class_docstr: ScreenGear is designed exclusively for targeting rapid Screencasting Capabilities, which means it can
  grab frames from your monitor in real-time, either by defining an area on the computer screen or full-screen,
  at the expense of inconsiderable latency. ScreenGear also seamlessly support frame capturing from multiple
  monitors as well as supports multiple backends.
  
  ScreenGear API implements a multi-threaded wrapper around dxcam, pyscreenshot, python-mss python library,
  and also flexibly supports its internal parameter.
docstr: Launches the internal *Threaded Frames Extractor* daemon
  
  **Returns:** A reference to the ScreenGear class object.
docstr_tok: ["Launches","the","internal","*","Threaded","Frames","Extractor","*","daemon","*","*","Returns",":","*","*","A","reference","to","the","ScreenGear","class","object","."]
code: def start(self):
      """
      Launches the internal *Threaded Frames Extractor* daemon
  
      **Returns:** A reference to the ScreenGear class object.
      """
      self.__thread = Thread(
          target=self.__update, name="ScreenGear", args=()
      )
      self.__thread.daemon = True
      self.__thread.start()
      if self.__backend == "dxcam":
          self.__capture_object.start(
              target_fps=self.__target_fps,
              video_mode=True,
          )
          self.__logging and self.__target_fps and logger.debug(
              "Targeting FPS: {}".format(self.__target_fps)
          )
      return self
  
file_path: vidgear/vidgear/gears/screengear.py
imports: import cv2
  import json
  import platform
  import numpy
  import logging
  from threading import Thread, Event
  from collections import OrderedDict
  from .helper import import_dependency_safe, capPropId, logger_handler, logcurr_vidgear_ver
label_desc: Use image node_id 2 for calling the ScreenGear obj's underlying member method code with example usage: obj.start() and returns: self