[Panel-devel] Superkaramba Qt4 Port

[Vinay Khaitan]

Hello, 

As I promised, All the themes in Examples section are working smoothly.
But there is problem in KNewsuff part. It is actually bug of KNewStuff 
library.
KNewStuff dialog is shown, but I get infinite recursion, when clicked on one 
tab. 
the bactrace shows this.......

#557 0x410ffe7e in QTabBar::setCurrentIndex () from 
/home/kde4/qt/lib/libQtGui_debug.so.4
#558 0x405f7f44 in KTabCtl::showTab (this=0x8271cd8, i=1) at qtabbar.h:119
#559 0x405f802d in KTabCtl::qt_metacall (this=0x8271cd8, 
_c=InvokeMetaMethod, _id=1, _a=0xbf68e5f8) at ktabctl.moc:68
#560 0x4161d6e1 in QMetaObject::activate () from 
/home/kde4/qt/lib/libQtCore_debug.so.4
#561 0x4161d7ef in QMetaObject::activate () from 
/home/kde4/qt/lib/libQtCore_debug.so.4
#562 0x4110171b in QTabBar::selected () from 
/home/kde4/qt/lib/libQtGui_debug.so.4
#563 0x410ffe7e in QTabBar::setCurrentIndex () from 
/home/kde4/qt/lib/libQtGui_debug.so.4
#564 0x405f7f44 in KTabCtl::showTab (this=0x8271cd8, i=1) at qtabbar.h:119
#565 0x405f802d in KTabCtl::qt_metacall (this=0x8271cd8, 
_c=InvokeMetaMethod, _id=1, _a=0xbf68eba8) at ktabctl.moc:68
#566 0x4161d6e1 in QMetaObject::activate () from 
/home/kde4/qt/lib/libQtCore_debug.so.4
#567 0x4161d7ef in QMetaObject::activate () from 
/home/kde4/qt/lib/libQtCore_debug.so.4
#568 0x4110171b in QTabBar::selected () from 
/home/kde4/qt/lib/libQtGui_debug.so.4
#569 0x410ffe7e in QTabBar::setCurrentIndex () from 
/home/kde4/qt/lib/libQtGui_debug.so.4

looking into backtrace, the infinite recursion is very clear. After looking 
into source, the reason is clear...
<snip KTabCtl>
void KTabCtl::showTab(int i)
{
unsigned int j;
for (j = 0; j < pages.size(); j++) {
if (j != (unsigned)i) {
pages[j]->hide();
}
}

if((unsigned)i < pages.size()) {
emit(tabSelected(i));
if( pages.size() >= 2 ) {
pages[i]->raise();
}
tabs->setCurrentTab(i); // line of interest...
pages[i]->setGeometry(getChildRect());
pages[i]->show();
}
}
</snip>

setCurrentTab() calls setCurrentIndex().
setCurrentIndex emits signal QTabBar::selected()
and in the constructor of KTabCtl
<snip>
{
tabs = new QTabBar(this);
connect(tabs, SIGNAL(selected(int)), this, SLOT(showTab(int))); //problematic 
point
tabs->move(2, 1);

blBorder = true;
}
</snip>
The reason of recursion is evident immediately. Corresponding person should 
resolve this matter.

I also got a crash when testing themes. That was because of these 
statements....
function()
{

QPixmap pm.;
QPainter p;
p.begin(&pm);
bitBlt(&pm,.............................); //The problem.
p.end();
}

BitBlt actually wants to open QPainter on QPaintdevice, which it cant do, 
when it cant do because of p.begin() already called. So there is trouble and 
finally crash(qFatal()).

I just changed the order and everything is smooth. My curiousity is that, 
how can this work in Qt3? Does qt allows to call bitBlt() with opened 
painter on QPaintDevice?

bye
Vinay Khaitan


On 9/2/05, Vinay Khaitan <vkhaitan at gmail.com> wrote:
> 
> As Qt4 port is now complete, I am now doing the bug hunting task. It looks 
> that perhaps KDE-3.5 branch also had bug, which crashes things.
> After some bug hunting When A nice theme is running smoothly, I will post 
> again.
> 
> On 9/1/05, Vinay Khaitan <vkhaitan at gmail.com > wrote:
> > 
> > oops, the image requires moderator approval. the link for it:-
> > http://k.domaindlx.com/vkhaitan/snapshot3.png
> > 
> 
>
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