Question

I’m trying to draw a transparent PNG file inside a QWidget. The problem is, I’m getting different results on Windows and Linux.

I uploaded the image, Windows screenshot, and Linux screenshot. The difference could be seen easily.

The code I used for testing is –

class TestWidget: public QWidget {
public:
    TestWidget(const char* imagePath)
    {
        m_pixmap = QPixmap(imagePath);
        setStyleSheet("background-color: black");
    }

protected:
    virtual void paintEvent(QPaintEvent *)
    {
        QPainter painter(this);
        painter.drawPixmap(QPoint(0,0), m_pixmap);
    }

    QPixmap m_pixmap;
};

And the main function looks like this:

TestWidget* testWidget = new TestWidget(imagePath);
testWidget->setGeometry(0, 10, 1024, 1024);
testWidget->show();

I’m using Qt 4.5.1/4.7.2, Windows XP and CentOS 5.5.

Any ideas what could be the problem?

---

Edit:

To elaborate on the selected answer, I had to use QImage with a 24bits format (QImage::Format_ARGB8565_Premultiplied).

Answer 1

Try using QImage instead of QPixmap.