- ScanConfig.nav places Home and Back in the scan as the bar is placed
(after the board, before it, or off); set_nav_items counts them, and
ScanHighlight::Nav/NavItem and ScanChoice::NavItem name them. With both
groups on one side of the board the bar comes first; with no board and
one group, its items are the top level.
- ScanAdvance: automatic, step (the person moves the highlight) or hold
(it moves while the switch is held). Passes run out only when the scan
moves by itself.
- retreat() moves the highlight back one step, back_out() leaves a row for
the rows; set_mode() changes pattern and starts again.
- resume_from_last starts each pass at what held the last choice.
- DwellTarget lets a dwell rest on a control as well as a cell (controls
take the person's own dwell); look_away keeps a target just chosen from
being chosen again until the eyes leave it; chosen_otherwise ends a
dwell when a tap or a switch chose instead.
Co-Authored-By: Claude Opus 5.5 <[email protected]>