#1. 导入模块
from PIL import Image

#2. 读取图片
img = Image.open('test.jpg')

#3. 保存文件
img.save(filename, format)
#E.g.
img.save(filename,"JPEG")

#4. 获取图片大小
(width, height) = img.size

#5. 获取图片的源格式
img_format = img.format

#6. 获取图片模式，有三种模式：L(灰度图像)，RGB(真彩色)和CMYK(pre-press图像)
img_mode = img.mode

#7. 图片模式的转换
img = img.convert("L")  #转化成灰度图像

#8. 获取每个坐标的像素点的RGB值
r,g,b = img.getpixel((j,i))

#9. 重设图片大小
img = img.resize(width,height)

#10. 创建缩略图
img.thumbnail(size)

#11. 显示图片
img.show()

#12. 提取色彩通道灰度图
r, g, b = img.split()
img = Image.merge("RGB", r, g, b)

from PIL import Image

def image_transfer(image_addr, file_name, out_size = None):
    """
    :param image_addr: image address
    :param file_name: name of output file (e.g. convert.txt)
    :param out_size: size of output file
    """

    #设置不同灰度值对应的 ASCII 字符
    ascii_char = list("@B$QMW&80#%XUOmbdpqoahkZYCjv" 
                 + "unxLJlIftizcr|/(){[1+?<>!;~\"^,:-.'` ")
    
    #打开图片文件并 resize
    img = Image.open(image_addr)
    if out_size:
        img = img.resize(out_size)

    #调用convert, 得到写入 text 的字符串
    text = convert(img, ascii_char)

    f = open(file_name, "w")
    f.write(text)
    f.close()

def convert(img, ascii_char):
    text = ""

    ascii_length = len(ascii_char)

    for i in range(img.size[1]):
        for j in range(img.size[0]):
            #获取每个pixel的 rgb 值
            r, g, b = img.getpixel((j, i))

            #经典灰度转换公式
            pixel_gray = r * 0.299 + g * 0.587 + b * 0.114

            #将灰度值转化为字符
            text += ascii_char[int((pixel_gray / 256) * ascii_length)]
        text += '\n'
    return  text

# Run
image_transfer("./joker.jpg", "./joker.txt", (265, 70))