End result

# The images will be processed using OpenCV and Numpy
import cv2
import numpy

# The decode_qrcode function will be used for decoding the found QR Code
from pyzbar.pyzbar import decode as decode_qrcode

# Used for sending the logs to the ':8888/logs' endpoint
import logging
# For identifying the source of the logs
logger = logging.getLogger("lampix.QRCodeDetector")

from watcher import Watcher
# Will be used to specify the used trigger for this Watcher
from watcher import TriggerType

class QRCodeDetector(Watcher):
    # Calling the base class constructor
    def __init__(self, id, contour):
        # self.contour is the property which holds the corners of the registered area
        Watcher.__init__(self, id, contour)

    def get_vision_trigger(self):
        return TriggerType.TRIGGER_RGB

    def on_movement(self, depth_frame, grey_frame, color_frame, movement_mask):
        # Code that will be executed when an object is placed on the projection surface, 
        # exactly where the watcher was registered
        logger.info('The QRCodeDetector Watcher was triggered')

        x, y, width, height = cv2.boundingRect(self.contour.astype(numpy.int))


        # Cropping the color_frame and getting the ROI (Region of Interest) containing the object that triggered the Watcher
        qr_code_roi = color_frame[y:y + height, x:x + width]

        # Decoding the QR Code and retrieving the data
        qr_code = decode_qrcode(qr_code_roi)[0]
        qr_code_data = qr_code.data

        if len(qr_code_data):
            # The self.report_to_js() method requires a formatted object
            reported_object = self.create_formatted_object(metadata=qr_code_data)
            self.report_to_js(reported_object, method='located')
        else:
            reported_object = self.create_formatted_object(message="QR Code not detected")
            self.report_to_js(reported_object, method='located')

    def on_delete(self):
        """
        Code that will be executed on Watcher's removal
        e.g. closing connections
        """

        pass