func calculateTextHeight(myString: String, myWidth: CGFloat, myFont: UIFont) -> CGFloat {
    let textStorage = NSTextStorage(string: myString)
    let textContainer = NSTextContainer.init(size: CGSize(width: myWidth, height: CGFloat.max))
    let layoutManager = NSLayoutManager()

    layoutManager.addTextContainer(textContainer)
    textStorage.addLayoutManager(layoutManager)

    textStorage.addAttribute(NSFontAttributeName, value: myFont, range: NSMakeRange(0, textStorage.length))
    textContainer.lineFragmentPadding = 0
    textContainer.lineBreakMode = .ByWordWrapping

    layoutManager.glyphRangeForTextContainer(textContainer)
    return layoutManager.usedRectForTextContainer(textContainer).size.height
}

var s = "ABCDE 12345"
print(calculateTextHeight(s, myWidth: 500, myFont: UIFont.systemFontOfSize(14)))
// prints 16.7 (correct)

s = "ABCDE 12345 💩"
print(calculateTextHeight(s, myWidth: 500, myFont: UIFont.systemFontOfSize(14)))
// prints 22.9 (should be 16.7)