Mac开发-NSScrollView

知识点：
1、隐藏滚动条、但可以保持滚动

    v.hasHorizontalScroller = true
    v.horizontalScroller?.alphaValue = 0

2、NSScrollView内嵌套一个NSScrollView，可以随着外侧的NSScrollView一起滚动

    private var isScrollingHorizontally = false
    
    override func scrollWheel(with event: NSEvent) {
        if event.phase == .mayBegin {
            super.scrollWheel(with: event)
            nextResponder?.scrollWheel(with: event)
            return
        }
        
        if event.phase == .began || (event.phase == .none && event.momentumPhase == .none) {
            isScrollingHorizontally = abs(event.scrollingDeltaX) > abs(event.scrollingDeltaY)
        }
        
        if isScrollingHorizontally {
            super.scrollWheel(with: event)
        } else {
            nextResponder?.scrollWheel(with: event)
        }
    }