Showing, hiding or editing a smart filter re-rendered the whole stack from the
placed source on the UI thread: on a 3000x4498 layer with five filters every
click on a filter's eye froze the window for about 1.5 s with no feedback.
- Each render keeps the placed source and the result after every visible filter
(blake3 of the source contents, the placement and the filters so far), so an
edit reruns only the filters from the edited one up. Edit > Purge > All drops
them.
- Smart filter edits apply the edit at once (so bad params still fail
immediately) and re-render as a background job when started with
Session::start: the window keeps drawing, with progress and Esc to cancel
between filters. Session::execute is unchanged.
twentymls
d3ae5aad0f