# Map demo

    import random
    import time
    import numpy as np

    from qtpy.QtWidgets import QMainWindow, QToolBar
    from qtpy.QtGui import QPen, QBrush
    from qtpy.QtCore import QSize, Qt
    from qwt import QwtPlot, QwtSymbol, QwtPlotCurve

    def standard_map(x, y, kappa):
        """provide one interate of the inital conditions (x, y)
        for the standard map with parameter kappa."""
        y_new = y - kappa * np.sin(2.0 * np.pi * x)
        x_new = x + y_new
        # bring back to [0,1.0]^2
        if (x_new > 1.0) or (x_new < 0.0):
            x_new = x_new - np.floor(x_new)
        if (y_new > 1.0) or (y_new < 0.0):
            y_new = y_new - np.floor(y_new)
        return x_new, y_new

    class MapDemo(QMainWindow):
        def __init__(self, *args):
            QMainWindow.__init__(self, *args)
            self.plot = QwtPlot(self)
            self.plot.setTitle("A Simple Map Demonstration")
            self.plot.setCanvasBackground(Qt.white)
            self.plot.setAxisTitle(QwtPlot.xBottom, "x")
            self.plot.setAxisTitle(QwtPlot.yLeft, "y")
            self.plot.setAxisScale(QwtPlot.xBottom, 0.0, 1.0)
            self.plot.setAxisScale(QwtPlot.yLeft, 0.0, 1.0)
            self.setCentralWidget(self.plot)
            # Initialize map data
            self.count = self.i = 1000
            self.xs = np.zeros(self.count, float)
            self.ys = np.zeros(self.count, float)
            self.kappa = 0.2
            self.curve = QwtPlotCurve("Map")
            self.curve.attach(self.plot)
            self.curve.setSymbol(
                QwtSymbol(QwtSymbol.Ellipse, QBrush(Qt.red), QPen(Qt.blue), QSize(5, 5))
            )
            self.curve.setPen(QPen(Qt.cyan))
            toolBar = QToolBar(self)
            self.addToolBar(toolBar)
            # 1 tick = 1 ms, 10 ticks = 10 ms (Linux clock is 100 Hz)
            self.ticks = 10
            self.tid = self.startTimer(self.ticks)
            self.timer_tic = None
            self.user_tic = None
            self.system_tic = None
            self.plot.replot()

        def setTicks(self, ticks):
            self.i = self.count
            self.ticks = int(ticks)
            self.killTimer(self.tid)
            self.tid = self.startTimer(ticks)

        def moreData(self):
            if self.i == self.count:
                self.i = 0
                self.x = random.random()
                self.y = random.random()
                self.xs[self.i] = self.x
                self.ys[self.i] = self.y
                self.i += 1
                chunks = []
                self.timer_toc = time.time()
                if self.timer_tic:
                    chunks.append("wall: %s s." % (self.timer_toc - self.timer_tic))
                    print(" ".join(chunks))
                self.timer_tic = self.timer_toc
            else:
                self.x, self.y = standard_map(self.x, self.y, self.kappa)
                self.xs[self.i] = self.x
                self.ys[self.i] = self.y
                self.i += 1

        def timerEvent(self, e):
            self.moreData()
            self.curve.setData(self.xs[: self.i], self.ys[: self.i])
            self.plot.replot()

    if __name__ == "__main__":
        from qwt import tests

        tests.test_widget(MapDemo, size=(600, 600))