Dynamic font resizing in collectionview [closed] - ios

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for my app I implemented a collectionview showing cards, that are rotated in a carousel-like animation. My problem is that the cards themselves resize correctly when swiped, but the fonts stay the same size or resize incorrectly. To be specific, the answers (bottommost 5 labels) are in a stackview.
Things I tried:
AutoLayout
Autoshrink
adjustsFontSizeToFitWidth
any number of different constraints
I attached a few screenshots below, where I colored the labels for better visibility.

Answer 1

To change the size of a view and have all of it's subviews / buttons / labels / etc scale with it - including label fonts, you are better off using CGAffineTransform for scaling.
Here is a simple example. It can be pasted into a Playground page to see the effect:
import UIKit
import PlaygroundSupport
class TestViewController : UIViewController {
let theStackView: UIStackView = {
let sv = UIStackView()
sv.translatesAutoresizingMaskIntoConstraints = false
sv.axis = .vertical
sv.distribution = .equalCentering
sv.alignment = .center
return sv
}()
let theContainerView: UIView = {
let v = UIView()
v.translatesAutoresizingMaskIntoConstraints = false
v.backgroundColor = .green
return v
}()
let btn: UIButton = {
let b = UIButton()
b.setTitle("Tap to Scale", for: .normal)
b.backgroundColor = .red
b.translatesAutoresizingMaskIntoConstraints = false
return b
}()
// on button tap, scale the Container view by 50% both ways
// note that Container view's subviews also scale
func btnTapped(_ sender: Any) {
theContainerView.transform = CGAffineTransform(scaleX: 0.5, y: 0.5)
}
override func viewDidLoad() {
super.viewDidLoad()
// add the button to self.view
self.view.addSubview(btn)
// button position
btn.centerXAnchor.constraint(equalTo: self.view.centerXAnchor).isActive = true
btn.topAnchor.constraint(equalTo: self.view.topAnchor, constant: 20.0).isActive = true
// add a target for the button tap
btn.addTarget(self, action: #selector(btnTapped(_:)), for: .touchUpInside)
// add our "Container" view
view.addSubview(theContainerView)
// add our Stack view to the Container view
theContainerView.addSubview(theStackView)
// add 5 labels to the Stack view
for i in 1...5 {
let label = UILabel()
label.font = UIFont.systemFont(ofSize: 20.0)
label.text = "This is Label \(i)"
label.backgroundColor = .cyan
label.translatesAutoresizingMaskIntoConstraints = false
theStackView.addArrangedSubview(label)
}
// pin Container view 20-pts from the bottom of the button, and 8-pts from left, right and bottom
theContainerView.topAnchor.constraint(equalTo: btn.bottomAnchor, constant: 20.0).isActive = true
theContainerView.leftAnchor.constraint(equalTo: view.leftAnchor, constant: 8.0).isActive = true
theContainerView.rightAnchor.constraint(equalTo: view.rightAnchor, constant: -8.0).isActive = true
theContainerView.bottomAnchor.constraint(equalTo: view.bottomAnchor, constant: -8.0).isActive = true
// pin Stack view 8-pts from top, left, right and bottom of the Container view
theStackView.topAnchor.constraint(equalTo: theContainerView.topAnchor, constant: 8.0).isActive = true
theStackView.leftAnchor.constraint(equalTo: theContainerView.leftAnchor, constant: 8.0).isActive = true
theStackView.rightAnchor.constraint(equalTo: theContainerView.rightAnchor, constant: -8.0).isActive = true
theStackView.bottomAnchor.constraint(equalTo: theContainerView.bottomAnchor, constant: -8.0).isActive = true
}
}
let vc = TestViewController()
vc.view.backgroundColor = .yellow
PlaygroundPage.current.liveView = vc