UIView+Extensions

UIView+Extensions.swift

import UIKit

extension UIView {
    var absoluteFrame: CGRect {
        return self.superview!.convert(self.frame, to: nil)
    }
    
    func convertFrame(toParentView parentView: UIView) -> CGRect {
        return self.superview!.convert(self.frame, to: parentView)
    }
    
    class func fromNib<T : UIView>(named: String? = nil) -> T? {
        guard let strongName = named else {
            return Bundle.main.loadNibNamed(String(describing: T.self), owner: nil, options: nil)![0] as? T
            
        }
        return Bundle.main.loadNibNamed(strongName, owner: nil, options: nil)![0] as? T
    }
    
    func circleify() {
        self.layer.cornerRadius = self.bounds.size.height / 2
    }
    
    /// Adds constraints to this `UIView` instances `superview` object to make sure this always has the same size as the superview.
    /// Please note that this has no effect if its `superview` is `nil` – add this `UIView` instance as a subview before calling this.
    func bindFrameToSuperviewBounds(leftMargin: Double = 0, rightMargin: Double = 0, topMargin: Double = 0, bottomMargin: Double = 0) {
        guard let superview = self.superview else {
            print("Error! `superview` was nil – call `addSubview(view: UIView)` before calling `bindFrameToSuperviewBounds()` to fix this.")
            return
        }
        
        self.translatesAutoresizingMaskIntoConstraints = false
        superview.addConstraints(NSLayoutConstraint.constraints(withVisualFormat: "H:|-\(leftMargin)-[subview]-\(rightMargin)-|", options: .directionLeadingToTrailing, metrics: nil , views: ["subview": self]))
        superview.addConstraints(NSLayoutConstraint.constraints(withVisualFormat: "V:|-\(topMargin)-[subview]-\(bottomMargin)-|", options: .directionLeadingToTrailing, metrics: nil, views: ["subview": self]))
    }
    
    func toImage() -> UIImage? {
        UIGraphicsBeginImageContextWithOptions(self.bounds.size, false, 0.0)
        defer { UIGraphicsEndImageContext() }
        if let context = UIGraphicsGetCurrentContext() {
            self.layer.render(in: context)
            let image = UIGraphicsGetImageFromCurrentImageContext()
            return image
        }
        return nil
    }
}