objective-c - OS X Cocoa - 如何检测触控板缩放手势？

Question

如何检测 MacBook 触控板上的两个手指缩放手势？ (在选定的 NSView 内)

Answer 1

一个简单的快速解决方案:

var zoom:CGFloat = 0
override func magnify(with event: NSEvent) {
    super.magnify(with: event)
    if(event.phase == .changed){
        zoom += event.deltaZ
    }else if(event.phase == .began){
        zoom = 0//reset
    }else if(event.phase == .ended){
        //Swift.print("zoom: " + "\(zoom)")
        var dir:Int
        if(zoom < -100){
            Swift.print("zoom out")
            dir = 1
        }else if(zoom > 100){
            Swift.print("zoom in")
            dir = -1
        }else{
            Swift.print("no zoom")
            dir = 0
        }
    }
}

它检测缩放手势是否发生 +-100 deltaZ (又名捏合/捏合缩放)

有关此方法的更多信息和研究:
http://eon.codes/blog/2016/02/10/Gesture-research/