Any way to determine if adjustsFontSizeToFitWidth has triggered? - swift

Question

Is there anyway to determine if adjustsFontSizeToFitWidth has been triggered? My app has a UILabel that takes up the entire view. By using the UIPinchGestureRecognizer you can pinch in and out to change the font size. Works great. However, when the font reaches the max size for the UILabel, it displays bizarre behaviour. The text in the UILabel moves down the UILabel. Without adding bannerLabel.adjustsFontSizeToFitWidth = true the text gets clipped. I would like to know when the font is at the maximum size for the UILabel, and i will stop trying to increase the font size.
import UIKit
class ViewController: UIViewController, UIGestureRecognizerDelegate {
#IBOutlet weak var bannerLabel: UILabel!
var perviousScale:CGFloat = 0
var fontSize:CGFloat = 0
var originalFontSize: CGFloat = 0
override func viewDidLoad() {
super.viewDidLoad()
let pinchGesture = UIPinchGestureRecognizer(target: self, action: Selector("pinch:"))
view.addGestureRecognizer(pinchGesture)
perviousScale = pinchGesture.scale
bannerLabel.adjustsFontSizeToFitWidth = true
originalFontSize = bannerLabel.font.pointSize
fontSize = originalFontSize
}
func pinch(sender:UIPinchGestureRecognizer) {
println("font size \(bannerLabel.font.pointSize)")
if perviousScale >= sender.scale //Zoom In
{
decreaseFontSize()
}
else if perviousScale < sender.scale //Zoom Out
{
increaseFontSize()
}
}
func threeFingers(sender:UIPanGestureRecognizer) {
println("threeFingers")
}
override func didRotateFromInterfaceOrientation(fromInterfaceOrientation: UIInterfaceOrientation) {
bannerLabel.font = UIFont(name: bannerLabel.font.fontName, size: fontSize)
}
func increaseFontSize(){
bannerLabel.font = UIFont(name: bannerLabel.font.fontName, size: fontSize)
fontSize = fontSize + 2.5
}
func decreaseFontSize(){
bannerLabel.font = UIFont(name: bannerLabel.font.fontName, size: fontSize)
if fontSize >= originalFontSize {
fontSize = fontSize - 2.5
}
}
}

Answer 1

Yup, you can add an observer:
1) Add the dynamic modifier to the property you would like to observe:
dynamic UILabel bannerLabel = UILabel()
2) Create a global context variable
private var myContext = 0
3) Add an observer for the key-path
bannerLabel.addObserver(self, forKeyPath: "adjustsFontSizeToFitWidth", options:.New, context:&myContext)
4) Override observeValueForKeyPath and remove observer in deinit
override func observeValueForKeyPath(keyPath: String, ofObject object: AnyObject, change: [NSObject: AnyObject], context: UnsafeMutablePointer<Void>) {
if context == &myContext {
println("Font size adjusted to fit width: \(change[NSKeyValueChangeNewKey])")
} else {
super.observeValueForKeyPath(keyPath, ofObject: object, change: change, context: context)
}
}
deinit {
bannerLabel .removeObserver(self, forKeyPath: "adjustsFontSizeToFitWidth", context: &myContext)
}