Qt resizeevent example By default, children are collapsible, meaning that the user can resize them down to size 0, even if they have a non-zero minimumSize() or minimumSizeHint(). If the window's width and height are left uninitialized, the window will get a reasonable default geometry from the platform window. I've seen snippets online of QObject::installEventFilter(). Custom Widgets and Painting Since QWidget is a subclass of QPaintDevice , subclasses can be used to display custom content that is composed using a series of painting operations with an instance of the QPainter class. Many of the examples provided with Qt use this approach, and it is also covered in the Qt Widgets Tutorial. width() self. I posted it already on here, but it is not solved yet. So, I believe the observed/reported behavior is a bug which might be limited to the MS Windows specific part of Qt. if the window size is changed and the graphicsView is resized, The scene gets scaled and you can see everything appropriately. sizeY = event. From the forums, I learned that the way to do that is to create a custom QLabel and edit its resize event. You can do it all in an event filter attached to the window / widget object that displays your QML interface. Code Example: Handling Resize Events. If the position is left uninitialized, then the platform window will allow the windowing system to position the window. My intention is, that the window expands until the widget fits inside, but can't find a way to Oct 27, 2018 · It seems that QOpenGLWidget::paintEvent and QOpenGLWidget::resizeEvent do unwanted glClear. run qmake on the project file: All Qt C++ Classes All QML Types All Qt Modules All Qt Reference Pages Getting Started Introduction to Qt Getting Started Examples and Tutorials Supported Platforms What's new in Qt 6 Qt Licensing Overviews Development Tools User Interfaces Core Internals Data Input Output Networking and Connectivity The resize event is guaranteed to be called prior to the window being shown on screen and will also be called whenever the window is resized while on screen. void QSplitter:: setCollapsible (int index, bool collapse). const QSize &QResizeEvent:: oldSize const. I am going to try this by finding out if resize event is called when mouse button is pressed. Aug 20, 2013 · In order to detect when the window is resized, you can use the event handler QWidget::resizeEvent(). (This does not only apply to layouts, you should do the same if you implement your own resizeEvent(), for example. Detailed Description. I have to resize the main window, where that widget is placed and then I should get the real size of that widget. Currently QWidget::resize() event is fired wheneven mouse is moved even a little. We use this to resize the back buffer, and defer rendering to the corresponding/following expose event. QWindow is the base class for most Qt window types like QWidget, QMainWindow, and QDialog. I don't want to clear the screen before every paintGL call, but Qt does it automatically, so i've overrided QOpenGLWidget::paintEvent like this: void GlWidget::paintEvent(QPaintEvent* event) { makeCurrent(); paintGL(); paintWithQPainter(); } Apr 2, 2025 · Here's a simple example to test: from PyQt6. A try/catch # is needed since the pane tab type may be changed elsewhere pane = self. Apr 26, 2025 · For example, consider using a flag to indicate whether a resize is actually needed before calling resizeEvent(). states clearly that QResizeEvent::size(). Because it's the only single stuff I miss. Constructs a resize event with the new and old widget sizes, size and oldSize respectively. Returns the new size of the widget. Apr 2, 2025 · Here's a simple example to test: from PyQt6. Sep 1, 2020 · QSize() : 윈도우 프레임을 제외한 위젯의 사이즈를 가지고 있음. Instead, use timers or deferred calls to update the size after the current event has finished. MainWindow provides a menu above the ScribbleArea. I. oldSize – PySide6. Cause If you modify the dialog's size within the resizeEvent() function, it can trigger another resize event, leading to an infinite loop. arg__1 – PySide6. A good typical example is the keyPressEvent() handler, that responds to keyboard key presses. size Detailed Description. To capture the resize event of a QMainWindow class, the method resizeEvent() method must be overrrided. 