Extensions for UIView that help out when building layouts manually!

UIView+Extensions.swift

//
//  UIView+Extensions.swift
//
//  Created by Luis Ramos on 17/5/18.
//

import UIKit

extension UIView {
    
    var left: CGFloat {
        get { return frame.origin.x }
        set { frame = CGRect(x: newValue, y: frame.origin.y, width: frame.size.width, height: frame.size.height) }
    }
    
    var top: CGFloat {
        get { return frame.origin.y }
        set { frame = CGRect(x: frame.origin.x, y: newValue, width: frame.size.width, height: frame.size.height) }
    }
    
    var width: CGFloat {
        get { return frame.size.width }
        set { frame = CGRect(x: frame.origin.x, y: frame.origin.y, width: newValue, height: frame.size.height) }
    }
    
    var height: CGFloat {
        get { return frame.size.height }
        set { frame = CGRect(x: frame.origin.x, y: frame.origin.y, width: frame.size.width, height: newValue) }
    }
    
    var right: CGFloat {
        get { return left + width }
        set { left = newValue - width }
    }
    
    var bottom: CGFloat {
        get { return top + height }
        set { top = newValue - height }
    }
    
    var centerX: CGFloat {
        get { return left + width * 0.5 }
        set { left = newValue - width * 0.5 }
    }
    
    var centerY: CGFloat {
        get { return top + height * 0.5 }
        set { top = newValue - height * 0.5 }
    }
    
    var relativeCenter : CGPoint {
        return CGPoint(x: bounds.width / 2.0, y: bounds.height / 2.0)
    }
    
    var size: CGSize {
        get { return frame.size }
        set { frame.size = newValue }
    }
}

extension UIView {
    
    func align(withView view: UIView, constant: CGFloat = 0.0) {
        translatesAutoresizingMaskIntoConstraints = false
        NSLayoutConstraint.activate([
            leftAnchor.constraint(equalTo: view.leftAnchor, constant: constant),
            rightAnchor.constraint(equalTo: view.rightAnchor, constant: -constant),
            topAnchor.constraint(equalTo: view.topAnchor, constant: constant),
            bottomAnchor.constraint(equalTo: view.bottomAnchor, constant: -constant),
            ])
    }
    
    func alignLeadingTrailing(withView view: UIView, constant: CGFloat = 0.0) {
        translatesAutoresizingMaskIntoConstraints = false
        NSLayoutConstraint.activate([
            leftAnchor.constraint(equalTo: view.leftAnchor, constant: constant),
            rightAnchor.constraint(equalTo: view.rightAnchor, constant: -constant),
            ])
    }
    
    func alignTopBottom(withView view: UIView, constant: CGFloat = 0.0) {
        translatesAutoresizingMaskIntoConstraints = false
        NSLayoutConstraint.activate([
            topAnchor.constraint(equalTo: view.topAnchor, constant: constant),
            bottomAnchor.constraint(equalTo: view.bottomAnchor, constant: -constant),
            ])
    }
    
    @discardableResult
    func alignTop(withView view: UIView, constant: CGFloat = 0.0, isActive: Bool = true) -> NSLayoutConstraint {
        translatesAutoresizingMaskIntoConstraints = false
        let constraint = topAnchor.constraint(equalTo: view.topAnchor, constant: constant)
        constraint.isActive = isActive
        return constraint
    }
    
    @discardableResult
    func alignTop(withGuide guide: UILayoutGuide, constant: CGFloat = 0.0, isActive: Bool = true) -> NSLayoutConstraint {
        translatesAutoresizingMaskIntoConstraints = false
        let constraint = topAnchor.constraint(equalTo: guide.topAnchor, constant: constant)
        constraint.isActive = isActive
        return constraint
    }
    
    @discardableResult
    func alignBottom(withView view: UIView, constant: CGFloat = 0.0, isActive: Bool = true) -> NSLayoutConstraint {
        translatesAutoresizingMaskIntoConstraints = false
        let constraint = bottomAnchor.constraint(equalTo: view.bottomAnchor, constant: constant)
        constraint.isActive = isActive
        return constraint
    }
    
    @discardableResult
    func alignBottom(withGuide guide: UILayoutGuide, constant: CGFloat = 0.0, isActive: Bool = true) -> NSLayoutConstraint {
        translatesAutoresizingMaskIntoConstraints = false
        let constraint = bottomAnchor.constraint(equalTo: guide.bottomAnchor, constant: constant)
        constraint.isActive = isActive
        return constraint
    }
    
