将图片转化为字符串形式

使用方法
原理说明
代码实现
使用例子

1. 使用方法

python main.py -i="image_path" -o="result_path" -s

-i 想要转换图片的路径(可以是网络路径)

-o 转换后的txt文件路径(默认为output.txt)

-s 打印转换后的结果

2. 原理说明

（1）调整图片的大小，高度45，宽度80（此比例在txt里接近1：1）

（2）将RGB图片转化为灰度图

（3）将不同灰度的像素用不同的符号表示

3. 代码实现


'''
通过灰度图与字符集之间的映射来转换图片
'''

from PIL import Image
import urllib.request
from io import BytesIO


class ImageToChartSet(object):
    def __init__(self, char_list = None) -> None:
        super(ImageToChartSet, self).__init__()
        self.char_list = char_list if char_list is not None else list("▁▂▃▅▆▇▇▇")[::-1]
        self.num_char = len(self.char_list)
        self.img_width = 80
        self.img_height = 45 
        
    def rgbToChar(self, r, g, b, alpha=256):
        if alpha == 0:
            return ''
        gray_value = int(0.2126 * r + 0.7152 * g + 0.0722 * b)
        resolution = 257.0 / self.num_char
        return self.char_list[int(gray_value/resolution)]
    
    def convert_image(self, img):
        txt = ''
        img = img.resize((self.img_width, self.img_height), Image.NEAREST)
        for i in range(self.img_height):
            for j in range(self.img_width):
                txt += self.rgbToChar(*img.getpixel((j,i)))
            txt += '\n'
        return txt

def ImageOnline(url):
    file = BytesIO(urllib.request.urlopen(url).read())
    img = Image.open(file)
    return img


 
def main(args):
    import os
    if args.image_path.startswith("http"):
        img = ImageOnline(args.image_path)
        
    elif args.image_path is None or not os.path.exists(args.image_path):
        print("please check if you have set the true image path.")
        return -1
    else:
        img = Image.open(args.image_path)

    img2char = ImageToChartSet()
    
    txt = img2char.convert_image(img)
    
    if args.show:
        print(txt)
    
    with open(args.output_path, 'w') as f:
        f.write(txt)
        
    
if __name__ == "__main__":
    import argparse
    parser = argparse.ArgumentParser(description="Image Convert to string")
    parser.add_argument('-i','--image_path', default=None)
    parser.add_argument('-o','--output_path', default="output.txt")
    parser.add_argument('-s','--show', action="store_true", default=False)
    args = parser.parse_args()
    print(args)
    main(args)