onTouchPinch method
Called when a touch-initiated pinch gesture occurs.
Touch-pinch mode starts with a single tap immediately followed by two pointers landing near the original touch.
Parameters
start1: Initial position of the first pointer.start2: Initial position of the second pointer.end1: Current position of the first pointer.end2: Current position of the second pointer.
Implementation
@override
void onTouchPinch(
final Point<int> start1,
final Point<int> start2,
final Point<int> end1,
final Point<int> end2,
) {
_touchPinchCallback?.call(start1, start2, end1, end2);
}