[Ipe-discuss] Antialiasing, delete

Otfried Cheong otfried at kaist.ac.kr
Sun Dec 11 16:23:42 CET 2005

Dmitriy Morozov wrote:
> While we are asking questions "Why..." before filing bug reports, I was
> wondering why anti-aliasing is not turned on? I'm talking about
> anti-aliasing for lines of course, not fonts. Qt4 supports it; it takes
> exactly 3 lines (2 in ipecanvas.cpp, 1 in ipecanvaspainter.cpp) to add it,
> and the result is so much easier on the eyes. 

I've just tried it out, it does look very nice.  Thanks for pointing me 
to this feature (it's not very visible in the Qt documentation).

 > On a related note, why is
> double-buffering explicitly turned off (with
> setAttribute(Qt::WA_PaintOnScreen);). It's not really noticeable without
> anti-aliasing, but I still don't see a reason to turn it off.

Have you tried removing the line?  It worked fine for me under Windows, 
but under Linux become unusably slow.  I didn't have time to figure out 
whether (a) I'm doing something wrong or (b) Qt is still buggy or (c) my 
  X server is not configured right...  I'd be nice if someone could 
figure this out for me :-)

Note that I don't expect it to make a big change: Ipe already draws all 
objects onto a bitmap, and only draws the overlays directly onto the 
screen.  I couldn't see any difference with or without double buffering 
under Windows.

> Also, can somebody confirm that the following is a bug, and not just a
> problem with my installation before I file it in Bugzilla? 

Yes, it's a bug (and has already been filed).


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