onDragUpdate method
when dragging the SlidablePanel, this method will be called each update of the ratio would trigger the RenderSlidable to re-layout
Implementation
void onDragUpdate(DragUpdateDetails details) {
assert(layoutSize != null);
final shift = switch (layoutSize!.axis) {
Axis.horizontal => details.delta.dx,
Axis.vertical => details.delta.dy,
};
_forwarding = _dragExtent * shift > 0;
_dragExtent += shift;
// print("forwarding: $_forwarding, direction: $direction");
final newRatio = layoutSize!
.getRatio(_dragExtent)
?.clamp(_lowerBound, _upperBound)
.toDouble();
if (newRatio != null && newRatio != ratio) {
_animationValue = newRatio;
}
}