It seems PKCanvasView overrides the property UIScrollViewDelegate which inherits from the UIScrollView to PKCanvasViewDelegate. And does not provide access to UIScrollViewDelegate. In order to implement zooming, so I added a PKCanvasView into my own UIScrollView. And implemented delegate method viewForZooming in which return PKCanvasView. But all drawing in PKCanvasView was blurred when zooming or scale. How to re-render drawing after zoom to make it has reasonable stroke width and clear ? Some related code: let canvasView = PKCanvasView() let scrollView = UIScrollView() override func viewDidLoad() {     super.viewDidLoad()     self.view.addSubview(scrollView)     scrollView.addSubview(canvasView)     scrollView.delegate = self     scrollView.minimumZoomScale = 0.5     scrollView.maximumZoomScale = 2.5 } func viewForZooming(in scrollView: UIScrollView) -> UIView? {     return canvasView } Some solutions I had tried: 1: Reset PKCanvasView contentScaleFactor func scrollViewDidEndZooming(_ scrollView: UIScrollView, with view: UIView?, atScale scale: CGFloat) {     if let canvas = view {       let contentScale = scale * UIScreen.main.scale       canvas.contentScaleFactor = contentScale     }   } Not worked! 2: Re-render PKStroke: func reRender(_ scale: CGFloat) {     let newStrokeWidth = strokeWidth * scale     var newDrawingStrokes: [PKStroke] = []     for stroke in canvasView.drawing.strokes {       canvasView.tool = PKInkingTool(.pen, color: .red, width: newStrokeWidth)       var newPoints = [PKStrokePoint]()       stroke.path.forEach { (point) in         let newPoint = PKStrokePoint(location: point.location,                        timeOffset: point.timeOffset,                        size: CGSize(width: newStrokeWidth, height: newStrokeWidth),                        opacity: CGFloat(1), force: point.force,                        azimuth: point.azimuth, altitude: point.altitude)         newPoints.append(newPoint)       }       let newPath = PKStrokePath(controlPoints: newPoints, creationDate: Date())       let newStroke = PKStroke(ink: PKInk(.pen, color: UIColor.red), path: newPath)       newDrawingStrokes.append(newStroke)     }     let newDrawing = PKDrawing(strokes: newDrawingStrokes)     canvasView.drawing = newDrawing   } Not worked! Still blurred, just changed strokeWidth by multiply scale. 3: I try to reset PKDrawing or PKStroke transform by using scrollView scale. Then PKDrawing position disordered and it was still blurred. Please help me.