[Kstars-devel] Qt4 porting pep talk

[Jasem Mutlaq]

Thanks for the Tips, Jason!

I finished porting almost half of INDI files, hopefully we'll be done soon. 
But I have a bad feeling that this porting process will introduce lots of 
bugs. I guess we're going to find that out soon!

- Jasem

----- Original Message ----- 
From: "Jason Harris" <kstars at 30doradus.org>
To: "KStars Development List" <kstars-devel at kde.org>
Sent: Friday, October 28, 2005 9:20 AM
Subject: [Kstars-devel] Qt4 porting pep talk


> Hello KStars team, and anyone monitoring the list who may be interested:
>
> If you want to help out with porting KStars to Qt4, but don't know
> where to start, I have some tips for you.
>
> I'll assume you have compiled Qt4 and kdelibs4-snapshot, and installed
> them to an alternate target directory.  You also need to checkout and
> install unsermake (SVN:trunk/kdenonbeta/unsermake)
>
> You can turn one of your terminal sessions into a KDE4 compile platform by
> issuing the commands:
> export QTDIR=/path/to/qt4
> export KDEDIR=/path/to/kde4
> export PATH=$QTDIR/bin:$KDEDIR/bin:$PATH:/home/jharris/kde4svn/unsermake
> export LD_LIBRARY_PATH=$QTDIR/lib:$KDEDIR/lib
>
> (note that if you try to *execute* a kde4 program from this terminal
> session, it will kill your current kdeinit, and replace it with the
> kdeinit from kde4!  This wreaks havoc with the rest of your desktop,
> but don't worry, you can just execute "kdeinit" from a different
> terminal session to restore sanity.)
>
> ----------------------------------------------------------------
>
> Once you are set up, there's plenty to do to help work toward the
> dream: KStars running under Qt4.  I personally can't wait to see the
> native antialiased graphics.  No more jaggies!  No more jitter as
> stars move across the screen! It's going to be beautiful... :)
>
> A lot of the work that needs to be done is pretty easy, even if you
> aren't very familiar with the codebase.  I don't recommend jsut going
> into the toplevel dir and typing "unsermake" at this point; there are
> just too many problems.  Instead, pick a class to work on and do
> "unsermake classname.o", which will compile that class only.
>
> Another suggestion: for now, you may want to work on the new classes
> in kstars/kstars/skycomponents.  These are brand-new classes, and they
> are actually still in a very rough state.  You'll get tons of compile
> errors, but they're generally easy to fix, like missing include files.
>
>
> Other things to do:
>
> + For antialiased drawing, Qt now allows floating-point pixel
> coordinate values in QPainter.  Coordinate pairs are stored in a new
> QPointF class, which is basically a QPoint with floats.  So, we need
> to change almost all of our QPoint variables to QPointF.  These will
> mostly be found in the various draw() functions in skycomponents/.  In
> particular, I have already modified the function SkyMap::getXY()
> (which translates from sky coordinates to screen pixel coordinates) to
> return a QPointF instead of a QPoint, but I haven't gone through the
> code to fix every instance where it is used.
>
> + QPainter no longer has lineTo(int, int) and moveTo(int, int)
> functions; instead, there is the drawLine(QPointF start, QPointF end)
> function.  In Qt3, QPainter stored a "current pen position", which was
> changed with moveTo().  It doesn't have this concept anymore, so if
> there is code that used moveTo(), we may have to store the pen
> position ourselves.  See EquatorComponent::draw() for an example.
>
> -------------------------------------
>
> I'm sure you'll discover many other issues if you try to compile
> anything.  If you find something you don't know how to fix, feel free
> to post to the list.
>
> Looking forward to your patches! :)
>
> Have fun,
> Jason
>
> -- 
> KStars: KDE Desktop Planetarium
> http://edu.kde.org/kstars
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