qt - QT4 How to blur QPixmap image?

Question

QT4 How to blur QPixmap image?

I am looking for something like one of the following:

Blur(pixmap); 
painter.Blur(); 
painter.Blur(rect);

What is the best way to do this?

Answer 1

1st) declare external QT routine:

QT_BEGIN_NAMESPACE
  extern Q_WIDGETS_EXPORT void qt_blurImage( QPainter *p, QImage &blurImage, qreal radius, bool quality, bool alphaOnly, int transposed = 0 );
QT_END_NAMESPACE

2nd) Use:

  extern QImage srcImg;//source image
  QPixmap pxDst( srcImg.size() );//blurred destination
  pxDst.fill( Qt::transparent );
  {
    QPainter painter( &pxDst );
    qt_blurImage( &painter, srcImg, 2, true, false );//blur radius: 2px
  }