getRatio method
if no SlideActionPanel, return null
by doing so, we could disable sliding if no actions along the axis
the ratio would be calculated: dragExtent
/ slidable space along the axis
the slidable space is calculated by maxSlideThreshold * the space along the axis
Implementation
double? getRatio(
double dragExtent,
) {
if ((dragExtent > 0 && !hasPreAction) ||
(dragExtent < 0 && !hasPostAction)) {
return null;
}
final mainAxis = axis == Axis.horizontal
? size.width * maxSlideThreshold
: size.height * maxSlideThreshold;
final ratio = dragExtent / mainAxis;
return ratio;
}