handlePanUpdate method
Implementation
void handlePanUpdate(
DragUpdateDetails details,
ZoomPanController zoomPan,
ChartContext context,
) {
if (!enableZoomPan) return;
final dx =
-details.delta.dx / context.bounds.width * context.viewport.width;
final dy =
details.delta.dy / context.bounds.height * context.viewport.height;
zoomPan.pan(dx, dy);
onPan?.call(dx, dy);
}