Multi demo

import numpy as np
from qtpy.QtCore import Qt
from qtpy.QtGui import QPen
from qtpy.QtWidgets import QGridLayout, QWidget

from qwt import QwtPlot, QwtPlotCurve
from qwt.tests import utils


def drange(start, stop, step):
    start, stop, step = float(start), float(stop), float(step)
    size = int(round((stop - start) / step))
    result = [start] * size
    for i in range(size):
        result[i] += i * step
    return result


def lorentzian(x):
    return 1.0 / (1.0 + (x - 5.0) ** 2)


class MultiDemo(QWidget):
    def __init__(self, *args):
        QWidget.__init__(self, *args)
        layout = QGridLayout(self)
        # try to create a plot for SciPy arrays

        # make a curve and copy the data
        numpy_curve = QwtPlotCurve("y = lorentzian(x)")
        x = np.arange(0.0, 10.0, 0.01)
        y = lorentzian(x)
        numpy_curve.setData(x, y)
        # here, we know we can plot NumPy arrays
        numpy_plot = QwtPlot(self)
        numpy_plot.setTitle("numpy array")
        numpy_plot.setCanvasBackground(Qt.white)
        numpy_plot.plotLayout().setCanvasMargin(0)
        numpy_plot.plotLayout().setAlignCanvasToScales(True)
        # insert a curve and make it red
        numpy_curve.attach(numpy_plot)
        numpy_curve.setPen(QPen(Qt.red))
        layout.addWidget(numpy_plot, 0, 0)
        numpy_plot.replot()

        # create a plot widget for lists of Python floats
        list_plot = QwtPlot(self)
        list_plot.setTitle("Python list")
        list_plot.setCanvasBackground(Qt.white)
        list_plot.plotLayout().setCanvasMargin(0)
        list_plot.plotLayout().setAlignCanvasToScales(True)
        x = drange(0.0, 10.0, 0.01)
        y = [lorentzian(item) for item in x]
        # insert a curve, make it red and copy the lists
        list_curve = QwtPlotCurve("y = lorentzian(x)")
        list_curve.attach(list_plot)
        list_curve.setPen(QPen(Qt.red))
        list_curve.setData(x, y)
        layout.addWidget(list_plot, 0, 1)
        list_plot.replot()


def test_multidemo():
    """Multiple plot demo"""
    utils.test_widget(MultiDemo, size=(400, 300))


if __name__ == "__main__":
    test_multidemo()