SheetController/Sources/SheetController/SheetContainerPresentationA...

87 lines
3.4 KiB
Swift

//
// SheetContainerPresentationAnimationController.swift
// SheetController
//
// Created by Shadowfacts on 9/24/19.
// Copyright © 2019 Shadowfacts. All rights reserved.
//
import UIKit
class SheetContainerPresentationAnimationController: NSObject, UIViewControllerAnimatedTransitioning {
func transitionDuration(using transitionContext: UIViewControllerContextTransitioning?) -> TimeInterval {
if UIAccessibility.prefersCrossFadeTransitionsBackwardsCompat {
return 0.25
} else {
return 0.5
}
}
func animateTransition(using transitionContext: UIViewControllerContextTransitioning) {
guard let toVC = transitionContext.viewController(forKey: .to) as? SheetContainerViewController else {
fatalError()
}
if UIAccessibility.prefersCrossFadeTransitionsBackwardsCompat {
animateCrossFadeTransition(using: transitionContext)
return
}
toVC.dimmingView.isHidden = true
let finalFrame = transitionContext.finalFrame(for: toVC)
let dimmingView = UIView(frame: finalFrame)
dimmingView.backgroundColor = toVC.dimmingView.backgroundColor
dimmingView.alpha = 0
let container = transitionContext.containerView
container.addSubview(dimmingView)
container.addSubview(toVC.view)
let initialConstant = toVC.initialConstant
toVC.topConstraint.constant = toVC.view.bounds.height
toVC.view.layoutIfNeeded()
let duration = transitionDuration(using: transitionContext)
let damping = SheetContainerViewController.springDamping
let pointsPerSecond: CGFloat = 50
let velocity = pointsPerSecond / initialConstant
UIView.animate(withDuration: duration, delay: 0, usingSpringWithDamping: damping, initialSpringVelocity: velocity, options: []) {
// we animate the dimming view's frame so that it doesn't go under the content view, in case there's a transparent background
// we also extend the dimming view under any rounded corners the content view has
dimmingView.frame = CGRect(x: 0, y: 0, width: dimmingView.bounds.width, height: initialConstant + toVC.content.view.layer.cornerRadius)
dimmingView.alpha = toVC.dimmingView.alpha
toVC.topConstraint.constant = initialConstant
toVC.view.layoutIfNeeded()
} completion: { (finished) in
dimmingView.removeFromSuperview()
toVC.dimmingView.isHidden = false
toVC.view.frame = finalFrame
transitionContext.completeTransition(!transitionContext.transitionWasCancelled)
}
}
func animateCrossFadeTransition(using transitionContext: UIViewControllerContextTransitioning) {
guard let toVC = transitionContext.viewController(forKey: .to) as? SheetContainerViewController else {
fatalError()
}
transitionContext.containerView.addSubview(toVC.view)
toVC.view.alpha = 0
let duration = transitionDuration(using: transitionContext)
UIView.animate(withDuration: duration) {
toVC.view.alpha = 1
} completion: { (finished) in
transitionContext.completeTransition(!transitionContext.transitionWasCancelled)
}
}
}