I want to display an image using QGraphicsView in a window. I have a basic QGraphicsView and a button based test.ui file generated from QtDesigner tool. Corresponding test.py file:
# -*- coding: utf-8 -*-
# Form implementation generated from reading ui file 'test.ui'
#
# Created by: PyQt5 UI code generator 5.9.2
#
# WARNING! All changes made in this file will be lost!
from PyQt5 import QtCore, QtGui, QtWidgets
class Ui_MainWindow(object):
def setupUi(self, MainWindow):
MainWindow.setObjectName("MainWindow")
MainWindow.resize(640, 480)
self.centralwidget = QtWidgets.QWidget(MainWindow)
self.centralwidget.setObjectName("centralwidget")
self.verticalLayout = QtWidgets.QVBoxLayout(self.centralwidget)
self.verticalLayout.setObjectName("verticalLayout")
self.graphicsView = QtWidgets.QGraphicsView(self.centralwidget)
self.graphicsView.setVerticalScrollBarPolicy(QtCore.Qt.ScrollBarAlwaysOn)
self.graphicsView.setHorizontalScrollBarPolicy(QtCore.Qt.ScrollBarAlwaysOn)
self.graphicsView.setObjectName("graphicsView")
self.verticalLayout.addWidget(self.graphicsView)
self.pushButton = QtWidgets.QPushButton(self.centralwidget)
self.pushButton.setObjectName("pushButton")
self.verticalLayout.addWidget(self.pushButton)
MainWindow.setCentralWidget(self.centralwidget)
self.menubar = QtWidgets.QMenuBar(MainWindow)
self.menubar.setGeometry(QtCore.QRect(0, 0, 640, 26))
self.menubar.setObjectName("menubar")
MainWindow.setMenuBar(self.menubar)
self.statusbar = QtWidgets.QStatusBar(MainWindow)
self.statusbar.setObjectName("statusbar")
MainWindow.setStatusBar(self.statusbar)
self.retranslateUi(MainWindow)
QtCore.QMetaObject.connectSlotsByName(MainWindow)
def retranslateUi(self, MainWindow):
_translate = QtCore.QCoreApplication.translate
MainWindow.setWindowTitle(_translate("MainWindow", "MainWindow"))
self.pushButton.setText(_translate("MainWindow", "PushButton"))
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_())
I made use of QGraphicsScene to display an image inside this QGraphicsView. My current working solution is to mess up the above .py file as follows:
# -*- coding: utf-8 -*-
# Form implementation generated from reading ui file 'test.ui'
#
# Created by: PyQt5 UI code generator 5.9.2
#
# WARNING! All changes made in this file will be lost!
from PyQt5 import QtCore, QtGui, QtWidgets
class Ui_MainWindow(object):
def setupUi(self, MainWindow):
MainWindow.setObjectName("MainWindow")
MainWindow.resize(640, 480)
self.centralwidget = QtWidgets.QWidget(MainWindow)
self.centralwidget.setObjectName("centralwidget")
self.verticalLayout = QtWidgets.QVBoxLayout(self.centralwidget)
self.verticalLayout.setObjectName("verticalLayout")
self.scene = QtWidgets.QGraphicsScene(self.centralwidget) #added
self.graphicsView = QtWidgets.QGraphicsView(self.scene) #edited
self.graphicsView.setVerticalScrollBarPolicy(QtCore.Qt.ScrollBarAlwaysOn)
self.graphicsView.setHorizontalScrollBarPolicy(QtCore.Qt.ScrollBarAlwaysOn)
self.graphicsView.setObjectName("graphicsView")
self.verticalLayout.addWidget(self.graphicsView)
self.pushButton = QtWidgets.QPushButton(self.centralwidget)
self.pushButton.setObjectName("pushButton")
self.verticalLayout.addWidget(self.pushButton)
MainWindow.setCentralWidget(self.centralwidget)
self.menubar = QtWidgets.QMenuBar(MainWindow)
self.menubar.setGeometry(QtCore.QRect(0, 0, 640, 26))
self.menubar.setObjectName("menubar")
MainWindow.setMenuBar(self.menubar)
self.statusbar = QtWidgets.QStatusBar(MainWindow)
self.statusbar.setObjectName("statusbar")
MainWindow.setStatusBar(self.statusbar)
self.retranslateUi(MainWindow)
QtCore.QMetaObject.connectSlotsByName(MainWindow)
def retranslateUi(self, MainWindow):
_translate = QtCore.QCoreApplication.translate
MainWindow.setWindowTitle(_translate("MainWindow", "MainWindow"))
self.pushButton.setText(_translate("MainWindow", "PushButton"))
self.pushButton.clicked.connect(self.display)
def display(self):
import imageio, numpy
self.scene.clear()
input_image = imageio.imread('image.jpg').copy()
height, width, channels = input_image.shape
bytesPerLine = channels * width
qimg = QtGui.QImage(input_image, width, height, bytesPerLine, QtGui.QImage.Format_RGB888)
self.pixmap = QtGui.QPixmap.fromImage(qimg)
self.scene.addPixmap(self.pixmap) #add pixmap to scene
self.graphicsView.scale(0.5,0.5)
self.scene.update()
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_())
However, this solution is not systematic. I want to do the same without editing the original test.ui generated test.py file.
