QTransform Pixel Issue

[meazza]

Hello peeps.

I got an issue with the usage of QTransform. As you can se in the attachment the pixmap after the transform is ugly and I cant figure out why this is.

The code I use is

void CDIPointer::paintEvent(QPaintEvent *)
{
    initMyResource();
    QPainter boolPainter(this);
 
    qreal width = m_pointer.size().width();
    qreal height = m_pointer.size().height();
 
    QTransform transform;
    transform.translate(size().width()/2, size().height()/2);
    transform.rotate(m_rotation);
    transform.translate(-size().width()/2, -size().height()/2);
    transform.scale(size().width() / width, size().height() / height);
 
    boolPainter.setTransform(transform);
 
    //boolPainter.setTransform(QTransform().translate(size().width()/2, size().height()/2)
    //                          .rotate(m_rotation).translate(-size().width()/2, -size().height()/2));
    boolPainter.drawPixmap(0, 0, m_pointer);
    boolPainter.end();
}

void CDIPointer::paintEvent(QPaintEvent *)
{
    initMyResource();
    QPainter boolPainter(this);

    qreal width = m_pointer.size().width();
    qreal height = m_pointer.size().height();

    QTransform transform;
    transform.translate(size().width()/2, size().height()/2);
    transform.rotate(m_rotation);
    transform.translate(-size().width()/2, -size().height()/2);
    transform.scale(size().width() / width, size().height() / height);

    boolPainter.setTransform(transform);

    //boolPainter.setTransform(QTransform().translate(size().width()/2, size().height()/2)
    //                          .rotate(m_rotation).translate(-size().width()/2, -size().height()/2));
    boolPainter.drawPixmap(0, 0, m_pointer);
    boolPainter.end();
}

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Can anybody see how I can improve this so the quality stays the same?

[Rachol]

boolPainter->setRenderHint(QPainter::Antialiasing);

[meazza]

boolPainter->setRenderHint(QPainter::Antialiasing);

Did not fix the issue. Also tried the boolPainter.setRenderHint(QPainter::HighQualityAnt ialiasing.

---

Added after 8 minutes:

Fixed it. Thank you Rachol for pointing me in the right direction.

boolPainter.setRenderHint(QPainter::SmoothPixmapTransform);

boolPainter.setRenderHint(QPainter::SmoothPixmapTransform);

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