타이머를 사용하여 이미지보기에서 마스크를 조정하면됩니다. 최적의 화면 업데이트를 위해 고유 한 시간을 가진 특별한 유형의 타이머, 즉 "디스플레이 링크"를 사용해야합니다. 예를 들어
는 :
class ViewController: UIViewController {
@IBOutlet weak var imageView: UIImageView!
weak var mask: CAShapeLayer?
override func viewDidLoad() {
super.viewDidLoad()
// add mask to imageview and save reference to it
let mask = CAShapeLayer()
mask.fillColor = #colorLiteral(red: 1, green: 1, blue: 1, alpha: 1).cgColor
mask.strokeColor = #colorLiteral(red: 1, green: 1, blue: 1, alpha: 0).cgColor
imageView.layer.mask = mask
self.mask = mask
}
override func viewDidLayoutSubviews() {
super.viewDidLayoutSubviews()
// update the mask for the image view for the size of the view (which was unknown at `viewDidLoad`, but is known here)
if mask != nil {
updatePath(percent: 0)
}
}
@IBAction func didTapButton(_ sender: Any) {
// when we tap button, start display link which will drive the animation
start = CACurrentMediaTime()
let displayLink = CADisplayLink(target: self, selector: #selector(handleDisplaylink(_:)))
displayLink.add(to: .main, forMode: .commonModes)
}
var start: CFTimeInterval! // when the animation was started
let duration: CFTimeInterval = 0.5 // how long will the animation take
@objc func handleDisplaylink(_ displayLink: CADisplayLink) {
// calculate, based upon elapsed time, how far along we are
let percent = CGFloat(min(1, (CACurrentMediaTime() - start)/duration))
// update the path based upon what percent of the animation has been completed
updatePath(percent: percent)
// if we're done, stop display link and go ahead and remove mask now that it's not needed any more
if percent >= 1 {
displayLink.invalidate()
imageView.layer.mask = nil
}
}
/// Update the circular mask for the image view based upon what percent of the animation is done
private func updatePath(percent: CGFloat) {
let center = CGPoint(x: imageView.bounds.midX, y: imageView.bounds.midY)
let startRadius = min(imageView.bounds.width, imageView.bounds.height) * 0.4 // start radius is 40% of smallest dimension
let endRadius = hypot(imageView.bounds.width, imageView.bounds.height) * 0.5 // stop radius is the distance from the center to the corner of the image view
let radius = startRadius + (endRadius - startRadius) * percent // given percent done, what is the radius
mask?.path = UIBezierPath(arcCenter: center, radius: radius, startAngle: 0, endAngle: .pi * 2, clockwise: true).cgPath
}
}
달성한다 :
출처
2017-10-26 03:51:12
Rob
https://www.youtube.com/watch?v=B9sH_VxPPo4 – CallMeLaNN