Change image into character

from PIL import Imageimport argparse#输入#命令行输入参数处理parser = argparse.ArgumentParser()parser.add_argument('file') #position argumentparser.add_argument('-o','--output') #optional argument and -o is a short optionparser.add_argument('--width', type = int, default = 80) #optional argumentparser.add_argument('--height', type = int, default = 80) #获取参数args = parser.parse_args()IMG = args.fileWIDTH = args.widthHEIGHT = args.heightOUTPUT = args.outputascii_char = list("$@B%8&WM#*oahkbdpqwmZO0QLCJUYXzcvunxrjft/\|()1{}[]?-_+~<>i!lI;:,\"^`'. ")#处理#构建映射def get_char(r,g,b, 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)]#输出if __name__ == '__main__':#When the Python interpreter reads a source file, it executes all of the code found in it.#in main program, __name__ = __main__    im = Image.open(IMG)    im = im.resize((WIDTH,HEIGHT), Image.NEAREST)#Image.resize(size, resample=0)#Parameters:    #size – The requested size in pixels, as a 2-tuple: (width, height).#resample – An optional resampling filter. This can be one of PIL.Image.NEAREST (use nearest neighbour), PIL.Image.BILINEAR (linear interpolation), PIL.Image.BICUBIC (cubic spline interpolation), or PIL.Image.LANCZOS (a high-quality downsampling filter). If omitted, or if the image has mode “1” or “P”, it is set PIL.Image.NEAREST.    txt = ""    for i in range(HEIGHT):        for j in range(WIDTH):            txt += get_char(*im.getpixel((j,i)))        txt += '\n'    print txt    if OUTPUT:        with open(OUTPUT, 'w') as f:            f.write(txt)    else:        with open("output.txt",'w') as f:            f.write(txt)