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#!/usr/bin/env python
# /*##########################################################################
#
# Copyright (c) 2016-2020 European Synchrotron Radiation Facility
#
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
#
# The above copyright notice and this permission notice shall be included in
# all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
# THE SOFTWARE.
#
# ###########################################################################*/
"""This script is a simple example of how to create a :class:`~silx.gui.plot.PlotWindow`
with a custom :class:`~silx.gui.plot.actions.PlotAction` added to the toolbar.
The action computes the FFT of all curves and plots their amplitude spectrum.
It also performs the reverse transform.
This example illustrates:
- how to create a checkable action
- how to store user info with a curve in a PlotWindow
- how to modify the graph title and axes labels
- how to add your own icon as a PNG file
See shiftPlotAction.py for a simpler example with more basic comments.
"""
__authors__ = ["P. Knobel"]
__license__ = "MIT"
__date__ = "27/06/2017"
import numpy
import os
import sys
from silx.gui import qt
from silx.gui.plot import PlotWindow
from silx.gui.plot.actions import PlotAction
# Custom icon
# make sure there is a "fft.png" file saved in the same folder as this script
scriptdir = os.path.dirname(os.path.realpath(__file__))
my_icon = os.path.join(scriptdir, "fft.png")
class FftAction(PlotAction):
"""QAction performing a Fourier transform on all curves when checked,
and reverse transform when unchecked.
:param plot: PlotWindow on which to operate
:param parent: See documentation of :class:`QAction`
"""
def __init__(self, plot, parent=None):
PlotAction.__init__(
self,
plot,
icon=qt.QIcon(my_icon),
text="FFT",
tooltip="Perform Fast Fourier Transform on all curves",
triggered=self.fftAllCurves,
checkable=True,
parent=parent,
)
def _rememberGraphLabels(self):
"""Store labels and title as attributes"""
self.original_title = self.plot.getGraphTitle()
self.original_xlabel = self.plot.getXAxis().getLabel()
self.original_ylabel = self.plot.getYAxis().getLabel()
def fftAllCurves(self, checked=False):
"""Get all curves from our PlotWindow, compute the amplitude spectrum
using a Fast Fourier Transform, replace all curves with their
amplitude spectra.
When un-checking the button, do the reverse transform.
:param checked: Boolean parameter signaling whether the action
has been checked or unchecked.
"""
allCurves = self.plot.getAllCurves(withhidden=True)
if checked:
# remember original labels
self._rememberGraphLabels()
# change them
self.plot.setGraphTitle("Amplitude spectrum")
self.plot.getXAxis().setLabel("Frequency")
self.plot.getYAxis().setLabel("Amplitude")
else:
# restore original labels
self.plot.setGraphTitle(self.original_title)
self.plot.getXAxis().setLabel(self.original_xlabel)
self.plot.getYAxis().setLabel(self.original_ylabel)
self.plot.clearCurves()
for curve in allCurves:
x = curve.getXData()
y = curve.getYData()
legend = curve.getName()
info = curve.getInfo()
if info is None:
info = {}
if checked:
# FAST FOURIER TRANSFORM
fft_y = numpy.fft.fft(y)
# amplitude spectrum
A = numpy.abs(fft_y)
# sampling frequency (samples per X unit)
Fs = len(x) / (max(x) - min(x))
# frequency array (abscissa of new curve)
F = [k * Fs / len(x) for k in range(len(A))]
# we need to store the complete transform (complex data) to be
# able to perform the reverse transform.
info["complex fft"] = fft_y
info["original x"] = x
# plot the amplitude spectrum
self.plot.addCurve(F, A, legend="FFT of " + legend, info=info)
else:
# INVERSE FFT
fft_y = info["complex fft"]
# we keep only the real part because we know the imaginary
# part is 0 (our original data was real numbers)
y1 = numpy.real(numpy.fft.ifft(fft_y))
# recover original info
x1 = info["original x"]
legend1 = legend[7:] # remove "FFT of "
# remove restored data from info dict
for key in ["complex fft", "original x"]:
del info[key]
# plot the original data
self.plot.addCurve(x1, y1, legend=legend1, info=info)
self.plot.resetZoom()
app = qt.QApplication([])
sys.excepthook = qt.exceptionHandler
plotwin = PlotWindow(control=True)
toolbar = qt.QToolBar("My toolbar")
plotwin.addToolBar(toolbar)
myaction = FftAction(plotwin)
toolbar.addAction(myaction)
# x range: 0 -- 10 (1000 points)
x = numpy.arange(1000) * 0.01
twopi = 2 * numpy.pi
# Sum of sine functions with frequencies 3, 20 and 42 Hz
y1 = (
numpy.sin(twopi * 3 * x)
+ 1.5 * numpy.sin(twopi * 20 * x)
+ 2 * numpy.sin(twopi * 42 * x)
)
# Cosine with frequency 7 Hz and phase pi / 3
y2 = numpy.cos(twopi * 7 * (x - numpy.pi / 3))
# 5 periods of square wave, amplitude 2
y3 = numpy.zeros_like(x)
for i in [0, 2, 4, 6, 8]:
y3[i * len(x) // 10 : (i + 1) * len(x) // 10] = 2
plotwin.addCurve(x, y1, legend="sin")
plotwin.addCurve(x, y2, legend="cos")
plotwin.addCurve(x, y3, legend="square wave")
plotwin.setGraphTitle("Original data")
plotwin.getYAxis().setLabel("amplitude")
plotwin.getXAxis().setLabel("time")
plotwin.show()
app.exec()
sys.excepthook = sys.__excepthook__
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