Stippling with sizes from merged dots after CAH

Do the merging based on the CAH and redraw the stipples based on the sizes of the merged dots.

Problems:

1) Not follow the edges well. Might be improved by adjusting the center position when redrawing.

2) Tone is not good, either.

Good:

1) It seems it is promising if we can find a good selection from CAH

(A)

Do not draw the small stipples.

(B)

All of stipples