QLabel size, for image display

[C167]

I got a new hdd, so i can't continue developing. Would it be possible to get the size if i add a QWidget into the QVBoxLayout and add the label to it? or any other constellation?

[jacek]

Yes, but you have to show that widget or at least wait for it to be polished, before you will get a valid size.

[C167]

nope, i tried several things to get the size, using widgets, labels etc. every time i want to have the size i get a QSize(100,30) (or the equivalent using geometry()) so i have no chance to resize the images using QImage

[ashukla]

nope, i tried several things to get the size, using widgets, labels etc. every time i want to have the size i get a QSize(100,30) (or the equivalent using geometry()) so i have no chance to resize the images using QImage

I hope this code help you.

QLabel *lab=new QLabel(0);
QPixmap *p=new QPixmap("plane.jpg");
QPixmap p1(p->scaled ( 300,300, Qt::IgnoreAspectRatio, Qt::SmoothTransformation ));
lab->setPixmap(p1);
lab->show();
lab->setFixedHeight(p1.height());
lab->setFixedWidth(p1.width());

QLabel *lab=new QLabel(0);
QPixmap *p=new QPixmap("plane.jpg");
QPixmap p1(p->scaled ( 300,300, Qt::IgnoreAspectRatio, Qt::SmoothTransformation ));
lab->setPixmap(p1);
lab->show();
lab->setFixedHeight(p1.height());
lab->setFixedWidth(p1.width());

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[ashukla]

lab->setFixedHeight(p1.height());
lab->setFixedWidth(p1.width());

lab->setFixedHeight(p1.height());
lab->setFixedWidth(p1.width());

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you can also use

lab->adjustSize();

lab->adjustSize();

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in spite of above.

[C167]

thanks
now i understand where i was wrong. your code is much easier than my resize-function. Now the main problem to solve: how to get the maximum size the label can occupy?
I attached two screenshots. The first shows the splash, i changed the window-size to be a bit more than the fixed size of the label. Here, you can see the following structure:

QMainWindow->setCentralWidget(QStackedWidget)->QWidget->QStackedLayout->QLabel

QMainWindow->setCentralWidget(QStackedWidget)->QWidget->QStackedLayout->QLabel

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where the label at the end holds the image that you can see. this should always use the maximum size, like your code does. I thought i could get the size by using a QWidget instead of the label and attach the label to the widgets layout (i used QVBoxLayout).

The next screenshot shows the same problem. The area with a black border is a QLabel, that should also display images, but now with Qt::KeepAspectRatio. The Label should resize when window resizes, but by keeping the proportions of the file (image.size=label.size). Would be quite easy i thought some weeks ago...

[ashukla]

how to get the maximum size the label can occupy

how to get the maximum size the label can occupy

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Use maximumSize() and setMaximumSize() for this.
And use this code for your problem;

#include <QtGui>
int main (int argc, char **argv)
{
 
	QApplication app(argc,argv);
	QWidget w;
 
	QLabel *lab=new QLabel(&w);
	QPixmap *p=new QPixmap("plane.jpg");
	QPixmap p1(p->scaled ( lab->width(),lab->height(), Qt::IgnoreAspectRatio, Qt::SmoothTransformation ));
	lab->setPixmap(p1);
	lab->show();
	lab->adjustSize();
	w.show();
	w.resize(300,200);
	return app.exec();
 
}

#include <QtGui>
int main (int argc, char **argv)
{

	QApplication app(argc,argv);
	QWidget w;
	
	QLabel *lab=new QLabel(&w);
	QPixmap *p=new QPixmap("plane.jpg");
	QPixmap p1(p->scaled ( lab->width(),lab->height(), Qt::IgnoreAspectRatio, Qt::SmoothTransformation ));
	lab->setPixmap(p1);
	lab->show();
	lab->adjustSize();
	w.show();
	w.resize(300,200);
	return app.exec();

}

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[C167]

how to get the maximum size the label can occupy

how to get the maximum size the label can occupy

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Use maximumSize() and setMaximumSize() for this.

i mean the maximum size inside the widget, the maximum is QSize(16777215, 16777215)...

And use this code for your problem;

#include <QtGui>
int main (int argc, char **argv)
{
 
	QApplication app(argc,argv);
	QWidget w;
 
	QLabel *lab=new QLabel(&w);
	QPixmap *p=new QPixmap("plane.jpg");
	QPixmap p1(p->scaled ( lab->width(),lab->height(), Qt::IgnoreAspectRatio, Qt::SmoothTransformation ));
	lab->setPixmap(p1);
	lab->show();
	lab->adjustSize();
	w.show();
	w.resize(300,200);
	return app.exec();
}

#include <QtGui>
int main (int argc, char **argv)
{

	QApplication app(argc,argv);
	QWidget w;
	
	QLabel *lab=new QLabel(&w);
	QPixmap *p=new QPixmap("plane.jpg");
	QPixmap p1(p->scaled ( lab->width(),lab->height(), Qt::IgnoreAspectRatio, Qt::SmoothTransformation ));
	lab->setPixmap(p1);
	lab->show();
	lab->adjustSize();
	w.show();
	w.resize(300,200);
	return app.exec();
}

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that generates a nixe little window with the picture at 100*30 in the top left corner...

[ashukla]

You can set and use after the maximumSize of a widget using maximumSize() and setMaximumSize().

[astodolski]

i mean the maximum size inside the widget, the maximum is QSize(16777215, 16777215)...


that generates a nixe little window with the picture at 100*30 in the top left corner...

How is that a solution? If I read the comments correctly you are adjusting the label to be displayed as BIG as it can be. yet it displays a 100 x 30 image.
I am experiencing the same problem and don't seem to be able to display an image other than 100 x 30 size