我使用下面显示的代码让用户触摸和绘图 . 在触摸期间,用户总是离开CGPoint或他/她的第一次和最后一次触摸的坐标 .
var lastPoint: CGPoint!
var firstPoint: CGPoint!
var swiped: Bool!
var allowTouches = true
override func touchesBegan(touches: Set<UITouch>,
withEvent event: UIEvent?) {
guard allowTouches else {
return
}
swiped = false
if let touch = touches.first {
lastPoint = touch.locationInView(self.imageView)
firstPoint = lastPoint
}
}
override func touchesMoved(touches: Set<UITouch>,
withEvent event: UIEvent?) {
guard allowTouches else {
return
}
swiped = true;
if let touch = touches.first {
let currentPoint = touch.locationInView(imageView)
UIGraphicsBeginImageContext(self.imageView.frame.size)
self.imageView.image?.drawInRect(CGRectMake(0, 0, self.imageView.frame.size.width, self.imageView.frame.size.height))
CGContextMoveToPoint(UIGraphicsGetCurrentContext(), lastPoint.x, lastPoint.y)
CGContextAddLineToPoint(UIGraphicsGetCurrentContext(), currentPoint.x, currentPoint.y)
CGContextSetLineCap(UIGraphicsGetCurrentContext(),CGLineCap.Round)
CGContextSetLineWidth(UIGraphicsGetCurrentContext(), 5.0)
CGContextStrokePath(UIGraphicsGetCurrentContext())
self.imageView.image = UIGraphicsGetImageFromCurrentImageContext()
UIGraphicsEndImageContext()
lastPoint = currentPoint
}
}
正如您在代码中看到的,当用户触摸屏幕时,firstPoint保存坐标,然后在滑动然后移除触摸之后,lastPoint保存坐标 .
我的问题:如何从override fi返回这两个坐标(firstPoint和lastPoint)?这样我就可以将这两个值用于覆盖func之外的其他计算 .
1 回答
使用
用户选择手指时计算最后一点触摸的方法 . 由于您已将它们声明为var和全局变量,因此您可以在类的任何函数(方法)中使用它们 . 只需计算lastPoint和firstPoint之间的差异,您就可以得到距离 .