[Tutor] my first pygame experiment

[Danny Yoo]

Hi everyone,

I'm finally starting to play around with pygame, and I really think it
looks great!  I thought it might be fun to show my first silly pygame
program:



###
"""A simple hypnotic pulsing screen.  Uses Python 2.2 generators.

Danny Yoo (dyoo@hkn.eecs.berkeley.edu)
"""

from __future__ import generators
import pygame
from pygame.locals import *
from random import randrange
import sys


def strobeIter(n, step=1, start=0):
    """Returns a "strobing" iterator.  This iterator bounces between
    the values [0, n].  Think KIT's red strobing light."""
    x = start
    direction = 1
    delta = step*direction
    while 1:
        yield x
        x = clamp(x+delta, 0, n)
        if x in (0, n):
            direction = direction * -1
            delta = step * direction


def clamp(x, low, high):
    """Clamps down x within the range: [low, high]."""
    return max(low, min(x, high))



def handleQuit():
    for event in pygame.event.get():
        if event.type is QUIT:
            sys.exit(0)
        elif event.type is KEYDOWN and event.key is K_ESCAPE:
            sys.exit(0)
        

if __name__ == '__main__':
    (r, g, b) = (strobeIter(255, randrange(1, 10)),
                 strobeIter(255, randrange(1, 10)),
                 strobeIter(255, randrange(1, 10)))
    display = pygame.display.set_mode((300, 300))
    while 1:
        handleQuit()
        bgcolor = r.next(), g.next(), b.next()
        display.fill(bgcolor)
        pygame.display.flip()
###