variable-image-and-content-height.swift

import UIKit
import Kingfisher

class EventTableViewCell: UITableViewCell {
    
    @IBOutlet weak var eventPhoto: UIImageView!
    @IBOutlet weak var eventDescription: UITextView!

    // constraint
    var aspectConstraint: NSLayoutConstraint? {
        didSet {
            if oldValue != nil {
                eventPhoto.removeConstraint(oldValue!)
            }
            if aspectConstraint != nil {
                eventPhoto.addConstraint(aspectConstraint!)
            }
        }
    }
    
    // clear
    override func prepareForReuse() {
        super.prepareForReuse()
        aspectConstraint = nil
    }
    
    // set image, called in cellForRow
    func setCustomImage(url: URL, width: CGFloat, height: CGFloat) {
        
        let aspect = width / height
        
        let constraint = NSLayoutConstraint(
            item: eventPhoto,
            attribute: .width,
            relatedBy: .equal,
            toItem: eventPhoto,
            attribute: .height,
            multiplier: aspect, 
            constant: 0.0
        )
        
        constraint.priority = UILayoutPriority(999)
        aspectConstraint = constraint
        
        // kf
        OperationQueue.main.addOperation {
            self.eventPhoto.kf.setImage(
                with: url,
                placeholder: nil,
                options: [.transition(.fade(0.3))],
                progressBlock: nil,
                completionHandler: { _ in
            })
        }
    }
}