Can't get UILabel to word wrap - swift3

Question

I have used Interface Builder to get UILabelViews to word wrap, but this is my first attempt to do it programmatically. I believe the issue is that although I'm setting:
label.lineBreakMode = .byWordWrapping
label.numberOfLines = 0
I'm setting a line height which might conflict with these properties?
override func layoutSubviews() {
super.layoutSubviews()
imageViewContent.frame = CGRect(x: 0, y: 0, width: frame.size.width, height: frame.size.height)
imageViewContent.loadImageWithURL(imageName!)
label.frame = CGRect(x: 0, y: 0, width: frame.size.width-10, height: 21)
label.center = imageViewContent.center
label.textAlignment = .center
label.clipsToBounds = true
label.layer.cornerRadius = 10.0
label.textColor = .white
label.font = UIFont(name: "AvenirNext-DemiBold", size: 15)
label.backgroundColor = UIColor.black.withAlphaComponent(0.5)
label.lineBreakMode = .byWordWrapping
label.numberOfLines = 0
label.text = photoName
}

Answer 1

As I suspected, hardcoding the height of the label prevented it from word wrapping. I've created a labelHeight variable and added a function at the bottom of the class to calculate the labelHeight based on the content, font size, and labelWidth I set. Code works fine now:
class NTWaterfallViewCell :UICollectionViewCell, NTTansitionWaterfallGridViewProtocol{
var photoName = ""
var imageName : String?
var labelHeight: CGFloat = 0.0
var imageViewContent : UIImageView = UIImageView()
var label = UILabel()
required init?(coder aDecoder: NSCoder) {
fatalError("init(coder:) has not been implemented")
}
override init(frame: CGRect) {
super.init(frame: frame)
backgroundColor = UIColor.lightGray
contentView.addSubview(imageViewContent)
contentView.addSubview(label)
}
override func layoutSubviews() {
super.layoutSubviews()
imageViewContent.frame = CGRect(x: 0, y: 0, width: frame.size.width, height: frame.size.height)
imageViewContent.loadImageWithURL(imageName!)
label.text = photoName
labelHeight = heightForText(photoName, width: frame.size.width-10)
label.frame = CGRect(x: 0, y: 0, width: frame.size.width-10, height: labelHeight)
label.center = imageViewContent.center
label.textAlignment = .center
label.clipsToBounds = true
label.layer.cornerRadius = 10.0
label.textColor = .white
label.font = UIFont(name: "AvenirNext-DemiBold", size: 15)
label.backgroundColor = UIColor.black.withAlphaComponent(0.5)
label.lineBreakMode = .byWordWrapping
label.numberOfLines = 0
}
func heightForText(_ text: String, width: CGFloat) -> CGFloat {
let font = UIFont(name: "AvenirNext-DemiBold", size: 15)
let rect = NSString(string: text).boundingRect(with: CGSize(width: width, height: CGFloat(MAXFLOAT)), options: .usesLineFragmentOrigin, attributes: [NSFontAttributeName: font], context: nil)
return ceil(rect.height)
}
}