onPanUpdateGesture method
Implementation
void onPanUpdateGesture(Offset globalPosition) {
_adjustPositionOnPanUpdate(globalPosition.dx, globalPosition.dy);
if (_pageWidth.value > 0) {
_xOffsetRatio = xOffset.value / _pageWidth.value;
}
if (_pageHeight.value > 0) {
_yOffsetRatio = yOffset.value / _pageHeight.value;
}
}