Display

Display Stream

class imutils.display.displaystream.DisplayStream(screen: bool = True, port: int = 8080)

clear()

Removes the display content

show(name, frame)

Displays an image on the display

Args:

frame (array): Image bitmap

stream(name: str, frame)

Sends image to the frame-streamer

Args:

name (str): Stream identifier name frame (array): Current frame that needs to be enqueued

waitForKey(delay: int = 0)

Blocks until a key is pressed

Screen Output

class imutils.display.screenoutput.ScreenOutput

Concrete class that implements a multimedia output that requires a screen. For this purpose, the ScreenOutput class uses the OpenCV API to display windows, which is already based on GTK (or Qt, depending on how OpenCV is built)

clear()

Closes all images and streams that are visible during the runtime

show(name: str, frame)

Displays on screen the frame. Subsequent calls of this method results in a window refresh. It can be used to display motion video

Args:

name (str): Title of the frame to show frame (array): Bitmap image

stream(name: str, frame)

Sends a frame to screen. Subsequent calls of this method results in a video stream. For this concrete implementation of the ScreenOutput, a stream can be achieved by calling the show method

Args:

name (str): Title of the frame to show frame (array): Bitmap image

waitForKey(delay: int = 0)

Waits for a pressed key. Waits indefinitely when delay is <= 0, and it waits delay millseconds

Args:

delay (int): Delay in milliseconds. 0 is the special value that means “forever”.

Web Output

class imutils.display.weboutput.CameraHandler(request, client_address, server)

Handles HTTP requests from the clients. For this particular case, server will return an image stream (.mjpg) when a client sends a GET request

do_GET()

Function called when the web browser generates a GET request

image_queue = {}

populate_files()

Creates an HTML list where each element corresponds to an image or video output

Returns:

HTML formatted string with the list with elements

put_image(image)

Enqueues a frame that will be shown on the HTTP server

Args:

frame (array): Bitmap image

stream_images(image)

Enqueues a frame in the video stream that will be shown on the HTTP server

Args:

name (str): Title of the stream to show frame (array): Bitmap image

stream_queue = {}

class imutils.display.weboutput.HttpStreamOutput(address: str = '0.0.0.0', port: int = 8080)

Helper class that implements a HTTP server. It wraps methods around the CameraHandler static class to ease the interaction between the WebOutput and the static class

DEFAULT_HOST_ADDRESS = '0.0.0.0'

DEFAULT_PORT = 8080

putImage(name, frame)

Sends a frame to the HTTP image display

Args:

name (str): Title of the frame to show frame (array): Bitmap image

startServer()

Starts serving

stopServer()

Stops serving

streamImage(name, frame)

Sends a frame to the HTTP video stream

Args:

name (str): Title of the stream to show frame (array): Bitmap image

class imutils.display.weboutput.ThreadedHTTPServer(server_address, RequestHandlerClass, bind_and_activate=True)

ThreadedHTTPServer integrates the Threading mixin, meaning that now the HTTP server can serve multiple clients, each one handled by a separated thread from the pool.

class imutils.display.weboutput.WebOutput(port: int)

Concrete class that implements a media output for devices that doesn’t support visual screen output, but count with LAN connection. For this purpose, the WebOutput class uses an HTTP server that renders both, images and video stream using a fixed address and port.

clear()

Remove all images and video stream entries on the webserver

show(name: str, frame)

Displays on server the frame. This method creates a new list entry that can be accesed in the HTTP server. By clicking in this list entry, the image will be displayed in the web browser.

Args:

name (str): Title of the frame to show frame (array): Bitmap image

stream(name: str, frame)

Sends a frame to the web server video stream. This method creates a new list entry that can be accesed in the HTTP server. The name will serve as a reference to the video stream queue, and the frames will be enqueued to the video stream queue.

Args:

name (str): Title of the stream to show frame (array): Bitmap image

waitForKey(delay: int = 0)

Waits for a pressed key. Waits indefinitely when delay is = 0, and it waits delay millseconds

Args:

delay (int): Delay in milliseconds. 0 is the special value that means “forever”.