langton ant example using kivy

langton.py

from threading import Thread
import numpy as np
from time import sleep

from kivy.app import App
from kivy.graphics.texture import Texture
from kivy.lang import Builder
from kivy.clock import Clock
from kivy.properties import ObjectProperty
from kivy.core.window import Window

SIZE = 1000, 1000


KV = '''
ScatterPlane:
    Widget:
        id: world
        size_hint: None, None
        size: {SIZE}
        pos_hint: {{'center': (.5, .5)}}
        canvas:
            Line:
                rectangle: self.pos + self.size
            Rectangle:
                pos: self.pos
                size: self.size
                texture: app.texture

'''.format(**locals())


world = np.array(
    [0. for i in range(SIZE[0] * SIZE[1])],
    dtype=np.float32,
)


def compute_langton():
    x, y = SIZE[0] // 2, SIZE[1] // 2
    direction = 0
    # 0 = left, 1 = down, 2 = right, 3 = up
    while True:
        # sleep(.0001)
        XY = y * SIZE[0] + x
        val = world[XY]
        direction += 1 if val else -1
        direction %= 4
        world[XY] = 1 - val
        x += (direction - 1) if not direction % 2 else 0
        y += (direction - 2) if direction % 2 else 0
        x %= SIZE[0]
        y %= SIZE[1]


class Langton(App):
    texture = ObjectProperty()

    def build(self):
        Clock.schedule_interval(self.refresh, 0)
        self.texture = Texture.create(size=SIZE, colorfmt='luminance')
        self.texture.min_filter = 'nearest'
        self.texture.mag_filter = 'nearest'
        compute = Thread(target=compute_langton)
        compute.daemon = True
        compute.start()
        return Builder.load_string(KV)

    def refresh(self, dt):
        self.texture.blit_buffer(world, colorfmt='luminance', bufferfmt='float')
        self.root.ids.world.canvas.flag_update()


if __name__ == '__main__':
    Langton().run()