Elided Label

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Revision as of 12:46, 17 December 2018 by Christian Ehrlicher (talk | contribs) (Updated to match current coding style, removed unneeded ctors, ...)
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Make sure to set the horizontal size policy to minimum and just call this function and you're good to go:

// Set the elide mode used for displaying text.
void ElidedLabel::setElideMode(Qt::TextElideMode elideMode)
{
    m_elideMode = elideMode;
    m_cachedText.clear();
    update();
}
#ifndef ELIDEDLABEL_H
#define ELIDEDLABEL_H

#include <QLabel>

// MIT - Yash : Speedovation.com [ Picked from internet and modified. if owner needs to add or change license do let me know.]

class ElidedLabel : public QLabel 
{
    Q_OBJECT
public:
    using QLabel::QLabel;
    // Set the elide mode used for displaying text.
    void setElideMode(Qt::TextElideMode elideMode);
    // Get the elide mode currently used to display text.
    Qt::TextElideMode elideMode() const { return m_elideMode; }

protected:
    void paintEvent(QPaintEvent *e) override;
    void resizeEvent(QResizeEvent *e) override;

private:
    void updateCachedTexts();

private:
    Qt::TextElideMode m_elideMode = Qt::ElideRight;
    QString m_cachedElidedText;
    QString m_cachedText;
};

#endif // ELIDEDLABEL_HPP
#include "ElidedLabel.h"

#include <QPaintEvent>
#include <QResizeEvent>

void ElidedLabel::setElideMode(Qt::TextElideMode elideMode)
{
    m_elideMode = elideMode;
    m_cachedText.clear();
    update();
}

void ElidedLabel::resizeEvent(QResizeEvent *e)
{
    QLabel::resizeEvent(e);
    m_cachedText.clear();
}

void ElidedLabel::paintEvent(QPaintEvent *e)
{
    if (m_elideMode == Qt::ElideNone)
        return QLabel::paintEvent(e);

    updateCachedTexts();
    QLabel::setText(m_cachedElidedText);
    QLabel::paintEvent(e);
    QLabel::setText(m_cachedText);
}

void ElidedLabel::updateCachedTexts()
{
    // setText() is not virtual ... :/
    const auto txt = text();
    if (m_cachedText == txt)
        return;
    m_cachedText = txt;
    const QFontMetrics fm(fontMetrics());
    m_cachedElidedText = fm.elidedText(text(),
                                       m_elideMode,
                                       width(),
                                       Qt::TextShowMnemonic);
    // make sure to show at least the first character
    if (!m_cachedText.isEmpty())
    {
      const QString showFirstCharacter = m_cachedText.at(0) + QStringLiteral("...");
      setMinimumWidth(fm.horizontalAdvance(showFirstCharacter) + 1);
    }
}