main.cpp Example File
^{demos/spreadsheet/main.cpp}

    /****************************************************************************
    **
    ** Copyright (C) 1992-2005 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
** this file.  Please review the following information to ensure GNU
** General Public Licensing requirements will be met:
** http://www.trolltech.com/products/qt/opensource.html
**
** If you are unsure which license is appropriate for your use, please
** review the following information:
** http://www.trolltech.com/products/qt/licensing.html or contact the
** sales department at sales@trolltech.com.
    **
    ** This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
    ** WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
    **
    ****************************************************************************/

    #include <QtGui>

    static QString encode_pos(int row, int col) {
        return QString(col + 'A') + QString(row + '0');
    }

    static void decode_pos(const QString &pos, int *row, int *col)
    {
        *col = pos.at(0).toLatin1() - 'A';
        *row = pos.at(1).toLatin1() - '0';
    }

    class SpreadSheetItem : public QTableWidgetItem
    {
    public:
        SpreadSheetItem();
        SpreadSheetItem(const QString &text);

        QTableWidgetItem *clone() const;

        QVariant data(int role) const;
        void setData(int role, const QVariant &value);
        QVariant display() const;

        inline QString formula() const
            { return QTableWidgetItem::data(Qt::DisplayRole).toString(); }

        QPoint convertCoords(const QString coords) const;

    private:
        mutable bool isResolving;
    };

    SpreadSheetItem::SpreadSheetItem()
        : QTableWidgetItem(), isResolving(false) {}

    SpreadSheetItem::SpreadSheetItem(const QString &text)
        : QTableWidgetItem(text), isResolving(false) {}

    QTableWidgetItem *SpreadSheetItem::clone() const
    {
        SpreadSheetItem *item = new SpreadSheetItem();
        *item = *this;
        return item;
    }

    QVariant SpreadSheetItem::data(int role) const
    {
        if (role == Qt::EditRole || role == Qt::StatusTipRole)
            return formula();

        if (role == Qt::DisplayRole)
            return display();

        QString t = display().toString();
        bool isNumber = false;
        int number = t.toInt(&isNumber);

        if (role == Qt::TextColorRole) {
            if (!isNumber)
                return qVariantFromValue(QColor(Qt::black));
            else if (number < 0)
                return qVariantFromValue(QColor(Qt::red));
            return qVariantFromValue(QColor(Qt::blue));
        }

        if (role == Qt::TextAlignmentRole)
            if (!t.isEmpty() && (t.at(0).isNumber() || t.at(0) == '-'))
                return (int)(Qt::AlignRight | Qt::AlignVCenter);

        return QTableWidgetItem::data(role);
    }

    void SpreadSheetItem::setData(int role, const QVariant &value)
    {
        QTableWidgetItem::setData(role, value);
        if (tableWidget())
            tableWidget()->viewport()->update();
    }

    QVariant SpreadSheetItem::display() const
    {
        // check if the string is actially a formula or not
        QString formula = this->formula();
        QStringList list = formula.split(' ');
        if (list.count() != 3)
            return formula; // its a normal string

        QString op = list.at(0).toLower();
        QPoint one = convertCoords(list.at(1));
        QPoint two = convertCoords(list.at(2));

        const QTableWidgetItem *start = tableWidget()->item(one.y(), one.x());
        QTableWidgetItem *end = tableWidget()->item(two.y(), two.x());

        if (!start || !end)
            return "Error: Item does not exist!";

        // avoid circular dependencies
        if (isResolving)
            return QVariant();
        isResolving = true;

        QVariant result;
        if (op == "sum") {
            int sum = 0;
            for (int r = tableWidget()->row(start); r <= tableWidget()->row(end); ++r) {
                for (int c = tableWidget()->column(start); c <= tableWidget()->column(end); ++c) {
                    const QTableWidgetItem *tableItem = tableWidget()->item(r, c);
                    if (tableItem && tableItem != this)
                        sum += tableItem->text().toInt();
                }
            }
            result = sum;
        } else if (op == "+") {
            result = (start->text().toInt() + end->text().toInt());
        } else if (op == "-") {
            result = (start->text().toInt() - end->text().toInt());
        } else if (op == "*") {
            result = (start->text().toInt() * end->text().toInt());
        } else if (op == "/") {
            if (end->text().toInt() == 0)
                result = QString("nan");
            else
                result = (start->text().toInt() / end->text().toInt());
        } else {
            result = "Error: Operation does not exist!";
        }

