Support for scanning QR-codes and barcodes through a camera plugin
This commit is contained in:
Fabio Manganiello
parent
c9db887505
commit
141275ecdf
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@ -0,0 +1,19 @@
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from typing import List
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from platypush.message.event import Event
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from platypush.message.response.qrcode import ResultModel
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class QrcodeEvent(Event):
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pass
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class QrcodeScannedEvent(Event):
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"""
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Event triggered when a QR-code or bar code is scanned.
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"""
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def __init__(self, results: List[ResultModel], *args, **kwargs):
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super().__init__(*args, results=results, **kwargs)
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# vim:sw=4:ts=4:et:
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@ -19,27 +19,39 @@ from platypush.plugins import Plugin, action
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class StreamingOutput:
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def __init__(self):
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def __init__(self, raw=False):
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self.frame = None
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self.raw_frame = None
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self.raw = raw
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self.buffer = io.BytesIO()
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self.ready = threading.Condition()
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@staticmethod
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def is_new_frame(buf):
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def is_new_frame(self, buf):
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if self.raw:
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return True
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# JPEG header begin
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return buf.startswith(b'\xff\xd8')
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def write(self, buf):
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if self.is_new_frame(buf):
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# New frame, copy the existing buffer's content and notify all clients that it's available
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self.buffer.truncate()
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with self.ready:
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self.frame = self.buffer.getvalue()
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self.ready.notify_all()
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self.buffer.seek(0)
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if self.raw:
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with self.ready:
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self.raw_frame = buf
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self.ready.notify_all()
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else:
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# New frame, copy the existing buffer's content and notify all clients that it's available
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self.buffer.truncate()
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with self.ready:
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self.frame = self.buffer.getvalue()
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self.ready.notify_all()
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self.buffer.seek(0)
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return self.buffer.write(buf)
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def close(self):
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self.buffer.close()
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class CameraPlugin(Plugin):
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"""
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@ -75,7 +87,7 @@ class CameraPlugin(Plugin):
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sleep_between_frames=_default_sleep_between_frames,
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max_stored_frames=_max_stored_frames,
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color_transform=_default_color_transform,
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scale_x=None, scale_y=None, rotate=None, flip=None, **kwargs):
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scale_x=None, scale_y=None, rotate=None, flip=None, stream_raw_frames=False, **kwargs):
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"""
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:param device_id: Index of the default video device to be used for
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capturing (default: 0)
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@ -145,6 +157,7 @@ class CameraPlugin(Plugin):
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self.frames_dir = os.path.abspath(os.path.expanduser(frames_dir or self._default_frames_dir))
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self.warmup_frames = warmup_frames
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self.video_type = video_type
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self.stream_raw_frames = stream_raw_frames
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if isinstance(video_type, str):
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import cv2
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@ -321,12 +334,15 @@ class CameraPlugin(Plugin):
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interpolation=cv2.INTER_CUBIC)
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if self._output:
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result, frame = cv2.imencode('.jpg', frame)
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if not result:
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self.logger.warning('Unable to convert frame to JPEG')
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continue
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if not self.stream_raw_frames:
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result, frame = cv2.imencode('.jpg', frame)
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if not result:
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self.logger.warning('Unable to convert frame to JPEG')
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continue
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self._output.write(frame.tobytes())
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self._output.write(frame.tobytes())
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else:
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self._output.write(frame)
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elif frames_dir:
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self._store_frame_to_file(frame=frame, frames_dir=frames_dir, image_file=image_file)
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@ -584,12 +600,14 @@ class CameraPlugin(Plugin):
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def __enter__(self):
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device_id = self.default_device_id
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self._output = StreamingOutput()
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self._output = StreamingOutput(raw=self.stream_raw_frames)
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self._init_device(device_id=device_id)
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self.start_recording(device_id=device_id)
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def __exit__(self, exc_type, exc_val, exc_tb):
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self.stop_recording(self.default_device_id)
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if self._output:
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self._output.close()
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self._output = None
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@ -1,10 +1,20 @@
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import base64
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import io
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import os
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from typing import Optional
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import threading
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import time
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from typing import Optional, List
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from platypush.message.response.qrcode import QrcodeGeneratedResponse, QrcodeDecodedResponse
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import numpy as np
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from PIL import Image
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from platypush import Config
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from platypush.context import get_bus
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from platypush.message.event.qrcode import QrcodeScannedEvent
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from platypush.message.response.qrcode import QrcodeGeneratedResponse, QrcodeDecodedResponse, ResultModel
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from platypush.plugins import Plugin, action
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from platypush.plugins.camera import CameraPlugin
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from platypush.utils import get_plugin_class_by_name
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class QrcodePlugin(Plugin):
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@ -19,13 +29,29 @@ class QrcodePlugin(Plugin):
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"""
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def __init__(self, **kwargs):
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def __init__(self, camera_plugin: Optional[str] = None, **kwargs):
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"""
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:param camera_plugin: Name of the plugin that will be used as a camera to capture images (e.g.
