Tusker/Packages/GalleryVC/Sources/GalleryVC/GalleryDismissInteraction.s...

84 lines
3.1 KiB
Swift

//
// GalleryDismissInteraction.swift
// GalleryVC
//
// Created by Shadowfacts on 3/1/24.
//
import UIKit
@MainActor
class GalleryDismissInteraction: NSObject {
private unowned let viewController: GalleryViewController
private var content: GalleryContentViewController?
private var origContentFrameInGallery: CGRect?
private var origControlsVisible: Bool?
private(set) var isActive = false
private(set) var dismissVelocity: CGPoint?
private(set) var dismissTranslation: CGPoint?
init(viewController: GalleryViewController) {
self.viewController = viewController
super.init()
let panRecognizer = UIPanGestureRecognizer(target: self, action: #selector(panRecognized))
panRecognizer.delegate = self
panRecognizer.allowedScrollTypesMask = .continuous
viewController.view.addGestureRecognizer(panRecognizer)
}
@objc private func panRecognized(_ recognizer: UIPanGestureRecognizer) {
switch recognizer.state {
case .began:
isActive = true
origContentFrameInGallery = viewController.view.convert(viewController.currentItemViewController.content.view.bounds, from: viewController.currentItemViewController.content.view)
content = viewController.currentItemViewController.takeContent()
content!.view.translatesAutoresizingMaskIntoConstraints = true
content!.view.frame = origContentFrameInGallery!
viewController.view.addSubview(content!.view)
origControlsVisible = viewController.currentItemViewController.controlsVisible
if origControlsVisible! {
viewController.currentItemViewController.setControlsVisible(false, animated: true)
}
case .changed:
let translation = recognizer.translation(in: viewController.view)
content!.view.frame = origContentFrameInGallery!.offsetBy(dx: translation.x, dy: translation.y)
case .ended:
let translation = recognizer.translation(in: viewController.view)
let velocity = recognizer.velocity(in: viewController.view)
dismissVelocity = velocity
dismissTranslation = translation
viewController.dismiss(animated: true)
// don't unset this until after dismiss is called, so that the dismiss animation controller can read it
isActive = false
default:
break
}
}
}
extension GalleryDismissInteraction: UIGestureRecognizerDelegate {
func gestureRecognizerShouldBegin(_ gestureRecognizer: UIGestureRecognizer) -> Bool {
let itemVC = viewController.currentItemViewController
if viewController.galleryDataSource.galleryContentTransitionSourceView(forItemAt: itemVC.itemIndex) == nil {
return false
} else if itemVC.scrollView.zoomScale > itemVC.scrollView.minimumZoomScale {
return false
} else if !itemVC.scrollAndZoomEnabled {
return false
} else {
return true
}
}
}