Javascript 将画布图像从js提取到flask但是图像'；的背景变白为透明

我一直在做一个项目，我必须将画布图像发送到烧瓶，但每次发送到烧瓶时，它都会失去白色背景，变得透明

我的问题是，如何拍摄白色背景的图像

我已经尝试了这么多代码，但都不适合我

代码如下：

js:

python:

@app.route("/predict",methods = ['GET','POST'])
def predict():

    #code-1
    data = request.values['url']
    encoded_data = data.split(',')[1]
    nparr = np.fromstring(encoded_data.decode('base64'), np.uint8)
    img = cv2.imdecode(nparr, cv2.IMREAD_COLOR)
    cv2.imshow(img)
    cv2.waitKey(10)
    cv2.destroyAllWindows()
   
    #code-2
    data_url = request.args.get('url')   # here parse the data_url out http://xxxxx/?image={dataURL}
    content = data_url.split(';')[1]
    image_encoded = content.split(',')[1]
    body = base64.decodebytes(image_encoded.encode('utf-8'))   
    img = Image.open(body)

    #code-3
    resp = urllib2.urlopen(url) 
    img = Image.open(urlopen(url).read())
    img = Image.open(requests.get(url, stream=True).raw)

---

听起来你的图像一开始并没有白色背景。您可能正在绘制一个在画布上有透明部分的PNG，并让画布元素（或其后面的东西）的背景色“透亮”…？

@app.route("/predict",methods = ['GET','POST'])
def predict():

    #code-1
    data = request.values['url']
    encoded_data = data.split(',')[1]
    nparr = np.fromstring(encoded_data.decode('base64'), np.uint8)
    img = cv2.imdecode(nparr, cv2.IMREAD_COLOR)
    cv2.imshow(img)
    cv2.waitKey(10)
    cv2.destroyAllWindows()
   
    #code-2
    data_url = request.args.get('url')   # here parse the data_url out http://xxxxx/?image={dataURL}
    content = data_url.split(';')[1]
    image_encoded = content.split(',')[1]
    body = base64.decodebytes(image_encoded.encode('utf-8'))   
    img = Image.open(body)

    #code-3
    resp = urllib2.urlopen(url) 
    img = Image.open(urlopen(url).read())
    img = Image.open(requests.get(url, stream=True).raw)