_do_property ( Object object, StringName property, Variant value )

Register a property that would change its value to value when the action is committed.

void add_do_reference ( Object object )

Register a reference for "do" that will be erased if the "do" history is lost. This is useful mostly for new nodes created for the "do" call. Do not use for resources.

void add_undo_method ( Callable callable )

Register a Callable that will be called when the action is undone.

void add_undo_property ( Object object, StringName property, Variant value )

Register a property that would change its value to value when the action is undone.

void add_undo_reference ( Object object )

Register a reference for "undo" that will be erased if the "undo" history is lost. This is useful mostly for nodes removed with the "do" call (not the "undo" call!).

void clear_history ( bool increase_version=true )

Clear the undo/redo history and associated references.

Passing false to increase_version will prevent the version number from increasing when the history is cleared.

void commit_action ( bool execute=true )

Commit the action. If execute is true (which it is by default), all "do" methods/properties are called/set when this function is called.

void create_action ( String name, MergeMode merge_mode=0 )

Create a new action. After this is called, do all your calls to add_do_method, add_undo_method, add_do_property, and add_undo_property, then commit the action with commit_action.

The way actions are merged is dictated by merge_mode. See MergeMode for details.

void end_force_keep_in_merge_ends ( )

Stops marking operations as to be processed even if the action gets merged with another in the MERGE_ENDS mode. See start_force_keep_in_merge_ends.

String get_action_name ( int id )

Gets the action name from its index.

int get_current_action ( )

Gets the index of the current action.

String get_current_action_name ( ) const

Gets the name of the current action, equivalent to get_action_name(get_current_action()).

int get_history_count ( )

Returns how many elements are in the history.

int get_version ( ) const

Gets the version. Every time a new action is committed, the UndoRedo's version number is increased automatically.

This is useful mostly to check if something changed from a saved version.

bool has_redo ( ) const

Returns true if a "redo" action is available.

bool has_undo ( ) const

Returns true if an "undo" action is available.

bool is_committing_action ( ) const

Returns true if the UndoRedo is currently committing the action, i.e. running its "do" method or property change (see commit_action).

bool redo ( )

Redo the last action.

void start_force_keep_in_merge_ends ( )

Marks the next "do" and "undo" operations to be processed even if the action gets merged with another in the MERGE_ENDS mode. Return to normal operation using end_force_keep_in_merge_ends.

bool undo ( )

Undo the last action.