I'm not sure of the "best way", but one a quick way would be to set the maximum height of the QLabel to the correct size to hold one line of text for the font used (look up QWidget::fontMetrics to help with this), then enable word wrapping.

This will give the effect you describe, for a nicer effect have a further look at QFontMetrics, specifically the elidedText() function.

Hope this helps.