I am trying to plot some random data using `pyqtgraph`. I used the
"scrolling graph" example from "`pyqtgraph.examples`" as template to create
a plot for my data.
I have defined two functions here one for button event and other for
update data.
I want to plot the data when the checkbox and plot button is clicked.
I found many more examples like this "Updating and PlotWidgets in
PyQt4 for Live Plotting" but din't get idea how to use it for
`pg.PlotWidget()`.
The below code I found in "`pyqtgraph.examples`" and here they used
`GraphicsWindow()`.
def update():
global data, curve, ptr
data[:-1] = data[1:]
data[-1] = np.random.normal()
curve.setData(data)
ptr += 1
curve.setData(data)
curve.setPos(ptr, 0)
timer = pg.QtCore.QTimer()
timer.timeout.connect(update)
timer.start(50)
But in my code i am using `self.graphicsView =
pg.PlotWidget(self.centralwidget)`. Here the graph is static and its not
rolling.So here i want to update the data but here data is not updating and
plot is not moving .
Can anyone help how can i update the data an how to use `plotWidget` and
`QTimer`?
class Ui_MainWindow(QtGui.QWidget):
def __init__(self, parent=None):
super(Ui_MainWindow, self).__init__(parent)
# Desired Frequency (Hz) = 1 / self.FREQUENCY
# USE FOR TIME.SLEEP (s)
self.FREQUENCY = .004
# Frequency to update plot (ms)
# USE FOR TIMER.TIMER (ms)
self.TIMER_FREQUENCY = self.FREQUENCY * 1000
# Set X Axis range. If desired is [-10,0] then set LEFT_X = -10
and RIGHT_X = 0
self.LEFT_X = 0
self.RIGHT_X = 3
self.X_Axis = np.arange(self.LEFT_X, self.RIGHT_X,
self.FREQUENCY)
self.buffer = int((abs(self.LEFT_X) +
abs(self.RIGHT_X))/self.FREQUENCY)
self.data = []
self.graphicsView = pg.PlotWidget(self.centralwidget)
## self.graphicsView = pg.PlotWidget()
self.graphicsView.plotItem.setMouseEnabled(x=False, y=False)
self.graphicsView.setXRange(self.LEFT_X, self.RIGHT_X)
self.graphicsView.setTitle('Scrolling Plot Example')
self.graphicsView.setLabel('left', 'Value')
self.graphicsView.setLabel('bottom', 'Time (s)')
self.scrolling_plot = self.graphicsView.plot()
## self.scrolling_plot.setPen(197,235,255)
self.layout = QtGui.QGridLayout()
self.layout.addWidget(self.graphicsView)
self.read_position_thread()
self.start()
def start(self):
self.position_update_timer = QtCore.QTimer()
self.position_update_timer.timeout.connect(self.Plot_Button)
self.position_update_timer.start(self.get_scrolling_plot_timer_frequency())
def read_position_thread(self):
self.current_position_value = 0
self.old_current_position_value = 0
self.position_update_thread = Thread(target=self.read_position,
args=())
self.position_update_thread.daemon = True
self.position_update_thread.start()
def read_position(self):
frequency = self.get_scrolling_plot_frequency()
while True:
try:
self.current_position_value = random.randint(1,101)
self.old_current_position_value =
self.current_position_value
time.sleep(frequency)
except:
self.current_position_value =
self.old_current_position_value
def Plot_Button(self):
if self.Sensor1.isChecked():
self.dataPoint = float(self.current_position_value)
if len(self.data) >= self.buffer:
del self.data[:1]
self.data.append(self.dataPoint)
self.scrolling_plot.setData(self.X_Axis[len(self.X_Axis) -
len(self.data):], self.data)
def clear_scrolling_plot(self):
self.data[:] = []
def get_scrolling_plot_frequency(self):
return self.FREQUENCY
def get_scrolling_plot_timer_frequency(self):
return self.TIMER_FREQUENCY
def get_scrolling_plot_layout(self):
return self.layout
def get_current_position_value(self):
return self.current_position_value
def get_scrolling_plot_widget(self):
return self.graphicsView
def Pause_Button(self):
QCoreApplication.instance().quit()
print("fail")
def setupUi(self, MainWindow):
MainWindow.setObjectName("MainWindow")
MainWindow.resize(795, 359)
self.centralwidget = QtWidgets.QWidget(MainWindow)
