Python将图片转换为字符画的方法

# coding:utf-8 
 
# 为一张图片生成对应的字符集图片 
 
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=80) # 输出字符画宽 
parser.add_argument('--height', type=int, default=80) # 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 
 
ascii_char = list("$@B%8&WM#*oahkbdpqwmZO0QLCJUYXzcvunxrjft/\|()1{}[]?-_+~<>i!lI;:,\"^`'. ") 
 
 
# 将256灰度映射到70个字符上 
def get_char(r, b, g, alpha=256): 
 if alpha == 0: 
  return ' ' 
 length = len(ascii_char) 
 gray = int(0.2126 * r + 0.7152 * g + 0.0722 * b) 
 
 unit = (256.0 + 1)/length 
 return ascii_char[int(gray/unit)] 
 
if __name__ == '__main__': 
 
 im = Image.open(IMG) 
 im = im.resize((WIDTH, HEIGHT), Image.NEAREST) 
 
 txt = "" 
 
 for i in range(HEIGHT): 
  for j in range(WIDTH): 
   txt += get_char(*im.getpixel((j, i))) 
  txt += '\n' 
 
 print txt 
 
 # 字符画输出到文件 
 if OUTPUT: 
  with open(OUTPUT,'w') as f: 
   f.write(txt) 
 else: 
  with open("output.txt", 'w') as f: 
   f.write(txt)