Problem in setting background image of a custom widget

[Ferdous]

I tried the following code but in vain.


setAutoFillBackground(true);
//QPalette palette = this->palette();
QPalette palette;
palette.setBrush(QPalette::Window, QBrush(QPixmap(":/Resources/topGradient.png")));
this->setPalette(palette);


I tried with stylesheet but doing so caused the child widgets (buttons, labels) inherit the background image. So it's not suitable for my need.


setStyleSheet("background-image: url(:/Resources/topGradient.png);");

Can you please tell me why the use of QPalette for setting background image did not work?

Thanks.

[wysota]

What does "didn't work" mean in this situation? What was the widget you were trying to apply the image on?

[Ferdous]

I meant by "didn't work" that the intended background image didn't show up.

I'm trying to apply it on my custom widget which inherits a QWidget.

[wysota]

Stylesheets won't work then and as for changing the palette, do you actually paint the background in your widget's paintEvent?

[Ferdous]

No. I didn't override paintEvent() method. Isn't palette change supposed to serve the purpose? I'm really confused.

[vonCZ]

Not sure if it's necessary in your case, but maybe: have a .qrc file? Image & path correctly listed there?

[Ferdous]

Yes. Images and path to images are correctly listed in a .qrc file.

When I tried with overriding paintEvent(), the background image is shown. It seems that custom derived classes of QWidget can't have background image through the use of QPalette. Can anyone please verify my guess?

[Lykurg]

Yes. Images and path to images are correctly listed in a .qrc file.

When I tried with overriding paintEvent(), the background image is shown. It seems that custom derived classes of QWidget can't have background image through the use of QPalette. Can anyone please verify my guess?

Times ago there was a problem: http://www.qtsoftware.com/developer/task-tracker/index_html?method=entry&id=166742. Now it's still back. The problem is, that the background is drawn (show your widget alone and resize it: for a short time you can see your image), but then it is covered by the background color. May you want to report this...

Working solution with style sheets:
#ifndef MYWIDGET_H
#define MYWIDGET_H

#include <QtGui>

class MyWidget : public QWidget
{
public:
MyWidget() {}

protected:
void paintEvent(QPaintEvent *)
{
QStyleOption opt;
opt.init(this);
QPainter p(this);
style()->drawPrimitive(QStyle::PE_Widget, &opt, &p, this);
}
};

#endif // MYWIDGET_H

int main(int argc, char *argv[])
{
QApplication a(argc, argv);
MyWidget *w = new MyWidget();
w->setStyleSheet("background-image: url(...);");
w->show();
return a.exec();
}

[Ferdous]

Thanks! Now I can use stylesheet for setting background-image of a custom widget :)

[kongkong163]

Thanks! Now I can use stylesheet for setting background-image of a custom widget :)

hello, Did you resolved your problem with Lykurg suggestions ? I tried with Lykurg suggestion, but it still caused the child widgets (buttons, labels) inherit the background image.

[MorrisLiang]

hello, Did you resolved your problem with Lykurg suggestions ? I tried with Lykurg suggestion, but it still caused the child widgets (buttons, labels) inherit the background image.

It's because your stylesheet doesn't specify which widget to apply.
If you have a widget, and you call QWidget::setObjectName("myWidget"); to set its object name.
Your stylesheet is like this:

#myWidget{background-image: url(:/Resources/topGradient.png);}
Or if your widget is an object of Class MyLittleWidget
then it's like this:

MyLittleWidget{background-image: url(:/Resources/topGradient.png);}