        isResolving = false;
        return result;
    }

    QPoint SpreadSheetItem::convertCoords(const QString coords) const
    {
        int r = 0;
        int c = coords.at(0).toUpper().toAscii() - 'A';
        for (int i = 1; i < coords.count(); ++i) {
            r *= 10;
            r += coords.at(i).digitValue();
        }
        return QPoint(c, r);
    }

    class SpreadSheet : public QMainWindow
    {
        Q_OBJECT
    public:
        SpreadSheet(int rows, int cols, QWidget *parent = 0);

    public slots:
        void updateStatus(QTableWidgetItem *item);
        void updateColor(QTableWidgetItem *item);
        void updateLineEdit(QTableWidgetItem *item);
        void returnPressed();
        void selectColor();
        void selectFont();
        void clear();
        void showAbout();

        void actionSum();
        void actionSubtract();
        void actionAdd();
        void actionMultiply();
        void actionDivide();

    protected:
        void setupContextMenu();
        void setupContents();

        void setupMenuBar();
        void createActions();

        void actionMath_helper(const QString &title, const QString &op);
        bool runInputDialog(const QString &title,
                            const QString &c1Text,
                            const QString &c2Text,
                            const QString &opText,
                            const QString &outText,
                            QString *cell1, QString *cell2, QString *outCell);

    private:
        QToolBar *toolBar;
        QAction *colorAction;
        QAction *fontAction;
        QAction *firstSeparator;
        QAction *cell_sumAction;
        QAction *cell_addAction;
        QAction *cell_subAction;
        QAction *cell_mulAction;
        QAction *cell_divAction;
        QAction *secondSeparator;
        QAction *clearAction;
        QAction *aboutSpreadSheet;
        QAction *exitAction;

        QLabel *cellLabel;
        QTableWidget *table;
        QLineEdit *formulaInput;
    };

    SpreadSheet::SpreadSheet(int rows, int cols, QWidget *parent)
        : QMainWindow(parent)
    {
        addToolBar(toolBar = new QToolBar());
        formulaInput = new QLineEdit();

        cellLabel = new QLabel(toolBar);
        cellLabel->setMinimumSize(80, 0);

        toolBar->addWidget(cellLabel);
        toolBar->addWidget(formulaInput);

        table = new QTableWidget(rows, cols, this);
        for (int c = 0; c < cols; ++c) {
            QString character(QChar('A' + c));
            table->setHorizontalHeaderItem(c, new QTableWidgetItem(character));
            table->horizontalHeaderItem(c)->setTextAlignment(Qt::AlignCenter);
        }
        table->setItemPrototype(table->item(rows - 1, cols - 1));

        createActions();

        updateColor(0);
        setupMenuBar();
        setupContextMenu();
        setupContents();
        setCentralWidget(table);

        statusBar();
        connect(table, SIGNAL(currentItemChanged(QTableWidgetItem*, QTableWidgetItem*)),
                this, SLOT(updateStatus(QTableWidgetItem*)));
        connect(table, SIGNAL(currentItemChanged(QTableWidgetItem*, QTableWidgetItem*)),
                this, SLOT(updateColor(QTableWidgetItem*)));
        connect(table, SIGNAL(currentItemChanged(QTableWidgetItem*, QTableWidgetItem*)),
                this, SLOT(updateLineEdit(QTableWidgetItem*)));
        connect(table, SIGNAL(itemChanged(QTableWidgetItem*)),
                this, SLOT(updateStatus(QTableWidgetItem*)));
        connect(formulaInput, SIGNAL(returnPressed()), this, SLOT(returnPressed()));
        connect(table, SIGNAL(itemChanged(QTableWidgetItem*)),
                this, SLOT(updateLineEdit(QTableWidgetItem*)));

        setWindowTitle(tr("Spreadsheet"));
    }

    void SpreadSheet::createActions()
    {
        cell_sumAction = new QAction(tr("Sum"), this);
        connect(cell_sumAction, SIGNAL(triggered()), this, SLOT(actionSum()));

        cell_addAction = new QAction(tr("&Add"), this);
        cell_addAction->setShortcut(Qt::CTRL | Qt::Key_Plus);
        connect(cell_addAction, SIGNAL(triggered()), this, SLOT(actionAdd()));

