滚动 NSTableView 使一行居中

func scrollTableViewToCenterRow(tableView: NSTableView, row: Int) {
    let rowRect = tableView.rect(ofRow: row)
    let scrollView = tableView.enclosingScrollView
    let scrollViewHeight = scrollView?.frame.height ?? 0
    let scrollViewVisibleRect = scrollView?.contentView.documentVisibleRect
    let scrollViewVisibleRectY = scrollViewVisibleRect?.origin.y ?? 0
    let rowRectY = rowRect.origin.y
    let rowRectHeight = rowRect.height
    let rowCenterY = rowRectY + rowRectHeight / 2
    let scrollViewCenterY = scrollViewVisibleRectY + scrollViewHeight / 2
    let scrollAmount = rowCenterY - scrollViewCenterY
    scrollView?.contentView.scroll(by: NSPoint(x: 0, y: scrollAmount))
}