2025-03-16. Layout Conflicts: We would like to show you a description here but the site won’t allow us. Qt Centre is a community site devoted to programming in C++ using the Qt framework. Write the Code: Copy and paste the following code into your resize_event. Its primary purpose is to adjust the view's internal state to reflect the new size and ensure proper display of the scene content. Quoting the documentation Jan 19, 2016 · To make it short: I have a bug regarding Qt in combination with optirun (or similiar things). It is not guaranteed that the construction of a widget triggers a resize event. These layouts automatically adjust the positions and sizes of widgets when the window is resized. virtual Dec 17, 2012 · Do not cheat yourself. You should use layouts. W owns a QLayout which owns QWidget. Window Flags Example. This widget works like the standard Windows resize handle. A demonstration of how to embed non-Qt UI elements into Qt applications. Example 1: Handling Resize Event for a Custom Widget. The example consists of two classes: ScribbleArea is a custom widget that displays a QImage and allows to the user to draw on it. 当用户调整窗口大小时，我们可以通过捕获并处理相应的信号，以执行特定的操作或更新界面元素。 阅读更多：PyQt5 教程 PyQt5简介 PyQt5是一个用于创建图形用户界面的Python库。它是Qt库（一个用于构建跨平台应用程序的C++框架）的Python绑定。 Instead, calculate the geometry and then set it. We would like to show you a description here but the site won’t allow us. If that handler is not found, then the event is discarded or fully ignored. QtCore. If you are looking for information about Qt related issue — register and post your question. The example shows how to make a round window with a translucent background. For example if a QMainWindow subclass has a central widget, with children and layout managers; then if widgets are hidden and variable size widgets like QTextEdit are visible it seems impossible to change the size of the window from code. 4 it occurs another bug. This signal and slot mechanism is an extension to the C++ programming language. setLabel("(Hidden) Qt Event Example") except: pass # Called when the widget's dimensions change def resizeEvent(self, event): # Store the new size so it can be drawn to the screen later on self. Widgets Gallery Example. 8 docs. The next time Qt's main event loop runs, it dispatches all posted events, with some optimization. This gets called every time the user resizes the window. If you use a QMainWindow the best practice will be to use a QMdiArea for handling internal windows. Oct 9, 2023 · It gives the intended effect of having the image always filling the entire window while keeping it's AspectRatio, but, since it's the Scene itself being scaled, if I try to add something else to that scene, for example a text, it will also appear scaled and streched. Nov 18, 2016 · @mrjj hey thanks for the quick reply, im currently doing it manually by having my mainwindow connect a resizeevent signal to all the child widgets (but that seems very tedious since i have over 20 widgets to resize and reposition) Jun 26, 2016 · This is okay. h class: void resizeEvent(QResizeEvent * /* event */); Apr 12, 2019 · In normal cases, Qt will try to propagate the event up the parent child relationship chain until it finds a handler willing to deal with the event. Qt5 click example. Member Function Documentation QResizeEvent:: QResizeEvent (const QSize &size, const QSize &oldSize) Constructs a resize event with the new and old widget sizes, size and oldSize respectively. Jul 14, 2014 · void MyView::resizeEvent(QResizeEvent *event) { fitInView(0, 0, 500, 500,Qt::KeepAspectRatio); QGraphicsView::resizeEvent(event); } This way the view will always display the whole scene. Experiment with different sizes Try resizing the widget to different values to identify any patterns or limitations. const QSize & size const Returns the new size of the widget. See also QWidget::resize() and QWidget::setGeometry(). oldSize ¶ Return type: QSize. One of the parts of my GUI is a video player. Initial Geometry. QResizeEvent. 