metatext/View Controllers/ImageViewController.swift

200 lines
8.9 KiB
Swift
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// Copyright © 2020 Metabolist. All rights reserved.
import Kingfisher
import UIKit
import ViewModels
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final class ImageViewController: UIViewController {
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let scrollView = UIScrollView()
let imageView = AnimatedImageView()
let playerView = PlayerView()
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private let viewModel: AttachmentViewModel?
private let imageURL: URL?
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private let contentView = UIView()
private let descriptionBackgroundView = UIVisualEffectView(effect: UIBlurEffect(style: .systemChromeMaterial))
private let descriptionTextView = UITextView()
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init(viewModel: AttachmentViewModel? = nil, imageURL: URL? = nil) {
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self.viewModel = viewModel
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self.imageURL = imageURL
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super.init(nibName: nil, bundle: nil)
}
@available(*, unavailable)
required init?(coder: NSCoder) {
fatalError("init(coder:) has not been implemented")
}
// swiftlint:disable:next function_body_length
override func viewDidLoad() {
super.viewDidLoad()
view.backgroundColor = .secondarySystemBackground
view.addSubview(scrollView)
scrollView.delegate = self
scrollView.translatesAutoresizingMaskIntoConstraints = false
scrollView.showsHorizontalScrollIndicator = false
scrollView.showsVerticalScrollIndicator = false
scrollView.maximumZoomScale = Self.maximumZoomScale
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let doubleTapGestureRecognizer = UITapGestureRecognizer(
target: self,
action: #selector(handleDoubleTap(gestureRecognizer:)))
doubleTapGestureRecognizer.numberOfTapsRequired = 2
scrollView.addGestureRecognizer(doubleTapGestureRecognizer)
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contentView.translatesAutoresizingMaskIntoConstraints = false
scrollView.addSubview(contentView)
contentView.addSubview(imageView)
imageView.translatesAutoresizingMaskIntoConstraints = false
imageView.contentMode = .scaleAspectFit
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imageView.kf.indicatorType = .activity
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contentView.addSubview(playerView)
playerView.translatesAutoresizingMaskIntoConstraints = false
view.addSubview(descriptionBackgroundView)
descriptionBackgroundView.translatesAutoresizingMaskIntoConstraints = false
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descriptionBackgroundView.isHidden = viewModel?.attachment.description == nil
|| viewModel?.attachment.description == ""
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descriptionBackgroundView.contentView.addSubview(descriptionTextView)
descriptionTextView.translatesAutoresizingMaskIntoConstraints = false
descriptionTextView.backgroundColor = .clear
descriptionTextView.font = .preferredFont(forTextStyle: .caption1)
descriptionTextView.adjustsFontForContentSizeCategory = true
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descriptionTextView.text = viewModel?.attachment.description
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descriptionTextView.isScrollEnabled = false
descriptionTextView.isEditable = false
NSLayoutConstraint.activate([
scrollView.leadingAnchor.constraint(equalTo: view.leadingAnchor),
scrollView.topAnchor.constraint(equalTo: view.topAnchor),
scrollView.trailingAnchor.constraint(equalTo: view.trailingAnchor),
scrollView.bottomAnchor.constraint(equalTo: view.bottomAnchor),
contentView.leadingAnchor.constraint(equalTo: scrollView.leadingAnchor),
contentView.topAnchor.constraint(equalTo: scrollView.topAnchor),
contentView.trailingAnchor.constraint(equalTo: scrollView.trailingAnchor),
contentView.bottomAnchor.constraint(equalTo: scrollView.bottomAnchor),
contentView.centerXAnchor.constraint(equalTo: scrollView.centerXAnchor),
contentView.centerYAnchor.constraint(equalTo: scrollView.centerYAnchor),
imageView.leadingAnchor.constraint(equalTo: contentView.leadingAnchor),
