checkPosition method
void
checkPosition()
Implementation
void checkPosition() {
if (p.isHidden(element))
return;
final offsetTop = this.offsetTop() ?? _defaultOffset,
offsetBottom = this.offsetBottom() ?? _defaultOffset,
scrollHeight = $document().height!,
scrollTop = window.pageYOffset,
positionTop = element.offsetTop,
affix = _unpin != null && scrollTop + _unpin! <= positionTop ? 'false' :
(positionTop + element.offsetHeight >= scrollHeight - offsetBottom) ? 'bottom' :
scrollTop <= offsetTop ? 'top' : 'false';
if (_affixed == affix)
return;
_affixed = affix;
_unpin = affix == 'bottom' ? positionTop - scrollTop : null;
element.classes
..remove('affix')
..remove('affix-top')
..remove('affix-bottom')
..add(affix == 'bottom' ? 'affix-bottom' : affix == 'top' ? 'affix-top' : 'affix');
}