title: python pygame blit - mixed pixels - added black rectangle
body: <p>while wrtiing chess engine , i am using blit for drawing the pieces on the board.
  the problem is that it looks very bad , a black rectangle is created and added to the 
  icons of the pieces . it looks like that:</p>
  
  <p><a href="http://i58.tinypic.com/n1fbzc.jpg" rel="nofollow">http://i58.tinypic.com/n1fbzc.jpg</a></p>
  
  <p>but i want it to look like this:</p>
  
  <p><a href="http://i62.tinypic.com/4zutfo.jpg" rel="nofollow">http://i62.tinypic.com/4zutfo.jpg</a></p>
  
  <p>here is the code, the first 2 lines is example for one piece,
  and the rest(the "for") is for drawing all of them:</p>
  
  <pre><code>    white_queen = pygame.image.load(os.path.join("images","wQn.png")).convert()
      self.icons['wQ'] = pygame.transform.scale(white_queen, (self.square_size,self.square_size))
  
      for r in range(boardSize):
          for c in range(boardSize):
              print "r is " + str(r) + ", and c is " + str(c)
              (screenX,screenY) = self.ConvertToScreenCoords((r,c))
              piece_name = board[r][c]
              print "screen x is " + str(screenX) + ", and y is " + str(screenY)
              print "name is " + piece_name
              if piece_name != 'e':
                  self.screen.blit(self.icons[piece_name],(screenX,screenY), special_flags = BLEND_RGBA_MULT)
  
      pygame.display.flip()
  </code></pre>
  
  <p>i guess that i am missing some parameter in calling to blit , or to call another function..</p>
  
  <p>tahnks for your help.</p>