So, I tried following code which to me appears like a systematic translation of the previous working code. However, it fails to produce any display on button click:
from PyQt5 import QtCore, QtGui, QtWidgets
from test import Ui_MainWindow
class myWindow(QtWidgets.QMainWindow, Ui_MainWindow):
def __init__(self, parent=None):
QtWidgets.QMainWindow.__init__(self, parent=parent)
self.setupUi(self)
self.scene = QtWidgets.QGraphicsScene(self.centralwidget) #append scene method
self.graphicsView = QtWidgets.QGraphicsView(self.scene) #graphicsView re-assigned with scene
self.pushButton.clicked.connect(self.display)
def display(self):
import imageio, numpy
self.scene.clear()
input_image = imageio.imread('image.jpg').copy()
height, width, channels = input_image.shape
bytesPerLine = channels * width
qimg = QtGui.QImage(input_image, width, height, bytesPerLine, QtGui.QImage.Format_RGB888)
self.pixmap = QtGui.QPixmap.fromImage(qimg)
self.scene.addPixmap(self.pixmap) #add pixmap to scene
self.graphicsView.scale(0.5,0.5)
self.scene.update()
if __name__ == "__main__":
import sys
app = QtWidgets.QApplication(sys.argv)
w = myWindow()
w.show()
sys.exit(app.exec_())
I am likely messing up something due to my limited understanding of class inheritance, QGraphicsView, and QGraphicsScene. Any pointers to my mistakes would be very helpful.
Note: I am using a myWindow class to integrate some key press functionality in future. I think the issue is more to do with how to selectively append/redefine few lines inside a parent class function. Is this even possible without re-writing the whole setupUi method? Or, is there another smarter way to perform the same task?
You have to set the scene to the existing QGraphicsView instead of creating a new QGraphicsView:
class myWindow(QtWidgets.QMainWindow, Ui_MainWindow):
def __init__(self, parent=None):
QtWidgets.QMainWindow.__init__(self, parent)
self.setupUi(self)
self.scene = QtWidgets.QGraphicsScene(self.centralwidget)
self.graphicsView.setScene(self.scene)
self.pushButton.clicked.connect(self.display)
def display(self):
# ...
Related
I have two files, "main.py", "debugger.py".
On "debugger.py" I have a "textEdit" where I want to get/show messages.
On "main.py" I import and instantiate the class from "debugger.py" but instead of just sending/showing the messages, it opens the "debugger.py" window UI and shows the messages, i just need to send the message without opening the window, how can I do that?
