It would be nice to be able to select frames and then tween just those.
I like to work on one animation at a time. Tweening everything doesn't really fit my workflow.
Image scaling, processing and analysing · By
I think app.range has all the current selection info. https://github.com/aseprite/api/blob/master/api/range.md#range
The selections in Aseprite can be sparse, though (with ctrl-click.) You could probably just find the first and last selected frame and then just iterator over all in that span. For cells, you could then only move them if that cell was selected maybe? I realize now that this could get complex fast because of how flexible selection is in Ase...