imageView.topAnchor.constraint(equalTo: contentView.topAnchor),
imageView.trailingAnchor.constraint(equalTo: contentView.trailingAnchor),
imageView.bottomAnchor.constraint(equalTo: contentView.bottomAnchor),
playerView.leadingAnchor.constraint(equalTo: contentView.leadingAnchor),
playerView.topAnchor.constraint(equalTo: contentView.topAnchor),
playerView.trailingAnchor.constraint(equalTo: contentView.trailingAnchor),
playerView.bottomAnchor.constraint(equalTo: contentView.bottomAnchor),
descriptionBackgroundView.leadingAnchor.constraint(equalTo: view.leadingAnchor),
descriptionBackgroundView.trailingAnchor.constraint(equalTo: view.trailingAnchor),
descriptionBackgroundView.bottomAnchor.constraint(equalTo: view.bottomAnchor),
descriptionTextView.leadingAnchor.constraint(
equalTo: descriptionBackgroundView.layoutMarginsGuide.leadingAnchor),
descriptionTextView.topAnchor.constraint(equalTo: descriptionBackgroundView.topAnchor),
descriptionTextView.trailingAnchor.constraint(
equalTo: descriptionBackgroundView.layoutMarginsGuide.trailingAnchor),
descriptionTextView.bottomAnchor.constraint(equalTo: view.safeAreaLayoutGuide.bottomAnchor)
])
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if let viewModel = viewModel {
switch viewModel.attachment.type {
case .image:
imageView.tag = viewModel.tag
playerView.isHidden = true
imageView.kf.setImage(
with: viewModel.attachment.previewUrl,
options: [.onlyFromCache],
completionHandler: { [weak self] in
guard let self = self else { return }
if case .success = $0 {
self.imageView.kf.indicatorType = .none
}
self.imageView.kf.setImage(
with: viewModel.attachment.url,
options: [.keepCurrentImageWhileLoading])
})
case .gifv:
playerView.tag = viewModel.tag
imageView.isHidden = true
let player = PlayerCache.shared.player(url: viewModel.attachment.url)
player.isMuted = true
playerView.player = player
player.play()
default: break
}
} else if let imageURL = imageURL {
imageView.tag = imageURL.hashValue
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playerView.isHidden = true
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imageView.kf.setImage(with: imageURL)
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}
}
}
extension ImageViewController {
func toggleDescriptionVisibility() {
UIView.animate(withDuration: .shortAnimationDuration) {
self.descriptionBackgroundView.alpha = self.descriptionBackgroundView.alpha > 0 ? 0 : 1
}
}
}
extension ImageViewController: UIScrollViewDelegate {
func viewForZooming(in scrollView: UIScrollView) -> UIView? {
contentView
}
// https://stackoverflow.com/a/40480610/2484482
func scrollViewDidZoom(_ scrollView: UIScrollView) {
if scrollView.zoomScale > 1,
let contentSize = imageView.image?.size ?? playerView.player?.currentItem?.presentationSize {
let ratio = min(contentView.frame.width / contentSize.width, contentView.frame.height / contentSize.height)
let newWidth = contentSize.width * ratio
let newHeight = contentSize.height * ratio
let horizontalInset = 0.5 * (newWidth * scrollView.zoomScale > contentView.frame.width
? (newWidth - contentView.frame.width)
: (scrollView.frame.width - scrollView.contentSize.width))
let verticalInset = 0.5 * (newHeight * scrollView.zoomScale > contentView.frame.height
? (newHeight - contentView.frame.height)
: (scrollView.frame.height - scrollView.contentSize.height))
scrollView.contentInset = .init(
top: verticalInset,
left: horizontalInset,
bottom: verticalInset,
right: horizontalInset)
} else {
scrollView.contentInset = .zero
}
}
}
private extension ImageViewController {
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static let maximumZoomScale: CGFloat = 4
@objc func handleDoubleTap(gestureRecognizer: UITapGestureRecognizer) {
if scrollView.zoomScale == scrollView.minimumZoomScale {
let width = contentView.frame.size.width / scrollView.maximumZoomScale
let height = contentView.frame.size.height / scrollView.maximumZoomScale
let center = scrollView.convert(gestureRecognizer.location(in: gestureRecognizer.view), from: contentView)
scrollView.zoom(
to: CGRect(x: center.x - (width / 2), y: center.y - (height / 2), width: width, height: height),
animated: true)
} else {
scrollView.setZoomScale(scrollView.minimumZoomScale, animated: true)
}
}
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}