computeNextValue#
bool computeNextValue({
required double dragT,
required double velocity,
required bool isRtl,
});
Computes the next switch value based on drag position and velocity.
dragT is the current 0..1 thumb position.
velocity is the horizontal fling velocity in px/sec (positive = right).
isRtl indicates right-to-left layout direction.
Returns the new switch value (true = on, false = off).
Logic (matches Flutter Switch):
- If velocity exceeds threshold → toggle based on velocity direction
- Otherwise → toggle based on position (>= 0.5 = on)