Scaled QPixmap looks bad

Use the transformMode parameter:

pixmap = QtGui.QPixmap(r'pics\cdaudio.png').scaled(100, 100, transformMode=QtCore.Qt.SmoothTransformation)

According to @iTayb, here's what I came up with:

// Scale the source to the requested size with 
//  the KeepAspectRatio as aspectMode & SmoothTransformation as mode
*source = source->scaled(width, height, Qt::KeepAspectRatio, Qt::SmoothTransformation);
target->setPixmap(*source);