learning_generative_art.py

### Mostly taken from this blog post
# http://superfluoussextant.com/circlepusher.html

import random
from PIL import Image, ImageDraw
import math

class Circle:
    def __init__(self, radius, location, color):
        """
        :param radius: radius of circle in pixels
        :param location: two tuple of x,y
        """
        self.radius = radius
        self.location = location
        self.angle = random.randint(0, 360)
        self.curve = random.randint(-45, 45)/100
        self.active = True
        self.color = color

    @property
    def x(self):
        return self.location[0]

    @property
    def y(self):
        return self.location[1]

    def draw(self):
        if not self.active:
            return
        image_draw.ellipse((self.x - self.radius,
                            self.y - self.radius,
                            self.x + self.radius,
                            self.y + self.radius), 
                           fill=self.color)

    def push(self):
        if not self.active:
            return

        if self.should_make_baby():
            circles.append(self.make_baby())

        # Let's step by 1/4 of the radius each time
        step = self.radius / 4
        rad_angle = math.radians(self.angle)
        next_step = (self.x + step*math.cos(rad_angle),
                     self.y + step*math.sin(rad_angle))
        # Stepping by 1/4 of the radius will put us still inside our current radius, so let's look a bit further ahead
        big_step = (self.x + self.radius*2*math.cos(rad_angle),
                    self.y + self.radius*2*math.sin(rad_angle))
        if self.within_bounds(next_step) and self.free_spot(big_step):
#         if self.within_bounds(next_step):    
            self.location = next_step
        else:
            self.active = False
            if self in circles:
                circles.remove(self)

        self.angle = (self.angle + self.curve) % 360

    @staticmethod
    def within_bounds(location):
        if location[0] < 0 or location[0] > image_bounds[0] or location[1] < 0 or location[1] > image_bounds[1]:
            return False
        return True

    def free_spot(self, spot):
        # Simply check the canvas to see if the passed spot is white
        return self.within_bounds(spot) and image.getpixel(spot) == (0,0,0)
    
    @staticmethod
    def should_make_baby():
        # 1/50 chance to make a baby
        return not random.randint(0, 15)

    def make_baby(self):
        return Circle(self.radius*.75, self.location, self.color)
      
image_bounds = (600, 600)
image = Image.new('RGB', image_bounds, 'black')
image_draw = ImageDraw.Draw(image)
circles = []

for _ in range(13):
    circles.append(Circle(random.randint(2,8), 
                          (random.randint(0, image_bounds[0]),
                           random.randint(0, image_bounds[1])), 
                         (random.randint(0,255),
                          random.randint(0,255),
                          random.randint(0,255))))

for _ in range(1000):
    for circle in circles:
        circle.draw()
        circle.push()

image.save('img/01.png')
image.show()