Matplotlib-FigureStream

A backend for serve Matplotlib animations as web streams.

Instalation

pip install figurestream

Bare minimum

By default, the stream serves on http://localhost:5000

# FigureStream replace any Figure object 
from figurestream import FigureStream

import numpy as np
from datetime import datetime

# FigureStream can be used like any Figure object
stream = FigureStream()
sub = stream.add_subplot(111)
x = np.linspace(0, 3, 1000)

# Update animation loop
while True:
    sub.clear()  # clear the canvas

    # ------------------------------------------------------------------------
    # Any plot operation 
    sub.set_title('FigureStream')
    sub.set_xlabel('Time [s]')
    sub.set_ylabel('Amplitude')
    sub.plot(x, np.sin(2 * np.pi * 2 * (x + datetime.now().timestamp())))
    sub.plot(x, np.sin(2 * np.pi * 0.5 * (x + datetime.now().timestamp())))
    # ------------------------------------------------------------------------
    
    stream.feed()  # push the frame into the server

For fast updates is recommended to use set_data, set_ydata and set_xdata instead of clear and draw again in each loop, also FigureStream can be implemented from a custom class.

# FigureStream replace any Figure object
from figurestream import FigureStream

import numpy as np
from datetime import datetime


class FastAnimation(FigureStream):

    def __init__(self, *args, **kwargs):
        super().__init__(*args, **kwargs)

        axis = self.add_subplot(111)
        self.x = np.linspace(0, 3, 1000)
        
        # ------------------------------------------------------------------------
        # Single time plot configuration
        axis.set_title('FigureStream')
        axis.set_xlabel('Time [s]')
        axis.set_ylabel('Amplitude')

        axis.set_ylim(-1.2, 1.2)
        axis.set_xlim(0, 3)
        
        # Lines objects
        self.line1, *_ = axis.plot(self.x, np.zeros(self.x.size))
        self.line2, *_ = axis.plot(self.x, np.zeros(self.x.size))
        # ------------------------------------------------------------------------

        self.anim()

    def anim(self):
        # Update animation loop
        while True:
            # ------------------------------------------------------------------------
            # Update only the data values is faster than update all the plot
            self.line1.set_ydata(np.sin(2 * np.pi * 2 * (self.x + datetime.now().timestamp())))
            self.line2.set_ydata(np.sin(2 * np.pi * 0.5 * (self.x + datetime.now().timestamp())))
            # ------------------------------------------------------------------------
            
            self.feed()  # push the frame into the server


if __name__ == '__main__':
    FastAnimation()

Set host, port and endpoint

If we want to serve the stream in a different place we can use the parameters host, port and endpoint, for example:

FigureStream(host='0.0.0.0', port='5500', endpoint='figure.jpeg')

Now the stream will serve on http://localhost:5500/figure.jpeg and due the 0.0.0.0 host is accesible for any device on network.
By default host is localhost, port is 5000 and endopoint is empty.