How do I make this coloring book effect work

Hey guys, so this is a question I'm trying to figure out that i'm sure will help a lot of you who want to make a coloring book. So from all the tutorials and videos I watched... I can get all the way from selecting a picture to color, pic pencil and size of pencil to use, all the way to actually coloring the pictures. The biggest issue I and a few others are trying to figure out is how do you keep the colors to stay inside the area you are coloring in just like in this game? Any ideas would be greatly appreciated by me and many others, thanks!!!

http://kizi.com/coloring_pages/dynamons-03

Hello,

You should start by looking for the Canvas or Paster plugins to draw something directly. The brushes could be a sprite with brush shapes as animations that you can switch and scale for size. To have different colored zones like your example, you could split a drawing in parts checking for overlapping with mouse,

Do you find a solution?