PencilKit save background image and drawing to Album Xcode

Question

I want to save my canvas to album, but my subview is not visible when I go back to album. I only have my canvas with my drawings.

What should I change ?

  struct Home : View {
        @State var canvas = PKCanvasView()
        @State var showingAlert = false
        var body: some View{
            
            NavigationView{
                MyCanvas(canvasView: canvas)
                    .navigationBarTitleDisplayMode(.inline)
                    .navigationBarItems(
                        leading:
                            HStack{
                                Button(action: { SaveImage()  }, label: { Image(systemName: "square.and.arrow.down.fill").padding() })
                            })
            }
        }

My function to save image to album :

        func SaveImage(){
            
            // getting image from canvas....
            
            let image = canvas.drawing.image(from: canvas.drawing.bounds, scale: 1)
            
            // saving to albums....
            
            UIImageWriteToSavedPhotosAlbum(image, nil, nil, nil)
            showingAlert = true
        }
    }

My Canvas, where I add my background image :

    struct MyCanvas: UIViewRepresentable {
        var canvasView: PKCanvasView
        let picker = PKToolPicker.init()
        
        func makeUIView(context: Context) -> PKCanvasView {
            self.canvasView.tool = PKInkingTool(.pen, color: .black, width: 15)
            self.canvasView.isOpaque = false
            self.canvasView.backgroundColor = UIColor.clear
            self.canvasView.becomeFirstResponder()
    
           let imageView = UIImageView(image: UIImage(named: "badmintoncourt"))
            let subView = self.canvasView.subviews[0]
                subView.addSubview(imageView)
                subView.sendSubviewToBack(imageView)
            return canvasView
        }
        
        func updateUIView(_ uiView: PKCanvasView, context: Context) {
            picker.addObserver(canvasView)
            picker.setVisible(true, forFirstResponder: uiView)
            DispatchQueue.main.async {
                uiView.becomeFirstResponder()
            }
        }
    }

Did you found a solution to your problem ? – Michel Melhem Dec 25 '21 at 15:41 — Michel Melhem, Dec 25 '21 at 15:41

score 0 · Answer 1 · answered Feb 18 '21 at 11:26

This is actually not answering the question, but I save my drawing like this to handle dark mode as well:

let drawing = canvasView.drawing
let frameForImage = canvasView.bounds
let darkImage = thumbnail(drawing: drawing, thumbnailRect: frameForImage, traitCollection: UITraitCollection(userInterfaceStyle: .light))

with the thumbnail function:

func thumbnail(drawing: PKDrawing, thumbnailRect: CGRect, traitCollection: UITraitCollection) -> UIImage {
    var image = UIImage()
    traitCollection.performAsCurrent {
        image = drawing.image(from: thumbnailRect, scale: 1.0)
    }
    return image
}

PencilKit save background image and drawing to Album Xcode

1 Answers1