在图像前放置标签

Question

我有一个图像小部件，它从流中获取帧并打印帧并每秒更新 30 次。我想在它上面放置一个标签小部件作为一种覆盖来提供额外的信息（例如帧速率、分辨率等）。但我似乎无法成功在我的小部件上绘制标签。我该怎么做？

到目前为止我有：

.kv:

KivyCamera:
            stream: "rtsp://my-stream"
            Label:
                text: "Testing12345"
                pos: self.pos
                size: 320, 240

.py:

class KivyCamera(Image):

status = 0
frame = 0
stream = ObjectProperty()
fps = NumericProperty(25)

def __init__(self, **kwargs):
    super(KivyCamera, self).__init__(**kwargs)
    self._capture = None

def on_stream(self, *args):
    if self._capture is not None:
        self._capture.release()
    self._capture = cv2.VideoCapture(self.stream)
    self.thread = Thread(target=self.update, args=())
    self.thread.daemon = True
    self.thread.start()
    Clock.schedule_interval(self.show_frame, 1.0 / self.fps)

@property
def capture(self):
    return self._capture

def update(self):
    while True:
        if self.capture.isOpened():
            (self.status, self.frame) = self.capture.read()
        time.sleep(.01)

def show_frame(self, dt):
    if self.status:
        buf1 = cv2.flip(self.frame, 0)
        buf = buf1.tostring()
        image_texture = Texture.create(
            size=(self.frame.shape[1], self.frame.shape[0]), colorfmt="bgr"
        )
        image_texture.blit_buffer(buf, colorfmt="bgr", bufferfmt="ubyte")
        self.texture = image_texture

Answer 1

只需将Label 添加为单独的Widget。比如：

FloatLayout:
    KivyCamera:
        stream: "rtsp://my-stream"
    Label:
        id: extra_info
        text: 'Testing12345'
        size_hint: None, None
        size: self.texture_size
        pos_hint: {'center_x':0.5, 'center_y':0.5}