camera.py 文件源码

def start_preview(self, **options):
        """
        Starts the preview.
        :param options: See :meth:`~picamera.camera.PiCamera.start_preview`
        """

        self.camera.rotation = 180
        self.preview_renderer = self.camera.start_preview(**options)

        wait = 0
        while True:
            if self.preview_renderer.window[2] > 0:
                break
            wait += 1
            if wait > 10:
                raise RuntimeError('Waited longer than 10 seconds for preview window')
            sleep(1)

        return self.preview_renderer