Voronoi Fun

bic

I'm translating some existing codes to Drawbot to generate custom Voronoi SVG, and am looking for suggestions. I'm starting with bezier paths or polygons. What would you use? (Don't give away the answer yet! I may still ask for more help later in the week.)

bic

Ok, maybe I need a bit more assistance. Not sure how the PIL library codes can be translated to drawbot's methods of creating images.
https://rosettacode.org/wiki/Voronoi_diagram#Python

This the the sample code I'm trying to translate to Drawbot:

from PIL import Image
import random
import math
 
def generate_voronoi_diagram(width, height, num_cells):
	image = Image.new("RGB", (width, height))
	putpixel = image.putpixel
	imgx, imgy = image.size
	nx = []
	ny = []
	nr = []
	ng = []
	nb = []
	for i in range(num_cells):
		nx.append(random.randrange(imgx))
		ny.append(random.randrange(imgy))
		nr.append(random.randrange(256))
		ng.append(random.randrange(256))
		nb.append(random.randrange(256))
	for y in range(imgy):
		for x in range(imgx):
			dmin = math.hypot(imgx-1, imgy-1)
			j = -1
			for i in range(num_cells):
				d = math.hypot(nx[i]-x, ny[i]-y)
				if d < dmin:
					dmin = d
					j = i
			putpixel((x, y), (nr[j], ng[j], nb[j]))
	image.save("VoronoiDiagram.png", "PNG")
        image.show()
 
generate_voronoi_diagram(500, 500, 25)

gferreira

hello @bic,

the PIL example in your second post creates a Voronoi diagram as a raster image. in DrawBot, raster images can be created from scratch using ImageObject.

don’t forget that color coordinates in DrawBot are expressed as floats between 0.0 and 1.0, not as integers between 0 and 255 like in PIL. (so you’ll need to use random() instead of randrange(256) to generate the RGB color values)

it works give it a try!

bic

@gferreira Thanks! I was actually trying to generate a custom sized eps. Maybe this is the wrong approach. Matplotlib generates something similar very easily with the scipy.spatial libary...but ugly....

gferreira

Voronoi is a lot of fun indeed. I gave scipy.spatial.Voronoi a try, and got it to work (sort of; some polygons are missing):

# based on http://stackoverflow.com/questions/27548363/from-voronoi-tessellation-to-shapely-polygons

from random import randrange
from scipy.spatial import Voronoi

size(600, 300)

pointsAmount = 160
points = [(randrange(width()), randrange(height())) for i in range(pointsAmount)]

V = Voronoi(points)
regions = [V.vertices[line] for line in V.regions if -1 not in line]

stroke(1)
strokeWidth(2)
for R in regions:
    pts = [(float(x), float(y)) for x, y in R]
    if len(pts):
        fill(random(), random(), 0.7, 0.7)
        polygon(*pts)

r = 1
stroke(None)
fill(0)
for x, y in points:
    oval(x-r, y-r, r*2, r*2)

saveImage('voronoi-drawbot-2.png')

and here is the bitmap version ported from PIL

happy voronoiing!