3.10. Use Undo Redo

USE UNDO/REDO

i. How to do it: from the Menu, choose Edit/Undo or Edit/Redo.

ii. Hints:

• there are at most 10 steps in the Undo/Redo history; the history is a FIFO list (first in first out) meaning that the oldest entry will be discarded to make room for a new one;

• only these types of actions can be reverted or redone using Undo/Redo:

— adding or deleting a child node (jump: The Project Hierarchy); — editing (jump: The Editor UI) a node property; — cutting or pasting (jump: Using Copy/Paste); — applying a macro (jump: Using The Macros); — outputting generated content (jump: Generate Music) to the score.

• the menu item Undo turns to Can't undo if no revertible action has ever been performed in the current project;

• the menu item Redo turns to Can't redo if Undo was never clicked, or a revertible action has been performed since the last undo;

• the Undo/Redo history is really a list of snapshots. Full snapshots of the jump: Project Hierarchy are maintained. All revertible actions trigger a snapshot after they are performed, and one snapshot is automatically taken when the Project is loaded or created: this way, the current state of affairs is always stored as a snapshot in the Undo/Redo history — referred to as the current snapshot;

• when available, Undo and Redo also include a snapshot name and timestamp, e.g.: Undo (to voice deletion @22:12:57). The exact snapshot used depends on the menu item and is relative to the current snapshot position: Undo shows the previous snapshot while Redo shows the next;

• timestamps can be of help when the same action has been carried out several times (ex., changing a Note pitch twice in a row).