"debugger.py".
import os, time
from PyQt5 import QtCore, QtGui, QtWidgets
from PyQt5.QtGui import QTextCursor
class Debugger_MainWindow(object):
def __init__(self):
super().__init__()
#def print_text(self):
#self.txtEdit_debugger.insertPlainText('hi')
def Debugger_setupUi(self, MainWindow):
MainWindow.setObjectName("MainWindow")
MainWindow.resize(800, 600)
self.centralwidget = QtWidgets.QWidget(MainWindow)
self.centralwidget.setObjectName("centralwidget")
self.lbl_info = QtWidgets.QLabel(self.centralwidget)
self.lbl_info.setGeometry(QtCore.QRect(90, 450, 451, 61))
self.lbl_info.setObjectName("lbl_info")
self.lbl_tittle = QtWidgets.QLabel(self.centralwidget)
self.lbl_tittle.setGeometry(QtCore.QRect(280, 40, 56, 15))
self.lbl_tittle.setObjectName("lbl_tittle")
self.txtEdit_debugger = QtWidgets.QTextEdit(self.centralwidget)
#self.txtEdit_debugger.setEnabled(False)
self.txtEdit_debugger.setGeometry(QtCore.QRect(70, 80, 481, 361))
self.txtEdit_debugger.setObjectName("txtEdit_debugger")
self.txtEdit_debugger.setReadOnly(True)
##Check box on/off
self.chkb_on_off_debugger = QtWidgets.QCheckBox(self.centralwidget)
self.chkb_on_off_debugger.setGeometry(QtCore.QRect(90, 500, 30, 20))
self.chkb_on_off_debugger.setObjectName("chkb_on_off_debugger")
#self.chkb_on_off_debugger.stateChanged.connect(self.print_text)#Show logger messages
self.chkb_on_off_debugger.setCheckable(True)
self.lbl_on_off_debugger = QtWidgets.QLabel(self.centralwidget)
self.lbl_on_off_debugger.setGeometry(QtCore.QRect(110, 500, 60, 20))
self.lbl_on_off_debugger.setObjectName("lbl_on_off_debugger")
MainWindow.setCentralWidget(self.centralwidget)
self.statusbar = QtWidgets.QStatusBar(MainWindow)
self.statusbar.setObjectName("statusbar")
MainWindow.setStatusBar(self.statusbar)
self.retranslateUi(MainWindow)
QtCore.QMetaObject.connectSlotsByName(MainWindow)
def retranslateUi(self, MainWindow):
_translate = QtCore.QCoreApplication.translate
MainWindow.setWindowTitle(_translate("MainWindow", "MainWindow"))
self.lbl_info.setText(_translate("MainWindow", "This is read only mode. "))
self.lbl_tittle.setText(_translate("MainWindow", "Debugger"))
self.lbl_on_off_debugger.setText(_translate("MainWindow", "Show messages"))
self.lbl_on_off_debugger.adjustSize()
if __name__ == "__main__":
import sys
app = QtWidgets.QApplication(sys.argv)
MainWindow = QtWidgets.QMainWindow()
ui = Debugger_MainWindow()
ui.Debugger_setupUi(MainWindow)
MainWindow.show()
sys.exit(app.exec_())
"main.py"
from PyQt5 import QtCore, QtGui, QtWidgets
from PyQt5.QtWidgets import *
from PyQt5.QtCore import pyqtSlot, QThreadPool, QTimer
from PyQt5.QtGui import QColor, QKeySequence, QIcon, QTextCursor
from Debugger import Debugger_MainWindow
class Ui_MainWindow(object):
def __init__(self):
super().__init__()
###### Methods
#this method opens a new window, i just want to send the message
def print_text(self):
self.ui_debugger = Debugger_MainWindow()
self.ui_debugger.Debugger_setupUi(MainWindow)
self.ui_debugger.txtEdit_debugger.insertPlainText('hi')
def setupUi(self, MainWindow):
MainWindow.setObjectName("MainWindow")
MainWindow.resize(500, 500)
MainWindow.setStyleSheet(open("styles.qss", "r").read())
self.centralwidget = QtWidgets.QWidget(MainWindow)
self.centralwidget.setObjectName("centralwidget")
##Group box
self.gpb_spell_main = QtWidgets.QGroupBox(self.centralwidget)
self.gpb_spell_main.setGeometry(QtCore.QRect(10, 5, 290, 230))
self.gpb_spell_main.setObjectName("gpb_spell_main")
self.gpb_spell_main.setCheckable(True)
self.gpb_spell_main.setChecked(False)
##Button
spell_main_color = QColor(255, 0, 255)
self.btn_spell_main = QtWidgets.QPushButton(self.gpb_spell_main)
self.btn_spell_main.setGeometry(QtCore.QRect(10, 35, 85, 27))
self.btn_spell_main.setObjectName("btn_spell_main")
self.btn_spell_main.clicked.connect(self.print_text)
#self.btn_spell_main.setEnabled(False)
MainWindow.setCentralWidget(self.centralwidget)
