Populate undo stack when loading a drawing?

[junsolOh]

In the demo, I tried to undo after reload. But undo doesn't work. What is the reason?

[stevelandeyasana]

The reason is there's a bug. :-) Unfortunately it's unlikely I'll have time to fix it.

[stevelandeyasana]

Oh, I think I understand better now. This might not actually be a bug.

The 'reload' feature is meant to test serialization. When you load a drawing, the user hasn't taken any action yet, so there's nothing to undo.

Unmarking this as a bug and retitling to capture the issue more clearly. I'm not sure we actually want to change this.

[ysvganesh]

It's working when I reassign operationStack delegate & buttons actions

  ......
  drawingView.drawing = try! JSONDecoder().decode(Drawing.self, from: drawingData)

  drawingView.operationStack.delegate = self
      
  undoButton.addTarget(drawingView.operationStack, action: #selector(DrawingOperationStack.undo), for: .touchUpInside)
  redoButton.addTarget(drawingView.operationStack, action: #selector(DrawingOperationStack.redo), for: .touchUpInside)

Reason to failed undo stack after reload

public var drawing: Drawing = Drawing(size: CGSize(width: 320, height: 320)) {
    didSet {
      tool?.deactivate(context: self.toolOperationContext)
      operationStack = DrawingOperationStack(drawing: drawing) // New Object will assign
     .........
  }

Hope this will help.