我有一个循环过渡，您可以在下面的代码中找到。此过渡将在内部的下一个视图控制器中创建一个扩展圆。
它可以正常工作，但是一段时间以来我一直在尝试增加圆圈的大小。
确切地说，当前正在执行的圆将从零开始绘制，但是我希望它具有一个初始大小，该大小会立即从其开始延伸。
如何更改圆的初始大小？
import UIKit
class CircularTransition: NSObject {
var circle = UIView()
var startingPoint = CGPoint.zero {
didSet {
circle.center = startingPoint
}
}
var circleColor = UIColor.white
var duration = 0.2
enum CircularTransitionMode:Int {
case present, dismiss, pop
}
var transitionMode:CircularTransitionMode = .present
}
extension CircularTransition:UIViewControllerAnimatedTransitioning {
func transitionDuration(using transitionContext: UIViewControllerContextTransitioning?) -> TimeInterval {
return duration
}
func animateTransition(using transitionContext: UIViewControllerContextTransitioning) {
let containerView = transitionContext.containerView
if transitionMode == .present {
if let presentedView = transitionContext.view(forKey: UITransitionContextViewKey.to) {
let viewCenter = presentedView.center
let viewSize = presentedView.frame.size
circle = UIView()
circle.frame = frameForCircle(withViewCenter: viewCenter, size: viewSize, startPoint: startingPoint)
circle.layer.cornerRadius = circle.frame.size.height / 2
circle.center = startingPoint
circle.backgroundColor = circleColor
circle.transform = CGAffineTransform(scaleX: 0.001, y: 0.001)
containerView.addSubview(circle)
presentedView.center = startingPoint
presentedView.transform = CGAffineTransform(scaleX: 0.001, y: 0.001)
presentedView.alpha = 0
containerView.addSubview(presentedView)
UIView.animate(withDuration: duration, animations: {
self.circle.transform = CGAffineTransform.identity
presentedView.transform = CGAffineTransform.identity
presentedView.alpha = 1
presentedView.center = viewCenter
}, completion: { (success:Bool) in
transitionContext.completeTransition(success)
})
}
}else{
let transitionModeKey = (transitionMode == .pop) ? UITransitionContextViewKey.to : UITransitionContextViewKey.from
if let returningView = transitionContext.view(forKey: transitionModeKey) {
let viewCenter = returningView.center
let viewSize = returningView.frame.size
circle.frame = frameForCircle(withViewCenter: viewCenter, size: viewSize, startPoint: startingPoint)
circle.layer.cornerRadius = circle.frame.size.height / 2
circle.center = startingPoint
UIView.animate(withDuration: duration, animations: {
self.circle.transform = CGAffineTransform(scaleX: 0.001, y: 0.001)
returningView.transform = CGAffineTransform(scaleX: 0.001, y: 0.001)
returningView.center = self.startingPoint
returningView.alpha = 0
if self.transitionMode == .pop {
containerView.insertSubview(returningView, belowSubview: returningView)
containerView.insertSubview(self.circle, belowSubview: returningView)
}
}, completion: { (success:Bool) in
returningView.center = viewCenter
returningView.removeFromSuperview()
self.circle.removeFromSuperview()
transitionContext.completeTransition(success)
})
}
}
}
func frameForCircle (withViewCenter viewCenter:CGPoint, size viewSize:CGSize, startPoint:CGPoint) -> CGRect {
let xLength = fmax(startPoint.x, viewSize.width - startPoint.x)
let yLength = fmax(startPoint.y, viewSize.height - startPoint.y)
let offestVector = sqrt(xLength * xLength + yLength * yLength) * 2
let size = CGSize(width: offestVector, height: offestVector)
return CGRect(origin: CGPoint.zero, size: size)
}
}