    @discardableResult
    func alignLeading(withView view: UIView, constant: CGFloat = 0.0, isActive: Bool = true) -> NSLayoutConstraint {
        translatesAutoresizingMaskIntoConstraints = false
        let constraint = leadingAnchor.constraint(equalTo: view.leadingAnchor, constant: constant)
        constraint.isActive = isActive
        return constraint
    }
    
    @discardableResult
    func alignTrailing(withView view: UIView, constant: CGFloat = 0.0, isActive: Bool = true) -> NSLayoutConstraint {
        translatesAutoresizingMaskIntoConstraints = false
        let constraint = trailingAnchor.constraint(equalTo: view.trailingAnchor, constant: constant)
        constraint.isActive = isActive
        return constraint
    }
    
    @discardableResult
    func constraintVerticalSpace(withView view: UIView, constant: CGFloat = 0.0, isActive: Bool = true) -> NSLayoutConstraint {
        translatesAutoresizingMaskIntoConstraints = false
        let constraint = bottomAnchor.constraint(equalTo: view.topAnchor, constant: constant)
        constraint.isActive = isActive
        return constraint
    }
    
    @discardableResult
    func constraintHorizontalSpace(withView view: UIView, constant: CGFloat = 0.0, isActive: Bool = true) -> NSLayoutConstraint {
        translatesAutoresizingMaskIntoConstraints = false
        let constraint = leadingAnchor.constraint(equalTo: view.trailingAnchor, constant: constant)
        constraint.isActive = isActive
        return constraint
    }
    
    @discardableResult
    func centerVertical(withView view: UIView, constant: CGFloat = 0.0, isActive: Bool = true) -> NSLayoutConstraint {
        translatesAutoresizingMaskIntoConstraints = false
        let constraint = centerYAnchor.constraint(equalTo: view.centerYAnchor, constant: constant)
        constraint.isActive = isActive
        return constraint
    }
    
    @discardableResult
    func centerHorizontal(withView view: UIView, constant: CGFloat = 0.0, isActive: Bool = true) -> NSLayoutConstraint {
        translatesAutoresizingMaskIntoConstraints = false
        let constraint = centerXAnchor.constraint(equalTo: view.centerXAnchor, constant: constant)
        constraint.isActive = isActive
        return constraint
    }
    
    @discardableResult
    func constrainHeight(_ value: CGFloat, isActive: Bool = true) -> NSLayoutConstraint {
        let constraint = heightAnchor.constraint(equalToConstant: value)
        constraint.isActive = isActive
        return constraint
    }
    
    @discardableResult
    func constrainWidth(_ value: CGFloat, isActive: Bool = true) -> NSLayoutConstraint {
        let constraint = widthAnchor.constraint(equalToConstant: value)
        constraint.isActive = isActive
        return constraint
    }
    
    @discardableResult
    func constrainWidth(to view: UIView, isActive: Bool = true) -> NSLayoutConstraint {
        let constraint = widthAnchor.constraint(equalTo: view.widthAnchor)
        constraint.isActive = isActive
        return constraint
    }
    
    @discardableResult
    func constrainHeight(to view: UIView, isActive: Bool = true) -> NSLayoutConstraint {
        let constraint = heightAnchor.constraint(equalTo: view.heightAnchor)
        constraint.isActive = isActive
        return constraint
    }
    
    func constraintSize(width: CGFloat, height: CGFloat, isActive: Bool = true) {
        widthAnchor.constraint(equalToConstant: width).isActive = true
        heightAnchor.constraint(equalToConstant: height).isActive = true
    }
    
    @discardableResult
    func constrainHeightToWidth(ratio: CGFloat = 1, isActive: Bool = true) -> NSLayoutConstraint {
        let constraint = heightAnchor.constraint(equalTo: widthAnchor, multiplier: ratio)
        constraint.isActive = isActive
        return constraint
    }
    
    @discardableResult
    func constrainWidthToHeight(ratio: CGFloat = 1, isActive: Bool = true) -> NSLayoutConstraint {
        let constraint = widthAnchor.constraint(equalTo: heightAnchor, multiplier: ratio)
        constraint.isActive = isActive
        return constraint
    }
}

extension UIView {
    var layoutGuide: UILayoutGuide {
        if #available(iOS 11.0, *) {
            return safeAreaLayoutGuide
        } else {
            return layoutMarginsGuide
        }
    }
}