        cell_subAction = new QAction(tr("&Subtract"), this);
        cell_subAction->setShortcut(Qt::CTRL | Qt::Key_Minus);
        connect(cell_subAction, SIGNAL(triggered()), this, SLOT(actionSubtract()));

        cell_mulAction = new QAction(tr("&Multiply"), this);
        cell_mulAction->setShortcut(Qt::CTRL | Qt::Key_multiply);
        connect(cell_mulAction, SIGNAL(triggered()), this, SLOT(actionMultiply()));

        cell_divAction = new QAction(tr("&Divide"), this);
        cell_divAction->setShortcut(Qt::CTRL | Qt::Key_division);
        connect(cell_divAction, SIGNAL(triggered()), this, SLOT(actionDivide()));

        fontAction = new QAction(tr("Font..."), this);
        fontAction->setShortcut(Qt::CTRL|Qt::Key_F);
        connect(fontAction, SIGNAL(triggered()), this, SLOT(selectFont()));

        colorAction = new QAction(QPixmap(16, 16), tr("Background &Color"), this);
        connect(colorAction, SIGNAL(triggered()), this, SLOT(selectColor()));

        clearAction = new QAction(tr("Clear"), this);
        clearAction->setShortcut(Qt::Key_Delete);
        connect(clearAction, SIGNAL(triggered()), this, SLOT(clear()));

        aboutSpreadSheet = new QAction(tr("About SpreadSheet"), this);
        connect(aboutSpreadSheet, SIGNAL(triggered()), this, SLOT(showAbout()));

        exitAction = new QAction(tr("E&xit"), this);
        connect(exitAction, SIGNAL(triggered()), qApp, SLOT(quit()));

        firstSeparator = new QAction(this);
        firstSeparator->setSeparator(true);

        secondSeparator = new QAction(this);
        secondSeparator->setSeparator(true);

    }

    void SpreadSheet::setupMenuBar()
    {
        QMenu *fileMenu = menuBar()->addMenu(tr("&File"));
        fileMenu->addAction(exitAction);

        QMenu *cellMenu = menuBar()->addMenu(tr("&Cell"));
        cellMenu->addAction(cell_addAction);
        cellMenu->addAction(cell_subAction);
        cellMenu->addAction(cell_mulAction);
        cellMenu->addAction(cell_divAction);
        cellMenu->addAction(cell_sumAction);
        cellMenu->addSeparator();
        cellMenu->addAction(colorAction);
        cellMenu->addAction(fontAction);

        menuBar()->addSeparator();

        QMenu *aboutMenu = menuBar()->addMenu(tr("&Help"));
        aboutMenu->addAction(aboutSpreadSheet);
    }

    void SpreadSheet::updateStatus(QTableWidgetItem *item)
    {
        if (item && item == table->currentItem()) {
            statusBar()->showMessage(item->data(Qt::StatusTipRole).toString(), 1000);
            cellLabel->setText("Cell: (" + encode_pos(table->row(item), table->column(item)) + ")");
        }
    }

    void SpreadSheet::updateColor(QTableWidgetItem *item)
    {
        QPixmap pix(16, 16);
        QColor col;
        if (item)
            col = item->backgroundColor();
        if (!col.isValid())
            col = palette().base().color();

        QPainter pt(&pix);
        pt.fillRect(0, 0, 16, 16, col);

        QColor lighter = col.light();
        pt.setPen(lighter);
        QPoint lightFrame[] = { QPoint(0, 15), QPoint(0, 0), QPoint(15, 0) };
        pt.drawPolyline(lightFrame, 3);

        pt.setPen(col.dark());
        QPoint darkFrame[] = { QPoint(1, 15), QPoint(15, 15), QPoint(15, 1) };
        pt.drawPolyline(darkFrame, 3);

        pt.end();

        colorAction->setIcon(pix);
    }

    void SpreadSheet::updateLineEdit(QTableWidgetItem *item)
    {
        if (item != table->currentItem())
            return;
        if (item)
            formulaInput->setText(item->data(Qt::EditRole).toString());
        else
            formulaInput->clear();
    }

    void SpreadSheet::returnPressed()
    {
        QString text = formulaInput->text();
        int row = table->currentRow();
        int col = table->currentColumn();
        QTableWidgetItem *item = table->item(row, col);
        if (!item)
            table->setItem(row, col, new SpreadSheetItem(text));
        else
            item->setData(Qt::EditRole, text);
        table->viewport()->update();
    }

    void SpreadSheet::selectColor()
    {
        QTableWidgetItem *item = table->currentItem();
        QColor col = item ? item->backgroundColor() : table->palette().base().color();
        col = QColorDialog::getColor(col, this);
        if (!col.isValid())
            return;

