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, String method, ... ) vararg
void	add_do_property ( Object object, String property, Variant value )
void	add_do_reference ( Object object )
void	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.

Method Descriptions

void add_do_method ( Object object, String method, ... ) vararg

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

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

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.

void add_undo_method ( Object object, String method, ... ) vararg

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

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

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.

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 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.

bool has_redo ( )

Returns true if a "redo" action is available.

bool has_undo ( )

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).

bool redo ( )

Redo the last action.

bool undo ( )

Undo the last action.