UndoRedo

Inherits: Object

Category: Core

Brief Description

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

Methods

Variant add_do_method ( Object object, String method, … ) vararg
void add_do_property ( Object object, String property, Variant value )
void add_do_reference ( Object object )
Variant add_undo_method ( Object object, String method, … ) vararg
void add_undo_property ( Object object, String property, Variant value )
void add_undo_reference ( Object object )
void clear_history ( bool increase_version=true )
void commit_action ( )
void create_action ( String name, MergeMode merge_mode=0 )
String get_current_action_name ( ) const
int get_version ( ) const
bool has_redo ( )
bool has_undo ( )
bool is_commiting_action ( ) const
bool redo ( )
bool undo ( )

Signals

  • version_changed ( )

Called when undo or redo was called.

Enumerations

enum MergeMode:

  • MERGE_DISABLE = 0 — Makes “do”/”undo” operations stay in separate actions.
  • MERGE_ENDS = 1 — Makes so that the action’s “do” operation is from the first action created and the “undo” operation is from the last subsequent action with the same name.
  • MERGE_ALL = 2 — Makes subsequent actions with the same name be merged into one.

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_MyButton_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()

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.

Method Descriptions

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


Register a property value change for “do”.


  • 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.


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


Register a property value change for “undo”.


  • 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 to be increased from this.


  • void commit_action ( )

Commit the action. All “do” methods/properties are called/set when this function is called.


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 the merge_mode argument. See MergeMode for details.


  • String get_current_action_name ( ) const

Gets the name of the current action.


  • 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.


Returns true if a “redo” action is available.


Returns true if an “undo” action is available.


  • bool is_commiting_action ( ) const

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


Redo the last action.


Undo the last action.