'''
Display the window with BLACK color initally.
When KKEYDOWN, change color to RED.
When KEYUP, change color to GREEN
When MOUSEBOTTONDOWN, change color BLUE
by Ching-Shoei Chiang
'''
import pygame, sys
from pygame.locals import *

#          (R,G,B)
BLACK    = (0,0,0)          # Three 0
RED      = (255,0,0)        # Two 0
GREEN    = (0,255,0)
BLUE     = (0,0,255)
CYAN     = (0,255,255)      # One 0
MAGENTA  = (255,0,255)
YELLOW   = (255,255,0)
WHITE    = (255, 255, 255)  # Three 255

pygame.init()
wcolor = BLACK
screen = pygame.display.set_mode((800, 800))
pygame.display.set_caption("Professor Chiang's Game")

r = 0

# Setting the main program loop
while True:
    # Main event loop
    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            pygame.quit()
            sys.exit()
        elif event.type == pygame.MOUSEBUTTONDOWN:
            if r == 0:
                r = 255
            else:
                r = 0
# draw rectangle
    pygame.draw.rect(screen, (r,0,0), (0,0,400,400))
    pygame.draw.rect(screen, (r,255,0), (400,0,400,400))
    pygame.draw.rect(screen, (r,0,255), (0,400,400,400))
    pygame.draw.rect(screen, (r,255,255), (400,400,400,400))

    pygame.display.update()