iOS/WolneLektury/Screens/NewsDetails/Gallery/Cells/GalleryCell.swift

   1 //
   2 //  GalleryCell.swift
   3 //  WolneLektury
   4 //
   5 //  Created by Pawel Dabrowski on 17/09/2018.
   6 //  Copyright © 2018 Fundacja Nowoczesna Polska. All rights reserved.
   7 //
   8
   9 import UIKit
  10 import Kingfisher
  11 import MBProgressHUD
  12
  13 public class GalleryCell: UICollectionViewCell {
  14
  15     var url: String?{
  16         didSet {
  17             configureForNewImageUrl()
  18         }
  19     }
  20
  21     private var scrollView: UIScrollView
  22     fileprivate let imageView: UIImageView
  23     var progressHud: MBProgressHUD?
  24
  25     func setScrollEnabled(scrollEnabled: Bool){
  26         scrollView.isUserInteractionEnabled = scrollEnabled
  27         if !scrollEnabled{
  28             setZoomScale()
  29         }
  30     }
  31
  32     override init(frame: CGRect) {
  33
  34         imageView = UIImageView()
  35         imageView.translatesAutoresizingMaskIntoConstraints = false
  36         scrollView = UIScrollView(frame: frame)
  37         scrollView.translatesAutoresizingMaskIntoConstraints = false
  38         scrollView.backgroundColor = Constants.Colors.darkGreenBgColor()
  39         super.init(frame: frame)
  40
  41         var scrollViewConstraints: [NSLayoutConstraint] = []
  42         var imageViewConstraints: [NSLayoutConstraint] = []
  43
  44         scrollViewConstraints.append(NSLayoutConstraint(item: scrollView, attribute: .leading, relatedBy: .equal, toItem: contentView, attribute: .leading, multiplier: 1, constant: 0))
  45         scrollViewConstraints.append(NSLayoutConstraint(item: scrollView, attribute: .top, relatedBy: .equal, toItem: contentView, attribute: .top, multiplier: 1, constant: 0))
  46         scrollViewConstraints.append(NSLayoutConstraint(item: scrollView, attribute: .trailing, relatedBy: .equal, toItem: contentView, attribute: .trailing, multiplier: 1, constant: 0))
  47         scrollViewConstraints.append(NSLayoutConstraint(item: scrollView, attribute: .bottom, relatedBy: .equal, toItem: contentView, attribute: .bottom, multiplier: 1, constant: 0))
  48         contentView.addSubview(scrollView)
  49         contentView.addConstraints(scrollViewConstraints)
  50
  51         imageViewConstraints.append(NSLayoutConstraint(item: imageView, attribute: .leading, relatedBy: .equal, toItem: scrollView, attribute: .leading, multiplier: 1, constant: 0))
  52         imageViewConstraints.append(NSLayoutConstraint(item: imageView, attribute: .top, relatedBy: .equal, toItem: scrollView, attribute: .top, multiplier: 1, constant: 0))
  53         imageViewConstraints.append(NSLayoutConstraint(item: imageView, attribute: .trailing, relatedBy: .equal, toItem: scrollView, attribute: .trailing, multiplier: 1, constant: 0))
  54         imageViewConstraints.append(NSLayoutConstraint(item: imageView, attribute: .bottom, relatedBy: .equal, toItem: scrollView, attribute: .bottom, multiplier: 1, constant: 0))
  55         scrollView.addSubview(imageView)
  56         scrollView.addConstraints(imageViewConstraints)
  57
  58         scrollView.delegate = self
  59
  60         let tapGestureRecognizer = UITapGestureRecognizer(target: self, action: #selector(tapGestureRecognizerAction(recognizer:)))
  61         tapGestureRecognizer.numberOfTapsRequired = 2
  62         self.addGestureRecognizer(tapGestureRecognizer)
  63     }
  64
  65     @objc public func tapGestureRecognizerAction(recognizer: UITapGestureRecognizer) {
  66         if (scrollView.zoomScale > scrollView.minimumZoomScale) {
  67             scrollView.setZoomScale(scrollView.minimumZoomScale, animated: true)
  68         } else {
  69             scrollView.setZoomScale(scrollView.maximumZoomScale, animated: true)
