History, snapshots and non-linear undo in Paint by Zaweba
Set undo limits, keep snapshots inside the .ptx, branch with non-linear history and keep undo after reopening a file in Paint by Zaweba.
Undo is the safety net under every edit, and the History panel in Paint by Zaweba makes it a lot more than a single key. You can set how far back it goes, take snapshots to return to in one click, keep alternative branches with non-linear history, and even carry undo across closing and reopening a file.
Steps and memory
Preferences sets a step limit and a memory cap. More steps let you go further back; the memory cap stops history from eating all your RAM on a big document. A scratch disk moves older undo steps out of memory onto disk, so you can keep a long history without slowing the computer down. If you work on large, many-layered files, give the scratch disk a fast drive with plenty of free space.
Snapshots
The camera button in the History panel takes a snapshot of the document as it is right now. Later, one click restores it, however many steps have passed and even if those steps have fallen off the bottom of the history list.
Snapshots are saved in the .ptx file. That means a snapshot taken on Monday is still there on Friday. Take one before any big change: before a heavy colour grade, before flattening part of a composite, before trying a bold crop. Take them at clear milestones, because a long row of near-identical snapshots is hard to use a week later.
Non-linear history
Normally, if you undo a few steps and then do something new, the steps you undid are thrown away. Non-Linear History keeps them as a branch instead. You can try a different direction, compare, and go back to the other one without losing either.
It is the history equivalent of saving a copy, but without the file clutter. Use it when experimenting with looks or compositions, where you're likely to want to compare two or three versions before deciding.
Toggle Last State
Toggle Last State, on Ctrl+Alt+Z, jumps between the current state and the one before it. Pressing it repeatedly is the quickest before-and-after check there is, especially for subtle adjustments like a small curve or a skin softening pass.
Undo after reopening
Saved history can keep undo working after you close and reopen a file. It is off by default, because it makes files larger. Switch it on for documents where you might need to go back later, such as long illustrations worked on over several days. With it on, Monday's last brush stroke can still be undone on Tuesday.
Working without fear
Snapshot before risky steps rather than relying on a long history. History has limits; a snapshot doesn't fall off the end.
Lean on non-destructive tools as well. Adjustment layers, masks and live Layer Art effects can be changed at any time without undo at all, which is often a better plan than stepping back twenty times.
Remember that the History Log in File Info is a separate thing: it records edits into the file's metadata for others to read, while the History panel is for your own undo.
Together, these features let you work boldly in Paint by Zaweba. Experiments are cheap when going back is a click away.
