import datetime as dts
from system.shared import LastErrorHolder
import time
import cv2 as cv
class CameraConnectionSupport(LastErrorHolder):
def __init__(self, camConnectionString, logger):
LastErrorHolder.__init__(self)
self.logger = logger
# date & time when class instance created
self.started = dts.datetime.utcnow()
# camera
self.cap = None
# frame height
self.frameHeight = None
# frame width
self.frameWidth = None
# total count of pixels
self.nb_pixels = None
self.camConnectionString = camConnectionString
def utcNow(self):
return dts.datetime.utcnow()
def onFrameSizeUpdate(self, frameWidth, frameHeight):
"""
Will be called when frame size will be updated or initialized
:param frameWidth: new width
:param frameHeight: new height
:return:
"""
pass
def _initCamera(self, callSleep = True):
"""
Initializes camera. If can't establish connection will write error message to log file and sleep for some
interval.
:return: True when camera successfully open, otherwise False
"""
self.cap = cv.VideoCapture(self.camConnectionString)
if self.cap is None:
self.setError("can't connect to camera")
if callSleep:
time.sleep(5)
return None
if not self.cap.isOpened(): # did we get a connection at all ?
self.setError("can't connect to camera")
if callSleep:
time.sleep(5)
return None
return self.cap