self.centralwidget.setObjectName("centralwidget")
self.Plot = QtWidgets.QPushButton(self.centralwidget)
self.Plot.setGeometry(QtCore.QRect(530, 260, 80, 23))
self.Plot.setObjectName("Plot")
self.Plot.clicked.connect(self.Plot_Button)
self.Pause = QtWidgets.QPushButton(self.centralwidget)
self.Pause.setGeometry(QtCore.QRect(620, 260, 80, 23))
self.Pause.setObjectName("Pause")#
self.Pause.clicked.connect(self.Pause_Button)
self.frame = QtWidgets.QFrame(self.centralwidget)
self.frame.setGeometry(QtCore.QRect(520, 10, 251, 291))
self.frame.setFrameShape(QtWidgets.QFrame.StyledPanel)
self.frame.setFrameShadow(QtWidgets.QFrame.Raised)
self.frame.setObjectName("frame")
self.label = QtWidgets.QLabel(self.frame)
self.label.setGeometry(QtCore.QRect(140, 6, 101, 20))
## self.label.setObjectName("Sampling Frequency")
self.label.setObjectName("label")
self.label_2 = QtWidgets.QLabel(self.frame)
self.label_2.setGeometry(QtCore.QRect(150, 40, 51, 20))
## self.label_2.setObjectName("Offset")
self.label_2.setObjectName("label_2")
self.Sensor1 = QtWidgets.QCheckBox(self.frame)
self.Sensor1.setGeometry(QtCore.QRect(30, 70, 74, 21))
self.Sensor1.setObjectName("Sensor1")
self.Sensor2 = QtWidgets.QCheckBox(self.frame)
self.Sensor2.setGeometry(QtCore.QRect(30, 90, 74, 21))
self.Sensor2.setObjectName("Sensor2")
self.Sensor3 = QtWidgets.QCheckBox(self.frame)
self.Sensor3.setGeometry(QtCore.QRect(30, 110, 74, 21))
self.Sensor3.setObjectName("Sensor3")
self.Sensor4 = QtWidgets.QCheckBox(self.frame)
self.Sensor4.setGeometry(QtCore.QRect(30, 130, 71, 21))
self.Sensor4.setObjectName("Sensor4")
self.Sensor5 = QtWidgets.QCheckBox(self.frame)
self.Sensor5.setGeometry(QtCore.QRect(30, 150, 74, 21))
self.Sensor5.setObjectName("Sensor5")
self.Sensor6 = QtWidgets.QCheckBox(self.frame)
self.Sensor6.setGeometry(QtCore.QRect(30, 170, 74, 21))
self.Sensor6.setObjectName("Sensor6")
self.Sensor7 = QtWidgets.QCheckBox(self.frame)
self.Sensor7.setGeometry(QtCore.QRect(30, 190, 74, 21))
self.Sensor7.setObjectName("Sensor7")
self.Sensor8 = QtWidgets.QCheckBox(self.frame)
self.Sensor8.setGeometry(QtCore.QRect(30, 210, 71, 21))
self.Sensor8.setObjectName("Sensor8")
self.lineEdit_1 = QtWidgets.QLineEdit(self.frame)
self.lineEdit_1.setGeometry(QtCore.QRect(20, 10, 113, 21))
self.lineEdit_1.setObjectName("lineEdit_1")
self.lineEdit_2 = QtWidgets.QLineEdit(self.frame)
self.lineEdit_2.setGeometry(QtCore.QRect(20, 40, 113, 20))
self.lineEdit_2.setObjectName("lineEdit_2")
## self.graphicsView =
QtWidgets.QGraphicsView(self.centralwidget)
self.graphicsView = pg.PlotWidget(self.centralwidget)
## self.graphicsView.setXRange(self.LEFT_X, self.RIGHT_X)
self.graphicsView.setLabel('bottom', 'Time (s)')
self.graphicsView.setLabel('left', 'Value')
self.graphicsView.setGeometry(QtCore.QRect(5, 11, 501, 291))
self.graphicsView.setObjectName("graphicsView")
self.frame.raise_()
self.Plot.raise_()
self.Pause.raise_()
self.graphicsView.raise_()
MainWindow.setCentralWidget(self.centralwidget)
self.menubar = QtWidgets.QMenuBar(MainWindow)
self.menubar.setGeometry(QtCore.QRect(0, 0, 795, 21))
self.menubar.setObjectName("menubar")
self.menuFile = QtWidgets.QMenu(self.menubar)
self.menuFile.setObjectName("menuFile")
self.menuAbout = QtWidgets.QMenu(self.menubar)
self.menuAbout.setObjectName("menuAbout")
MainWindow.setMenuBar(self.menubar)
self.statusbar = QtWidgets.QStatusBar(MainWindow)
self.statusbar.setObjectName("statusbar")
MainWindow.setStatusBar(self.statusbar)
self.actionOpen = QtWidgets.QAction(MainWindow)
self.actionOpen.setObjectName("actionOpen")
self.actionSave_As = QtWidgets.QAction(MainWindow)
self.actionSave_As.setObjectName("actionSave_As")
self.actionScreenshot = QtWidgets.QAction(MainWindow)
self.actionScreenshot.setObjectName("actionScreenshot")
self.actionExit = QtWidgets.QAction(MainWindow)
