plot.py

import queue
from threading import Thread

import logging
import numpy as np
import time

from bokeh.models import Range1d
from bokeh.plotting import figure, curdoc
from bokeh.models.sources import ColumnDataSource
from bokeh.client import push_session
from datetime import datetime

logger = logging.getLogger('Backend')


class Plot(Thread):
    def __init__(self):
        super().__init__(daemon=True)

        self.x = np.zeros(10)
        self.y1 = np.zeros(10)
        self.y2 = np.zeros(10)
        self.last_data = (0, 0)

        self.figure = figure(plot_width=800, plot_height=400, y_range=Range1d(-0.1, 1.1))
        self.figure.xaxis.axis_label = "Time passed (s)"
        self.figure.yaxis.axis_label = "Normalized value"
        datacoords = ColumnDataSource(data=dict(x=self.x, y1=self.y1, y2=self.y2))

        self.linea = self.figure.line("x", "y1", line_color="red", source=datacoords, legend="Potential")
        self.lineb = self.figure.line("x", "y2", source=datacoords, legend="Current")

        self.start_time = datetime.now()

    def update_data(self, y1, y2):
        self.last_data = (y1, y2)

    def run(self):
        # open a session to keep our local document in sync with server
        session = push_session(curdoc())
        # curdoc().add_periodic_callback(self.update, 1000)  # period in ms
        # session.loop_until_complete()
        session.show(self.figure)
        self.update()

    def update(self):
        while True:
            timestamp = datetime.now()

            new_x = ((timestamp - self.start_time).total_seconds())
            self.x = np.roll(self.x, -1)
            self.y1 = np.roll(self.y1, -1)
            self.y2 = np.roll(self.y2, -1)
            self.x[-1] = new_x
            self.y1[-1] = self.last_data[0]
            self.y2[-1] = self.last_data[1]

            self.linea.data_source.data["x"] = self.x
            self.linea.data_source.data["y1"] = self.y1
            self.lineb.data_source.data["y2"] = self.y2

            push_session(curdoc())
            time.sleep(0.1)