I'm thinking about buying an iPad mini or Nexus 7 to draw, but I'm worried about the rather small screen size being limitation. One question in particular - Is it like the screen size has to be the canvas size, always? Or can you, in the middle of drawing, drag your finger on the screen and keep making the canvas larger horizontally, vertically & diagonally, essentially making the canvas size infinite? I'd like to be able to do that when I realize I needed bigger canvas after I started drawing. (like in Photoshop) Cuz if not, then I might be better off getting the larger iPad. Or is this dependent on the app? Then which apps allow you to do this? And can you do it on any tablet that the app is compatible to? Sorry I hope I'm explaining this right.