metatext/Transitions/ZoomAnimator.swift

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2020-10-22 05:05:50 +00:00
// Copyright © 2020 Metabolist. All rights reserved.
import UIKit
protocol ZoomAnimatorDelegate: class {
func transitionWillStartWith(zoomAnimator: ZoomAnimator)
func transitionDidEndWith(zoomAnimator: ZoomAnimator)
func referenceView(for zoomAnimator: ZoomAnimator) -> UIView?
func referenceViewFrameInTransitioningView(for zoomAnimator: ZoomAnimator) -> CGRect?
}
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final class ZoomAnimator: NSObject {
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weak var fromDelegate: ZoomAnimatorDelegate?
weak var toDelegate: ZoomAnimatorDelegate?
var transitionView: UIView?
var isPresenting = true
}
extension ZoomAnimator: UIViewControllerAnimatedTransitioning {
func transitionDuration(using transitionContext: UIViewControllerContextTransitioning?) -> TimeInterval {
isPresenting ? .defaultAnimationDuration : .shortAnimationDuration
}
func animateTransition(using transitionContext: UIViewControllerContextTransitioning) {
fromDelegate?.transitionWillStartWith(zoomAnimator: self)
toDelegate?.transitionWillStartWith(zoomAnimator: self)
if isPresenting {
animateZoomInTransition(using: transitionContext)
} else {
animateZoomOutTransition(using: transitionContext)
}
}
}
private extension ZoomAnimator {
private func animateZoomInTransition(using transitionContext: UIViewControllerContextTransitioning) {
guard
let toVC = transitionContext.viewController(forKey: .to),
let fromVC = transitionContext.viewController(forKey: .from),
let fromReferenceView = fromDelegate?.referenceView(for: self),
let toReferenceView = toDelegate?.referenceView(for: self),
let fromReferenceViewFrame = fromDelegate?.referenceViewFrameInTransitioningView(for: self)
else { return }
toVC.view.alpha = 0
toReferenceView.isHidden = true
transitionContext.containerView.addSubview(toVC.view)
if transitionView == nil, let transitionView = (fromReferenceView as? ZoomAnimatableView)?.transitionView() {
transitionView.frame = fromReferenceViewFrame
self.transitionView = transitionView
transitionContext.containerView.addSubview(transitionView)
}
fromReferenceView.isHidden = true
let finalTransitionSize = (fromReferenceView as? ZoomAnimatableView)?.frame(inView: toVC.view) ?? .zero
UIView.animate(
withDuration: transitionDuration(using: transitionContext),
delay: 0,
usingSpringWithDamping: 0.8,
initialSpringVelocity: 0,
options: [.transitionCrossDissolve]) {
self.transitionView?.frame = finalTransitionSize
toVC.view.alpha = 1.0
fromVC.tabBarController?.tabBar.alpha = 0
} completion: { _ in
self.transitionView?.removeFromSuperview()
toReferenceView.isHidden = false
fromReferenceView.isHidden = false
self.transitionView = nil
transitionContext.completeTransition(!transitionContext.transitionWasCancelled)
self.toDelegate?.transitionDidEndWith(zoomAnimator: self)
self.fromDelegate?.transitionDidEndWith(zoomAnimator: self)
}
}
private func animateZoomOutTransition(using transitionContext: UIViewControllerContextTransitioning) {
let containerView = transitionContext.containerView
guard
let toVC = transitionContext.viewController(forKey: UITransitionContextViewControllerKey.to),
let fromVC = transitionContext.viewController(forKey: UITransitionContextViewControllerKey.from),
let fromReferenceView = fromDelegate?.referenceView(for: self),
let fromReferenceViewFrame = fromDelegate?.referenceViewFrameInTransitioningView(for: self)
else { return }
let toReferenceView = toDelegate?.referenceView(for: self)
let toReferenceViewFrame = toDelegate?.referenceViewFrameInTransitioningView(for: self)
toReferenceView?.isHidden = true
if transitionView == nil, let transitionView = (fromReferenceView as? ZoomAnimatableView)?.transitionView() {
transitionView.frame = fromReferenceViewFrame
self.transitionView = transitionView
containerView.addSubview(transitionView)
}
containerView.insertSubview(toVC.view, belowSubview: fromVC.view)
fromReferenceView.isHidden = true
UIView.animate(
withDuration: transitionDuration(using: transitionContext)) {
fromVC.view.alpha = 0
if let toReferenceViewFrame = toReferenceViewFrame {
self.transitionView?.frame = toReferenceViewFrame
} else {
self.transitionView?.alpha = 0
}
toVC.tabBarController?.tabBar.alpha = 1
} completion: { _ in
self.transitionView?.removeFromSuperview()
toReferenceView?.isHidden = false
fromReferenceView.isHidden = false
transitionContext.completeTransition(!transitionContext.transitionWasCancelled)
self.toDelegate?.transitionDidEndWith(zoomAnimator: self)
self.fromDelegate?.transitionDidEndWith(zoomAnimator: self)
}
}
}