[Qt-interest] [Mac] Interesting/annoying multi-user font bug...

[Dave Thorup]

I ran into an annoying multi-user font bug a little while back and  
thought I'd share the details of it here in case anyone else gets  
bitten by it.  The problem is that if you install Qt or a Qt  
application in one user account - say it's the main user account that  
you use - then everything is fine, fonts are displayed properly.   
However, if you then switch to a different user or create a new user  
account and switch to it, then the application's fonts are messed up  
in the other user account.  The default Mac application font should be  
Lucida Grande, however in the other user account when running a Qt  
application the application font will be Helvetica instead, which  
really stands out and looks bad.  This can easily be observed by  
running the Qt Assistant application in your main user account and  
then running it in a new user account.

I was able to track down why this is happening but I don't know if  
it's Apple's bug or Qt's.  The reason why it happens is that for  
whatever reason the other user account does not contain a font named  
"Lucida Grande" (as seen by the Qt application), instead it contains a  
font named "Lucida Grande CE".  So the Qt app can't find "Lucida  
Grande" and loads Helvetica instead as the default app font.  To work  
around this annoying bug I do the following before creating our  
QApplication:

--------------------------------------------
QFontDatabase	fontDb;
QStringList	lst = fontDb.families();

if ( lst.contains( "Lucida Grande", Qt::CaseInsensitive ) )
	QApplication::setFont( QFont( "Lucida Grande", 13 ) );
else if ( lst.contains( "Lucida Grande CE", Qt::CaseInsensitive ) )
	QApplication::setFont( QFont( "Lucida Grande CE", 13 ) );
--------------------------------------------

Does anyone have any ideas as to why this happens?  If not, well  
hopefully this will help other Mac Qt developers around this annoying  
little bug.

Qt 4.4
Mac OS X 10.5.6
--
Dave Thorup
Software Engineer
http://bibblelabs.com



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