title: Relative font sizes in QT or the most portable way to define them
body: <p>Coming from a Web Development background I am now into QT Applications development.</p>
  
  <p>Working with QFonts I have seen that I have only two options apparently, to define fonts sizes in QT; either by pixel size, or point size.</p>
  
  <p>When making web layouts I am used to define all my fonts in a relative way... using <strong>em</strong> units which refer to the inherited font size, where <strong>1em</strong>  equals the font-size of the container element, <strong>0.5em</strong> 50% the font-size, <strong>1.5em</strong> 50% bigger, and so on.</p>
  
  <p>I am worried about portability and device/OS idenpendence of my applications. Is there any better way to define these fonts or should I instead stick to one of these methods?
  If possible, can I inherit font-sizes and define sizes in relative units such as <strong>ems</strong> or percentages?</p>