Flies will fly

flies_will_fly.py

#!/usr/bin/env python

import time
import random
import sys

import pygame
from pygame import gfxdraw
from pygame.time import Clock
from pygame import DOUBLEBUF, HWSURFACE
from pygame.locals import *
from pygame.color import THECOLORS

class Fly:
    def __init__(self, screen, fly_size, velocity, bg_color):
        self.screen = screen
        self.screenwidth, self.screenheight = self.screen.get_size()
        self.fly_height, self.fly_width = fly_size

        # Calculate the max x and y position for our fly,
        # in order for it not to get out of screen
        self.absolute_max_x = self.screenwidth - self.fly_width
        self.absolute_max_y = self.screenheight - self.fly_height
        self.absolute_min_x, self.absolute_min_y = 0, 0

        # minus the fly width/height in order to be able to still
        # place a fly when the max_x/y is very high
        self.min_x = random.randint(self.absolute_min_x, int(self.absolute_max_y * 0.5))
        self.max_x = random.randint(int(self.absolute_max_x * 0.5), self.absolute_max_x)
        self.min_y = random.randint(self.absolute_min_y, int(self.absolute_min_y * 0.5))
        self.max_y = random.randint(int(self.absolute_max_y * 0.5), self.absolute_max_y)

        # Generating a random (inscreen) x and y fly position
        self.x, self.y = self.genRandomPos(self.max_x, self.max_y)

        self.vel_x, self.vel_y = velocity
        self.bg_color = bg_color
        self.fly = pygame.rect.Rect(self.x, self.y,
                                    self.fly_height, self.fly_width)


    def genRandomLimits(self, min_value,
                        max_value, fly_border_size):
        return random.randint(min_value, max_value * fly_border_size)


    def genRandomPos(self, max_x, max_y):
        rand_x = random.randint(0, max_x)
        rand_y = random.randint(0, max_y)

        return rand_x, rand_y


    def clearScreen(self, screen, color, rect):
        pygame.draw.rect(screen, color, rect)

        return

    def updateFlyPosition(self):
        """
        """
        new_x, new_y = self.x + self.vel_x, self.y + self.vel_y

        # If reaching and x border, invert the movement
        # by inverting the velocity
        if new_x >= self.max_x or new_x <= self.min_x:
            self.max_x = random.randint(int(self.absolute_max_x * 0.5), self.absolute_max_x)
            self.min_x = random.randint(self.absolute_min_x, int(self.absolute_max_y * 0.5))
            self.vel_x *= -1
#            print "new min_x: %s ; new max_x : %s\n" % (self.min_x, self.max_x)
        else:
            self.x = new_x

        if new_y >= self.max_y or new_y <= self.min_y:
            self.max_y = random.randint(int(self.absolute_max_y * 0.5), self.absolute_max_y)
            self.min_y = random.randint(self.absolute_min_y, int(self.absolute_min_y * 0.5))
            self.vel_y *= -1
#            print "new min_y: %s ; new max_y : %s\n" % (self.min_y, self.max_y)
        else:
            self.y = new_y

        return new_x, new_y


    def draw(self):
        # Updating position
        new_x, new_y = self.updateFlyPosition()

        # Drawing new fly position
        self.fly = pygame.rect.Rect(new_x, new_y,
                                     self.fly_height, self.fly_width)
        pygame.draw.rect(self.screen, THECOLORS["black"], self.fly)


def main():
    WINSIZE = 160, 120

    pygame.init()
    screen = pygame.display.set_mode(WINSIZE, DOUBLEBUF|HWSURFACE, 16)
    pygame.display.set_caption('Flies from limbes')
    screen.fill(THECOLORS["white"])

    first_fly = Fly(screen, (8, 8), (1, 1),
                    THECOLORS["white"])
    fps = 60
    clock = Clock()

    while 42:
        events = pygame.event.get()
        for e in events:
            if (e.type == QUIT):
                sys.exit()
            elif (e.type == KEYDOWN):
                if (e.key == K_ESCAPE):
                    sys.exit()
                if (e.key == K_f):
                    pygame.display.toggle_fullscreen()

        screen.fill(THECOLORS["white"])
        first_fly.draw()
        pygame.display.flip()
        clock.tick(fps)

    print "Exiting!"

    return

if __name__ == "__main__":
    main()