This code correctly displays an image, and resizes it when the window is resized:
QLabel *imageLabel;
QTabWidget *imageTabWidget;
// new...
imageTabWidget->addTab(imageLabel, "Image");
I would like the same behaviour putting the image in a table (still inside the previous tab).
However all I can get now is a fixed size image:
QTableWidget *innerTable = new QTableWidget;
innerTable->setRowCount(1);
innerTable->setColumnCount(1);
innerTable->setCellWidget(0, 0, imageLabel);
innerTable->resizeColumnsToContents();
innerTable->resizeRowsToContents();
imageTabWidget->addTab(innerTable, "Image");
Is it possible to have a resizeable table at all?
Thank you.
You need to use layouts to get things to re-size how you'd like, see:
http://doc.qt.digia.com/qt/layout.html
Using the designer makes creating layouts much easier. (Create a widget in the designer then create an instance of it in code, then add to the tab widget).
Related
When I run my program it will display all content properly, and when I resizing the main window, the layout along with all associated widgets remain fixed, rather than resizing with the main window. I used to increase my all widget and listWidget respect to window computer resolution size but still this not one work properly.
I used this one code finding the system height and width.
QWidget widget;
widget.resize(widget.width(), widget.minimumHeight());
QRect rec = QApplication::desktop()->screenGeometry();
int h = rec.height();
int w = rec.width();
// Increasing the listwidget size
ui->listWidget->setFixedHeight(h);
ui->listWidget->setFixedWidth(w);
//increasing the button size
ui->pushButton->setFixedHeight(h0.2);
ui->pushButton->setFixedWidth(w0.2);
At this link you will find two screenshots that illustrate my problem.
Please resolve to solve my problem. Thanks very much in advance.
When defining the layout of your windows and forms in Qt Designer you have to define each element of your form in advance, in order to have a working layout.
This solution is based on the screenshots provided in the comments to the question. Follow these steps:
Add an empty widget to the central area of your form, if there is nothing there. It will be used as a placeholder for the controls you will add later, and of course you can replace it with whatever widget you want. But you need it there to define a proper layout.
In the property panel, set the horizontal QSizePolicy of this widget to MinimumExpanding.
Add an horizontal spacer to the left side of your progress bar.
Define a minimum/maximum width for the white widget on the left (I guess it's a text area). As an example set the maximum width to 200
pixels.
Make the same for the QTabWidget on the right.
Give a minimum height to the Groupbox on top.
Then give the grid layout to the MainWindow.
You should get something similar in the designer view (I use a dark theme, yours will have different colors of course):
If you complete all steps you should have a nicely resizing window.
For the future: remember to integrally define your layouts, also using placeholder widgets when needed, read carefully the documentation about the widgets size policies (there are several, you need to play with them to fully understand each one) and keep in mind that Qt uses a container based approach which is different, as an example from those used by the .Net framework that relies on the concept of anchors.
EDIT : to answer questions in the comments
You will need to add a layout to any widget that contains other widgets, e.g. adding controls to your groupbox will require to give it a grid, horizontal or vertical layout in order to scale nicely on resize. Again use spacers and size policies to make it look the way you want. If you need to add or remove controls, or change their positions, you may need to brake the layout, rearrange and then set it again.
You can also select groups of widgets and give them a layout e.g. vertical, than another group and set them horizontal and so on... then give a grid layout to the container widget to build a compound layout.
There are endless possibilities, you just need to practice and go through trial and error as for everything else...
You can also do it all programmatically, check the Qt widgets documentation for this. But for complex layouts I would not go that way: it's a lot of code... and you have to compile and run to test every modification.
Using the QtCreator, within the designer you can simply right-click on the parent-widget and add a Grid-Layout.
This one resizes it's children to it's dimensions.
In qt, I have a form that contains among other things, a group with
A combo box
a checkbox
a spacer
a button
Based on some logic, I want sometimes to show another combo box... Where the spacer is, but smaller.
When I add it though, everything resizes automatically
I don't see a way to make it invisible, and yet keep items of the same size when I make it visible again.
I tried making it fixed size... But unless I use fixed sizes and positioning for everything, which I think is a bad idea, the items still move around when I change visibility.
It seems silly... But how can I make my little combo box show up instead of the spacer not next to it ? Spacers don't seem to have a name...
I would do
combo.setVisible(condition);
Spacer.setVisible(!condition);
Very easy... Except how do I access the spacer from code ?
My suggestion is to use a container QWidget instead of the spacer. Here is how it will look:
A combo box
a checkbox
a widget-container
a button
Widget-container is a QWidget with fixed size. Put your combo-box there and it will maintain it's size when you show/hide the combo-box.
Regarding your question (You will not need it but just to know in the future):
how do I access the spacer from code
You can create a spacer from code like this:
QSpacerItem* spacer = new QSpacerItem(0, 15, QSizePolicy::Fixed, QSizePolicy::Fixed);
layout->addItem(spacer);
...
Also you can get it from a layout if you know its index:
QLayoutItem* item = layout->itemAt(index);
But there is no such method as show/hide for layout items.
