I am working on GUI where I have a system with graphs.
I want to use the spanselector in the graph i do visualize.
I have searched and i can't understand how to use the span selector while calling the matplotlib widget.
This is an example i'm following to plot. it has 3 parts(main,mplwidget,ui file)
the main code file
# ------------------------------------------------------
# ---------------------- main.py -----------------------
# ------------------------------------------------------
from PyQt5.QtWidgets import*
from PyQt5.uic import loadUi
from matplotlib.backends.backend_qt5agg import (NavigationToolbar2QT as NavigationToolbar)
import numpy as np
import random
#from matplotlib.widgets import SpanSelector
class MatplotlibWidget(QMainWindow):
def __init__(self):
QMainWindow.__init__(self)
loadUi("qt_designer.ui",self)
self.setWindowTitle("PyQt5 & Matplotlib Example GUI")
self.pushButton_generate_random_signal.clicked.connect(self.update_graph)
self.addToolBar(NavigationToolbar(self.MplWidget.canvas, self))
def update_graph(self):
fs = 500
f = random.randint(1, 100)
ts = 1/fs
length_of_signal = 100
t = np.linspace(0,1,length_of_signal)
cosinus_signal = np.cos(2*np.pi*f*t)
sinus_signal = np.sin(2*np.pi*f*t)
self.MplWidget.canvas.axes.clear()
self.MplWidget.canvas.axes.plot(t, cosinus_signal)
self.MplWidget.canvas.axes.plot(t, sinus_signal)
self.MplWidget.canvas.axes.legend(('cosinus', 'sinus'),loc='upper right')
self.MplWidget.canvas.axes.set_title('Cosinus - Sinus Signal')
self.MplWidget.canvas.draw()
#span = self.MplWidget.canvas.axes.SpanSelector(ax1, onselect, 'horizontal', useblit=True,rectprops=dict(alpha=0.5, facecolor='red'))
def onselect(min_value, max_value):
print(min_value, max_value)
return min_value, max_value
app = QApplication([])
window = MatplotlibWidget()
window.show()
app.exec_()
the mplwidget file
# ------------------------------------------------------
# -------------------- mplwidget.py --------------------
# ------------------------------------------------------
from PyQt5.QtWidgets import*
from matplotlib.backends.backend_qt5agg import FigureCanvas
from matplotlib.figure import Figure
class MplWidget(QWidget):
def __init__(self, parent = None):
QWidget.__init__(self, parent)
self.canvas = FigureCanvas(Figure())
vertical_layout = QVBoxLayout()
vertical_layout.addWidget(self.canvas)
self.canvas.axes = self.canvas.figure.add_subplot(111)
self.setLayout(vertical_layout)
the ui file is attached to this link with all the codes: here
in the other way this is the example code to use the span selector:
import matplotlib.pyplot as plt
import matplotlib.widgets as mwidgets
fig, ax = plt.subplots()
ax.plot([1, 2, 3], [10, 50, 100])
def onselect(vmin, vmax):
print(vmin, vmax)
rectprops = dict(facecolor='blue', alpha=0.5)
span = mwidgets.SpanSelector(ax, onselect, 'horizontal',span_stays=True,button=1,,rectprops=rectprops)
fig.show()
//////////////////////////////////////////////////////////////////////////////
i tried a lot of ways to assess the span selector but im a little bit confused in the way it works and how i should connect the the structure of code?
if i run whithin The comented line:
span = self.MplWidget.canvas.axes.SpanSelector(ax1, onselect, 'horizontal', useblit=True,rectprops=dict(alpha=0.5, facecolor='red'))
its shown the following error:
AttributeError:'AxesSubplot' object has no attribute 'SpanSelector'
finally, this is the desire result
You have to pass the self.MplWidget.canvas.axes as ax:
# ...
self.MplWidget.canvas.draw()
self.span = SpanSelector(
self.MplWidget.canvas.axes,
self.onselect,
"horizontal",
useblit=True,
rectprops=dict(alpha=0.5, facecolor="red"),
)
def onselect(self, min_value, max_value):
print(min_value, max_value)Note: since select is a method of the class, it must have self as the first parameter, and it must be invoked with self.select.
