Springs

arkui::motion

What moves a while and stops, on springs: a value sliding, something shown and hidden, whether to move at all, and a widget that draws what it holds moved, scaled and veiled.

• Spring { damping, response }, state(x, v, t), or_instant()
• SMOOTH, INSTANT, FADE
• Shown::new(spring, now), at(now), hide(now), show(now), moving(now), gone(now)
• Slide::new(from, to, now, spring), moving_at(speed), at(now), speed(now), toward(to, now, spring)
• reduced(), ALWAYS_ANIMATE
• transformed(content, by, scale, veil, radius)

Rules

• Nothing ticks at rest: where a spring is, is worked out from the time whenever it is drawn.
• Sent somewhere else on its way, a move turns from where it is drawn at the speed it was going: nothing jumps.
• With less motion asked for (reduced), what slides or grows only fades.
• iced has no opacity for a group of widgets, so a fade is a veil of the ground over what fades, thinning.

rust/arkui/src/motion.rs