Palm rejection #139

I really like this app for its simplicity! Thanks!

One thing that bugs me when using it on a tablet is that I get a lot of accidental dots and lines when using my s-pen stylus. This happens because my palm touches the screen. While some palm presses get rejected, it seems to me that palm rejection only gets triggered when a really large part of my hand touches the screen.

What would also be excellent is to allow drawing only with input by styluses on devices that have them.