Thanks for your quick reply, clement. I have tried the Vectorize plug-in, it is quite nice, but seems it is doing the similar thing as Rooster did… It is also tracing the color boundary. I am curious if it can be set to trace the hand sketch as single lines, rather than double lines.
Or maybe it is right to trace the color boundary for the first step, but need another magic to turn the boundary to be single lines/curves?
