[英]How do I circulate an image in Swift using/without using UIBezierPath?
我正在尝试使用UIBezierPath
使图像循环。 这是我用来确定图像的x
和y
坐标,其宽度和高度的代码。
var frm : CGRect = self.image.frame
let originX = frm.origin.x
let originY = frm.origin.y
let originWidth = frm.size.width
let originHeight = frm.size.height
self.image.frame = frm
但是,如果我在此代码中放入originX
和originY
:
let path = UIBezierPath()
path.moveToPoint(CGPoint(x: originX+50, y: originY))
path.addCurveToPoint(CGPoint(x: originX-20, y: originY),
controlPoint1: CGPoint(x: originX+20, y: originY),
controlPoint2: CGPoint(x: originX-10, y: originY))
let anim = CAKeyframeAnimation(keyPath: "position")
// set the animations path to our bezier curve
anim.path = path.CGPath
anim.repeatCount = Float.infinity
anim.duration = 5.0
image.layer.addAnimation(anim, forKey: "animate position along path")
图像仅停留在屏幕的左上方(而不是靠近中心放置)。 为什么? 顺便说一句,除了使用UIPathBezier
之外,还有其他方法可以使图像循环吗?
好吧,首先,您需要重写UIBezierPath()
构造函数,以便可以将参数指定为originX
和originY
,还必须使用var
而不是let
因为var
是一个简单变量,let是一个constant
,并且不能在Swift中进行修改。
我没有Xcode,但代码应如下所示:
override func UIBezierPath(#x:CGFloat, andOriginX:CGFloat) {
}
let path = UIBezierPath(x, y)
path.moveToPoint(CGPoint(x: x+50, y: y)) // and so one...
path.addCurveToPoint(CGPoint(x: originX-20, y: originY),
controlPoint1: CGPoint(x: originX+20, y: originY),
controlPoint2: CGPoint(x: originX-10, y: originY))
let anim = CAKeyframeAnimation(keyPath: "position")
// set the animations path to our bezier curve
anim.path = path.CGPath
anim.repeatCount = Float.infinity
anim.duration = 5.0
image.layer.addAnimation(anim, forKey: "animate position along path")
)
声明:本站的技术帖子网页,遵循CC BY-SA 4.0协议,如果您需要转载,请注明本站网址或者原文地址。任何问题请咨询:yoyou2525@163.com.