만약 위젯이 visible상태에서 resize된다면, 이것은 resizeEvent()를 즉시 전달받는다. g. const QSize &QResizeEvent:: size const. See also restoreState(). To demonstrate handling resize events, follow these steps: Create a New Python File: Open your IDE or text editor and create a new Python file named resize_event. In the X11 version this resize handle generally works differently from the one provided by the system if the X11 window manager does not support necessary modern post-ICCCM specifications. Jan 23, 2020 · For example when the user resizes the main window with mouse on a desktop, or when a mobie is turned? Long version: I want to have an "area" where I can display items one below the other and scroll trough them. So once you get the size you can emit a signal to the dialog to resize itself. } The Qt Scribble example also has an example of overriding the resize event (though not on the main window). e. You see this all the time. May 3, 2020 · I'm trying to do things in as flexibly and dynamically as possible. , QHBoxLayout, QVBoxLayout, QGridLayout) to help you arrange and manage child widgets within the window. May 25, 2019 · Filter the relevant events out until the mouse button has been released. What I'm trying to do as a first project is an image viewer in python using pyside6. If this property is set to false (the default), the scroll area honors the size of its widget. In resizeEvent(), you can recompute the size of the widgets. Mar 16, 2025 · Solution Avoid changing the dialog's size directly within resizeEvent(). May 27, 2007 · This would be done by storing the image as a member variable, scaling it for example in resizeEvent() and setting the scaled image on the same label. const QSize &QResizeEvent Constructs a resize event with the new and old widget sizes, size and oldSize respectively. For example, if you place a child widget in a parent and the parent is too small, the child widget will be clipped. This code shows how to implement the resize event for a "QMainWindow" class in PyQt. Using command line, navigate into the folder with the 4 files. The first example Apr 26, 2025 · Consult the Qt documentation The official Qt documentation provides detailed information on QWidget::resize() and related functions, including examples and troubleshooting tips. QtWidgets import QApplication, QMainWindow, QLabel Mar 19, 2009 · It could be anything (for example a QButton) If it's really impossible, I will create a custom widget, but I really would avoid deriving a QWidget, just to be able to reimplement resizeEvent. Specifically, "eat" the resize event while the mouse button is held down, and then synthesize the final resize event once the mouse is released. We reimplement the paintEvent() function to update the scribble area, and the resizeEvent() function to ensure that the QImage on which we draw is at least as large as the widget at any time. Cause Frequent calls to resizeEvent() can be computationally expensive, especially for large or complex widgets. The window will always get a resize event before the first expose event. Apr 16, 2015 · @p3c0 Could you please show me the proper way of doing this? So far I have added the method in my . With updating to the Qt version 5. Sets whether the child widget at index is collapsible to collapse. Adding the QWidget to the QLayout does not change the size of W. I guess I'm being a bit lazy by hoping someone would past in an example of it including the resizeEvent. In the resizing of the QDialog you may need to disconnect or set a flags in our QTableview so as not to get the circular calling: QTable::resize->QDialog::resize->QTable::resize Nov 2, 2024 · Override the resizeEvent method to handle resize events. Constructs a resize event with the new and old Jul 16, 2022 · The latter ones vary depending on your OS type. When the widget is resized, the resizeEvent() method is automatically called, allowing us to execute custom code in Apr 26, 2025 · In this example, a QWidget is created you can connect to the resizeEvent() In Qt programming, QAbstractSocket::waitForReadyRead() is a function that allows Jun 25, 2008 · Welcome to Qt Centre. Aug 3, 2024 · 如果子控件没有使用布局管理器，而是直接在 resizeEvent 中手动调整大小和位置，那么在父控件的 resizeEvent 中重新计算和调整子控件的大小通常是一个良好的做法。 子控件的 resizeEvent 事件： 当父控件大小变化时，Qt 框架会自动管理子控件的 resizeEvent 事件的触发。 