How do I scale an image with QPainter?

lansing

I have an image stored as QPixmap and I want to draw it out with QPainter and scale it. I overloaded the QPaintEvent in my widget and drew the QPixmap, but I don't know how to get it to scale.

void ImagePainter::paintEvent(QPaintEvent *a_pEvent)
{
    QPainter painter(this);
    painter.drawPixmap(10,10, m_image.width(), m_image.height(), m_image);
    painter.scale(1000,800);
    painter.end();    
}

The scale function in here didn't do anything.

Bonnie

Scale first, then draw. Or you could also just do like

painter.drawPixmap(10,10, m_image.width() * 1000, m_image.height() * 800, m_image);

You may also call painter.setRenderHint(QPainter::SmoothPixmapTransform) before drawing any pixmap to make it scales more smoothly.

lansing

@Bonnie

Thank you, setting it before drawPixmap works. I don't need any smoothing so nearest neighbor resize is fine for me.