I have a QGLWidget, which I want to resize to a given resolution (bigger than the containing window).
My intention is, that the window expands until the widget fits inside, but can't find a way to do it.
I tried several commands after resizing the QGLWidget to make it work without success.
I will list the results here:
do nothing else: The Widget overlaps the whole window. Eventually it will be resized to fit back into the smaller window
mainWindow.adjustSize(): The widget gets resized to (0, 0)
mainWindow.resize(mainWindow.sizeHint()): see above
mainWindow.resize(mainWindow.minimumSizeHint()): see above
I also read in this thread, that before doing the mainWindow resize I the event loop needs to be run to recalculate the new sizes, so I inserted QCoreApplication::processEvents to do so, without any visible effect.
So how do I resize the window via the widget?
Edit
The GLWidget is not the only widget of the window.
It is embedded in splitter together with a group box.
http://qt-project.org/doc/qt-4.8/qwidget.html#sizePolicy-prop
http://qt-project.org/doc/qt-4.8/qsizepolicy.html#Policy-enum
http://qt-project.org/doc/qt-4.8/qwidget.html#setFixedSize
So assuming that you have your QGLWidget nested inside your QMainWindow as the central widget, you need to set the size policy of your QGLWidget.
For example:
QGLWidget * glw; // in your header for QMainWindow
...
// In your constructor for QMainWindow
glw = new QGLWidget;
this->setCentralWidget(glw);
glw->setFixedSize(500, 500);
this->adjustSize();
Hope that helps.
I have an app that needed to be very similar to your requirements, so I'll post my solution here. An image covering the window which is freely expandable and shrinkable, and can be changed to the original size, and remain expandable / shrinkable after that.
I used a QLabel widget to display the image, but it should work with other widget types too. I created the widget with an initial size and the QSizePolicy::Ignored.
label->resize (w, h); // initial size
label->setSizePolicy (QSizePolicy::Ignored, QSizePolicy::Ignored);
The label widget was in a QVBoxLayout with a few buttons in the window, but this may work with other layout types too.
The window and image widget can be resized to the image's original size with this code:
label->resize (w, h); // change to original size
label->setMinimumSize (w, h); // prevent it from collapsing to zero immediately
window->adjustSize (); // resize the window
label->setMinimumSize (0, 0); // allow shrinking afterwards
Related
I have a QDialog subclass that contains a spacer as its only immediate child; all of the window’s UI elements are contained in the spacer. The user cannot change the window size directly, but UI elements will be shown or hidden as the user interacts with the window. I’d like the dialog to resize each time this happens so that the spacer (and the dialog itself) always takes up the minimum possible amount of space. How can I configure my dialog and my spacer to get the desired behavior?
(This question dealt with something similar, although in that case the user was able to resize the window. It was also not clear to me what the OP actually ended up doing in that case.)
You can resize the window to minimumSizeHint() after the number of widgets is changed :
resize(minimumSizeHint());
This will shrink the window to minimum size. But you should consider that the minimum size is not computed until some events are processed in the event loop. So after some widgets are hidden and some other are shown, just process the event loop for some iterations and then resize to minimum.
It's like :
for(int i=0;i<10;i++)
qApp->processEvents();
resize(minimumSizeHint());
A better solution is to single shot a QTimer which calls a slot in which you resize the window to minimum. This way when you resize the window, the minimum size hint is computed correctly.
void QWidget::adjustSize()
Adjusts the size of the widget to fit its contents.
