[kde-artists] Re: Oxygen Tab Widgets.

Soo. Just for the record, I just started digging seriously into the issue.
Aside from the fact that I hate the way Qt uses 10 different metrics to render 
tab widgets (with obviously some unsafe combinations of them, based on the bug 
you report), ... there is hope.
This is likely to get fixed by kde4.7.

(damn it. I thought I was done with tabwidgets for good !)

Hugo (ranting)

> Hello all,
> 
> I was wondering why the scrolling in Rekonq was SO damn slow,
> basically any application which uses a tab widget with at least a tab
> and Oxygen.
> 
> Take konqueror for example and a debug build of Qt.
> 
> run it with QT_FLUSH_PAINT=1 konqueror . QT_FLUSH_PAINT shows what Qt
> redraws in yellow. Open two tabs. Navigate to google.com and make a
> search (so the scrollbars appears). Scroll and you will see that the
> entire widget in the middle (the web page) is repainted. It should not
> be like that, because QWidget has a mechanism to handle scrolling way
> better, by invalidating only the exposed areas. This bug does not
> happen with any other style (plastique and so on). It happens in all
> KDE more or less.
> 
> I tracked down the problem to QRect Style::tabWidgetTabPaneRect( const
> QStyleOption* option, const QWidget* ) const in
> kdebase/kstyles/oxygenstyle.cpp
> 
> l1663  r.setTop( r.top() + qMax( tabOpt->tabBarSize.height() /*-
> overlap*/, 0 ) ); there is this overlap thing. If I remove it then
> everything works as expected. Unfortunately this is not right fix but
> I was wondering what is this overlap thing?
> 
> If you take the small app attached, you can clearly see with
> QT_FLUSH_PAINT=1 that when you hover a tab in Oxygen the repainted
> area is overlapping the content (the actual web view). This is really
> wrong and it should not be like that. The two thing MUST not overlap
> otherwise it will confuse the backing store of Qt and its
> optimizations.
> 
> Now I don't have the required skills to fix oxygen the right way but I
> believe some of you guys can. I'll be happy to help like I did to
> track down the problem so we can have decent apps :D.
> 
> Thanks.
> 
> PS: Please keep me in CC I'm not registered to kde-artists.
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