Function scatter_position_info 

pub fn scatter_position_info(pick: Option<ScatterPick>) -> PositionInfo

Build the silx ScatterView position-info bar — the X, Y, Data, Index columns (ScatterView.py:90-101). When a scatter point is picked, X/Y snap to it and Data/Index show its value/index; otherwise X/Y show the bare cursor coordinates (%.7g) and Data/Index show "-" (silx _getPickedValue/_getPickedIndex fallback).