Python trip - the image of characters drawn with

The image of a character drawn with

The second blog, a daily record of learning bit by bit.

Knowledge summary

1. Python PIL third-party image processing libraries
2. Gray value equation gray = 0.2126 * r + 0.7152 * g + 0.0722 * b
   sign small symbol mapping with local gray value at the beginning of the list, with a large gray value of the local end of the list of maps.
3. getpixel ((j, i)) to give the color of a pixel, typically return (r, g, b)

from PIL import Image

ascii_char = list ('"$%_&WM#*oahkbdpqwmZO0QLCJUYXzcvunxrjft/\|()1{}[]?-/+@<>i!;:,\^`.')
def get_char(r, b, g, alpha = 256):
    if alpha == 0:
        return ' '
    #计算每个像素点应该放入列表中哪个字符
    gray = int(0.2126 * r + 0.7152 * g + 0.0722 * b)
    unit = 256 / len(ascii_char)
    return ascii_char[int(gray / unit)]

def main():
    im = Image.open('boy.jpg')
    WIDTH , HEIGHT = 90,34
    im = im.resize((WIDTH,HEIGHT))
    #初试化文本
    txt = ""
    for i in range (HEIGHT):
        for j in range(WIDTH):
            txt +=  get_char(*im.getpixel((j,i)))
        txt += '\n' #遍历每行结束后切换到下一行
	#创建文本文件，将转换的字符串图画保存进去
    fo = open("pic_char.txt","w")
    fo.write(txt)
    fo.close()

if __name__ == '__main__':
    main()