self.statusbar = QtWidgets.QStatusBar(MainWindow)
self.statusbar.setObjectName("statusbar")
MainWindow.setStatusBar(self.statusbar)
self.retranslateUi(MainWindow)
QtCore.QMetaObject.connectSlotsByName(MainWindow)
def retranslateUi(self, MainWindow):
_translate = QtCore.QCoreApplication.translate
MainWindow.setWindowTitle(_translate("MainWindow", "MainWindow"))
self.gpb_spell_main.setTitle(_translate("HeallingWindow", "Spell Main"))
self.btn_spell_main.setText(_translate("MainWindow", "Click Here"))
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_())
Note: I couldn't fix my issue reading similar questions. PyQt5 - Show QDialog from a different class
I don't know if I understand problem but you may have to create new QtWidgets.QMainWindow() to create separated Debug Window. If you use existing MainWindow then it replaces widgets in existing window.
You may also set None to Debug Window in __init__ and later check if Debug Window is not None - to create only one window.
class Ui_MainWindow(object):
def __init__(self):
super().__init__()
self.DebugWindow = None
def print_text(self):
if self.DebugWindow is None:
self.DebugWindow = QtWidgets.QMainWindow()
self.ui_debugger = Debugger_MainWindow()
self.ui_debugger.Debugger_setupUi(self.DebugWindow)
self.DebugWindow.show()
self.ui_debugger.txtEdit_debugger.insertPlainText('hi\n')
Other problem cam be when you close Debug Window because it will not opne it again. It may need to change code in Debug Window and assign function which will hide it instead of destroing it.
This is a sample code with just a push button and a textedit, i need to write line x line using a loop in a textedit when button is clicked.
The problem is that i need to implement threads because without them the program crashes or it doesn't write line x line, but all together when the loop ends;
and i need to implement in my application a textedit that shows info while the program loads "something".
So my question is, how to rewrite this code using threads to write in textedit when button is clicked?
The method i should run when the button is clicked is "write"
it should work like a print inside a for loop , it would print not all at once
from PyQt5 import QtCore, QtGui, QtWidgets
class Ui_MainWindow(object):
def setupUi(self, MainWindow):
MainWindow.setObjectName("MainWindow")
MainWindow.resize(640, 480)
self.centralwidget = QtWidgets.QWidget(MainWindow)
self.centralwidget.setObjectName("centralwidget")
self.textEdit = QtWidgets.QTextEdit(self.centralwidget)
self.textEdit.setGeometry(QtCore.QRect(150, 220, 321, 71))
self.textEdit.setObjectName("textEdit")
self.pushButton = QtWidgets.QPushButton(self.centralwidget)
self.pushButton.setGeometry(QtCore.QRect(240, 100, 75, 23))
self.pushButton.setObjectName("pushButton")
MainWindow.setCentralWidget(self.centralwidget)
self.menubar = QtWidgets.QMenuBar(MainWindow)
self.menubar.setGeometry(QtCore.QRect(0, 0, 640, 21))
self.menubar.setObjectName("menubar")
MainWindow.setMenuBar(self.menubar)
self.statusbar = QtWidgets.QStatusBar(MainWindow)
self.statusbar.setObjectName("statusbar")
MainWindow.setStatusBar(self.statusbar)
self.retranslateUi(MainWindow)
QtCore.QMetaObject.connectSlotsByName(MainWindow)
def retranslateUi(self, MainWindow):
_translate = QtCore.QCoreApplication.translate
MainWindow.setWindowTitle(_translate("MainWindow", "MainWindow"))
self.pushButton.setText(_translate("MainWindow", "PushButton"))
self.pushButton.clicked.connect(self.write)
def write(self):
string=""
for i in range(1000):
string="\n"+str(i)
self.textEdit.insertPlainText(string)
import sys
app = QtWidgets.QApplication(sys.argv)
MainWindow = QtWidgets.QMainWindow()
ui = Ui_MainWindow()
ui.setupUi(MainWindow)
MainWindow.show()
sys.exit(app.exec_())
First of all it is recommended not to modify the class generated by Qt Designer so you must regenerate the file and assume that it is called mainwindow.py: pyuic5 your_file.ui -o mainwindow.py -x.
