Instance Method


Begins a new undo group.



- (BOOL)startUndoGroup:(NSString *)name;



The name of the undo group. Some hosts may display this name in their undo menu (i.e. "Undo Apply Preset"). This name should be localized and suitable for user display.

Return Value

YES if the undo group was successfully started; otherwise NO.


A plug-in can use this method to collapse multiple operations into one undo operation. Subsequent undo operations will be coalesced into this group until endUndoGroup is called. Each call to startUndoGroup: must be balanced with a call to endUndoGroup.

For example, a plug-in may implement a "preset" popup, which changes the values of 20 other parameters using the FxParameterSettingAPI. By nesting the parameter changes in a startUndoGroup/endUndoGroup block, the 20 changes will be collapsed into one undo operation. This allows the user to undo the preset application by hitting undo once, instead of once per each changed parameter.

See Also

Creating Undo Groups

- endUndoGroup

Closes the current undo group.