  70         }
  71     }
  72
  73     required public init?(coder aDecoder: NSCoder) {
  74         fatalError("init(coder:) has not been implemented")
  75     }
  76
  77     public func configureForNewImageUrl() {
  78
  79         guard let imageUrl = url?.getPhotoUrl() else{
  80             self.setupImage(image: nil)
  81             return
  82         }
  83
  84         if progressHud == nil{
  85             progressHud = MBProgressHUD.showAdded(to: contentView, animated: true)
  86             progressHud?.label.text = "loading".localized
  87         }
  88         else{
  89             progressHud?.show(animated: true)
  90         }
  91
  92         //        let freeSpace = contentView.bounds.size.height - textContainerHeight
  93         let contentOffsetY = ((contentView.bounds.size.height/2 /*- freeSpace/2*/) * -1)
  94         progressHud!.offset.y = contentOffsetY
  95
  96         KingfisherManager.shared.retrieveImage(with: ImageResource(downloadURL: imageUrl), options: nil, progressBlock: nil) { (image, error, cacheType, url) in
  97             self.progressHud?.hide(animated: true)
  98             self.setupImage(image: image)
  99         }
 100     }
 101
 102
 103     // ############################################
 104     // MARK: - Private
 105     // ############################################
 106
 107     private func setupImage(image: UIImage?){
 108         imageView.image = image
 109         imageView.sizeToFit()
 110         imageView.alpha = 0.0
 111
 112         setZoomScale()
 113         scrollViewDidZoom(scrollView)
 114
 115         UIView.animate(withDuration: 0.5) {
 116             self.imageView.alpha = 1.0
 117         }
 118     }
 119
 120     private func setZoomScale() {
 121
 122         let imageViewSize = imageView.bounds.size
 123
 124         guard imageViewSize.width > 0 && imageViewSize.height > 0 else {
 125             return
 126         }
 127
 128         let scrollViewSize =  UIScreen.main.bounds.size// scrollView.bounds.size
 129         let widthScale = scrollViewSize.width / imageViewSize.width
 130         let heightScale = scrollViewSize.height / imageViewSize.height
 131         let miminumZoomScale = min(widthScale, heightScale)
 132         scrollView.minimumZoomScale = miminumZoomScale
 133
 134         let initialZoomScale = max(widthScale, heightScale)
 135
 136         scrollView.maximumZoomScale = initialZoomScale * 1.5
 137
 138         scrollView.setZoomScale(miminumZoomScale, animated: false)
 139
 140         let newContentOffsetX = (scrollView.contentSize.width/2) - (scrollView.bounds.size.width/2);
 141
 142         scrollView.contentOffset = CGPoint(x: newContentOffsetX, y: scrollView.contentOffset.y)
 143     }
 144 }
 145
 146 extension GalleryCell: UIScrollViewDelegate {
 147
 148     public func viewForZooming(in scrollView: UIScrollView) -> UIView? {
 149         return imageView
 150     }
 151
 152     public func scrollViewDidZoom(_ scrollView: UIScrollView) {
 153
 154         let imageViewSize = imageView.frame.size
 155         let scrollViewSize = scrollView.bounds.size
 156
 157         let verticalPadding = imageViewSize.height < scrollViewSize.height ? (scrollViewSize.height - imageViewSize.height) / 2 : 0
 158         let horizontalPadding = imageViewSize.width < scrollViewSize.width ? (scrollViewSize.width - imageViewSize.width) / 2 : 0
 159
 160         if verticalPadding >= 0 {
 161             // Center the image on screen
 162             scrollView.contentInset = UIEdgeInsets(top: verticalPadding, left: horizontalPadding, bottom: verticalPadding, right: horizontalPadding)
 163         } else {
 164             // Limit the image panning to the screen bounds
 165             scrollView.contentSize = imageViewSize
 166         }
 167     }
 168 }