Nov 25, 2014 · I have a QGLWidget, which I want to resize to a given resolution (bigger than the containing window). I think you can can a contents resize event of the viewport judging by the 4. Many Qt Widgets examples already use layouts, however, several examples exist to showcase various layouts. QtGui import QResizeEvent from PyQt6. The event handler QWidget::resizeEvent() receives resize events. Best way to find it out, is to install an eventFilter on your object, listen to the resize event and qDebug the result. In addition the Help menu provides the users with information about the Scribble example in particular, and about Qt in general. size(). In principle, a zero-to-X change would, a null-to-X change wouldn’t. This is the same as QWidget::size(). The Widgets Gallery example shows widgets relevant for designing UIs. The Window Flags example shows how to use the window flags Mar 16, 2025 · Mastering QGraphicsView::resizeEvent() in Qt . __repr__ ¶ Return type: str. Parameters:. In the below example, we define a custom widget class that inherits from QWidget. Public Member Functions inherited from QEvent QEvent (Type type) Constructs an event object of type type. ) Layout Examples. paneTab pane. 만약 위젯이 not visible상태라면, visible이 되기 전에 이벤트를 받는 것을 보장한다. py file: Oct 9, 2023 · It gives the intended effect of having the image always filling the entire window while keeping it's AspectRatio, but, since it's the Scene itself being scaled, if I try to add something else to that scene, for example a text, it will also appear scaled and streched. All 4 files must be in the same folder. Oct 10, 2012 · void MyMainWindow::resizeEvent(QResizeEvent* event) { QMainWindow::resizeEvent(event); // Your code here. . Qt provides various layout managers (e. Jul 5, 2019 · I have overrided the resizeEvent of the QDialog in my own dialog: void CurveDialog::resizeEvent(QResizeEvent *event) { mChartView->resize(ui->widget->size()); } This works, and the chart gets resizedbut the problem is it is terribly slow! because it will resize for all the steps that user drags the window corner to resize it! Detailed Description. QSize. I'd suggest doing it a bit delayed so that each and every resizeEvent() in a row doesn't scale and set a new image. Returns the old size of the widget. 기본값은 To build and run the example: Create an empty folder; Create a file for each of the below code snippets and add the example code to them (the name of the file should match the name above the snippet). For example, if there are several resize events, they are compressed into one. I put my project in copy : Oct 9, 2013 · Welcome to Qt Centre. Window Embedding. The ScribbleArea class inherits from QWidget. size – PySide6. QtCore import Qt, QSize from PyQt6. I want the video player to stop playing the video if I'm resizing the GUI. sizeX = event. Resize events are sent to widgets that have been resized. Apr 12, 2018 · I want to create two widgets, when I change the size of the first one, I want it to change the size of the other one. Sep 4, 2018 · The Qt doc. Purpose. It overrides the resizeEvent() method to print the size of the widget whenever it's resized. size ¶ Return type: QSize. This property holds whether the scroll area should resize the view widget. Apr 20, 2019 · This has not been satisfactorily answered. Oct 18, 2023 · Qt has a unique signal and slot mechanism. Constructs a resize event with the new and old widget sizes, size and oldSize respectively. Note that due to Jun 14, 2013 · I also would need to know when resize is finished - mousebutton is released. Jun 13, 2014 · Hi, I have a method that get pointer to widget where should be setted some other widgets. The same applies to paint events: QWidget::update() calls postEvent(), which eliminates flickering and increases speed by avoiding multiple repaints. Incorrect Event Handling: Solution Always call QWidget::resizeEvent(event) at the end of your custom implementation. const QSize & oldSize const Returns the old size of the widget. Oct 9, 2023 · Hello, so I am very new to coding but wanna learn as a hobby. I have the same or similar issues. qsize는 minimumSize(), maximumSize()에 의해서 범위가 지정될 수 있다. May 22, 2019 · I cannot create a functioning resize event for a custom QT class. py. QtWidgets import QApplication, QMainWindow, QLabel widgetResizable: bool. If you use a simple QWidget, just apply one of the layouts (for example QVBoxLayout) and you will be sure that everything will be look perfect. Over 90 percent of questions asked here gets answered. We reimplement the mousePressEvent(), mouseMoveEvent() and mouseReleaseEvent() functions to implement the drawing. Then I can be quite certain windows is being resized. QtGui. The QResizeEvent class contains event parameters for resize events. Sep 14, 2006 · Welcome to Qt Centre. dhbwb bsym xomcf mnjhqv tsyk ihjf vvtzk hvapgq ovax edgoc