Slider in PyQt5 is used to set a value with the help of an indicator which can move back and forth over a graphical slide or bar. Many times one needs to provide values which lie between a range and in such cases slider is very useful. QSlider is the class used to add slider in an application.
Example:
A window has a slider and a label(QSlider). The size of the text gets scaled in or out as one move the indicator of the slider.
from PyQt5 import QtCore, QtGui, QtWidgets import sys class Ui_MainWindow(object): def setupUi(self, MainWindow): MainWindow.resize(550, 393) self.centralwidget = QtWidgets.QWidget(MainWindow) self.centralwidget.setObjectName("centralwidget") self.slider = QtWidgets.QSlider(self.centralwidget) self.slider.setGeometry(QtCore.QRect(190, 100, 160, 16)) self.slider.setOrientation(QtCore.Qt.Horizontal) # After each value change, slot "scaletext" will get invoked. self.slider.valueChanged.connect(self.scaletext) self.label = QtWidgets.QLabel(self.centralwidget) self.label.setGeometry(QtCore.QRect(230, 150, 301, 161)) # set initial font size of label. self.font = QtGui.QFont() self.font.setPointSize(7) self.label.setFont(self.font) MainWindow.setCentralWidget(self.centralwidget) self.retranslateUi(MainWindow) QtCore.QMetaObject.connectSlotsByName(MainWindow) def retranslateUi(self, MainWindow): _translate = QtCore.QCoreApplication.translate MainWindow.setWindowTitle(_translate("MainWindow", "MainWindow")) self.label.setText(_translate("MainWindow", "QSlider")) def scaletext(self, value): # Change font size of label. Size value could # be anything consistent with the dimension of label. self.font.setPointSize(7 + value//2) self.label.setFont(self.font) if __name__ == "__main__": app = QtWidgets.QApplication(sys.argv) MainWindow = QtWidgets.QMainWindow() ui = Ui_MainWindow() ui.setupUi(MainWindow) MainWindow.show() sys.exit(app.exec_()) |
Output:
