Restoring a Window's Geometry
This document describes how to save and restore a window's geometry using the geometry properties. On Windows, this is basically storing the result of QWindow::geometry() and calling QWindow::setGeometry() in the next session before calling show().
On X11, this might not work because an invisible window does not have a frame yet. The window manager will decorate the window later. When this happens, the window shifts towards the bottom/right corner of the screen depending on the size of the decoration frame. Although X provides a way to avoid this shift, some window managers fail to implement this feature.
When using Qt Widgets, Qt provides functions that saves and restores a widget window's geometry and state for you. QWidget::saveGeometry() saves the window geometry and maximized/fullscreen state, while QWidget::restoreGeometry() restores it. The restore function also checks if the restored geometry is outside the available screen geometry, and modifies it as appropriate if it is:
void MyMainWindow::closeEvent(QCloseEvent *event) { QSettings settings("MyCompany", "MyApp"); settings.setValue("geometry", saveGeometry()); settings.setValue("windowState", saveState()); QMainWindow::closeEvent(event); } void MainWindow::readSettings() { QSettings settings("MyCompany", "MyApp"); restoreGeometry(settings.value("myWidget/geometry").toByteArray()); restoreState(settings.value("myWidget/windowState").toByteArray()); }
Another solution is to store both pos() and size() and to restore the geometry using QWidget::resize() and move() before calling show(), as demonstrated in the Application example.
© 2024 The Qt Company Ltd. Documentation contributions included herein are the copyrights of their respective owners. The documentation provided herein is licensed under the terms of the GNU Free Documentation License version 1.3 as published by the Free Software Foundation. Qt and respective logos are trademarks of The Qt Company Ltd. in Finland and/or other countries worldwide. All other trademarks are property of their respective owners.