[iOS] figure out UITextView's height based on a given string with value

.swift

func calculateTextViewHeight(inset: UIEdgeInsets, lineFragmentPadding: CGFloat = 5.0, maxWidth: CGFloat, text: String, font: UIFont) -> CGSize {
  let widthWithoutInset = maxWidth - (inset.left + inset.right + (2 * lineFragmentPadding))
  let contraintRect = CGSize(width: widthWithoutInset, height: CGFloat.max)
  let style = NSMutableParagraphStyle()
  style.lineBreakMode = .ByWordWrapping
  let attributes = [NSFontAttributeName: font, NSParagraphStyleAttributeName: style]
  let boudingBox = NSString(string: text).boundingRectWithSize(contraintRect, options: .UsesLineFragmentOrigin, attributes: attributes, context: nil)
  let newWidth = (boudingBox.size.width + (inset.left + inset.right + (2 * lineFragmentPadding) + 0.25)).roundNearest(0.5)
  let newHeight = (boudingBox.size.height + ((inset.top + inset.bottom) + 0.25)).roundNearest(0.5)
  return CGSize(width: newWidth, height: newHeight)
}