        QList<QTableWidgetItem*> selected = table->selectedItems();
        if (selected.count() == 0)
            return;

        foreach(QTableWidgetItem *i, selected)
            if (i) i->setBackgroundColor(col);

        updateColor(table->currentItem());
    }

    void SpreadSheet::selectFont()
    {
        QList<QTableWidgetItem*> selected = table->selectedItems();
        if (selected.count() == 0)
            return;
        bool ok = false;
        QFont fnt = QFontDialog::getFont(&ok, font(), this);
        if (!ok)
            return;
        foreach(QTableWidgetItem *i, selected)
            if (i) i->setFont(fnt);
    }

    bool SpreadSheet::runInputDialog(const QString &title,
                                     const QString &c1Text,
                                     const QString &c2Text,
                                     const QString &opText,
                                     const QString &outText,
                                     QString *cell1, QString *cell2, QString *outCell)
    {
        const QStringList rows = QStringList() << "0" << "1" << "2" << "3" << "4"
                                               << "5" << "6" << "7" << "8" << "9";
        const QStringList cols = QStringList() << "A" << "B" << "C" << "D" << "E" << "F";

        QDialog addDialog(this);
        addDialog.setWindowTitle(title);

        QGroupBox group(title, &addDialog);
        group.setMinimumSize(250, 100);

        QLabel cell1Label(c1Text, &group);
        QComboBox cell1RowInput(&group);
        cell1RowInput.addItems(rows);
        cell1RowInput.setCurrentIndex(cell1->at(1).toLatin1() - '0');
        QComboBox cell1ColInput(&group);
        cell1ColInput.addItems(cols);
        cell1ColInput.setCurrentIndex(cell1->at(0).toLatin1() - 'A');

        QLabel operatorLabel(opText, &group);
        operatorLabel.setAlignment(Qt::AlignHCenter);

        QLabel cell2Label(c2Text, &group);
        QComboBox cell2RowInput(&group);
        cell2RowInput.addItems(rows);
        cell2RowInput.setCurrentIndex(cell2->at(1).toLatin1() - '0');
        QComboBox cell2ColInput(&group);
        cell2ColInput.addItems(cols);
        cell2ColInput.setCurrentIndex(cell2->at(0).toLatin1() - 'A');

        QLabel equalsLabel("=", &group);
        equalsLabel.setAlignment(Qt::AlignHCenter);

        QLabel outLabel(outText, &group);
        QComboBox outRowInput(&group);
        outRowInput.addItems(rows);
        outRowInput.setCurrentIndex(outCell->at(1).toLatin1() - '0');
        QComboBox outColInput(&group);
        outColInput.addItems(cols);
        outColInput.setCurrentIndex(outCell->at(0).toLatin1() - 'A');

        QPushButton cancelButton(tr("Cancel"), &addDialog);
        connect(&cancelButton, SIGNAL(clicked()), &addDialog, SLOT(reject()));

        QPushButton okButton(tr("OK"), &addDialog);
        okButton.setDefault(true);
        connect(&okButton, SIGNAL(clicked()), &addDialog, SLOT(accept()));

        QHBoxLayout *buttonsLayout = new QHBoxLayout;
        buttonsLayout->addStretch(1);
        buttonsLayout->addWidget(&okButton);
        buttonsLayout->addSpacing(10);
        buttonsLayout->addWidget(&cancelButton);

        QVBoxLayout *dialogLayout = new QVBoxLayout(&addDialog);
        dialogLayout->addWidget(&group);
        dialogLayout->addStretch(1);
        dialogLayout->addItem(buttonsLayout);

        QHBoxLayout *cell1Layout = new QHBoxLayout;
        cell1Layout->addWidget(&cell1Label);
        cell1Layout->addSpacing(10);
        cell1Layout->addWidget(&cell1ColInput);
        cell1Layout->addSpacing(10);
        cell1Layout->addWidget(&cell1RowInput);

        QHBoxLayout *cell2Layout = new QHBoxLayout;
        cell2Layout->addWidget(&cell2Label);
        cell2Layout->addSpacing(10);
        cell2Layout->addWidget(&cell2ColInput);
        cell2Layout->addSpacing(10);
        cell2Layout->addWidget(&cell2RowInput);

