title: Getting the center of surfaces in pygame with python 3.4
body: <p>I'm having troubles getting the center of surfaces with pygame. It defaults to the upper left corner of surfaces when trying to place them on other surfaces.</p>
  
  <p>To demonstrate what I mean I wrote a short program.</p>
  
  <pre><code>import pygame
  
  WHITE = (255, 255, 255)
  
  pygame.init()
  #creating a test screen
  screen = pygame.display.set_mode((500, 500), pygame.RESIZABLE)
  #creating the canvas
  game_canvas = screen.copy()
  game_canvas.fill(WHITE)
  #drawing the canvas onto screen with coords 50, 50 (tho its using the upper left of game_canvas)
  screen.blit(pygame.transform.scale(game_canvas, (200, 200)), (50, 50))
  pygame.display.flip()
  
  
  #you can ignore this part.. just making the program not freeze on you if you try to run it
  import sys
  
  clock = pygame.time.Clock()
  while True:
      delta_time = clock.tick(60) / 1000
      for event in pygame.event.get():
          if event.type == pygame.QUIT:
              pygame.quit()
              sys.exit()
  </code></pre>
  
  <p>If you run this program it will draw a 200 by 200 white game_canvas on the screen (display) at the coords 50, 50. But instead of using the center of the game_canvas at the coords 50, 50.. the upper left is at 50, 50. </p>
  
  <p>So how do I use the center of the game_canvas to have it place at the coords 50, 50 or any other given coords?</p>