Considering the above, the logic is to generate the information in another thread and send it to the GUI to modify it:
main.py
import threading
from PyQt5 import QtCore, QtGui, QtWidgets
from mainwindow import Ui_MainWindow
class WriterWorker(QtCore.QObject):
textChanged = QtCore.pyqtSignal(str)
def start(self):
threading.Thread(target=self._execute, daemon=True).start()
def _execute(self):
string = ""
for i in range(1000):
string = "\n"+str(i)
self.textChanged.emit(string)
class MainWindow(QtWidgets.QMainWindow, Ui_MainWindow):
def __init__(self, parent=None):
super(MainWindow, self).__init__(parent)
self.setupUi(self)
self.writer_worker = WriterWorker()
self.writer_worker.textChanged.connect(self.on_text_changed)
self.pushButton.clicked.connect(self.writer_worker.start)
#QtCore.pyqtSlot(str)
def on_text_changed(self, text):
self.textEdit.insertPlainText(text)
if __name__ == "__main__":
import sys
app = QtWidgets.QApplication(sys.argv)
w = MainWindow()
w.show()
sys.exit(app.exec_())
I'm facing the problem with Threads. I'm displaying current CPU usage with progress bar and it seems to be working well but the performance of whole window is terrible. Can't even click the button without laggy behavior. Is there any simple solution to fix it?
Here is my main code
from PyQt5 import QtCore, QtGui, QtWidgets
from PyQt5.QtCore import QThread, pyqtSignal
import progressBarUI
import sys
import sysnfo
class MainWindow(QtWidgets.QMainWindow, progressBarUI.Ui_MainWindow):
def __init__(self, parent = None):
super(MainWindow, self).__init__(parent)
self.setupUi(self)
self.threadclass = ThreadClass()
self.threadclass.start()
self.threadclass.signal.connect(self.updateProgressBar)
def updateProgressBar(self):
current_percentage = sysnfo.getCpuPercentage()
self.progressBar.setValue(current_percentage)
class ThreadClass(QThread):
signal = pyqtSignal(int)
def __init__(self, parent=None):
super(ThreadClass, self).__init__(parent)
def run(self):
while True:
current_percentage = sysnfo.getCpuPercentage()
self.signal.emit(current_percentage)
if __name__ == "__main__":
app = QtWidgets.QApplication(sys.argv)
mainAppWin = MainWindow()
mainAppWin.show()
app.exec_()
Here is sysnfo module:
import psutil as ps
def getCpuPercentage():
return ps.cpu_percent(interval=1)
And UI file (converted to .py file):
from PyQt5 import QtCore, QtGui, QtWidgets
class Ui_MainWindow(object):
def setupUi(self, MainWindow):
MainWindow.setObjectName("MainWindow")
MainWindow.resize(787, 203)
self.centralwidget = QtWidgets.QWidget(MainWindow)
self.centralwidget.setObjectName("centralwidget")
self.progressBar = QtWidgets.QProgressBar(self.centralwidget)
self.progressBar.setGeometry(QtCore.QRect(370, 20, 381, 111))
self.progressBar.setProperty("value", 0)
self.progressBar.setObjectName("progressBar")
self.pushButton = QtWidgets.QPushButton(self.centralwidget)
self.pushButton.setGeometry(QtCore.QRect(20, 50, 151, 41))
self.pushButton.setObjectName("pushButton")
MainWindow.setCentralWidget(self.centralwidget)
self.menubar = QtWidgets.QMenuBar(MainWindow)
self.menubar.setGeometry(QtCore.QRect(0, 0, 787, 21))
self.menubar.setObjectName("menubar")
MainWindow.setMenuBar(self.menubar)
self.statusbar = QtWidgets.QStatusBar(MainWindow)
self.statusbar.setObjectName("statusbar")
MainWindow.setStatusBar(self.statusbar)
self.retranslateUi(MainWindow)
QtCore.QMetaObject.connectSlotsByName(MainWindow)
def retranslateUi(self, MainWindow):
_translate = QtCore.QCoreApplication.translate
MainWindow.setWindowTitle(_translate("MainWindow", "MainWindow"))
