I've got an existing drawing app, the drawing part is very lackluster. I'm excited to use PencilKit and have it working, but the existing markup data a user already has out there i've stored as a PNG with clear background. There's no way to load that into the PKDrawing, so even if i display the existing markup data, it won't be editable by the user if I use PencilKit. They'd be able to add additional markings, but not erase what they've already done. Anyone else have similar issues?