with_ImageHub.py

"""with_ImageHub.py -- demonstrate using ImageHub class in with statement

An ImageHub can be instantiated in a "with" statement. This will cause the
ImageHub to be closed after the completion of the with statment block.

1. Run this program in its own terminal window on the mac:
python with_ImageHub.py

This 'receive and display images' program must be running before starting
the RPi image sending program.

2. Run the image sending program on the RPi:
python with_ImageSender.py

A cv2.imshow() window will appear on the Mac showing the tramsmitted images
as a video stream. You can repeat Step 2 and start the with_ImageSender.py
on multiple RPis and each one will cause a new cv2.imshow() window to open.

To end the programs, press Ctrl-C in the terminal window of each program.
"""

import sys
import time
import traceback
import numpy as np
import cv2
from imutils.video import FPS
import imagezmq

try:
    with imagezmq.ImageHub() as image_hub:
        while True:  # receive images until Ctrl-C is pressed
            sent_from, jpg_buffer = image_hub.recv_jpg()
            image = cv2.imdecode(np.frombuffer(jpg_buffer, dtype='uint8'), -1)
            # see opencv docs for info on -1 parameter
            cv2.imshow(sent_from, image)  # display images 1 window per sent_from
            cv2.waitKey(1)
            image_hub.send_reply(b'OK')  # REP reply
except (KeyboardInterrupt, SystemExit):
    pass  # Ctrl-C was pressed to end program; FPS stats computed below
except Exception as ex:
    print('Python error with no Exception handler:')
    print('Traceback error:', ex)
    traceback.print_exc()
finally:
    cv2.destroyAllWindows()  # closes the windows opened by cv2.imshow()
    sys.exit()