characterwidget.cpp Example File
^{widgets/charactermap/characterwidget.cpp}

    /****************************************************************************
    **
    ** Copyright (C) 2004-2005 Trolltech AS. All rights reserved.
    **
    ** This file is part of the documentation of the Qt Toolkit.
    **
    ** This file may be used under the terms of the GNU General Public
** License version 2.0 as published by the Free Software Foundation
** and appearing in the file LICENSE.GPL included in the packaging of
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    #include <QtGui>

    #include "characterwidget.h"

    CharacterWidget::CharacterWidget(QWidget *parent)
        : QWidget(parent)
    {
        lastKey = -1;
        setMouseTracking(true);
    }

    void CharacterWidget::updateFont(const QString &fontFamily)
    {
        displayFont.setFamily(fontFamily);
        displayFont.setPixelSize(16);
        update();
    }

    void CharacterWidget::updateStyle(const QString &fontStyle)
    {
        QFontDatabase fontDatabase;
        displayFont = fontDatabase.font(displayFont.family(), fontStyle, 12);
        displayFont.setPixelSize(16);
        update();
    }

    QSize CharacterWidget::sizeHint() const
    {
        return QSize(32*24, (65536/32)*24);
    }

    void CharacterWidget::mouseMoveEvent(QMouseEvent *event)
    {
        QPoint widgetPosition = mapFromGlobal(event->globalPos());
        int key = (widgetPosition.y()/24)*32 + widgetPosition.x()/24;
        QToolTip::showText(event->globalPos(), QString::number(key), this);
    }

    void CharacterWidget::mousePressEvent(QMouseEvent *event)
    {
        if (event->button() == Qt::LeftButton) {
            lastKey = (event->y()/24)*32 + event->x()/24;
            if (QChar(lastKey).category() != QChar::NoCategory)
                emit characterSelected(QString(QChar(lastKey)));
            update();
        }
        else
            QWidget::mousePressEvent(event);
    }

    void CharacterWidget::paintEvent(QPaintEvent *event)
    {
        QPainter painter(this);
        painter.fillRect(event->rect(), QBrush(Qt::white));
        painter.setFont(displayFont);

        QRect redrawRect = event->rect();
        int beginRow = redrawRect.top()/24;
        int endRow = redrawRect.bottom()/24;
        int beginColumn = redrawRect.left()/24;
        int endColumn = redrawRect.right()/24;

        painter.setPen(QPen(Qt::gray));
        for (int row = beginRow; row <= endRow; ++row) {
            for (int column = beginColumn; column <= endColumn; ++column) {
                painter.drawRect(column*24, row*24, 24, 24);
            }
        }

        QFontMetrics fontMetrics(displayFont);
        painter.setPen(QPen(Qt::black));
        for (int row = beginRow; row <= endRow; ++row) {

            for (int column = beginColumn; column <= endColumn; ++column) {

                int key = row*32 + column;
                painter.setClipRect(column*24, row*24, 24, 24);

                if (key == lastKey)
                    painter.fillRect(column*24, row*24, 24, 24, QBrush(Qt::red));

                painter.drawText(column*24 + 12 - fontMetrics.width(QChar(key))/2,
                                 row*24 + 4 + fontMetrics.ascent(),
                                 QString(QChar(key)));
            }
        }
    }