@davidrevoy You scribble where the color should go and Krita fills based on scribbles amd line-art? Does this work where a normal fill (if Krita has that) would not work because of the lineart not being closed perfectly everyhwere? (Sorry for all the questions, never used Krita but interested in it ^__^)
@jfml Hey, with hi-resolution artworks; the lines are rarely all the same color (eg. not all black pixels for lineart) ; they have grayscale, smudge, texture, aliasing and thickness. Also, an effect is to reduce the the line-width until it become suggested. This type of algorythm try to locate the 'best frontier' between the mass of color by analysing the edge. You can see how it behave on this zoom under:
Fill tools would stop where it meets the first pixels and only fill similar colors.
