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Inherits: Object<class_Object>
Provides a high-level interface for implementing undo and redo operations.
classref-introduction-group
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<class_UndoRedo_method_undo> method is used, the undo_* methods will run. If the redo<class_UndoRedo_method_redo> method is used, once again, all of the do_* methods will run.
Here's an example on how to add an action:
gdscript
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()
csharp
private UndoRedo _undoRedo;
public override void _Ready() { _undoRedo = new UndoRedo(); }
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(); }
Before calling any of the add_(un)do_* methods, you need to first call create_action<class_UndoRedo_method_create_action>. Afterwards you need to call commit_action<class_UndoRedo_method_commit_action>.
If you don't need to register a method, you can leave add_do_method<class_UndoRedo_method_add_do_method> and add_undo_method<class_UndoRedo_method_add_undo_method> out; the same goes for properties. You can also register more than one method/property.
If you are making an EditorPlugin<class_EditorPlugin> and want to integrate into the editor's undo history, use EditorUndoRedoManager<class_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.
gdscript
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()
csharp
_undo_redo.CreateAction("Add object");
// DO _undo_redo.AddDoMethod(new Callable(this, MethodName.CreateObject)); _undo_redo.AddDoMethod(new Callable(this, MethodName.AddObjectToSingleton));
// UNDO _undo_redo.AddUndoMethod(new Callable(this, MethodName.RemoveObjectFromSingleton)); _undo_redo.AddUndoMethod(new Callable(this, MethodName.DestroyThatObject));
_undo_redo.CommitAction();
classref-reftable-group
int<class_int> |
max_steps<class_UndoRedo_property_max_steps> |
0 |
classref-reftable-group
void (No return value.) |
:ref:add_do_method<class_UndoRedo_method_add_do_method>(callable: Callable<class_Callable>) |
void (No return value.) |
:ref:add_do_property<class_UndoRedo_method_add_do_property>(object: Object<class_Object>, property: StringName<class_StringName>, value: Variant<class_Variant>) |
void (No return value.) |
:ref:add_do_reference<class_UndoRedo_method_add_do_reference>(object: Object<class_Object>) |
void (No return value.) |
:ref:add_undo_method<class_UndoRedo_method_add_undo_method>(callable: Callable<class_Callable>) |
void (No return value.) |
:ref:add_undo_property<class_UndoRedo_method_add_undo_property>(object: Object<class_Object>, property: StringName<class_StringName>, value: Variant<class_Variant>) |
void (No return value.) |
:ref:add_undo_reference<class_UndoRedo_method_add_undo_reference>(object: Object<class_Object>) |
void (No return value.) |
:ref:clear_history<class_UndoRedo_method_clear_history>(increase_version: bool<class_bool> = true) |
void (No return value.) |
:ref:commit_action<class_UndoRedo_method_commit_action>(execute: bool<class_bool> = true) |
void (No return value.) |
:ref:create_action<class_UndoRedo_method_create_action>(name: String<class_String>, merge_mode: MergeMode<enum_UndoRedo_MergeMode> = 0, backward_undo_ops: bool<class_bool> = false) |
void (No return value.) |
:ref:end_force_keep_in_merge_ends<class_UndoRedo_method_end_force_keep_in_merge_ends>() |
String<class_String> |
get_action_name<class_UndoRedo_method_get_action_name>(id: int<class_int>) |
int<class_int> |
get_current_action<class_UndoRedo_method_get_current_action>() |
String<class_String> |
get_current_action_name<class_UndoRedo_method_get_current_action_name>() const (This method has no side effects. It doesn't modify any of the instance's member variables.) |
int<class_int> |
get_history_count<class_UndoRedo_method_get_history_count>() |
int<class_int> |
get_version<class_UndoRedo_method_get_version>() const (This method has no side effects. It doesn't modify any of the instance's member variables.) |
bool<class_bool> |
has_redo<class_UndoRedo_method_has_redo>() const (This method has no side effects. It doesn't modify any of the instance's member variables.) |
bool<class_bool> |
has_undo<class_UndoRedo_method_has_undo>() const (This method has no side effects. It doesn't modify any of the instance's member variables.) |
bool<class_bool> |
is_committing_action<class_UndoRedo_method_is_committing_action>() const (This method has no side effects. It doesn't modify any of the instance's member variables.) |
bool<class_bool> |
redo<class_UndoRedo_method_redo>() |
void (No return value.) |
:ref:start_force_keep_in_merge_ends<class_UndoRedo_method_start_force_keep_in_merge_ends>() |
bool<class_bool> |
undo<class_UndoRedo_method_undo>() |
classref-section-separator
classref-descriptions-group
classref-signal
version_changed()
Called when undo<class_UndoRedo_method_undo> or redo<class_UndoRedo_method_redo> was called.