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``camera`` or ``camera.pi``).
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"""
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super().__init__(**kwargs)
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self.camera_plugin = camera_plugin
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self._capturing = threading.Event()
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def _get_camera(self, camera_plugin: Optional[str] = None, **config) -> CameraPlugin:
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camera_plugin = camera_plugin or self.camera_plugin
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if not config:
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config = Config.get(camera_plugin) or {}
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config['stream_raw_frames'] = True
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cls = get_plugin_class_by_name(camera_plugin)
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assert cls and issubclass(cls, CameraPlugin), '{} is not a valid camera plugin'.format(camera_plugin)
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return cls(**config)
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# noinspection PyShadowingBuiltins
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@action
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def generate(self, content: str, output_file: Optional[str] = None, show: bool = False,
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format: str = 'png') -> QrcodeGeneratedResponse:
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format: str = 'png', camera_plugin: Optional[str] = None) -> QrcodeGeneratedResponse:
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"""
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Generate a QR code.
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If you configured the :class`:platypush.backend.http.HttpBackend` then you can also generate
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@ -38,6 +64,8 @@ class QrcodePlugin(Plugin):
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:param show: If True, and if the device where the application runs has an active display,
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then the generated QR code will be shown on display.
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:param format: Output image format (default: ``png``).
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:param camera_plugin: If set then this plugin (e.g. ``camera`` or ``camera.pi``) will be used to capture
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live images from the camera and search for bar codes or QR-codes.
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:return: :class:`platypush.message.response.qrcode.QrcodeGeneratedResponse`.
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"""
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import qrcode
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@ -76,5 +104,72 @@ class QrcodePlugin(Plugin):
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results = pyzbar.decode(img)
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return QrcodeDecodedResponse(results)
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def _convert_frame(self, frame) -> Image:
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assert isinstance(frame, np.ndarray), 'Image conversion only works with numpy arrays for now'
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mode = 'RGB'
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if len(frame.shape) > 2 and frame.shape[2] == 4:
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mode = 'RGBA'
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return Image.frombuffer(mode, (frame.shape[1], frame.shape[0]), frame, 'raw', mode, 0, 1)
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@action
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def start_scanning(self, camera_plugin: Optional[str] = None, duration: Optional[float] = None,
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n_codes: Optional[int] = None) -> Optional[List[ResultModel]]:
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"""
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Decode QR-codes and bar codes using a camera.
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Triggers:
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- :class:`platypush.message.event.qrcode.QrcodeScannedEvent` when a code is successfully scanned.
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:param camera_plugin: Camera plugin (overrides default ``camera_plugin``).
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:param duration: How long the capturing phase should run (default: until ``stop_scanning`` or app termination).
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:param n_codes: Stop after decoding this number of codes (default: None).
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:return: When ``duration`` or ``n_codes`` are specified or ``stop_scanning`` is called, it will return a list of
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:class:`platypush.message.response.qrcode.ResultModel` instances with the scanned results,
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"""
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from pyzbar import pyzbar
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assert not self._capturing.is_set(), 'A capturing process is already running'
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camera = self._get_camera(camera_plugin)
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codes = []
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last_results = {}
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last_results_timeout = 10.0
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last_results_time = 0
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self._capturing.set()
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try:
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with camera:
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start_time = time.time()
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while self._capturing.is_set() \
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and (not duration or time.time() < start_time + duration) \
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and (not n_codes or len(codes) < n_codes):
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output = camera.get_stream()
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with output.ready:
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output.ready.wait()
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img = self._convert_frame(output.raw_frame)
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results = pyzbar.decode(img)
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if results:
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results = [
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result for result in QrcodeDecodedResponse(results).output['results']
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if result['data'] not in last_results
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or time.time() >= last_results_time + last_results_timeout
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]
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if results:
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codes.extend(results)
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get_bus().post(QrcodeScannedEvent(results=results))
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last_results = {result['data']: result for result in results}
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last_results_time = time.time()
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finally:
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self._capturing.clear()
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return codes
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@action
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def stop_scanning(self):
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self._capturing.clear()
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# vim:sw=4:ts=4:et:
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