How do I make touch painting game?

Hi!

I want to make a game, where the mechanik is:

- there is a colorless shape

- when the player dragging his finger inside the form, is it painted with the pre-selected color?

Any idea where to start?

I have a demo but it's not very good:

howtoconstructdemos.com/using-flood-fill-for-drawing-canvas-to-make-a-coloring-game

dop2000 thanx a lot! Will check and report back :)