Multiple Background Colors

[jjpantano]

Have you considered allowing more than 1 background color? In the case of digitizing lines between different filled shapes (example below) using a larger mask could be used if I could assign two or more background colors.

Thanks for the this wonderful tool! John

[ankitrohatgi]

If you pick "foreground color" option then any color outside the distance range is assumed to be background. Looks like in this case, just foreground color is not sufficient to easily identify the curve?