How undo and redo work in Easel by Zaweba
Undo in Easel by Zaweba works by tiles, keeps at least 50 steps (80 by default), and even covers tilt runs and drying. Here is how to use it well.
Real paint has no undo. That is part of its charm and most of its frustration. Easel by Zaweba keeps the behaviour of real materials, wet paint that runs and dries and stains, but gives you a safety net real painters never had. Ctrl+Z undoes and Ctrl+Y redoes, and the undo history goes further than you might expect.
Undo by tiles
Undo in Easel works by tiles. Instead of saving a copy of the whole canvas after every stroke, it stores just the parts of the picture that changed. That is why it can keep so many steps even on a large canvas. Big canvases need plenty of memory already (an A3 sheet at 300 DPI uses about 1 GB), so storing only what changed keeps the history affordable.
How many steps
Undo keeps at least 50 steps, and 80 by default. That is plenty for most sessions. You can step back through a run of experiments, try something else, and still have room.
The history is about steps, not time. A long session of small strokes uses steps faster than a short session of big washes. If you are about to try something risky after a long stretch of detailed work, saving first is a good habit.
Undoing runs and drying
This is the part that surprises people. Undo includes tilt runs and drying.
When you tilt the canvas, wet paint runs downhill on its own. When paint dries, it locks in place and never moves or mixes again. In real life, both are final. In Easel, both can be undone.
So if a tilt sends a wash further than you wanted, undo takes it back. If paint dried before you had finished blending, undo can take you back to before it dried. That makes Easel an excellent place to experiment with gravity and pours, because a bad run is not a ruined painting.
Redo
Redo, Ctrl+Y, brings back what you undid. It is handy when you undo to compare and then decide the later version was better after all.
Undo versus the studio tools
Undo is not the only way to correct things. Easel has many tools that remove or change paint the way real painters would: the rag and tissue lift wet paint, the eraser takes off pencil and pastel, the scraper reveals what's underneath, and the water brush adds water to wet work.
Use those tools for corrections that are part of painting, and undo for mistakes and experiments. A watercolour with a lifted cloud looks natural. One where you undid every stroke until it was perfect can look stiff. The real tools leave the traces that make a painting feel handmade.
Saving as a second safety net
Saving to .zeasel keeps the rest of your work, the state of the paint, the surface, the palette, masks, the tracing sheet and the time-lapse, so wet paint is still wet when you reopen. A sensible habit is to save before big changes and use undo for small ones. Between the two, Easel by Zaweba lets you be as bold as you like.
