Vertical QLabel, or the equivalent?

Question

I want axis labels for a plot I\'m making, and naturally the y-axis label should be oriented vertically. I\'m pretty sure QwtPlot does this, but I\'m trying to

Answer 1

Here is a variant of Mostafa's implementation.

void VerticalLabel::paintEvent(QPaintEvent*)
{
    QPainter painter(this);

//    painter.translate(sizeHint().width(),0);
//    painter.rotate(90);
    painter.translate(0,sizeHint().height());
    painter.rotate(270);

    painter.drawText(QRect (QPoint(0,0),QLabel::sizeHint()),Qt::AlignCenter,text());
}

basically i have removed setPen and setBrush to preserve stylesheet and i have used an overload of drawText that uses the rect instead of point. This allows to have the '\n' inside the text or use WordWrap as a flag.

Answer 2

try using this:

#ifndef VERTICALLABEL_H
#define VERTICALLABEL_H

#include <QLabel>

class VerticalLabel : public QLabel
{
    Q_OBJECT

public:
    explicit VerticalLabel(QWidget *parent=0);
    explicit VerticalLabel(const QString &text, QWidget *parent=0);

protected:
    void paintEvent(QPaintEvent*);
    QSize sizeHint() const ;
    QSize minimumSizeHint() const;
};

#endif // VERTICALLABEL_H

///cpp

#include "verticallabel.h"

#include <QPainter>

VerticalLabel::VerticalLabel(QWidget *parent)
    : QLabel(parent)
{

}

VerticalLabel::VerticalLabel(const QString &text, QWidget *parent)
: QLabel(text, parent)
{
}

void VerticalLabel::paintEvent(QPaintEvent*)
{
    QPainter painter(this);
    painter.setPen(Qt::black);
    painter.setBrush(Qt::Dense1Pattern);

    painter.rotate(90);

    painter.drawText(0,0, text());
}

QSize VerticalLabel::minimumSizeHint() const
{
    QSize s = QLabel::minimumSizeHint();
    return QSize(s.height(), s.width());
}

QSize VerticalLabel::sizeHint() const
{
    QSize s = QLabel::sizeHint();
    return QSize(s.height(), s.width());
}

Answer 3

You can also create a new QGraphicsScene, add to it QLabel and then rotate it. Like this:

QLabel* label = QLabel("Y axis"); 
QGraphicsScene scene;
QGraphicsProxyWidget  * proxy = scene.addWidget(label);
proxy->rotate(-45);
QGraphicsView view(&scene);
view.show();  

Take a look at the similar example (the output image has a wrong ratio, look at the direct URL).

Answer 4

So indeed I gave up on finding any simple way to achieve this, and looking over Uwe Rathmann's Qwt code indeed he uses QPainter::drawText() in his QwtPainter::drawText wrapper function, and a QTransform to achieve the rotation, in QwtScaleDraw::labelTransformation. So I've just put these together as follows:

void LabelWidget::paintEvent(QPaintEvent*)
{
    QPainter painter(this);
    painter.setPen(Qt::black);
    //... Need an appropriate call to painter.translate() for this to work properly
    painter.rotate(90);
    painter.drawText(QPoint(0,0), _text);
}

Didn't need a QPixmap, it turns out.

Answer 5

There is no handy function in QLabel to do what you want, no. So:

1. Use QGraphicsView, which allows you to transform items however you want.

2. Use QPainter. Probably the easiest approach would be to draw the text rotated into a QPixmap, then set it on your QLabel.