QPixmap pix1(":/PixmapTest/Resources/Chrysanthemum.jpg");

QPixmap temp(pix1.size());

temp.fill(Qt::transparent);

QPainter p1(&temp);

p1.setCompositionMode(QPainter::CompositionMode_Source);

p1.drawPixmap(0, 0, pix1);

p1.setCompositionMode(QPainter::CompositionMode_DestinationIn);

p1.fillRect(temp.rect(), QColor(0, 0, 0, 64));

p1.end();

pix1 = temp;