self.actionExit.setObjectName("actionExit")
self.menuFile.addAction(self.actionOpen)
self.menuFile.addAction(self.actionSave_As)
self.menuFile.addAction(self.actionScreenshot)
self.menuFile.addAction(self.actionExit)
self.menubar.addAction(self.menuFile.menuAction())
self.menubar.addAction(self.menuAbout.menuAction())
self.retranslateUi(MainWindow)
QtCore.QMetaObject.connectSlotsByName(MainWindow)
def retranslateUi(self, MainWindow):
_translate = QtCore.QCoreApplication.translate
MainWindow.setWindowTitle(_translate("MainWindow",
"MainWindow"))
self.Plot.setText(_translate("MainWindow", "Plot"))
self.Pause.setText(_translate("MainWindow", "Pause"))
self.label.setText(_translate("MainWindow", "Sampling
Frequency"))
self.label_2.setText(_translate("MainWindow", "Offset"))
self.Sensor1.setText(_translate("MainWindow", "Sensor1"))
self.Sensor2.setText(_translate("MainWindow", "Sensor2"))
self.Sensor3.setText(_translate("MainWindow", "Sensor3"))
self.Sensor4.setText(_translate("MainWindow", "Sensor4"))
self.Sensor5.setText(_translate("MainWindow", "Sensor5"))
self.Sensor6.setText(_translate("MainWindow", "Sensor6"))
self.Sensor7.setText(_translate("MainWindow", "Sensor7"))
self.Sensor8.setText(_translate("MainWindow", "Sensor8"))
self.menuFile.setTitle(_translate("MainWindow", "File"))
self.menuAbout.setTitle(_translate("MainWindow", "About"))
self.actionOpen.setText(_translate("MainWindow", "Open"))
self.actionSave_As.setText(_translate("MainWindow", "Save As"))
self.actionScreenshot.setText(_translate("MainWindow",
"Screenshot"))
self.actionExit.setText(_translate("MainWindow", "Exit"))
if __name__ == "__main__":
import sys
app = QtWidgets.QApplication(sys.argv)
MainWindow = QtWidgets.QMainWindow()
ui = Ui_MainWindow()
ui.setupUi(MainWindow)
MainWindow.show()
sys.exit(app.exec_())
if (sys.flags.interactive != 1) or not hasattr(QtCore,
'PYQT_VERSION'):
QtGui.QApplication.instance().exec_()
Now I made changes in my code. Values are updating but I am not able to
see the graph on widget since I am using `self.graphicsView =
pg.PlotWidget(self.centralwidget)` inside the function .
In the above example they using `self.scrolling_plot_widget =
pg.PlotWidget()`.
How do I change it for plotting in `pg.PlotWidget(self.centralwidget)`.
where I am missing the code and where and in which funcion i need to call
the PlotWidget()????.
On Monday, 30 June 2014 00:13:40 UTC+5:30, Federico Bolaños wrote:
>
>
> Hello everyone!
>
> I am wondering if it's possible to develop a script that uses pyqtgraph
> and mimics the performance of this script:
> https://www.youtube.com/watch?v=HsV-LK3KO1U#t=77
> source code:
> http://www.swharden.com/blog/2012-06-14-multichannel-usb-analog-sensor-with-atmega48/
>
> If so, could anyone point me to an example that does this? or help me
> write part of the code?
>
> The reason I don't want to use that particular script is because I think
> pyqtgraph will offer much more flexibility, I can resize the plot, perhaps
> have another plot that does an FFT of the signal, or even do real time
> signal processing which may be harder to implement on that example script.
>
> In short, I want to be able to plot the signal coming from an ADC as fast
> as I can. I wrote a class that allows me to interface with said ADC and I
> would like to obtain the data as fast as I can and at the same time plot
> the data a correct time x axis. The ADC class that I wrote returns an
> integer each time it is polled, sort of like if I were to do
> random.randint(0, 1024).
>
> I have been looking for an example that uses this library since it is very
> lightweight and runs nicely on a raspberry pi! (So does the above script,
> but I would really like the flexibility that pyqtgraph provides)
>
>
> Thanks for reading,
> Federico
>
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