Borderless Window Flickering while resizing

Emrecp

Hello,
This is Video: Click me to watch video

When resizing in borderless window, window flickering (being transparent for 0.5 second) as you can see in video. When windows has a lot of widgets, this happens more. But this not happens in normal window. So my borderless window code here too. Any idea to fix this issue?
Thanks!

Qt: 5.15.2
This is python demo code :

import sys
from PyQt5.QtWidgets import QApplication, QMainWindow
from PyQt5 import QtCore, QtGui, QtWidgets
from PyQt5.Qt import *
from PyQt5.QtCore import QSize, QPropertyAnimation
from PyQt5.QtGui import QPalette, QColor, QFont
from PyQt5.QtWidgets import QDialog, QApplication, QWidget, QMainWindow, QSizePolicy, QTableWidgetItem, QPushButton, \
    QProgressBar, QMessageBox, QHBoxLayout, QInputDialog, QLineEdit, QAbstractItemView, QHeaderView, QListWidget, \
    QListWidgetItem, QTextEdit, QLabel
app = QApplication(sys.argv)

from datetime import datetime


class BorderlessWindow(QWidget):

    def __init__(self, w, parent=None):
        QWidget.__init__(self, parent)
        self.parent = parent
        self._w = w
        self.setupUi()
        contentLayout = QHBoxLayout()
        contentLayout.setContentsMargins(0, 0, 0, 0)
        contentLayout.addWidget(w)
        self.windowContent.setLayout(contentLayout)
        self.setWindowTitle(w.windowTitle())
        self.setGeometry(w.geometry())
        self._w.setAttribute(Qt.WA_DeleteOnClose, True)
        self._w.destroyed.connect(self.__child_was_closed)

    def __child_was_closed(self):
        self._w = None  # The child was deleted, remove the reference to it and close the parent window
        self.close()

    def setupUi(self):
        # create title bar, content

        self.vboxWindow = QtWidgets.QVBoxLayout(self)
        self.vboxWindow.setContentsMargins(0, 0, 0, 0)

        self.windowFrame = QWidget(self)
        self.windowFrame.setObjectName('windowFrame')

        self.vboxFrame = QtWidgets.QVBoxLayout(self.windowFrame)
        self.vboxFrame.setContentsMargins(0, 0, 0, 0)

        self.titleBar = QWidget()

        self.titleBar.setContentsMargins(0, 0, 0, 0)
        self.titleBar.setObjectName('titleBar')

        self.titleBar.setSizePolicy(QSizePolicy(QSizePolicy.Preferred,
                                                QSizePolicy.Fixed))

        self.setWindowIcon(self._w.windowIcon())
        self.hboxTitle = QHBoxLayout(self.titleBar)
        self.hboxTitle.setContentsMargins(0, 0, 4, 0)
        self.hboxTitle.setSpacing(0)


        self.lblTitle = QLabel('title')
        self.lblTitle.setFont(QFont("Arial", 12))
        self.lblTitle.setObjectName('lblTitle')
        self.lblTitle.setAlignment(Qt.AlignBottom | Qt.AlignHCenter)
        self.lblTitle.setAttribute(Qt.WA_TransparentForMouseEvents, True)

        spButtons = QSizePolicy(QSizePolicy.Fixed, QSizePolicy.Expanding)


        self.btnMaximize = QPushButton("[]")  # clicked pyqtSlot => on_btnMaximize_clicked
        self.btnMaximize.setObjectName('btnMaximize')
        self.btnMaximize.setSizePolicy(spButtons)



        self.btnClose = QPushButton("x")  # clicked pyqtSlot => on_btnClose_clicked
        self.btnClose.setObjectName("btnClose")
        self.btnClose.setContentsMargins(0, 0, 0, 0)


        self.btnClose.setSizePolicy(spButtons)




        self.btnClose.setContentsMargins(3, 0, 0, 0)

        self.btnMinimize = QPushButton("_")  # click => on_btnMinimize_clicked
        self.btnMinimize.setObjectName("btnMinimize")

        self.vboxFrame.addWidget(self.titleBar)
        self.windowContent = QWidget(self.windowFrame)
        self.vboxFrame.addWidget(self.windowContent)

        self.vboxWindow.addWidget(self.windowFrame)


        self.hboxTitle.addWidget(self.lblTitle)
        self.hboxTitle.addWidget(self.btnMinimize)


        self.hboxTitle.addWidget(self.btnMaximize)

        self.hboxTitle.addWidget(self.btnClose)
        self.CONTROLBOX_WIDTH = self.btnClose.width()


        self.setWindowFlags(
                Qt.Window | Qt.FramelessWindowHint | Qt.WindowSystemMenuHint | Qt.WindowCloseButtonHint |
                Qt.WindowMinimizeButtonHint | Qt.WindowMaximizeButtonHint)


        self.setAttribute(Qt.WA_TranslucentBackground)