        QHBoxLayout *outLayout = new QHBoxLayout;
        outLayout->addWidget(&outLabel);
        outLayout->addSpacing(10);
        outLayout->addWidget(&outColInput);
        outLayout->addSpacing(10);
        outLayout->addWidget(&outRowInput);

        QVBoxLayout *vLayout = new QVBoxLayout(&group);
        vLayout->addItem(cell1Layout);
        vLayout->addWidget(&operatorLabel);
        vLayout->addItem(cell2Layout);
        vLayout->addWidget(&equalsLabel);
        vLayout->addStretch(1);
        vLayout->addItem(outLayout);

        if (addDialog.exec()) {
            *cell1 = cell1ColInput.currentText() + cell1RowInput.currentText();
            *cell2 = cell2ColInput.currentText() + cell2RowInput.currentText();
            *outCell = outColInput.currentText() + outRowInput.currentText();
            return true;
        }

        return false;
    }

    void SpreadSheet::actionSum()
    {

        int row_first = 0;
        int row_last = 0;
        int row_cur = 0;

        int col_first = 0;
        int col_last = 0;
        int col_cur = 0;

        QList<QTableWidgetItem*> selected = table->selectedItems();
        if (!selected.isEmpty()) {
            QTableWidgetItem *first = selected.first();
            QTableWidgetItem *last = selected.last();
            row_first = table->row(first);
            row_last = table->row(last);
            col_first = table->column(first);
            col_last = table->column(last);
        }

        QTableWidgetItem *current = table->currentItem();
        if (current) {
            row_cur = table->row(current);
            col_cur = table->column(current);
        }

        QString cell1 = encode_pos(row_first, col_first);
        QString cell2 = encode_pos(row_last, col_last);
        QString out = encode_pos(row_cur, col_cur);

        if (runInputDialog(tr("Sum cells"), tr("First cell:"), tr("Last cell:"),
                           QString("%1").arg(QChar(0x03a3)), tr("Output to:"),
                           &cell1, &cell2, &out)) {
            int row, col;
            decode_pos(out, &row, &col);
            table->item(row, col)->setText("sum " + cell1 + " " + cell2);
        }
    }

    void SpreadSheet::actionMath_helper(const QString &title, const QString &op)
    {
        QString cell1 = "B1";
        QString cell2 = "B2";
        QString out = "B3";

        QTableWidgetItem *current = table->currentItem();
        if (current) {
            out = QString(table->currentColumn() + 'A') + QString(table->currentRow() + '0');
        }

        if (runInputDialog(title, tr("Cell 1"), tr("Cell 2"), op, tr("Output to:"),
                           &cell1, &cell2, &out)) {
            int row, col;
            decode_pos(out, &row, &col);
            table->item(row, col)->setText(op + " " + cell1 + " " + cell2);
        }
    }

    void SpreadSheet::actionAdd()
    {
        actionMath_helper(tr("Addition"), "+");
    }

    void SpreadSheet::actionSubtract()
    {
        actionMath_helper(tr("Subtraction"), "-");
    }

    void SpreadSheet::actionMultiply()
    {
        actionMath_helper(tr("Multiplication"), "*");
    }

    void SpreadSheet::actionDivide()
    {
        actionMath_helper(tr("Division"), "/");
    }

    void SpreadSheet::clear()
    {
        foreach (QTableWidgetItem *i, table->selectedItems())
            i->setText("");
    }

    void SpreadSheet::setupContextMenu()
    {
        addAction(cell_addAction);
        addAction(cell_subAction);
        addAction(cell_mulAction);
        addAction(cell_divAction);
        addAction(cell_sumAction);
        addAction(firstSeparator);
        addAction(colorAction);
        addAction(fontAction);
        addAction(secondSeparator);
        addAction(clearAction);
        setContextMenuPolicy(Qt::ActionsContextMenu);
    }

    void SpreadSheet::setupContents()
    {
        QColor titleBackground(Qt::lightGray);
        QFont titleFont = table->font();
        titleFont.setBold(true);

