我已将 PencilKit 集成到我的 SwftUI Photo 应用程序中，但我无法在所附屏幕截图中看到的图像上绘图。背景图像称为 selectedImage 并在 CanvasView 结构内触发
我在打开此屏幕的按钮中调用了 showPencilPanel 和 CanvasIsVisible：
// Draw
ZStack {
Button(action: {
doIWantThisViewToShow.toggle()
self.showPencilPanel = true
canvasIsVisible.toggle()
print("draw")
}) {
ZStack {
Spacer()
Image("Draw Btn").resizable().renderingMode(.original)
.frame(width: 22, height: 22)
.offset(y: -30)
Text("Draw").font(.system(size: 10.0)).foregroundColor(.black)
Spacer()
.offset(y: 0)
}
}}
.frame(minWidth: 0, maxWidth: .infinity)
.contentShape(Rectangle())
if canvasIsVisible {
CanvasView(canvasView: $canvasView,
toolPickerIsActive: $toolPickerIsActive, hideToolButtons: $hideToolButtons, selectedImage: $selectedImage,
onChange: canvasDidChange)
.onAppear { toolPickerIsActive = true
}
.onDisappear { toolPickerIsActive = false }
}
当 showPencilPanel 可见时，它显示：
ZStack (alignment: .center) {
//Show Pencil
if self.showPencilPanel {
HStack {
Button(action: {
self.blackOpacity = true
canvasIsVisible.toggle()
toolPickerIsActive = false
doIWantThisViewToShow.toggle()
self.showPencilPanel = false
self.navOpen = true
// self.hideToolButtons = true
print("Cancel")
})
{
Text("Cancel").font(.system(size: 16.0)).foregroundColor(.gray)
}
.frame(minWidth: 70)
// Spacer().frame(maxWidth:.infinity)
Button(action: {
self.blackOpacity = true
canvasIsVisible.toggle()
toolPickerIsActive = false
doIWantThisViewToShow.toggle()
self.showPencilPanel = false
// self.hideToolButtons = true
self.navOpen = true
print("Done")
}) {
Text("Done").font(.system(size: 16.0)).foregroundColor(.blue)
}
// Spacer()
.frame(minWidth: 70)
}
.position(x: -40, y: 25)
// .frame(minWidth: 100, maxHeight: 25)
}
当 CanvasIsVisible 它显示：
struct CanvasView: UIViewRepresentable {
class Coordinator: NSObject, PKCanvasViewDelegate {
var canvasView: Binding<PKCanvasView>
let onChange: () -> Void
private let toolPicker: PKToolPicker
deinit { // << here !!
toolPicker.setVisible(false, forFirstResponder: canvasView.wrappedValue)
toolPicker.removeObserver(canvasView.wrappedValue)
}
init(canvasView: Binding<PKCanvasView>, toolPicker: PKToolPicker, onChange: @escaping () -> Void) {
self.canvasView = canvasView
self.onChange = onChange
self.toolPicker = toolPicker
}
func canvasViewDrawingDidChange(_ canvasView: PKCanvasView) {
if canvasView.drawing.bounds.isEmpty == false {
onChange()
}
}
}
@Binding var canvasView: PKCanvasView
@Binding var toolPickerIsActive: Bool
@Binding var hideToolButtons: Bool
private let toolPicker = PKToolPicker()
@Binding var selectedImage: UIImage
let onChange: () -> Void
func makeUIView(context: Context) -> PKCanvasView {
canvasView.isOpaque = false
canvasView.backgroundColor = .clear
canvasView.delegate = context.coordinator
canvasView.becomeFirstResponder()
showToolPicker()
let imageView = UIImageView(image: self.selectedImage)
imageView.contentMode = .scaleAspectFill
imageView.clipsToBounds = true
let contentView = canvasView.subviews[0]
contentView.addSubview(imageView)
contentView.sendSubviewToBack(imageView)
return canvasView
}
func updateUIView(_ uiView: PKCanvasView, context: Context) {
toolPicker.setVisible(toolPickerIsActive, forFirstResponder: uiView)
}
func showToolPicker() {
toolPicker.setVisible(true, forFirstResponder: canvasView)
toolPicker.addObserver(canvasView)
canvasView.becomeFirstResponder()
}
func makeCoordinator() -> Coordinator {
Coordinator(canvasView: $canvasView, toolPicker: toolPicker, onChange: onChange)
}
}