iOS 添加陰影后 屏幕卡頓 抖動

- (void)awakeFromNib {
    // Initialization code
    _btnViews.layer.shadowPath =[UIBezierPath bezierPathWithRect:_btnViews.bounds].CGPath;
    _btnViews.layer.shadowColor = [UIColor grayColor].CGColor;//shadowColor陰影顏色
    _btnViews.layer.shadowOffset = CGSizeMake(0,3);//shadowOffset陰影偏移,x向右偏移4，y向下偏移4，默認(0, -3),這個跟shadowRadius配合使用
    _btnViews.layer.shadowOpacity = 0.5;//陰影透明度，默認0
    _btnViews.layer.shadowRadius = 2;//陰影半徑，默認3
    
    
    _labAuthorTitle.layer.shadowPath =[UIBezierPath bezierPathWithRect:_labAuthorTitle.bounds].CGPath;
    _labAuthorTitle.layer.shadowColor = [UIColor grayColor].CGColor;//shadowColor陰影顏色
    _labAuthorTitle.layer.shadowOffset = CGSizeMake(2,2);//shadowOffset陰影偏移,x向右偏移4，y向下偏移4，默認(0, -3),這個跟shadowRadius配合使用
    _labAuthorTitle.layer.shadowOpacity = 0.5;//陰影透明度，默認0
    _labAuthorTitle.layer.shadowRadius = 2;//陰影半徑，默認3
    
    _labAuthorSubTitle.layer.shadowPath =[UIBezierPath bezierPathWithRect:_labAuthorSubTitle.bounds].CGPath;
    _labAuthorSubTitle.layer.shadowColor = [UIColor grayColor].CGColor;//shadowColor陰影顏色
    _labAuthorSubTitle.layer.shadowOffset = CGSizeMake(2,2);//shadowOffset陰影偏移,x向右偏移4，y向下偏移4，默認(0, -3),這個跟shadowRadius配合使用
    _labAuthorSubTitle.layer.shadowOpacity = 0.5;//陰影透明度，默認0
    _labAuthorSubTitle.layer.shadowRadius = 2;//陰影半徑，默認3
   
   
}

 如上，給Cell添加完陰影后 ，屏幕出現卡頓現象，tableview 拖動時有抖動現象。

增長此句就OK了。

_labAuthorSubTitle.layer.shadowPath =[UIBezierPath bezierPathWithRect:_labAuthorSubTitle.bounds].CGPath;