variables_chart.py

# This script is licensed under BSD License, see file LICENSE.txt.
#
# (c) TASKING Germany GmbH, 2023
 
"""
This script plots several variables in one chart. The chart is
automatically scaled so that all the data is visible.
To use this script as a module, import it to your scripts and
call function startRecorder() with the list of variable you want to
observe.
 
This script requires additional python modules: matplotlib ver 1.1,
and numpy.
"""
 
import time
import isystem.connect as ic
 
import numpy as np
import matplotlib.pyplot as plt
import matplotlib.animation as animation
 
 
winidea_id = ''
 
 
def initTarget(cmgr):
    """
    This function initializes the target. Customize it according to
    your needs.
    """
 
    debugCtrl = ic.CDebugFacade(cmgr)
 
    debugCtrl.download()
    debugCtrl.runUntilFunction("main")
    debugCtrl.waitUntilStopped()
    debugCtrl.run()
    
    return debugCtrl
 
 
def _read_data(watches):
    """
    This function reads variables from the target. It is called
    periodically from updateChart()
    """
    global g_startTime
 
    # read value of variables
    row = []
    for expression in watches:
 
        value = g_debugCtrl.evaluate(ic.IConnectDebug.fRealTime, expression)
        # CValueType contains also other methods, if you want to get
        # value as integer, float, ... See
        # http://isystem.com/files/isystem.connect/api/classisys_1_1_c_value_type.html
        row.append(value.getInt())
 
    current_time = time.time() - g_startTime
    return current_time, row
 
 
def updateChart(num, watches, xRange, isScale):
    """
    This function is periodically called by the animation loop.
    """
    global xdata, ydata
 
    # read the data
    t, y = _read_data(watches)
    
    # append the data to the existing vectors of data
    xdata = np.hstack((xdata, t))
    ydata = np.row_stack((ydata, y))
 
    # adjust axes
    xmin, xmax = ax.get_xlim()
    ymin, ymax = ax.get_ylim()
 
    is_redraw = False
    if t >= xmax:
        if isScale:
            ax.set_xlim(xmin, 2*xmax)
            is_redraw = True
        else:
            ax.set_xlim(t - xRange, t)
            is_redraw = True
 
    delta_y_max = np.max(ydata)
    delta_y_min = np.min(ydata)
    
    delta_y = (delta_y_max - delta_y_min) / 10  # scale by 10% more if needed
    if delta_y_max > ymax:
        ax.set_ylim(ymin, delta_y_max + delta_y)
        is_redraw = True
        
    if delta_y_max < ymin:
        ax.set_ylim(delta_y_min - delta_y, ymax)
        is_redraw = True
 
    if is_redraw:
        ax.figure.canvas.draw()
 
    # refresh lines
    for i in range(len(g_lines)):
        g_lines[i].set_data(xdata, ydata[:, i])
 
    return g_lines,
 
 
def startRecorder(isInitTarget, watches, samplingInterval, xRange, isScale):
    """
    This is the main function of this module.
    Parameters:
 
    isInitTarget - if true, function initTarget() is called, otherwise
                   the target must be initialized and running
                   
    watches - list of variables to plot, for example ['g_int', 'g_char']
 
    samplingInterval - time in milliseconds between reading of samples
 
    xRange - initiali range on x-axis
 
    isScale if true, data is scale along x axis so that everything is visible,
            otherwise x-axis is shifted.
    """
    global g_lines, ax, xdata, ydata, \
           g_debugCtrl, g_startTime
    
    cmgr = ic.ConnectionMgr()
    cmgr.connect(ic.CConnectionConfig().instanceId(winidea_id))
 
    if isInitTarget:
        g_debugCtrl = initTarget(cmgr)
    else:
        g_debugCtrl = ic.CDebugFacade(cmgr)
 
    g_startTime = time.time()
    xdata = np.zeros(0)
    ydata = np.zeros((0, len(watches)))
 
    figure = plt.figure()
    ax = figure.add_subplot(111)
 
    g_lines = ax.plot([0], [[0]*len(watches)], lw=1)
    ax.set_ylim(-1, 1)
    ax.set_xlim(0, xRange)
    ax.grid()
 
    ani = animation.FuncAnimation(figure, updateChart, 40, blit=False,
                                  interval=samplingInterval,
                                  fargs=[watches, xRange, isScale])
    plt.show()
 
 
if __name__ == '__main__':
    startRecorder(True, ['g_complexStruct.i_cplx', 'g_char'], 10, 10, False)