Drag image when is zoomed in

[ioanmeri]

I would like to zoom in/out not only with scroll but with 2 buttons (+, -) as well. But in this case, canvas should be able to be dragged in all directions so we can navigate into the image. Is there a way to support this functionality ?

[NurbekGithub]

@ioanmeri I made a pr with this functionality. You can always use this fork;