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UndoRedo

Inherits: Object

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

Description

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:

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()

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.

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()

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, bool backward_undo_ops=false )

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.

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()

void add_undo_method ( Callable ca