        QtCore.QMetaObject.connectSlotsByName(self)

        def Pencere_QGraphicEfektOlustur():
            EFEKTGOLGE = QtWidgets.QGraphicsDropShadowEffect()
            EFEKTGOLGE.setColor(QColor(0, 255, 0, 200))
            EFEKTGOLGE.setBlurRadius(9.0)
            EFEKTGOLGE.setOffset(0)
            return EFEKTGOLGE
        self.windowFrame.window().layout().setContentsMargins(2, 2, 2, 2)
        self.windowFrame.setGraphicsEffect(Pencere_QGraphicEfektOlustur()) # border effect color
        self.setStyleSheet("""#windowFrame {
  border-radius:10px;
  background-color: palette(Window);
}
#titleBar {
  border: 0px none palette(base);
  border-top-left-radius: 5px;
  border-top-right-radius: 5px;
  background-color: palette(Window);
  height: 24px;
}
#btnClose, #btnMaximize, #btnMinimize { 
    margin: 4px;  
	border: none;
	border-radius: 8px;	
	width:17px;
	height:17px;
	max-height:17px; /* Asagi dogru uzuyor sadece */
	max-width:17px;
	
		
}
#btnMaximize {
  	border: none;
	border-radius: 8px;	
	background-color: rgb(255, 170, 0);
}
#btnMaximize::hover {
  	background-color: rgba(255, 170, 0, 175);
}
#btnMinimize {
 	border: none;
	border-radius: 8px;		
	
	background-color: rgb(0, 120, 0);
}
#btnMinimize::hover {
    background-color: rgba(0, 120, 0, 175);
  	
}
#btnClose {
	border: none;
	border-radius: 8px;		
	background-color: rgb(255, 0, 0);
}
#btnClose::hover {
  background-color: rgba(255, 0, 0, 175);
}
#btnClose::disabled, #btnMaximize::disabled, #btnMinimize::disabled {
  background-color: palette(midlight);
}
""")


class Window(QMainWindow):
    def __init__(self):
        super(Window,self).__init__()
        self.resize(QSize(800,640))
        self.WID_MAIN_CENTER=QWidget(self)
        self.QV_MAIN = QVBoxLayout(self.WID_MAIN_CENTER)
        self.list = QListWidget(self)
        self.list.setResizeMode(QListView.Adjust)
        self.list.setVerticalScrollBarPolicy(Qt.ScrollBarAsNeeded)
        self.list.setHorizontalScrollBarPolicy(Qt.ScrollBarAlwaysOff)
        self.list.setStyleSheet("QListWidget{background-color:transparent}QListWidget:item{border-radius:5px}QPushButton{border-bottom-left-radius: 7px;border-bottom-right-radius: 7px;background-color:transparent}")

        self.QV_MAIN.addWidget(self.list)
        index=1
        for i in range(3000):
            item = QListWidgetItem()
            self.list.insertItem(0, item)
            myWid = QWidget()
            qvWid = QHBoxLayout(myWid)
            for y in range(3):
                qvWid.addWidget(QPushButton(f"Button {i*3+y+1}"))
            item.setSizeHint(QSize(100,200))
            self.list.setItemWidget(item, myWid)
            index+=1
        self.setCentralWidget(self.WID_MAIN_CENTER)

        Screen_x = app.primaryScreen().size().width()
        Screen_y = app.primaryScreen().size().height()


        EnableBorderlessWindow = True
        if EnableBorderlessWindow:
            self.mac = BorderlessWindow(w=self, parent=None )
            self.mac.lblTitle.setText('PyQt5 Borderless Window Flicker while resizing Qt: %s'%(QtCore.QT_VERSION_STR))
            self.sizerSagAlt = QSizeGrip(self)
            self.QV_MAIN.addWidget(self.sizerSagAlt,0,Qt.AlignRight)
            self.mac.resize(self.size())
            self.mac.move(int((Screen_x - self.width()) / 2), int((Screen_y - self.height()) / 2))  # center form
            self.mac.show()
        else:
            self.show()


window = Window()
app.exec()

Emrecp

Any idea?

Emrecp

I fixed, i was forget disable this;

self.setAttribute(Qt.WA_TranslucentBackground)

Emrecp

I have bad news.
I fixed issue with removing :

self.setAttribute(Qt.WA_TranslucentBackground)

this, but now form when try to add rounded corners, background (gray) shows up. This was not happens with WA_TranslucentBackground.

Any idea to add border-radius to form without flickering (WA_TranslucentBackground)?

Emrecp

Up. Any idea?

fcarney

@Emrecp said in Borderless Window Flickering while resizing:

Qt.Window | Qt.FramelessWindowHint | Qt.WindowSystemMenuHint | Qt.WindowCloseButtonHint |
Qt.WindowMinimizeButtonHint | Qt.WindowMaximizeButtonHint

Doesn't the FramelessWindowHint turn off the windows system menu? What is the point of mixing those options? Borderless means no system menu right? What does it look like with just these options?
Qt.Window | Qt.FramelessWindowHint

Emrecp

@fcarney Same :/

Emrecp

The issue remains. Need help.

Emrecp

The problem continues

Iyad Ahmed

Try with Qt::WA_NoSystemBackground

Doberman_ww

I also encountered this problem. I found relevant information in the official documentation, and finally found that using the following settings can eliminate flickering. But I don't know if it will have any effect on other components. But at least it works on framelesswindow flashing.

QApplication.setAttribute(Qt.AA_NativeWindows)

https://doc.qt.io/qtforpython-6/PySide6/QtWidgets/QWidget.html#creating-translucent-windows