Lanefan
Victoria Rules
Preamble: what I know about roll20 could fit in a thimble with space left over - I use it only because I've no other choice if I want to stay in the game I play in, and only as a player - so if this is a dumb question I apologize in advance; please humour me. 
So, for you roll20 experts out there:
In roll20 there's a 'draw' function where you can use your mouse to draw lines or freehand or shapes onto the map, and everyone can see what you've drawn.
My question is, what has to be done (or is it even possible) to have that input come from a touchscreen rather than a mouse? Drawing with a finger (or a stylus) on a screen is both much easier and immensely more accurate - not to mention considerably faster - than trying to draw with a mouse, thus my interest in doing it that way. I just tried this, however, using my touchscreen windows PC, and it doesn't seem to work.
Why am I asking? If one can accurately draw on the screen then the DM doesn't have to futz around uploading maps etc.; he can just upload a blank grid once and then draw on it the same way we use the chalkboard when playing face-to-face, meaning he's not caught scrambling if we-the-players pull a left turn on him and go somewhere he hasn't uploaded or prepped maps for.

So, for you roll20 experts out there:
In roll20 there's a 'draw' function where you can use your mouse to draw lines or freehand or shapes onto the map, and everyone can see what you've drawn.
My question is, what has to be done (or is it even possible) to have that input come from a touchscreen rather than a mouse? Drawing with a finger (or a stylus) on a screen is both much easier and immensely more accurate - not to mention considerably faster - than trying to draw with a mouse, thus my interest in doing it that way. I just tried this, however, using my touchscreen windows PC, and it doesn't seem to work.
Why am I asking? If one can accurately draw on the screen then the DM doesn't have to futz around uploading maps etc.; he can just upload a blank grid once and then draw on it the same way we use the chalkboard when playing face-to-face, meaning he's not caught scrambling if we-the-players pull a left turn on him and go somewhere he hasn't uploaded or prepped maps for.