Function hscroller_chrome 

pub fn hscroller_chrome<R>(
    ui: &Ui,
    out: &ScrollAreaOutput<R>,
    bar: Rect,
    line: f32,
)

Draw and run a horizontal scroller in bar for out (an area whose own bar is hidden): grouped arrows scroll line points per click, the beveled knob drags, and a click in the trough beside the knob pages by a view.