pub fn place(sel: Rect, size: Vec2, region: Rect) -> Option<Rect>Expand description
Where a bar of size stands over a selection of sel, inside region —
the part of the viewport the front end’s chrome leaves clear.
Centred above the selection, flipped below when that would land under the
top chrome, and — for a selection taller than the region, which is an area
whose interior is not hit-testable anyway — inside it. The fit test is
vertical only: both candidates are wholly clear of the selection in y
and the clamp moves the bar in x, which is why the bar provably never
covers what is selected.
None only when there is no region at all to put it in.