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_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.

Methods

void

add_do_method ( Object object, StringName method, ... ) vararg

void

add_do_property ( Object object, StringName property, Variant value )

void

add_do_reference ( Object object )

void

add_undo_method ( Object object, StringName method, ... ) vararg

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:

  • MERGE_DISABLE = 0 --- Makes "do"/"undo" operations stay in separate actions.

  • 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.

  • MERGE_ALL = 2 --- Makes subsequent actions with the same name be merged into one.

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 ( bool execute=true )

Commit the action. If execute is true (default), 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.


  • 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.


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 ( )

Return 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).


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.


Undo the last action.