如何在pygame中获取屏幕中颜色的百分比？

import pygame
import sys

pygame.init()
screen = pygame.display.set_mode((800, 600))

def get_color_percentage(rect):
    pixels = pygame.surfarray.array3d(screen)
    total_pixels = rect.width * rect.height
    color_count = 0

    for x in range(rect.x, rect.x + rect.width):
        for y in range(rect.y, rect.y + rect.height):
            r, g, b = pixels[x][y]
            if r != 0 or g != 0 or b != 0:  # 排除黑色像素
                color_count += 1

    return (color_count / total_pixels) * 100

while True:
    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            pygame.quit()
            sys.exit()

    # 获取屏幕中(100, 100)位置开始，宽度为200，高度为200的区域的颜色百分比
    rect = pygame.Rect(100, 100, 200, 200)
    color_percentage = get_color_percentage(rect)
    print("颜色百分比：", color_percentage)

    pygame.display.update()