I'm new with Qt and I want to implement a scrollable widget which can grow dynamically, e.g. by adding buttons into it when another button is pressed. I try to implement it using the following layout and code:
scrollArea = new QScrollArea(ui->outerWidget);
scrollArea->setWidget(ui->innerWidget);
layout = new QVBoxLayout(ui->outerWidget);
ui->innerWidget->setLayout(layout);
scrollArea->setVerticalScrollBarPolicy(Qt::ScrollBarAlwaysOn);
scrollArea->setHorizontalScrollBarPolicy(Qt::ScrollBarAlwaysOff);
// code for PushButton to add buttons in innerWidget
void MainWindow::on_pushButton_clicked()
{
QPushButton *button = new QPushButton("button"+QString::number( nameCounter ));
nameCounter ++;
ui->innerWidget->layout()->addWidget(button);
}
This implementation has two problems when I run the program, first the innerWidget appears out of place (I define its position in Qt Creator's Design mode) and second after many widgets are added in the layout the scroll bar is doesn't grow, but instead the widgets are become smaller to fit into the layout:
In another thread it was suggested to set widgetResizable to true:
scrollArea->setWidgetResizable(true);
The scroll bar seems to work now but the new problem is that the innerWidget becomes very small so it is barely visible:
So, how can I achieve a scrollable widget that will respect the size and position of the design?
have no environment to verify but good luck.
to place scrollArea the target position,
Manually call SetGeometry, or
Place a QScrollArea in ui form, (suggested if it's static), or
Place a widget in your target position, and set QScrollArea's parent to it, and add QScrollArea to its layout, and Set QScrollArea to be expanding.
manually create a QWidget innerWidget and assign it to scrollArea via QScrollArea::setWidget(*QWidget), try different size policy to innerWidget, such as "Preferred".
Also be aware of Qt's reference mentioned : void QScrollArea::setWidget ( QWidget * widget )
Sets the scroll area's widget.
....
Note that You must add the layout of widget before you call this function; if you add it later, the widget will not be visible - regardless of when you show() the scroll area. In this case, you can also not show() the widget later.
Above list solutions, below are reasons to the problems you mentioned:
scrollArea->setWidget(ui->innerWidget); Setting a widget to ScrollArea will change the parenting and layouting of ui->innerWidget, so the geometry values written in ui form (in Qt Creater) will no longer take effect, this is the reason of innerWidget out of place. ui->innerWidget is no longer a child of outerWidget, it's geometry will follow its new parent (but not scrollArea, there's some tricky layouting inside QScrollArea". To be clear, innerWidget is not helpful to locate scrollArea in such scenario.
In your first clip of code, widget 'scrollArea' is created with parent outerWidget, again no size policy or layout or geometry is specified, so scrollArea will by default be placed at the left top corner of the parent "outerWidget". To place scrollArea to your target geometry, you can " set geometry manually " or " assign innerWidget as scrollArea's parent and expand scrollArea". Obviously the latter method cannot assign ui->innerWiget to scrollArea->setWidget().
scrollArea->setWidgetResizable(true); makes the scrollArea "shrink" at left top corner of outerWidget. This is because, QScrollArea does not increase along with it's contents, it can scroll to display all of it contents so the required size of QScrollArea can be as small as possible. Once the 'Resizable' property is set to "true", QScrollArea decides to shrink to its minimum necessary size, thus the size to display its scroll bar and scroll buttons....
I'm trying to create a QMainWindow to encapsulate a QGraphicsView that I'm putting in it. I want it to start out maximized, so I do this:
QMainWindow *mainWindow = new QMainWindow();
mainWindow->setWindowState(Qt::WindowMaximized);
mainWindow->show();
qDebug() << mainWindow->size();
Which says my maximized window is 200x100, which is obviously incorrect.
Am I missing some sort of update function? I don't get why it wouldn't update the size. I've also tried using showMaximized() with the same result.
EDIT
My end-goal is to use the QMainWindow as a container for a QGraphicsView containing a QGraphicsScene. On top of all this, I want to have a QWebView at 50% width and 100% height, centered over everything.
So, I need the width and height in order to get all the coordinates and sizes correct.
Well, the effect of setWindowState() is not immediate, it gets executed asynchronously. When the window state changes, the widget receives a changeEvent(), so you should reimplement this or resizeEvent() to get the width() and height() after the maximization takes place.
