Pythonの画像を文字描画に変換するコードは何ですか?

gray ＝ 0.2126 * r + 0.7152 * g + 0.0722 * b

# !/usr/bin/env python
# -*- coding:utf-8 -*-
from PIL import Image
import argparse
#命令行输入参数处理
parser = argparse.ArgumentParser()
parser.add_argument('file')   #输入文件
parser.add_argument('-o', '--output')  #输出文件
parser.add_argument('--width', type = int, default = 50) #输出字符画宽
parser.add_argument('--height', type = int, default = 50) #输出字符画高
#获取参数
args = parser.parse_args()
IMG = args.file
WIDTH = args.width
HEIGHT = args.height
OUTPUT = args.output
# 字符画使用的字符集
ascii_char = list("$@B%8&WM#*oahkbdpqwmZO0QLCJUYXzcvunxrjft/\|()1{}[]?-_+~<>i!lI;:,\"^`&#39;. ")
def get_char(r,g,b,alpha = 256):
  """将256灰度映射到70个字符上"""
  if alpha == 0:
    return &#39; &#39;
  length = len(ascii_char)
  # 计算灰度的公式
  gray = int(0.2126 * r + 0.7152 * g + 0.0722 * b)
  unit = (256.0 + 1)/length
  index=int(gray/unit)
  return ascii_char[index]
if __name__ == &#39;__main__&#39;:
  im = Image.open(IMG)
  im = im.resize((WIDTH,HEIGHT), Image.NEAREST)
  txt = ""
  # 获取每个像素点对应的字符
  for i in range(HEIGHT):
    for j in range(WIDTH):
      txt += get_char(*im.getpixel((j,i)))
    txt += &#39;\n&#39;
  print(txt)
  #字符画输出到文件
  if OUTPUT:
    with open(OUTPUT,&#39;w&#39;) as f:
      f.write(txt)
  else:
    with open("output.txt",&#39;w&#39;) as f:
      f.write(txt)z