Line generation

genline.py

#!/usr/bin/env python

# Code for https://blogs.bencrowder.net/cg/2012/line-art-experiments/
# Uses PIL (pip install pillow)

import random, math
from PIL import Image, ImageDraw

image_size = 4800

num_lines = 80 
line_size = 2

start_angle = 2.094
angle_diff = 0.08
max_angle = start_angle + angle_diff
min_angle = start_angle - angle_diff

change_chance = 10

class Line:
	x = 0
	y = 0
	angle = 0
	canvas = None

	type = 0		      # 0 = top, 1 = right

	start_loc = 0		  # where we're starting (x or y, depends on type)
	target_loc = 0		  # the target

	def __init__(self, canvas, type, start_loc, target_loc):
		self.canvas = canvas
		self.type = type
		self.start_loc = start_loc
		self.target_loc = target_loc

		if self.type == 0: # top
			self.x = self.start_loc
			self.y = 0
		elif self.type == 1: # right
			self.x = image_size
			self.y = self.start_loc

		self.angle = start_angle + random.random() * angle_diff

	def update(self):
		# Only change angles once in a while
		change_angle = random.randint(0, change_chance)
		if change_angle == 0:
			# Modify the angle
			self.angle += (random.random() * angle_diff) - (angle_diff / 2)

		# Cap the angle
		if self.angle > max_angle:
			self.angle = max_angle
		if self.angle < min_angle:
			self.angle = min_angle

		# Move the location by the angle
		self.x = 1 * math.cos(self.angle) + self.x
		self.y = 1 * math.sin(self.angle) + self.y


	def draw(self):
		x1 = self.x - (line_size / 2)
		x2 = self.x + (line_size / 2)
		y1 = self.y - (line_size / 2)
		y2 = self.y + (line_size / 2)
		
		self.canvas.ellipse((x1, y1, x2, y2), fill="black")
	
	def run(self):
		if self.type == 0: # top
			while (self.x > 0):
				self.update()
				self.draw()
		elif self.type == 1: # right
			while (self.y < image_size):
				self.update()
				self.draw()


# Create the image
img = Image.new('RGB', (image_size, image_size), (255, 255, 255))
canvas = ImageDraw.Draw(img)

# Initialize the lines
top_line_locs = []
right_line_locs = []
for i in range(0, num_lines):
	top_line_locs.append(random.random() * image_size)

	if i < num_lines / 2:
		right_line_locs.append(random.random() * image_size)

top_line_locs.sort()
right_line_locs.sort()

# Now create each line, setting its target appropriately
top_lines = []
right_lines = []
for i in range(0, num_lines):
	# For the top, set the target to the equivalent right_lines[]
	top_lines.append(Line(canvas, 0, top_line_locs[i], 5))

	# For the right, set the target to the equivalent top_lines[]
	if i < num_lines / 2:
		right_lines.append(Line(canvas, 1, right_line_locs[i], top_line_locs[i]))

# Now go through the image and draw
for line in top_lines:
	line.run()

for line in right_lines:
	line.run()

img.save("output.png", "PNG")