I have a QScrollArea Widget, which starts empty;
It has a vertical layout, with a QGridLayout, and a vertical spacer to keep it at the top, and prevent it from stretching over the whole scroll area;
Elsewhere in the program, there is a QTextEdit, which when changed, has its contents scanned for "species" elements, and then they are added to the QGridLayout. Any species elements which have been removed are removed too. This bit works;
I have turned the vertical scrollbar on all the time, so that when it appears it does not sit on top of the other stuff in there. Note that the scroll bar is larger than the scroll box already though, despite not needing to be.
This is the problem. The scroll area seems to be preset, and i cannot change it. If i add more rows to the QGridLayout, the scroll area doesn't increase in size.
Instead, it stays the same size, and squeezes the QGridLayout, making it look ugly (at first);
And then after adding even more it becomes unusable;
Note that again, the scroll bar is still the same size as in previous images. The first two images are from Qt Designer, the subsequent 3 are from the program running.
If I resize the window so that the QScrollArea grows, then I see this:
Indicating that there's some layout inside the scroll area that is not resizing properly.
My question is; what do I need to do to make the scrollable area of the widget resize dynamically as I add and remove from the QGridLayout?
If you're coming here from Google and not having luck with the accepted answer, that's because you're missing the other secret invocation: QScrollArea::setWidget. You must create and explicitly identify a single widget which is to be scrolled. It's not enough to just add the item as a child! Adding multiple items directly to the ScrollArea will also not work.
This script demonstrates a simple working example of QScrollArea:
from PySide.QtGui import *
app = QApplication([])
scroll = QScrollArea()
scroll.setWidgetResizable(True) # CRITICAL
inner = QFrame(scroll)
inner.setLayout(QVBoxLayout())
scroll.setWidget(inner) # CRITICAL
for i in range(40):
b = QPushButton(inner)
b.setText(str(i))
inner.layout().addWidget(b)
scroll.show()
app.exec_()
The documentation provide an answer :
widgetResizable : bool
This property holds whether the scroll area should resize the view widget.
If this property is set to false (the default), the scroll area honors the size of its widget.
Set it to true.
Why don't you use a QListView for your rows, it will manage all the issues for you? Just make sure that after you add it you click on the Class (top right window of designer) and assign a layout or it wont expand properly.
I use a QLIstWidget inside a QScrollArea to make a scrollable image list
Try this for adding other objects to the list, this is how I add an image to the list.
QImage& qim = myclass.getQTImage();
QImage iconImage = copyImageToSquareRegion(qim, ui->display_image->palette().color(QWidget::backgroundRole()));
QListWidgetItem* pItem = new QListWidgetItem(QIcon(QPixmap::fromImage(iconImage)), NULL);
pItem->setData(Qt::UserRole, "thumb" + QString::number(ui->ImageThumbList->count())); // probably not necessary for you
QString strTooltip = "a tooltip"
pItem->setToolTip(strTooltip);
ui->ImageThumbList->addItem(pItem);
Update on Artfunkel's answer:
Here's a PySide6 demo that uses a "Populate" button to run the for loop adding items to the scroll area. Each button will also delete itself when clicked.
from PySide6.QtWidgets import *
app = QApplication([])
scroll = QScrollArea()
scroll.setWidgetResizable(True) # CRITICAL
inner = QFrame(scroll)
inner.setLayout(QVBoxLayout())
scroll.setWidget(inner) # CRITICAL
def on_remove_widget(button):
button.deleteLater()
def populate():
for i in range(40):
b = QPushButton(inner)
b.setText(str(i))
b.clicked.connect(b.deleteLater)
inner.layout().addWidget(b)
b = QPushButton(inner)
b.setText("Populate")
b.clicked.connect(populate)
inner.layout().addWidget(b)
scroll.show()
app.exec()
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).
I want to display a table and a image side by side. i.e Left side the image and right side the table. I want this because the image is the reference image for the data present in the table. I want that output in pdf. So I am using QTextDocument, QTextCursor and QPrinter to get the output in pdf. So how it is possible to display the image and table in QtextDocument i.e within a single page of the pdf? I am using Qt 4.5.3 and Windows Xp. Any pointers regarding this are welcome.
Hi i managed to do that. Just adding the snippet if someone might need that..
QTextImageFormat m_ReferenceImageFormat;
m_ReferenceImageFormat.setWidth(525);
m_ReferenceImageFormat.setHeight(450);
m_ReferenceImageFormat.setName(imageFileName);
m_pReportCursor->insertImage(m_ReferenceImageFormat,QTextFrameFormat::FloatRight);
QTextTableFormat m_TableFormat;
m_TableFormat.setBorderStyle(QTextFrameFormat::BorderStyle_Solid);
m_TableFormat.setAlignment(Qt::AlignTop);
m_TableFormat.setWidth(400);
m_pReportCursor->insertTable(5,2,m_TableFormat);
// Table implementation goes here..
Just make sure that the image and table are not overlapping. Adjust width and height accordingly. It should work fine. Thats all.