Make a pixmap transparent for a QLabel

Question

I have a MainWindow with a QLabel and a pixmap. I want to make it transparent (or less opaque)

I am using the following code below.

ui->label->setAttribute(Qt::WA_TranslucentBackground);
ui->label->repaint();

However it does not seem to work. The image looks the same without any changes. I also tried to use to the following statement:

    ui->label->setStyleSheet("background-color: rgba(255, 255, 255, 10);");

Unfortunately, this does not seem to work either.

Anyone knows how can I make an image transparent or make it less opaque?

Thank you for your time.

Are you sure that your image is transparent? Did you try `background-color: transparent;`? — Dmitry Sazonov, Sep 12 '13 at 11:26
Could you provide simple program, that reproduce your problem? Because labels with images are transparent in my test app. — Dmitry Sazonov, Sep 12 '13 at 11:42
@DmitrySazonov I think he wants to adjust the transparency of the image, not the `QLabel` itself. — thuga, Sep 12 '13 at 12:01

score 7 · Accepted Answer · answered Sep 12 '13 at 11:55

If your image isn't transparent as it is and you want it to be, you can do something like this:

QLabel *l = new QLabel(this);
QImage image(":/img/myimage.png");
QPainter p;
p.begin(&image);
p.setCompositionMode(QPainter::CompositionMode_DestinationIn);
p.fillRect(image.rect(), QColor(0, 0, 0, 50));
p.end();
l->setPixmap(QPixmap::fromImage(image));

score 2 · Answer 2 · answered Jul 13 '22 at 10:11

2

You can use method fill, example:

pixmap = QPixmap(width_size_in_pixels, height_size_in_pixels)
pixmap.fill(Qt.transparent)

answered Jul 13 '22 at 10:11

antipups

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score 0 · Answer 3 · answered Sep 12 '13 at 14:17

0

You can apply QGraphicsOpacityEffect to a label to adjust it's opacity.

answered Sep 12 '13 at 14:17

Dmitry Sazonov

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Make a pixmap transparent for a QLabel

3 Answers3

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