panZoomUpdate method Null safety

PointerPanZoomUpdateEvent panZoomUpdate(
  1. Offset location,
  2. {Offset pan = Offset.zero,
  3. double scale = 1,
  4. double rotation = 0,
  5. Duration timeStamp = Duration.zero}
)

Create a PointerPanZoomUpdateEvent to update the active pan/zoom sequence on this pointer with updated pan, scale, and/or rotation values.

rotation is in units of radians.

By default, the time stamp on the event is Duration.zero. You can give a specific time stamp by passing the timeStamp argument.

Implementation

PointerPanZoomUpdateEvent panZoomUpdate(
  Offset location, {
  Offset pan = Offset.zero,
  double scale = 1,
  double rotation = 0,
  Duration timeStamp = Duration.zero,
}) {
  assert(isPanZoomActive);
  assert(kind == PointerDeviceKind.trackpad);
  _location = location;
  final Offset panDelta = pan - _pan!;
  _pan = pan;
  return PointerPanZoomUpdateEvent(
    timeStamp: timeStamp,
    device: _device,
    pointer: pointer,
    position: location,
    pan: pan,
    panDelta: panDelta,
    scale: scale,
    rotation: rotation,
  );
}