Pygame lab: creating Rectangle class with "draw" & "move" method - pygame

Question

I'm working on a lab 8 on programarcadegames: http://programarcadegames.com/index.php?chapter=lab_classes_and_graphics - and got stuck with move method in a Rectangle class. Will appreciate any hints.
import pygame
black = ( 0, 0, 0)
white = ( 255, 255, 255)
green = ( 0, 255, 0)
red = ( 255, 0, 0)
class Rectangle():
def draw(self, x, y, height, width, screen):
self.x = x
self.y = y
self.height = height
self.width = width
self.screen = screen
pygame.draw.rect(self.screen, white, [self.x, self.y, self.height, self.width])
print "meth draw: x,y", self.x, self.y
def move(self, change_x, change_y):
self.change_x = change_x
self.change_y = change_y
self.x += self.change_x
self.y += self.change_y
if self.x > 300 or self.x < 0:
self.change_x = -self.change_x
if self.y > 300 or self.y < 0:
self.change_y = -self.change_y
print "x,y,s_x,s_y", self.x, self.y, self.change_x, self.change_y # debug
pygame.init()
size = [300,300]
screen = pygame.display.set_mode(size)
pygame.display.set_caption("My Game")
done = False
clock = pygame.time.Clock()
myObject = Rectangle()
# -------- Main Program Loop -----------
while done == False:
# ALL EVENT PROCESSING SHOULD GO BELOW THIS COMMENT
for event in pygame.event.get(): # User did something
if event.type == pygame.QUIT: # If user clicked close
done = True # Flag that we are done so we exit this loop
screen.fill(black)
myObject.draw(100, 100, 50, 50, screen)
myObject.move(10, 10)
pygame.display.flip()
clock.tick(20)
pygame.quit()

Answer 1

You have to change draw() because in every loop you draw retangle in the same place so you can't see result of your move.
class Rectangle:
def __init__(self, x, y, width, height, screen):
self.x = x
self.y = y
self.width = width
self.height = height
self.screen = screen
def draw(self):
pygame.draw.rect(self.screen, white, [self.x, self.y, self.height, self.width])
print "meth draw: x,y", self.x, self.y
def move(self, change_x, change_y):
# rest of your code
# rest of your code
myObject = Rectangle(100, 100, 50, 50, screen)
# rest of your code
myObject.move(10, 10) # move to new place
myObject.draw() # draw in new place

Answer 2

Very good hints furas - especially on order of drawing on screen. I did play a little bit more, set few debugs (prints) and eventually got it sorted. The issue was with "move" method - as each time the screen was drawn - I was resetting "change_x" and "change_y" to values given in method call. Of course that was wrong. What I did is I created extra method "speed" and I'm calling it BEFORE main program loop.
The correct version is listed below. For the sake of clarity I changed "change_x" and "change_y" to "speed_x" and "speed_y".
We may close this topic
import pygame
# Define some colors
black = ( 0, 0, 0)
white = ( 255, 255, 255)
green = ( 0, 255, 0)
red = ( 255, 0, 0)
class Rectangle():
def __init__(self, x, y, width, height):
self.x = x
self.y = y
self.height = height
self.width = width
def speed(self,*speed):
self.speed_x = speed[0]
self.speed_y = speed[1]
def draw(self, screen):
self.screen = screen
pygame.draw.rect(self.screen, white, [self.x, self.y, self.height, self.width])
print "meth draw: x,y", self.x, self.y
def move(self):
print "self.x", self.x
print "self.speed_x:", self.speed_x
self.x += self.speed_x
self.y += self.speed_y
if self.x > 250 or self.x < 0:
self.speed_x = -self.speed_x
if self.y > 250 or self.y < 0:
self.speed_y = -self.speed_y
pygame.init()
# Set the width and height of the screen [width,height]
size = [300,300]
screen = pygame.display.set_mode(size)
pygame.display.set_caption("My Game")
done = False
clock = pygame.time.Clock()
myObject = Rectangle(100, 100, 50, 50,)
myObject.speed(2,4)
# -------- Main Program Loop -----------
while done == False:
for event in pygame.event.get(): # User did something
if event.type == pygame.QUIT: # If user clicked close
done = True # Flag that we are done so we exit this loop
screen.fill(black)
myObject.move()
myObject.draw(screen)
pygame.display.flip()
clock.tick(20)
pygame.quit()