self.pushButton.setText(_translate("MainWindow", "Click me"))
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_())
When you use the "interval" parameter you are indicating that it measures the information during that time and calculates the average causing the execution of that function to take "interval" seconds, and the correct thing is to execute it in another thread, but you make the mistake of executing it too in the updateProgressBar method that lives in the main thread blocking it, instead use the information that sends you the signal:
#QtCore.pyqtSlot(int)
def updateProgressBar(self, percentage):
self.progressBar.setValue(percentage)
I have just worked out how to show an svg image in pyqt5 using QSvgWidget and have tried to transplant it into a blank gui created with the qt designer. The svg image displays but in it's own window instead of in a container or boarder.
I have tried to read through the QSvgWidget docs to see what I am doing wrong but I have a feeling this is a problem with how I am using PyQT5 rather than QSvgWidget.
from PyQt5 import QtCore, QtGui, QtWidgets, QtSvg
import sys
class Ui_MainWindow(object):
def setupUi(self, MainWindow):
MainWindow.setObjectName("MainWindow")
MainWindow.resize(800, 600)
self.centralwidget = QtWidgets.QWidget(MainWindow)
self.centralwidget.setObjectName("centralwidget")
self.viewer = QtSvg.QSvgWidget()
self.viewer.load('C:/Windows/Temp/tubesheetsvgpreview.svg')
self.viewer.setGeometry(QtCore.QRect(0,0,600,600))
self.viewer.show()
MainWindow.setCentralWidget(self.centralwidget)
self.menubar = QtWidgets.QMenuBar(MainWindow)
self.menubar.setGeometry(QtCore.QRect(0, 0, 800, 21))
self.menubar.setObjectName("menubar")
MainWindow.setMenuBar(self.menubar)
self.statusbar = QtWidgets.QStatusBar(MainWindow)
self.statusbar.setObjectName("statusbar")
MainWindow.setStatusBar(self.statusbar)
self.retranslateUi(MainWindow)
QtCore.QMetaObject.connectSlotsByName(MainWindow)
def retranslateUi(self, MainWindow):
_translate = QtCore.QCoreApplication.translate
MainWindow.setWindowTitle(_translate("MainWindow", "MainWindow"))
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_())
The results look like this:
whereas I would just like the svg to appear in a boarder within the main window and scaled to the boarder or window size
For a widget to be part of a window it must be a child of the window or child of a child from a window, in the case of QMainWindow it must be from the centralWidget, for this there are 2 methods:
Pass to the window as a parent.
# ...
# pass self.centralwidget as parent
self.viewer = QtSvg.QSvgWidget(self.centralwidget)
self.viewer.load('C:/Windows/Temp/tubesheetsvgpreview.svg')
self.viewer.setGeometry(QtCore.QRect(0,0,600,600))
# ...
Set the widget through a layout.
# ...
self.centralwidget.setObjectName("centralwidget")
self.viewer = QtSvg.QSvgWidget()
self.viewer.load('C:/Windows/Temp/tubesheetsvgpreview.svg')
self.viewer.setGeometry(QtCore.QRect(0,0,600,600))
# set the layout to centralWidget
lay = QtWidgets.QVBoxLayout(self.centralwidget)
# add the viewer to the layout
lay.addWidget(self.viewer)
MainWindow.setCentralWidget(self.centralwidget)
# ...
Update:
If you want to center the widget, it is best to use the second method and establish an alignment:
# ...
lay = QtWidgets.QVBoxLayout(self.centralwidget)
lay.addWidget(self.viewer, alignment=QtCore.Qt.AlignCenter) # <---
# ...
In the case of the first method, move the official widget (and in essence it is what the layout does in the other method) but you would have to do the same every time the widget changes in size.
