Create LogCurveDemo.py

Author: PierreRaybaut

qwt/tests/LogCurveDemo.py

@@ -0,0 +1,43 @@
+# -*- coding: utf-8 -*-
+#
+# Licensed under the terms of the PyQwt License
+# Copyright (C) 2003-2009 Gerard Vermeulen, for the original PyQwt example
+# Copyright (c) 2015 Pierre Raybaut, for the PyQt5/PySide port and further 
+# developments (e.g. ported to PythonQwt API)
+# (see LICENSE file for more details)
+
+SHOW = True # Show test in GUI-based test launcher
+
+import numpy as np
+
+np.seterr(all='raise')
+
+from qwt.qt.QtGui import QApplication, QPen
+from qwt.qt.QtCore import Qt
+from qwt import QwtPlot, QwtPlotCurve, QwtLogScaleEngine
+
+
+def create_log_plot():
+    plot = QwtPlot('LogCurveDemo.py (or how to handle -inf values)')
+    plot.enableAxis(QwtPlot.xBottom)
+    plot.setAxisScaleEngine(QwtPlot.yLeft, QwtLogScaleEngine())
+    curve = QwtPlotCurve()
+    curve.setRenderHint(QwtPlotCurve.RenderAntialiased)
+    pen = QPen(Qt.magenta)
+    pen.setWidth(1.5)
+    curve.setPen(pen)
+    curve.attach(plot)
+    x = np.arange(0.0, 10.0, 0.1)
+    y = 10*np.cos(x)**2-.1
+    print("y<=0:", y<=0)
+    curve.setData(x, y)
+    plot.replot()
+    return plot
+
+
+if __name__ == '__main__':
+    app = QApplication([])
+    plot = create_log_plot()
+    plot.resize(800, 500)
+    plot.show()
+    app.exec_()