pygame随着时间的推移旋转图像

Question

I am trying to use a class to make an image spin over time after it has been created but I keep getting an error:

"pygame.error: Width or height is too large".

game_display=pygame.display.set_mode((display_width,display_height))
    display_rect=game_display.get_rect()
    forest_img=pygame.image.load("forest.jpg")
    game_display.blit(forest_img,(0,0)
    kunai=pygame.image.load("Kunai.png")
    kunai=pygame.transform.scale(kunai, (13,55))
    kunai_rect=kunai.get_rect(center=display_rect.center)
    angle = 0
    done = False

    global done
    global kunai
    global angle
    global kunai_rect

    class Knife():
        def __init__(self, vx):
            self.x=display_width//2+30
            self.y=int(ground+65)
            self.vx=vx
        def update(self):
            self.x+=self.vx

        def draw(self):
            global done
            global kunai
            global angle
            global kunai_rect

            while not done:
                kunai=pygame.transform.rotate(kunai, angle)
                kunai_rect=kunai.get_rect(center=kunai_rect.center)
                game_display.blit(kunai, kunai_rect)
                clock.tick(60)
                angle+=1

    knifes=[]
    while True:
        for event in pygame.event.get():
            if event.type==pygame.KEYDOWN:
               if event.key == pygame.K_SPACE:
                    knifes.append(Knife(20))
        for knife in knifes:
            knife.draw()
            knife.update()

Could someone help me? Thanks.

Answer 1

The surface that you rotate, kunai is a global variable. When it has been rotated, it will be stored into the same variable again:

kunai=pygame.transform.rotate(kunai, angle)

Each time you rotate a surface it will become larger. You can imagine rotating an rectangle, and if you want to store the rotated rectangle in a unrotated rectangle, you will in most cases have to make the unrotated rectangle larger.

So what happens is that the kunai rectangle becomes larger and larger for each iteration. You could try to print out the size to see this.

You should rotate the original image instead.