Undo/redo function

[gereleth]

ctrl-z for undo
shift-ctrl-z for redo (?)

And two buttons too.

Should multiple rotations of the same tile be combined into one undo?

[rjsmith64]

Undo would be great. I would keep each rotation as a separate undo step. Visually, it would be more obvious how the "unwinding" is happening. If a Y-piece were flipped back by 3 rotations, for example, it could be jarring to follow what's happening.

Having a "state stack" would be a cool feature. Maybe easier to implement too. When I'm stuck, I'll often make a guess and continue the logic until I find a conflict (or complete the puzzle). If you could save and restore the current puzzle state, you could revert back to the initial guess.

One save slot would be enough 90% of the time. Maybe offer three save slots and let the user manage them as they wish? It's not often I go more than 2 or 3 guesses deep. At that point I should be looking somewhere else.

[Jaybrainer]

Ctrl-Z = undo
Ctrl-Shift-Z / Ctrl-Y = redo

What needs logged for undo/redo?
2 types of rotations
pin
2 types of edge marks
coordinates

if there is some "checkpoint" system, will that consist of a list of moves which will be undone, or will it be a copy of the entire state? Consider for massive puzzles that a full copy could include a lot, such as the 100x100 that I am currently solving. I would assume that logging the moves since the checkpoint would take less to store.