pub(crate) fn new_pin_grab() -> WorldPxExpand description
How near the pointer must come to a free slot’s marker for a press to place a pin there.
The user asked for it as wide as it will go: “Increase the hit radius on the ‘add pin’ affordance around the blocks. Make it as large as possible without overlapping other affordances (I assume that it should be at least 1 grid unit in radius).” So it is not a number written down here — it is the smallest clearance the neighbouring affordances leave, computed from their own constants. Move a neighbour closer and this shrinks to suit rather than silently starting to overlap it.