[Interest] double-buffering, quality drop

[Alexander Semke]

Am Dienstag, 3. Februar 2015, 11:06:08 schrieb Michael Sué:
> You can set a breakpoint in Curve::Paint, go up in the stack trace and look
> for yourself. It is way more than just QPixmap pixmap(width,height).
I'll do that. But maybe later :-) 

> But seeing your attachment I have another idea: There can be a problem with
> the missing background: Antialiasing usually happens with a real
> background, as it produces a mixture (smearing of the colors) between your
> curve and the background. So it seems your real problem is that
> antialiasing with a transparent background does not work correctly, or at
> least not with a simple QPixmap pixmap(width,height). On the other hand, in
> Curve::paint you already draw on the real background which gives AA
> something to work with.
I also checked this with pixmap.fill(Qt::white) -> same problem. So, it has 
something to do with the setup of the QPainter.


-- 
Alexander