Drawing frame corners and dashed border on view, and drag, scale, rotate the view with gesture recognizers.

DrawRectCornersAndDashedBorder.swift

//
//  SecondViewController.swift
//  DrawLines
//
//  Created by Onur Işık on 17.12.2018.
//  Copyright © 2018 Onur Işık. All rights reserved.
//

import UIKit

class SecondViewController: UIViewController {

    @IBOutlet weak var rectBorderedView: UIView!
    
    lazy var panGesture: UIPanGestureRecognizer = {
        let panGesture = UIPanGestureRecognizer(target: self, action: #selector(handleDragging(_:)))
        return panGesture
    }()
    lazy var rotateGesture: UIRotationGestureRecognizer = {
        let rotateGesture = UIRotationGestureRecognizer(target: self, action: #selector(handleRotate(_:)))
        return rotateGesture
    }()
    lazy var pinchGesture: UIPinchGestureRecognizer = {
        let pinchGestureRecognizer = UIPinchGestureRecognizer(target: self, action: #selector(handleScale(_:)))
        return pinchGestureRecognizer
    }()
    
    override func viewDidLoad() {
        super.viewDidLoad()
        
        self.view.backgroundColor = .black
        self.rectBorderedView.backgroundColor = .clear
        self.addDashedBorder(for: self.rectBorderedView)
        self.drawCorners(for: self.rectBorderedView, lineWidth: 5, color: .white)

        self.addGestures()
    }
    
    fileprivate func addGestures() {
    
        panGesture.delegate = self
        pinchGesture.delegate = self
        rotateGesture.delegate = self
        
        self.rectBorderedView.isUserInteractionEnabled = true
        self.rectBorderedView.addGestureRecognizer(panGesture)
        self.rectBorderedView.addGestureRecognizer(pinchGesture)
        self.rectBorderedView.addGestureRecognizer(rotateGesture)
    }
    
    @objc fileprivate func handleDragging(_ gestureRecognizer: UIPanGestureRecognizer) {
        guard let currentShape = gestureRecognizer.view else { return }
        self.view.bringSubviewToFront(currentShape)
        
        let translation = gestureRecognizer.translation(in: currentShape.superview)
        
        let centerPoint = CGPoint(x: currentShape.center.x + translation.x, y: currentShape.center.y + translation.y)
        currentShape.center = centerPoint
        gestureRecognizer.setTranslation(.zero, in: currentShape)
    }
    
    @objc fileprivate func handleRotate(_ gestureRecognizer: UIRotationGestureRecognizer) {
        guard let currentShape = gestureRecognizer.view else { return }
        self.view.bringSubviewToFront(currentShape)
        
        currentShape.transform = currentShape.transform.rotated(by: gestureRecognizer.rotation)
        gestureRecognizer.rotation = 0.0
    }
    
    @objc fileprivate func handleScale(_ gestureRecognizer: UIPinchGestureRecognizer) {
        guard let currentShape = gestureRecognizer.view else { return }
        self.view.bringSubviewToFront(currentShape)
        
        if gestureRecognizer.state == .began || gestureRecognizer.state == .changed {
            currentShape.transform = (currentShape.transform.scaledBy(x: gestureRecognizer.scale, y: gestureRecognizer.scale))
            gestureRecognizer.scale = 1.0
        }
    }
    
    fileprivate func addDashedBorder(for view: UIView) {
        
        let borderFrame: CGRect = view.frame
        
        let shapeLayer = CAShapeLayer()
        shapeLayer.name = "borderLayer"
        shapeLayer.bounds = borderFrame
        shapeLayer.lineJoin = .miter
        shapeLayer.lineCap = .square
        shapeLayer.lineWidth = 2
        shapeLayer.strokeColor = UIColor.white.cgColor
        shapeLayer.lineDashPattern = [6, 3]
        shapeLayer.frame = borderFrame
        shapeLayer.fillColor = UIColor.clear.cgColor
        
        let path = UIBezierPath(rect: view.bounds)
        shapeLayer.path = path.cgPath

        view.layer.addSublayer(shapeLayer)
    }

    fileprivate func drawCorners(for view: UIView, lineWidth: CGFloat, color: UIColor) {
        let cornerLengthToShow = view.bounds.size.height * 0.05
        print(cornerLengthToShow)
        
        // Create Paths Using BeizerPath for all four corners
        let topLeftCorner = UIBezierPath()
        topLeftCorner.move(to: CGPoint(x: view.bounds.minX, y: view.bounds.minY + cornerLengthToShow))
        topLeftCorner.addLine(to: CGPoint(x: view.bounds.minX, y: view.bounds.minY))
        topLeftCorner.addLine(to: CGPoint(x: view.bounds.minX + cornerLengthToShow, y: view.bounds.minY))
        
        let topRightCorner = UIBezierPath()
        topRightCorner.move(to: CGPoint(x: view.bounds.maxX - cornerLengthToShow, y: view.bounds.minY))
        topRightCorner.addLine(to: CGPoint(x: view.bounds.maxX, y: view.bounds.minY))
        topRightCorner.addLine(to: CGPoint(x: view.bounds.maxX, y: view.bounds.minY + cornerLengthToShow))
        
        let bottomRightCorner = UIBezierPath()
        bottomRightCorner.move(to: CGPoint(x: view.bounds.maxX, y: view.bounds.maxY - cornerLengthToShow))
        bottomRightCorner.addLine(to: CGPoint(x: view.bounds.maxX, y: view.bounds.maxY))
        bottomRightCorner.addLine(to: CGPoint(x: view.bounds.maxX - cornerLengthToShow, y: view.bounds.maxY ))
        
        let bottomLeftCorner = UIBezierPath()
        bottomLeftCorner.move(to: CGPoint(x: view.bounds.minX, y: view.bounds.maxY - cornerLengthToShow))
        bottomLeftCorner.addLine(to: CGPoint(x: view.bounds.minX, y: view.bounds.maxY))
        bottomLeftCorner.addLine(to: CGPoint(x: view.bounds.minX + cornerLengthToShow, y: view.bounds.maxY))
        
        let combinedPath = CGMutablePath()
        combinedPath.addPath(topLeftCorner.cgPath)
        combinedPath.addPath(topRightCorner.cgPath)
        combinedPath.addPath(bottomRightCorner.cgPath)
        combinedPath.addPath(bottomLeftCorner.cgPath)
        
        let shapeLayer = CAShapeLayer()
        shapeLayer.path = combinedPath
        shapeLayer.strokeColor = color.cgColor
        shapeLayer.fillColor = UIColor.clear.cgColor
        shapeLayer.lineWidth = lineWidth
        
        view.layer.addSublayer(shapeLayer)
    }
}

extension SecondViewController: UIGestureRecognizerDelegate {
    
    func gestureRecognizer(_ gestureRecognizer: UIGestureRecognizer,
                           shouldRecognizeSimultaneouslyWith otherGestureRecognizer: UIGestureRecognizer) -> Bool {
        return true
    }
}