LKLabel.swift

open class LKLabel : UILabel {
    open override class var layerClass: AnyClass {
        get {
            return LKLabelLayer.self
        }
    }
    
    /// The underlying attributed string drawn by the label, if set, the label ignores the `font`, 
    /// `textColor`, `shadowColor`, and `shadowOffset` properties.
    /// If `.paragraphStyle` attribute is absent in the attributed string, it is created incorporating 
    /// the label's `textAlignment` property.
    /// Animatable.
    open override var attributedText: NSAttributedString? {
        didSet(previousValue) {
            CATransaction.begin()
            CATransaction.setAnimationDuration(UIView.inheritedAnimationDuration)
            labelLayer?.attributedText = alignedAttributedText(attributedText)
            CATransaction.commit()
        }
    }
    
    /// The current text that is displayed by the label.
    /// Animatable.
    open override var text: String? {
        didSet(previousValue) {
            CATransaction.begin()
            CATransaction.setAnimationDuration(UIView.inheritedAnimationDuration)
            labelLayer?.attributedText = alignedAttributedText(attributedText)
            CATransaction.commit()
        }
    }
    
    override open func display(_ layer: CALayer) {
        if let labelLayer = layer as? LKLabelLayer {
            let rect = self.bounds
            UIGraphicsBeginImageContextWithOptions(rect.size, false, UIScreen.main.scale)
            let textRect = rect.inset(by: self.layoutMargins)
            drawText(in: textRect)
            layer.contents = UIGraphicsGetImageFromCurrentImageContext()?.cgImage
            UIGraphicsEndImageContext()
            return
        }
        super.display(layer)
    }
    
    open override var intrinsicContentSize: CGSize {
        get {
            var ics = super.intrinsicContentSize
            ics.width = (ics.width < CGFloat(UINT16_MAX)) ? CGFloat(ceil(ics.width + 
                                                                         self.layoutMargins.left + 
                                                                         self.layoutMargins.right)) : 
                                                            ics.width
            ics.height = (ics.height < CGFloat(UINT16_MAX)) ? CGFloat(ceil(ics.height + 
                                                                           self.layoutMargins.top + 
                                                                           self.layoutMargins.bottom)) : 
                                                              ics.height
            return ics
        }
    }
}