How to draw UIBezierPath identical to MKPolyline in a UIView

Question

Currently I am tracking my location on an MKMapView. My objective is to draw a bezier path identical to an MKPolyline created from tracked locations.

What I have att

Answer 1

this might help you, in case you haven't solved it yet.

I wanted the shape of an MKPolyline as an image without any background. I used the code above as an inspiration and had the same troubles as you had, the route was not shown.

In fact it was kind a scaling problem I think. At least it looked like that in the playground. Anyway, with this methods I get an image of the polylines shape.

private func createPolylineShapeAsImage() -> UIImage? {
    let vw = UIView(frame: mapView.bounds)
    var image : UIImage?
    if let polyline = viewModel.tourPolyline {
        let path = createBezierPath(mapView, polyline, to: mapView)
        let layer = getShapeLayer(path: path, lineColor: UIColor.white, fillColor: .clear)
        vw.layer.addSublayer(layer)
        image = vw.asImage()
    }
    return image
}

func createBezierPath(_ mapView : MKMapView, _ polyline : MKPolyline, to view : UIView) -> UIBezierPath  {
    let mapPoints = polyline.points()
    var points = [CGPoint]()
    let max = polyline.pointCount - 1
    for point in 0...max {
       let coordinate = mapPoints[point].coordinate
       points.append(mapView.convert(coordinate, toPointTo: view))
    }
    let path = UIBezierPath(points: points)
    path.lineWidth = 5.0
    return path
}

private func getShapeLayer(path:UIBezierPath, lineColor:UIColor, fillColor:UIColor) -> CAShapeLayer {
    let layer = CAShapeLayer()
    layer.path = path.cgPath
    layer.strokeColor = lineColor.cgColor
    layer.fillColor = fillColor.cgColor
    layer.lineWidth = path.lineWidth

    layer.opacity = 1
    layer.frame = path.bounds
    return layer
}

And to get the image of the view use this extension

import UIKit
extension UIView {
  // Using a function since `var image` might conflict with an existing variable
  // (like on `UIImageView`)
  func asImage() -> UIImage {
    if #available(iOS 10.0, *) {
        let renderer = UIGraphicsImageRenderer(bounds: bounds)
        return renderer.image { rendererContext in
            layer.render(in: rendererContext.cgContext)
        }
    } else {
        UIGraphicsBeginImageContext(self.frame.size)
        self.layer.render(in:UIGraphicsGetCurrentContext()!)
        let image = UIGraphicsGetImageFromCurrentImageContext()
        UIGraphicsEndImageContext()
        return UIImage(cgImage: image!.cgImage!)
    }
  }
}