python实现图片转字符串

学习pillow库 argparse库

原理

我们需要把一张彩色的图片对应到单色的字符画上。

灰度值：指黑白图像中点的颜色深度，范围一般从0到255，白色为255，黑色为0，故黑白图片也称为灰度图像

公式：

gray = int(0.2126*r+0.7152*g+0.0722*b)

安装pillow库

pip install pillow

获取图片

wget http://labfile.oss.aliyuncs.com/courses/370/ascii_dora.png

字符集

ascii_char = list("$@B%8&WM#*oahkbdpqwmZO0QLCJUYXzcvunxrjft/\()1{}[]?-_+~i!lI;:,\"^`'.")

代码

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# -*- coding: utf-8 -*-
# !/usr/bin/env python
from PIL import Image
import argparse
import numpy as np
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)]
def get_args():
	#命令行输入参数处理
	parser = argparse.ArgumentParser()
	parser.add_argument('file')
	parser.add_argument('-o','--output')
	parser.add_argument('--width',type=int,default=80) #输出字符串画宽
	parser.add_argument('--height',type=int,default=80) #输出字符串画宽
	#获取参数
	args = parser.parse_args()
	IMG = args.file
	WIDTH = args.width
	OUTPUT = args.output
	HEIGHT = args.height
	return IMG,WIDTH,OUTPUT,HEIGHT
if __name__ == '__main__':
	IMG,WIDTH,OUTPUT,HEIGHT = get_args()
	im = Image.open(IMG)
	im = im.resize((WIDTH,HEIGHT),Image.NEAREST)
	ascii_char = list("$@B%8&WM#*oahkbdpqwmZO0QLCJUYXzcvunxrjft/\()1{}[]?-_+~i!lI;:,\"^`'.")
	txt = ""
	for i in range(HEIGHT):
		for j in range(WIDTH):
			txt += get_char(*im.getpixel((j,i)))
		txt += '\n'
	#字符串输出到文件
	if OUTPUT:
		with open(OUTPUT,'w') as f:
			f.write(txt)
	else:
		with open("dora.txt",'w') as f:
			f.write(txt)

运行

python pic.py ascii_dora.png

结果

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						  			  $$$$                                       
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