So the simplest method is to use the layout.
So I have this Ui_MainWindow class generated by pyuic5.
# -*- coding: utf-8 -*-
# Form implementation generated from reading ui file 'MainWindow.ui'
#
# Created by: PyQt5 UI code generator 5.9
#
# WARNING! All changes made in this file will be lost!
from PyQt5 import QtCore, QtGui, QtWidgets
class Ui_MainWindow(object):
def setupUi(self, MainWindow):
MainWindow.setObjectName("MainWindow")
MainWindow.resize(800, 450)
self.centralWidget = QtWidgets.QWidget(MainWindow)
self.centralWidget.setObjectName("centralWidget")
self.canvas = QtWidgets.QWidget(self.centralWidget)
self.canvas.setGeometry(QtCore.QRect(70, 30, 621, 341))
self.canvas.setAutoFillBackground(False)
self.canvas.setObjectName("canvas")
self.gview = QtWidgets.QGraphicsView(self.canvas)
self.gview.setGeometry(QtCore.QRect(80, 50, 256, 192))
self.gview.setObjectName("gview")
MainWindow.setCentralWidget(self.centralWidget)
self.menuBar = QtWidgets.QMenuBar(MainWindow)
self.menuBar.setGeometry(QtCore.QRect(0, 0, 800, 22))
self.menuBar.setObjectName("menuBar")
self.menuhola = QtWidgets.QMenu(self.menuBar)
self.menuhola.setObjectName("menuhola")
self.menust = QtWidgets.QMenu(self.menuBar)
self.menust.setObjectName("menust")
MainWindow.setMenuBar(self.menuBar)
self.menuBar.addAction(self.menuhola.menuAction())
self.menuBar.addAction(self.menust.menuAction())
self.retranslateUi(MainWindow)
QtCore.QMetaObject.connectSlotsByName(MainWindow)
def retranslateUi(self, MainWindow):
_translate = QtCore.QCoreApplication.translate
MainWindow.setWindowTitle(_translate("MainWindow", "MainWindow"))
self.menuhola.setTitle(_translate("MainWindow", "hola"))
self.menust.setTitle(_translate("MainWindow", "splendid"))
And I want to paint on something, as long as it's not the main window. However, no matter what I try, it just doesn't work.
Here's my code:
import sys
from PyQt5 import QtWidgets
from PyQt5.QtGui import QPainter
from src.qt_design.main_window import Ui_MainWindow
class SystemApp(QtWidgets.QMainWindow):
def __init__(self):
super().__init__()
self.ui = Ui_MainWindow()
self.ui.setupUi(self)
def paintEvent(self, event):
# Nope
painter = QPainter(self.ui.gview)
painter.drawLine(0, 0, 50, 50)
# Nope
painter = QPainter(self.ui.canvas)
painter.drawLine(0, 0, 50, 50)
if __name__ == '__main__':
app = QtWidgets.QApplication(sys.argv)
window = SystemApp()
window.show()
sys.exit(app.exec_())
I'm not sure if I should either:
1. Paint with this parent on its children (like what I tried above)
2. Override children's paintEvent, but it's maybe a bad idea, see here
Any help will be appreciated!
You can get what you are trying to accomplish with an event filter
class SystemApp(QtWidgets.QMainWindow):
def __init__(self):
super().__init__()
self.ui = Ui_MainWindow()
self.ui.setupUi(self)
self.ui.gview.installEventFilter(self)
self.ui.canvas.installEventFilter(self)
def eventFilter(self, obj, e):
if e.type() == QtCore.QEvent.Paint:
painter = QPainter()
painter.begin(obj)
if obj == self.ui.canvas:
painter.setPen(QtCore.Qt.red) # Some specific painting
painter.drawLine(0, 0, 50, 50)
painter.end()
return True
return super().eventFilter(obj, e)