GIMPphototolineart

2018年8月28日 — Outline the Picture. Click GIMP's File menu and the Open option to open the photo you want to use to create line art. · Posterize the Image.

Small trick to get to black-on-transparent. Invert the Sobel edge detect (you did keep a copy, right?) with Layer -> Colors -> Invert and apply our highpass- ...