QTabBar paintEvent issue

Cobra91151

Hi! I want to set the tabs to the right direction in my application. I have set it - setTabPosition(QTabWidget::West);. The problem is with the text of the tabs, it is vertical.

I have sub-classed the QTabBar and re-implement the paintEvent.

void TestTabBar::paintEvent(QPaintEvent *event)
{
    QStyleOptionTab tab;
    initStyleOption(&tab, 0);
    tab.text = QString();
    QStylePainter tabPainter(this);
    tabPainter.setRenderHint(QPainter::Antialiasing);
    tabPainter.drawControl(QStyle::CE_TabBarTab, tab);
    tabPainter.setPen(Qt::black);
    tabPainter.drawText(this->tabRect(0), Qt::AlignBottom | Qt::AlignHCenter, this->tabText(0));
    QTabBar::paintEvent(event);
}

Test::Test(QWidget *parent) :
    QWidget(parent),
    ui(new Ui::Test)
{
     QTabWidget *tabControl = new QTabWidget(this); 
     tabControl->setTabPosition(QTabWidget::West);
     TestTabBar *tabBar1 = new TestTabBar(tabControl);
     TestTabBar *tabBar2 = new TestTabBar(tabControl);
     tabControl->addTab(tabBar1, "Test1");
     tabControl->addTab(tabBar2, "Test2");
     tabControl->setStyleSheet("QTabBar::tab {width: 115px; height: 30px; color: #000000;}");
}

Any ideas how to display the tabs text horizontally? Thanks.

AasiApina

Try adding Qt::Horizontal flag to the drawText function.

Cobra91151

@AasiApina

I have set it: tabPainter.drawText(this->tabRect(0), Qt::Horizontal, this->tabText(0)); but it is still vertical:

I think the problem is with qDebug() << this->tabRect(0).size();, it returns QSize(0, 0). So the tab text could not be drawn at 0 width and height.

Cobra91151

I have fixed it by this code:

#include <QApplication>
#include <QStyleOptionTab>
#include <QStylePainter>
#include <QTabBar>
#include <QTabWidget>

class TabBar: public QTabBar {
public:
    QSize tabSizeHint(int index) const{
        QSize s = QTabBar::tabSizeHint(index);
        s.transpose();
        return s;
    }
protected:
    void paintEvent(QPaintEvent * /*event*/){
        QStylePainter painter(this);
        QStyleOptionTab opt;

        for(int i = 0;i < count();i++)
        {
            initStyleOption(&opt,i);
            painter.drawControl(QStyle::CE_TabBarTabShape, opt);
            painter.save();

            QSize s = opt.rect.size();
            s.transpose();
            QRect r(QPoint(), s);
            r.moveCenter(opt.rect.center());
            opt.rect = r;

            QPoint c = tabRect(i).center();
            painter.translate(c);
            painter.rotate(90);
            painter.translate(-c);
            painter.drawControl(QStyle::CE_TabBarTabLabel,opt);
            painter.restore();
        }
    }
};

class TabWidget : public QTabWidget
{
public:
    TabWidget(QWidget *parent=0):QTabWidget(parent){
        setTabBar(new TabBar);
        setTabPosition(QTabWidget::West);
    }
};

int main(int argc, char *argv[])
{
    QApplication a(argc, argv);
    TabWidget w;
    w.addTab(new QWidget, "tab1");
    w.addTab(new QWidget, "tab2");
    w.addTab(new QWidget, "tab3");
    w.show();

    return a.exec();
}

Now the problem is solved. Thank you.

SkyBoy

The following code also works well.

#include <QApplication>
#include <QStyleOptionTab>
#include <QStylePainter>
#include <QTabBar>
#include <QTabWidget>

class TabBar: public QTabBar {
public:
    QSize tabSizeHint(int index) const{
        QSize s = QTabBar::tabSizeHint(index);
        s.transpose();
        return s;
    }
protected:
    void paintEvent(QPaintEvent * /*event*/){
        QStylePainter painter(this);
        QStyleOptionTabV2 opt;
        
        for(int i = 0;i < count();i++)
        {
            initStyleOption(&opt,i);
            painter.drawControl(QStyle::CE_TabBarTabShape, opt);
            painter.drawItemPixmap(opt.rect, Qt::AlignHCenter|Qt::AlignTop, opt.icon.pixmap(opt.iconSize));
            painter.drawItemText(opt.rect, Qt::AlignHCenter|Qt::AlignBottom, palette(), 1, opt.text);
        }
    }
};

class TabWidget : public QTabWidget
{
public:
    TabWidget(QWidget *parent=0):QTabWidget(parent){
        setTabBar(new TabBar);
        setTabPosition(QTabWidget::West);
    }
};

int main(int argc, char *argv[])
{
    QApplication a(argc, argv);
    TabWidget w;
    w.setStyleSheet(QStringLiteral("QTabBar::tab{ min-height: 45px;}"));
    w.resize(600, 400);
    w.addTab(new QWidget, QIcon(qApp->style()->standardIcon(QStyle::SP_MediaPlay)), "tab1");
    w.addTab(new QWidget, QIcon(qApp->style()->standardIcon(QStyle::SP_MediaStop)),"tab2");
    w.addTab(new QWidget, QIcon(qApp->style()->standardIcon(QStyle::SP_MediaPause)),"tab3");
    
    w.show();

    return a.exec();
}