[kde-artists] Re: Oxygen Tab Widgets.

Hello Alexis,

Last time I checked this qmax code was required to have ktabwidget and 
qtabwidget being rendered the same way with oxygen (though I don't remember 
the details). This to say, it might well be an upstream bug (I'd say, in 
ktabwidget), but I'll double check.


> 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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