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classref-enumeration
enum MergeMode:
classref-enumeration-constant
MergeMode<enum_UndoRedo_MergeMode> MERGE_DISABLE = 0
Makes "do"/"undo" operations stay in separate actions.
classref-enumeration-constant
MergeMode<enum_UndoRedo_MergeMode> MERGE_ENDS = 1
Merges this action with the previous one if they have the same name. Keeps only the first action's "undo" operations and the last action's "do" operations. Useful for sequential changes to a single value.
classref-enumeration-constant
MergeMode<enum_UndoRedo_MergeMode> MERGE_ALL = 2
Merges this action with the previous one if they have the same name.
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classref-property
int<class_int> max_steps = 0
classref-property-setget
void (No return value.)set_max_steps(value:int<class_int>)int<class_int>get_max_steps()
The maximum number of steps that can be stored in the undo/redo history. If the number of stored steps exceeds this limit, older steps are removed from history and can no longer be reached by calling undo<class_UndoRedo_method_undo>. A value of 0 or lower means no limit.
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classref-method
void (No return value.) add_do_method(callable: Callable<class_Callable>)
Register a Callable<class_Callable> that will be called when the action is committed.
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void (No return value.) add_do_property(object: Object<class_Object>, property: StringName<class_StringName>, value: Variant<class_Variant>)
Register a property that would change its value to value when the action is committed.
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classref-method
void (No return value.) add_do_reference(object: Object<class_Object>)
Register a reference to an object that will be erased if the "do" history is deleted. This is useful for objects added by the "do" action and removed by the "undo" action.
When the "do" history is deleted, if the object is a RefCounted<class_RefCounted>, it will be unreferenced. Otherwise, it will be freed. 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()classref-item-separator
classref-method
void (No return value.) add_undo_method(callable: Callable<class_Callable>)
Register a Callable<class_Callable> that will be called when the action is undone.
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classref-method
void (No return value.) add_undo_property(object: Object<class_Object>, property: StringName<class_StringName>, value: Variant<class_Variant>)
Register a property that would change its value to value when the action is undone.
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classref-method
void (No return value.) add_undo_reference(object: Object<class_Object>)
Register a reference to an object that will be erased if the "undo" history is deleted. This is useful for objects added by the "undo" action and removed by the "do" action.
When the "undo" history is deleted, if the object is a RefCounted<class_RefCounted>, it will be unreferenced. Otherwise, it will be freed. Do not use for resources.
var node = $Node2D
undo_redo.create_action("Remove node")
undo_redo.add_do_method(remove_child.bind(node))
undo_redo.add_undo_method(add_child.bind(node))
undo_redo.add_undo_reference(node)
undo_redo.commit_action()classref-item-separator
classref-method
void (No return value.) clear_history(increase_version: bool<class_bool> = 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.
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classref-method
void (No return value.) commit_action(execute: bool<class_bool> = 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.
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classref-method
void (No return value.) create_action(name: String<class_String>, merge_mode: MergeMode<enum_UndoRedo_MergeMode> = 0, backward_undo_ops: bool<class_bool> = false)
Create a new action. After this is called, do all your calls to add_do_method<class_UndoRedo_method_add_do_method>, add_undo_method<class_UndoRedo_method_add_undo_method>, add_do_property<class_UndoRedo_method_add_do_property>, and add_undo_property<class_UndoRedo_method_add_undo_property>, then commit the action with commit_action<class_UndoRedo_method_commit_action>.
The way actions are merged is dictated by merge_mode. See MergeMode<enum_UndoRedo_MergeMode> for details.
The way undo operation are ordered in actions is dictated by backward_undo_ops. When backward_undo_ops is false undo option are ordered in the same order they were added. Which means the first operation to be added will be the first to be undone.
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classref-method
void (No return value.) 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<class_UndoRedo_constant_MERGE_ENDS> mode. See start_force_keep_in_merge_ends<class_UndoRedo_method_start_force_keep_in_merge_ends>.
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classref-method
String<class_String> get_action_name(id: int<class_int>)
Gets the action name from its index.
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classref-method
int<class_int> get_current_action()
Gets the index of the current action.
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String<class_String> get_current_action_name() const (This method has no side effects. It doesn't modify any of the instance's member variables.)
Gets the name of the current action, equivalent to get_action_name(get_current_action()).
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int<class_int> get_history_count()
Returns how many elements are in the history.
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int<class_int> get_version() const (This method has no side effects. It doesn't modify any of the instance's member variables.)
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.
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bool<class_bool> has_redo() const (This method has no side effects. It doesn't modify any of the instance's member variables.)
Returns true if a "redo" action is available.
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bool<class_bool> has_undo() const (This method has no side effects. It doesn't modify any of the instance's member variables.)
Returns true if an "undo" action is available.
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classref-method
bool<class_bool> is_committing_action() const (This method has no side effects. It doesn't modify any of the instance's member variables.)
Returns true if the UndoRedo is currently committing the action, i.e. running its "do" method or property change (see commit_action<class_UndoRedo_method_commit_action>).
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bool<class_bool> redo()
Redo the last action.
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void (No return value.) 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<class_UndoRedo_constant_MERGE_ENDS> mode. Return to normal operation using end_force_keep_in_merge_ends<class_UndoRedo_method_end_force_keep_in_merge_ends>.
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bool<class_bool> undo()
Undo the last action.