[Interest] Fonts and Qt5

[Duane]

We're moving our apps from Qt4.8 to Qt 5.5.  There seems to be an issue 
with fonts and font rendering.  Our targets are Windows Xp/7  and 
TinyCore Linux 5.

For a sample test on Linux, I built a simple hello world app on both Qt4 
and Qt5 with basically a new Qt main window and a couple labels. 
Without setting font or styles, the Qt4 label text looks fine but with 
Qt5 the font family looks different and the font size is half as large.

Both on Windows and Linux we're using the open source versions installed 
by the online installer for Windows and the  maintenance tool for Linux. 
  No custom builds.

One thing that I notice is that for my Linux build, if I check the font 
family using QApplciation::font(), on Qt4 I get DejaVu which exists on 
my system and the point size is 12.  With Qt5 this returns "Sans Serif" 
which doesn't exist and the point size is 9.  If I set the Qt5 version 
to use DejaVu with a point size of 12 this works.

But this is not a solution for us as we use styles and style sheets and 
need to support several resolutions.

Any idea what is different here?  Does the "default" Qt that gets 
installed with the online installer or maintenance tool have fontconfig 
support built in or not?