mohammaadhaji9056 | 2020-12-16 11:23:10 UTC | #1
I'm following this tutorial on how to embed pyqtgraph in pyqt5.
I need to enable pyqtgraph to show cursor position. but i don't know how to do that. please help me.
martin | 2021-01-23 16:18:06 UTC | #2
Hi @mohammaadhaji9056
This is a little trickier than I expected, but I've got it figured out. You need to manually draw the crosshair yourself, and then update the position of those lines based on mouse movements using a signal proxy.
Create GUI Applications with Python & Qt5 by Martin Fitzpatrick — (PyQt5 Edition) The hands-on guide to making apps with Python — Over 10,000 copies sold!
The code below is an updated version of the example on the site, adding the crosshair lines. The lines are drawn in the plot() method, and then updated in the mouseMoved method. See the SignalProxy which forwards mouse movements to this custom handler.
from PyQt5 import QtWidgets, QtCore
from pyqtgraph import PlotWidget, plot
import pyqtgraph as pg
import sys # We need sys so that we can pass argv to QApplication
import os
class MainWindow(QtWidgets.QMainWindow):
def __init__(self, *args, **kwargs):
super().__init__(*args, **kwargs)
self.graphWidget = pg.PlotWidget()
self.setCentralWidget(self.graphWidget)
hour = [1,2,3,4,5,6,7,8,9,10]
temperature = [30,32,34,32,33,31,29,32,35,45]
#Add Background colour to white
self.graphWidget.setBackground('w')
# Add Title
self.graphWidget.setTitle("Your Title Here", color="b", size="30pt")
# Add Axis Labels
styles = {"color": "#f00", "font-size": "20px"}
self.graphWidget.setLabel("left", "Temperature (°C)", **styles)
self.graphWidget.setLabel("bottom", "Hour (H)", **styles)
#Add legend
self.graphWidget.addLegend()
#Add grid
self.graphWidget.showGrid(x=True, y=True)
#Set Range
self.graphWidget.setXRange(0, 10, padding=0)
self.graphWidget.setYRange(20, 55, padding=0)
pen = pg.mkPen(color=(255, 0, 0))
self.graphWidget.plot(hour, temperature, name="Sensor 1", pen=pen, symbol='+', symbolSize=30, symbolBrush=('b'))
# Add crosshair lines.
self.crosshair_v = pg.InfiniteLine(angle=90, movable=False)
self.crosshair_h = pg.InfiniteLine(angle=0, movable=False)
self.graphWidget.addItem(self.crosshair_v, ignoreBounds=True)
self.graphWidget.addItem(self.crosshair_h, ignoreBounds=True)
self.proxy = pg.SignalProxy(self.graphWidget.scene().sigMouseMoved, rateLimit=60, slot=self.mouseMoved)
def mouseMoved(self, e):
pos = e[0]
if self.graphWidget.sceneBoundingRect().contains(pos):
mousePoint = self.graphWidget.getPlotItem().vb.mapSceneToView(pos)
self.crosshair_v.setPos(mousePoint.x())
self.crosshair_h.setPos(mousePoint.y())
app = QtWidgets.QApplication(sys.argv)
main = MainWindow()
main.show()
sys.exit(app.exec_())
