Zoom UILabel & Re-render font at correct size

Question

I have a multi-line UILabel that I want to enable zooming on.

I embedded it with a UIScrollView and set min zoom to .25 and max zoom to 4.

Answer 1

Here is something that I have come up with:

func scrollViewDidEndZooming(scrollView: UIScrollView, withView view: UIView?, atScale scale: CGFloat) {
        label.font = UIFont(name: "YourFont", size: fontSize * scale)
        label.transform = CGAffineTransformConcat(CGAffineTransformMakeScale(1 / scale, 1 / scale), CGAffineTransformMakeRotation(0))
    }

Updated for Swift 4.0:

func scrollViewDidEndZooming(_ scrollView: UIScrollView, with view: UIView?, atScale scale: CGFloat) {
    label.font = label.font.withSize(fontSize * scale)
    label.transform = CGAffineTransform(scaleX: 1 / scale, y: 1 / scale).concatenating(CGAffineTransform(rotationAngle: 0))
}

And also remember that the label should be large enough to show the whole text. It sometimes takes a tiny bit to redraw, but this method is fairly simple.