IOS 触摸获取坐标点、缩放图片实例

override func touchesBegan(touches: Set<NSObject>, withEvent event: UIEvent) {
println("began")
}
override func touchesMoved(touches: Set<NSObject>, withEvent event: UIEvent) {
println("move")

println((touches as NSSet).anyObject()?.locationInView(self.view))//移动时输出当前坐标

}

override func touchesEnded(touches: Set<NSObject>, withEvent event: UIEvent) {
println("end")
}

override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view, typically from a nib.
self.view.multipleTouchEnabled = true  //多点触摸开启
}

override func touchesMoved(touches: Set<NSObject>, withEvent event: UIEvent) {
println("move")

//        println((touches as NSSet).anyObject()?.locationInView(self.view))
for touch in (touches as NSSet){
println(touch.locationInView(self.view))
}

}

//定义最后一次的操作
private var lastDistance:CGFloat = 0.0

override func touchesMoved(touches: Set<NSObject>, withEvent event: UIEvent) {
//        println("move")

//        println((touches as NSSet).anyObject()?.locationInView(self.view))

//        for touch in (touches as NSSet){
//            println(touch.locationInView(self.view))
//        }

//缩放即判断两点移动前后的距离是变大变小
if touches.count == 2{      //触摸点是否等于2
var a = (touches as NSSet).allObjects[0].locationInView(self.view)              //第一个点
var b = (touches as NSSet).allObjects[1].locationInView(self.view)                 //第二个点

//计算x与y的差
var xx = a.x - b.x
var yy = a.y - b.y
//c为两点间距离
var c = sqrt(xx*xx+yy*yy)

if lastDistance == 0.0{
lastDistance = c        //lastDistance一开始初始化为0.0，所以把距离赋值给 lastDistance后进行再进行距离差距的比较
}else{
if lastDistance - c > 5{
println("缩小")
lastDistance = c
//图片的缩放
iv.transform = CGAffineTransformScale(iv.transform, 0.9, 0.9)
}else if lastDistance - c < -5{
println("放大")
lastDistance = c

iv.transform = CGAffineTransformScale(iv.transform, 1.1, 1.1)
}
}

}
}