[Interest] Image on QLabel doesn't show at all

Henry Skoglund henry at tungware.com
Sat Dec 8 20:13:15 CET 2018

On 2018-12-08 18:23, Tamás Nagy wrote:
> Hi,
> pixmap = new QPixmap(imageUrl.toString());
> ui->imageLabel->setGeometry(QRect(QPoint(0,0), QPoint(pixmap->width(),
> pixmap->height()) ));
> ui->imageLabel->setPixmap(*pixmap);
> ui->imageLabel->setStyleSheet("background-image: url(" +
> imageUrl.toString() + ")");
> ui->imageLabel->update();
> ui->imageLabel->show();
> My image is C:\untitled.bmp
> I also have a second error: my signal is not found. It always tells me:
> 18:18:07: Debugging starts
> QMetaObject::connectSlotsByName: No matching signal for 
> QObject::connect: No such signal
> MainWindow::MainWindow::graphicsChanged() in
> ..\untitled\mainwindow.cpp:11
> QObject::connect: (sender name: 'MainWindow')
> QObject::connect: (receiver name: 'MainWindow')

Hi, the 1st error is because you're doing a simple
imageUrl.toString() which returns % chars instead of backslashes,  this 
confuses QPixmap's constructor. To give QPixmap Windows-style filenames, 
pixmap = new QPixmap(imageUrl.toString(QUrl::PreferLocalFile));

And for making C:\untitled.bmp show up, try lose/commenting away that
->setStyleSheet() call, setPixmap(*pixmap); should suffice.

The 2nd error is actually a warning and then an error, the warning is
from setupUI() which sees your slot name on_graphics_changed(). Slot
names beginning with "on_" are kind of reserved, see more for example

And that 2nd error is most likely because on your line 11 in your
mainwindow.cpp (which I **cannot see** so I'm guessing :-) you wrote:

Try change to

Rgrds Henry
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