Commodity price simulator

price_pygame.py

# Commodity price simulator
#
# pip install pygame
# pip install matplotlib

import random
import pygame
import matplotlib
matplotlib.use("Agg")

from matplotlib import pyplot
from matplotlib.backends import backend_agg

# Important constants
PRICE = 100.0
LOW, HIGH = 75, 140
mu = 0.0
sigma = 2.0

# most monitors are 96 dpi so calculate size in inches
fig = pyplot.figure(figsize=[1024 / 96, 768 / 96], dpi=96)
ax = fig.add_subplot(111)
canvas = backend_agg.FigureCanvasAgg(fig)


def plot_data(data):
    ax.cla()
    ax.plot(data, color="black")
    ax.set_ylim(75, 140)
    canvas.draw()
    renderer = canvas.get_renderer()

    raw_data = renderer.tostring_rgb()
    size = canvas.get_width_height()

    return pygame.image.fromstring(raw_data, size, "RGB")


screen = pygame.display.set_mode((1024, 768))
clock = pygame.time.Clock()

nums = []

price = PRICE
target_period = random.randint(5, 15)
delta_price = random.gauss(mu, sigma) / target_period

for i in range(500):
    price += delta_price
    target_period -= 1
    if not target_period:
        target_period = random.randint(5, 15)
        delta_price = random.gauss(mu, sigma) / target_period
    if price < LOW:
        delta_price *= -1.0
        price += delta_price
    if price > HIGH:
        delta_price *= -1.0
        price += delta_price

    nums.append(price)

# Warm up clock
for _ in range(10):
    clock.tick(60)

update_clock = 0.25
running = True
while running:
    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            running = False

    dt = clock.tick(60) / 1000.0

    update_clock -= dt
    if update_clock <= 0.0:
        update_clock = 0.25
        price += delta_price
        target_period -= 1
        if not target_period:
            target_period = random.randint(5, 15)
            delta_price = random.gauss(mu, sigma) / target_period
        if price < LOW:
            delta_price *= -1.0
            price += delta_price
        if price > HIGH:
            delta_price *= -1.0
            price += delta_price

        nums.pop(0)
        nums.append(price)


    screen.fill((0, 0, 0))

    screen.blit(plot_data(nums), (0, 0))
    pygame.display.flip()

# Be nice...
pygame.quit()