在线剪辑图片

1. 需求：需要使用大小不同的图片以供显示

2. 条件：请求服务器图片，在不需要保存其余尺寸图片的情况下，返回任意大小图片

3. 代码:

def handler_size(once, now):
    once_x, once_y = once
    ratio = once_x / once_y
    now_x, now_y = now
    if all([now_x, now_y]):
        return now
    if now_y and not now_x:
        return int(ratio * now_y), now_y
    if now_x and not now_y:
        return now_x, int((1 / ratio) * now_x)
    return once


def img(request, path) -> HttpResponse:
    """
    :param request: 请求
    :param path: 路径
    :return: 图片二进制
    """
    url = 'http://192.168.0.157:8001/' + mykeys.relieve(path)[:-4]
    response = requests.get(url)
    if response.status_code == 200:
        image_data = response.content
        x = int(request.GET.get('x', 0))
        y = int(request.GET.get('y', 0))
        i = Image.open(BytesIO(image_data))
        temp = handler_size(i.size, (x, y))
        if temp == i.size:
            return HttpResponse(image_data, content_type="image/png")
        # 获取原图片的size
        out = i.resize(temp, Image.ANTIALIAS)
        # 开辟一个内存
        f = BytesIO()
        # 将图片对象保存到内存中
        out.save(f, 'jpeg')
        # 取出内存数据，此时就是转化过后的二进制，可直接返回给前端图片流
        data = f.getvalue()
    else:
        data = b''
    return HttpResponse(data, content_type="image/png")