QT Custom QStyle for QTabBar and QIcon - qt

Question

I have customize a Qtabbar's QMdiarea to get horizontal tab instead of vertical tab like this :
http://www.qtcentre.org/wiki/index.php?title=Customizing_QTabWidget%27s_QTabBar
But i want to insert icon in my QTabBar.
If I apply my custom style to my QTabBar my icons doesn't appear.
If I don't apply, my icon appear.
here my custom style :
class CustomTabStyle : public QPlastiqueStyle
{
Q_OBJECT
public:
QSize sizeFromContents(ContentsType type, const QStyleOption *option,const QSize &size, const QWidget *widget) const
{
QSize s = QPlastiqueStyle::sizeFromContents(type, option, size, widget);
if (type == QStyle::CT_TabBarTab)
s.transpose();
return s;
}
void drawControl(ControlElement element, const QStyleOption *option, QPainter *painter, const QWidget *widget) const
{
if (element == CE_TabBarTabLabel)
{
if (const QStyleOptionTab *tab = qstyleoption_cast<const QStyleOptionTab *>(option))
{
QStyleOptionTab opt(*tab);
opt.shape = QTabBar::RoundedNorth;
QPlastiqueStyle::drawControl(element, &opt, painter, widget);
return;
}
}
QPlastiqueStyle::drawControl(element, option, painter, widget);
}
};
and i apply my style like this :
mMdiAreaDock=aMdiArea;
m_pMdiAreaTabBar = NULL;
QObjectList listChildren = mMdiAreaDock->children();
for (QObjectList::Iterator i = listChildren.begin(); i != listChildren.end(); ++i)
{
if (QString((*i)->metaObject()->className()) == "QTabBar")
{
m_pMdiAreaTabBar = dynamic_cast<QTabBar*>(*i);
break;
}
}
m_pMdiAreaTabBar->setStyle(new CustomTabStyle());
return 0;
where mMdiAreaDock is an QMdiArea
and m_pMdiAreaTabBar is a QTabBar

Answer 1

Look at this code:
const QStyleOptionTab *tab = qstyleoption_cast<const QStyleOptionTab *>(option));
QStyleOptionTab opt(*tab);
option is an instance of QStyleOptionTabV2.
When you create a new object QStyleOptionTab opt with copy constructor, you lose some important data which extended QStyleOptionTabV2 contains including information about an icon.
Use this code instead:
if (const QStyleOptionTabV2 *tab = qstyleoption_cast<const QStyleOptionTabV2 *>(option))
{
QStyleOptionTabV2 opt(*tab);
opt.shape = QTabBar::RoundedNorth;
QPlastiqueStyle::drawControl(element, &opt, painter, widget);
return;
}
ps. I used this code to assign an icon for a specific tab:
m_pMdiAreaTabBar->setTabIcon(0, icon);