Swift UILable 设置内边距实例代码

class UILabelPadding : UILabel {
 
 private var padding = UIEdgeInsetsZero
 
 @IBInspectable
 var paddingLeft: CGFloat {
  get { return padding.left }
  set { padding.left = newValue }
 }
 
 @IBInspectable
 var paddingRight: CGFloat {
  get { return padding.right }
  set { padding.right = newValue }
 }
 
 @IBInspectable
 var paddingTop: CGFloat {
  get { return padding.top }
  set { padding.top = newValue }
 }
 
 @IBInspectable
 var paddingBottom: CGFloat {
  get { return padding.bottom }
  set { padding.bottom = newValue }
 }
 
 override func drawTextInRect(rect: CGRect) {
  super.drawTextInRect(UIEdgeInsetsInsetRect(rect, padding))
 }

 override func textRectForBounds(bounds: CGRect, limitedToNumberOfLines numberOfLines: Int) -> CGRect {
  let insets = self.padding
  var rect = super.textRectForBounds(UIEdgeInsetsInsetRect(bounds, insets), limitedToNumberOfLines: numberOfLines)
  rect.origin.x -= insets.left
  rect.origin.y -= insets.top
  rect.size.width += (insets.left + insets.right)
  rect.size.height += (insets.top + insets.bottom)
  return rect
 }

}