Create o3_iOS_PencilKitDrawing.swift

Author: amosgyamfi

AI/VibeCoding/iOS_visionOS_Drawing/o3_iOS_PencilKitDrawing.swift

@@ -0,0 +1,206 @@
+//
+//  o3PencilKitDrawing.swift
+//  CoreSwiftUI
+//
+//  Created by Amos Gyamfi on 19.4.2025.
+//
+
+import SwiftUI
+import PencilKit
+import UIKit
+
+struct o3PencilKitDrawing: View {
+    @State private var canvasView = PKCanvasView()
+    @State private var toolPicker = PKToolPicker()
+    @State private var importedImage: UIImage? = nil
+    @State private var showingImagePicker = false
+    @State private var pdfURL: URL? = nil
+    
+    var body: some View {
+        NavigationStack {
+            ZStack {
+                if let importedImage = importedImage {
+                    Image(uiImage: importedImage)
+                        .resizable()
+                        .scaledToFit()
+                        .clipped()
+                }
+
+                CanvasRepresentable(canvasView: $canvasView, toolPicker: $toolPicker)
+                    .onAppear {
+                        toolPicker.setVisible(true, forFirstResponder: canvasView)
+                        toolPicker.addObserver(canvasView)
+                        canvasView.becomeFirstResponder()
+                    }
+            }
+            .navigationTitle("o3Draw")
+            .navigationBarTitleDisplayMode(.inline)
+            .sheet(isPresented: $showingImagePicker) {
+                ImagePicker(image: $importedImage)
+            }
+            .sheet(item: $pdfURL) { url in
+                ActivityView(activityItems: [url])
+            }
+            .toolbar {
+                ToolbarItem(placement: .navigationBarLeading) {
+                    Button {
+                        exportDrawingAsPDF()
+                    } label: {
+                        Image(systemName: "square.and.arrow.up")
+                    }
+                }
+                ToolbarItemGroup(placement: .navigationBarTrailing) {
+                    Button {
+                        showingImagePicker = true
+                    } label: {
+                        Image(systemName: "photo.badge.plus")
+                    }
+                    Menu {
+                        Button {
+                            // Save the current drawing to Photos
+                            saveToPhotos()
+                        } label: {
+                            Label("Save", systemImage: "square.and.arrow.down")
+                        }
+
+                        Button {
+                            // Undo the last stroke
+                            canvasView.undoManager?.undo()
+                        } label: {
+                            Label("Undo", systemImage: "arrow.uturn.backward")
+                        }
+
+                        Button {
+                            // Redo the last undone stroke
+                            canvasView.undoManager?.redo()
+                        } label: {
+                            Label("Redo", systemImage: "arrow.uturn.forward")
+                        }
+
+                        Button {
+                            // Clear the current drawing
+                            canvasView.drawing = PKDrawing()
+                        } label: {
+                            Label("Clear", systemImage: "trash")
+                        }
+                    } label: {
+                        Image(systemName: "ellipsis.circle.fill")
+                    }
+                }
+            }
+         }
+    }
+
+    // Save the current drawing to the Photos album
+    private func saveToPhotos() {
+        let image = canvasView.drawing.image(from: canvasView.bounds, scale: UIScreen.main.scale)
+        UIImageWriteToSavedPhotosAlbum(image, nil, nil, nil)
+    }
+
+    // Export the current composition (background image + drawing) as a single‑page PDF
+    private func exportDrawingAsPDF() {
+        let bounds = canvasView.bounds
+        let renderer = UIGraphicsPDFRenderer(bounds: bounds)
+        
+        let data = renderer.pdfData { ctx in
+            ctx.beginPage()
+            
+            // Draw imported background image first, if any
+            if let importedImage = importedImage {
+                importedImage.draw(in: bounds)
+            }
+            
+            // Draw the PencilKit strokes on top
+            let drawingImage = canvasView.drawing.image(from: bounds, scale: UIScreen.main.scale)
+            drawingImage.draw(in: bounds)
+        }
+        
+        // Write to a temporary file so we can share a URL
+        let tempURL = FileManager.default.temporaryDirectory.appendingPathComponent("o3Drawing.pdf")
+        do {
+            try data.write(to: tempURL)
+            DispatchQueue.main.async {
+                pdfURL = tempURL
+            }
+        } catch {
+            print("Failed to write PDF: \(error)")
+        }
+    }
+}
+
+struct CanvasRepresentable: UIViewRepresentable {
+    @Binding var canvasView: PKCanvasView
+    @Binding var toolPicker: PKToolPicker
+    
+    func makeUIView(context: Context) -> PKCanvasView {
+        canvasView.drawingPolicy = .anyInput
+        canvasView.alwaysBounceVertical = false
+        canvasView.backgroundColor = .clear
+        canvasView.isOpaque = false
+        return canvasView
+    }
+    
+    func updateUIView(_ uiView: PKCanvasView, context: Context) {
+        // No dynamic updates needed for the static canvas
+    }
+}
+
+struct ImagePicker: UIViewControllerRepresentable {
+    @Environment(\.presentationMode) private var presentationMode
+    @Binding var image: UIImage?
+    
+    func makeCoordinator() -> Coordinator {
+        Coordinator(self)
+    }
+    
+    class Coordinator: NSObject, UINavigationControllerDelegate, UIImagePickerControllerDelegate {
+        let parent: ImagePicker
+        
+        init(_ parent: ImagePicker) {
+            self.parent = parent
+        }
+        
+        func imagePickerController(_ picker: UIImagePickerController,
+                                   didFinishPickingMediaWithInfo info: [UIImagePickerController.InfoKey : Any]) {
+            if let edited = info[.editedImage] as? UIImage {
+                parent.image = edited
+            } else if let original = info[.originalImage] as? UIImage {
+                parent.image = original
+            }
+            parent.presentationMode.wrappedValue.dismiss()
+        }
+        
+        func imagePickerControllerDidCancel(_ picker: UIImagePickerController) {
+            parent.presentationMode.wrappedValue.dismiss()
+        }
+    }
+    
+    func makeUIViewController(context: Context) -> UIImagePickerController {
+        let picker = UIImagePickerController()
+        picker.sourceType = .photoLibrary
+        picker.allowsEditing = true // enables built‑in cropping UI
+        picker.delegate = context.coordinator
+        return picker
+    }
+    
+    func updateUIViewController(_ uiViewController: UIImagePickerController, context: Context) { }
+}
+
+struct ActivityView: UIViewControllerRepresentable {
+    let activityItems: [Any]
+    let applicationActivities: [UIActivity]? = nil
+    
+    func makeUIViewController(context: Context) -> UIActivityViewController {
+        UIActivityViewController(activityItems: activityItems, applicationActivities: applicationActivities)
+    }
+    
+    func updateUIViewController(_ uiViewController: UIActivityViewController, context: Context) { }
+}
+
+extension URL: Identifiable {
+    public var id: String { absoluteString }
+}
+
+#Preview {
+    o3PencilKitDrawing()
+}