如何旋转图像而不丢失像素数据？（pygame的）

这里是我的代码（Python的3.5）：如何旋转图像而不丢失像素数据？（pygame的）

import sys 
import pygame 
pygame.init() 

screen_width = 640 
screen_height = 480 
screen = pygame.display.set_mode((screen_width, screen_height)) 
running = True 

class Actor: 

    def __init__(self, x, y, w, h): 
     self.x = x 
     self.y = y 
     self.w = w 
     self.h = h 
     self.surface = pygame.image.load("GFX/player.bmp") 

    def draw(self): 
     screen.blit(self.surface, (self.x, self.y)) 

class Player(Actor): 

    def __init__(self): 
     Actor.__init__(self, 0, 0, 32, 32) 
     self.directions = [False, False, False, False] 
     self.speed = 0.1 

    def update(self): 
     if self.directions[0]: 
      self.y -= self.speed 
     if self.directions[1]: 
      self.y += self.speed 
     if self.directions[2]: 
      self.x -= self.speed 
     if self.directions[3]: 
      self.x += self.speed 

player = Player() 

def rot_center(image, angle): 
    orig_rect = image.get_rect() 
    rot_image = pygame.transform.rotate(image, angle) 
    rot_rect = orig_rect.copy() 
    rot_rect.center = rot_image.get_rect().center 
    rot_image = rot_image.subsurface(rot_rect).copy() 
    return rot_image 

def redraw(): 
    screen.fill((75, 0, 0)) 
    player.draw() 
    player.update() 
    pygame.display.flip() 

while (running): 
    for e in pygame.event.get(): 
     if e.type == pygame.QUIT: 
      sys.exit() 
     elif e.type == pygame.KEYDOWN: 
      if e.key == pygame.K_ESCAPE: 
       sys.exit() 
      if e.key == pygame.K_w: 
       player.directions[0] = True 
      if e.key == pygame.K_s: 
       player.directions[1] = True 
      if e.key == pygame.K_a: 
       player.directions[2] = True 
      if e.key == pygame.K_d: 
       player.directions[3] = True 
     elif e.type == pygame.KEYUP: 
      if e.key == pygame.K_w: 
       player.directions[0] = False 
      if e.key == pygame.K_s: 
       player.directions[1] = False 
      if e.key == pygame.K_a: 
       player.directions[2] = False 
      if e.key == pygame.K_d: 
       player.directions[3] = False 
     elif e.type == pygame.MOUSEMOTION: 
      player.surface = rot_center(player.surface, pygame.mouse.get_pos()[0]/64) 

    redraw()

非常简单的pygame的代码。我有一个用mspaint创建的简单图像的播放器，我用this function来旋转图像而不会导致内存不足的问题。我用鼠标旋转图像（考虑到某个玩家“瞄准”某个地方）。这里的原始图像：