1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
|
#!/usr/bin/env python
# coding: utf-8
# /*##########################################################################
#
# 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__
|