I have QMdiArea object in QMainWindow which I did not have set with setCentralWidget() but as mentioned below.
MainWindow::createMdiArea() {
QMdiArea mdiArea = new QMdiArea(this)
mdiArea.setGeometry(0,0,1024,600);
mdiArea.show();
}
I don't want to set this QMdiArea as the center widget. Now I am creating some child windows inside this QMdiArea, as following
MainWindow::createChildWindow()
{
HelpWindow child1 = new HelpWindow(). // HelpWindow is a very simple class derived from QWidget and containing one QLineEdit.
mdiArea.addSubWindow(&child1);
// Set the geometry of Child widget.
child1.parentWidget()->setGeometry(0,0,400,100); // Setting geometry which I have saved.
child1.show();
}
So far so good. But the problem is in the child window resize / close events I need to save the size of the HelpWindow and I am doing following to save the size of the child window in its resize / close events.
saveHelpWindowSize(size());
saveHelpWindowPos(pos());
Ok. Here comes the problem. The size I have got from the size() function inside the child window is different from the one which I have used in setGeometry() function, even I see it in some method other than resize event (i.e Close event).
So, Suppose first time the child window was created with the size (using setGeometry) 400, 200, when I go to close this window the size I will get from HelpWindow::size() might be say (385, 190) which I will save, and next time setGeometry() will get this size from settings, and at this time on close event I will get more smaller size, and eventually my child window will have size (0, 0).
1: Any thoughts on how to sync both these sizes (i.e., the size if the child widget being set by setGeometry() function and the size of the widget I am getting from size() function of the widget)
2: Another question, I am receiving resizeEvent / closeEvent events etc in the child widget (HelpWindow) class, but I am not getting moveEvent when I move the child window inside QMdiArea, the only time I receive this event is when I maximize the child window inside QMdiArea (which I won't be doing). So I need to save the position of my child window when its position is changed. How can I do it?
I am new to QT. I'm trying to understand the layout mechanism by trying to implement this small window seen below. It has the following elements under the QWidget that's the main window:
One big QWidget that stretches on all the client area.
Two QWidget containers on the top of the window. Both should have the same height, but the right one stretches horizontally, as the window grows/shrinks.
one button container widget on the top right, with fixed height and width
Large QWidget container filling the rest of the client area, that should resize as the window resizes.
The parent window itself is resizeable.
I'm looking for hints as to what layout I should use. How do I achieve this programatically? define what stretches automatically, what stays with a fix size? and how the proportions are kept where they need to be kept.
I'd appreciate any pointer you may have.
The easiest, and IMHO best, way to accomplish this is via the QHBoxLayout and QVBoxLayouts. You can do this via the designer in QtCreator, but I find it doesn't work perfectly if you need to adapt things over time. If it's a static set of widgets, I do suggest designing it using the QtCreator designer as it'll greatly simplify your life.
If you're going to do it programatically, the main window should be set to use a QVBoxLayout and then two sub-QVBoxLayout's after that, where the bottom one is configured to take any space it can get. Then in the top QVBoxLayout, add a QHBoxLayout with your two upper components.
to set a widget to fixed size in code you call setFixedSize( int h, int w ) on the widget. To do it in Designer click on the widget and look in the property editor in the QWidget section. open the sizePolicy thingy and set horizontal and/or vertical to fixed. Then open Geometry and set the width and Height.
To make them stretch at different ratios in code you use a separate argument when using a box layout. eg layout->addWidget( button1, 1 ); layout->addWidget (button2, 2); this would cause button2 to expand at twice the rate of button1. To do this in designer, open the sizePolicy property of the widgets and set the HorizontalStrech and/or VerticalSretch. Note that the size policy needs to not be Fixed in this case for the direction you want to set the stretch on. Also it will never let a widget shrink below its minimum size (it would rather mess up the ratio than shrink something too small).