python图片转ascii文本

from PIL import Image
# 定义ASCII字符集
ASCII_CHARS = [' ', '.', '*', ':', 'o', '&', '8', '#', '@']
# 将像素值转换为灰度值
def get_gray_value(pixel):
    # 灰度值计算公式：gray = 0.2989 * r + 0.5870 * g + 0.1140 * b
    gray = 0.2989 * pixel[0] + 0.5870 * pixel[1] + 0.1140 * pixel[2]
    return int(gray)
# 将灰度值转换为ASCII字符
def gray_to_ascii(gray):
    # 灰度值范围为0-255，字符集长度为9，每个灰度值映射到字符集中的一个字符
    index = int(gray / (256 / len(ASCII_CHARS)))
    return ASCII_CHARS[index]
# 将图像转换为ASCII文本
def image_to_ascii(image):
    width, height = image.size
    ascii_text = ''
    for y in range(height):
        for x in range(width):
            pixel = image.getpixel((x, y))
            gray = get_gray_value(pixel)
            ascii_text += gray_to_ascii(gray)
        ascii_text += '\n'
    return ascii_text
# 打开图像文件并将其转换为ASCII文本
def main(filename):
    image = Image.open(filename)
    ascii_text = image_to_ascii(image)
    print(ascii_text)
# 运行程序
if __name__ == '__main__':
    main('example.png')