draglabel.cpp Example File
^{draganddrop/fridgemagnets/draglabel.cpp}

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    **
    ** Copyright (C) 2005-2006 Trolltech ASA. All rights reserved.
    **
    ** This file is part of the documentation of the Qt Toolkit.
    **
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    ** License version 2.0 as published by the Free Software Foundation
    ** and appearing in the file LICENSE.GPL included in the packaging of
    ** this file.  Please review the following information to ensure GNU
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    #include <QtGui>

    #include "draglabel.h"

    DragLabel::DragLabel(const QString &text, QWidget *parent)
        : QLabel(parent)
    {
        QFontMetrics fm(font());
        QSize size = fm.size(Qt::TextSingleLine, text);

        QImage image(size.width() + 12, size.height() + 12, QImage::Format_ARGB32_Premultiplied);
        image.fill(qRgba(0, 0, 0, 0));

        QFont font;
        font.setStyleStrategy(QFont::ForceOutline);

        QPainter painter;
        painter.begin(&image);
        painter.setRenderHint(QPainter::Antialiasing);
        painter.setBrush(Qt::white);
        painter.drawRoundRect(QRectF(0.5, 0.5, image.width()-1, image.height()-1), 25, 25);

        painter.setFont(font);
        painter.setBrush(Qt::black);
        painter.drawText(QRect(QPoint(6, 6), size), Qt::AlignCenter, text);
        painter.end();

        setPixmap(QPixmap::fromImage(image));
        labelText = text;
    }

    void DragLabel::mousePressEvent(QMouseEvent *event)
    {
        QByteArray itemData;
        QDataStream dataStream(&itemData, QIODevice::WriteOnly);
        dataStream << labelText << QPoint(event->pos() - rect().topLeft());

        QMimeData *mimeData = new QMimeData;
        mimeData->setData("application/x-fridgemagnet", itemData);
        mimeData->setText(labelText);

        QDrag *drag = new QDrag(this);
        drag->setMimeData(mimeData);
        drag->setHotSpot(event->pos() - rect().topLeft());
        drag->setPixmap(*pixmap());

        hide();

        if (drag->start(Qt::MoveAction) == Qt::MoveAction)
            close();
        else
            show();
    }