from PIL import Image
import argparse

#输入
#命令行输入参数处理
parser = argparse.ArgumentParser()

parser.add_argument(‘file‘) #position argument
parser.add_argument(‘-o‘,‘--output‘) #optional argument and -o is a short option
parser.add_argument(‘--width‘, type = int, default = 80) #optional argument
parser.add_argument(‘--height‘, type = int, default = 80) 

#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;:,\"^`‘. ")

#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)