我如何可以改变一个矩形

我用一个功能Rabbid76. 这个函数，我可以旋转矩形。 矩形获得大小的图像。我想的大小来改变形所以那是比较小的图像。 我尝试与不断变化的左上和topright. 这击的工作。

import pygame

pygame.init()
screen = pygame.display.set_mode((400, 400))
font = pygame.font.SysFont(None, 50)
clock = pygame.time.Clock()

#orig_image = font.render("rotated rectangle", True, (255, 0, 0))
angle =0
orig_image = pygame.image.load("Bilder/baum2.png")
rotated_image = pygame.transform.rotate(orig_image, angle)

def draw_rect_angle(surf, rect, pivot, angle):   
    rect.topleft = (rect.topleft[0] +25 , rect.topleft[1])
    rect.topright = (rect.topright[0] -25, rect.topright[1])    
    pts = [rect.topleft, rect.topright, rect.bottomright, rect.bottomleft]
    pts = [(pygame.math.Vector2(p) - pivot).rotate(-angle) + pivot for p in pts]
    pygame.draw.lines(surf, (255, 255, 0), True, pts, 3)

run = True
while run:
    clock.tick(60)
    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            run = False    

    screen.fill(0)
    screen_center = screen.get_rect().center
    screen.blit(rotated_image, rotated_image.get_rect(center = screen_center))
    rect = orig_image.get_rect(center = screen_center)
    draw_rect_angle(screen, rect, screen_center, angle)
    pygame.display.flip()

pygame.quit()
exit()