Method scrollActionDelta

core/scroll.go:202–213

scrollActionDelta moves the scrollbar in given dimension by given delta. returns whether actually scrolled.

(d math32.Dims, delta float32)

// scrollActionDelta moves the scrollbar in given dimension by given delta.
// returns whether actually scrolled.
func (fr *Frame) scrollActionDelta(d math32.Dims, delta float32) bool {
	if fr.HasScroll[d] && fr.scrolls[d] != nil {
		sb := fr.scrolls[d]
		nval := sb.Value + sb.scrollScale(delta)
		chg := sb.setValueEvent(nval)
		if chg {
			fr.NeedsRender() // only render needed -- scroll updates pos
		}
		return chg
	}
	return false
}

// scrollDelta processes a scroll event.  If only one dimension is processed,
// and there is a non-zero in other, then the consumed dimension is reset to 0