        // column 0
        table->setItem(0, 0, new SpreadSheetItem("Item"));
        table->item(0, 0)->setBackgroundColor(titleBackground);
        table->item(0, 0)->setToolTip("This column shows the purchased item/service");
        table->item(0, 0)->setFont(titleFont);
        table->setItem(1, 0, new SpreadSheetItem("AirportBus"));
        table->setItem(2, 0, new SpreadSheetItem("Flight (Munich)"));
        table->setItem(3, 0, new SpreadSheetItem("Lunch"));
        table->setItem(4, 0, new SpreadSheetItem("Flight (LA)"));
        table->setItem(5, 0, new SpreadSheetItem("Taxi"));
        table->setItem(6, 0, new SpreadSheetItem("Dinner"));
        table->setItem(7, 0, new SpreadSheetItem("Hotel"));
        table->setItem(8, 0, new SpreadSheetItem("Flight (Oslo)"));
        table->setItem(9, 0, new SpreadSheetItem("Total:"));
        table->item(9, 0)->setFont(titleFont);
        table->item(9,0)->setBackgroundColor(Qt::lightGray);
        // column 1
        table->setItem(0, 1, new SpreadSheetItem("Price"));
        table->item(0, 1)->setBackgroundColor(titleBackground);
        table->item(0, 1)->setToolTip("This column shows the price of the purchase");
        table->item(0, 1)->setFont(titleFont);
        table->setItem(1, 1, new SpreadSheetItem("150"));
        table->setItem(2, 1, new SpreadSheetItem("2350"));
        table->setItem(3, 1, new SpreadSheetItem("-14"));
        table->setItem(4, 1, new SpreadSheetItem("980"));
        table->setItem(5, 1, new SpreadSheetItem("5"));
        table->setItem(6, 1, new SpreadSheetItem("120"));
        table->setItem(7, 1, new SpreadSheetItem("300"));
        table->setItem(8, 1, new SpreadSheetItem("1240"));
        table->setItem(9, 1, new SpreadSheetItem());
        table->item(9,1)->setBackgroundColor(Qt::lightGray);
        // column 2
        table->setItem(0, 2, new SpreadSheetItem("Currency"));
        table->item(0, 2)->setBackgroundColor(titleBackground);
        table->item(0, 2)->setToolTip("This column shows the currency");
        table->item(0, 2)->setFont(titleFont);
        table->setItem(1, 2, new SpreadSheetItem("NOK"));
        table->setItem(2, 2, new SpreadSheetItem("NOK"));
        table->setItem(3, 2, new SpreadSheetItem("EUR"));
        table->setItem(4, 2, new SpreadSheetItem("EUR"));
        table->setItem(5, 2, new SpreadSheetItem("USD"));
        table->setItem(6, 2, new SpreadSheetItem("USD"));
        table->setItem(7, 2, new SpreadSheetItem("USD"));
        table->setItem(8, 2, new SpreadSheetItem("USD"));
        table->setItem(9, 2, new SpreadSheetItem());
        table->item(9,2)->setBackgroundColor(Qt::lightGray);
        // column 3
        table->setItem(0, 3, new SpreadSheetItem("Ex.Rate"));
        table->item(0, 3)->setBackgroundColor(titleBackground);
        table->item(0, 3)->setToolTip("This column shows the exchange rate to NOK");
        table->item(0, 3)->setFont(titleFont);
        table->setItem(1, 3, new SpreadSheetItem("1"));
        table->setItem(2, 3, new SpreadSheetItem("1"));
        table->setItem(3, 3, new SpreadSheetItem("8"));
        table->setItem(4, 3, new SpreadSheetItem("8"));
        table->setItem(5, 3, new SpreadSheetItem("7"));
        table->setItem(6, 3, new SpreadSheetItem("7"));
        table->setItem(7, 3, new SpreadSheetItem("7"));
        table->setItem(8, 3, new SpreadSheetItem("7"));
        table->setItem(9, 3, new SpreadSheetItem());
        table->item(9,3)->setBackgroundColor(Qt::lightGray);
        // column 4
        table->setItem(0, 4, new SpreadSheetItem("NOK"));
        table->item(0, 4)->setBackgroundColor(titleBackground);
        table->item(0, 4)->setToolTip("This column shows the expenses in NOK");
        table->item(0, 4)->setFont(titleFont);
        table->setItem(1, 4, new SpreadSheetItem("* B1 D1"));
        table->setItem(2, 4, new SpreadSheetItem("* B2 D2"));
        table->setItem(3, 4, new SpreadSheetItem("* B3 D3"));
        table->setItem(4, 4, new SpreadSheetItem("* B4 D4"));
        table->setItem(5, 4, new SpreadSheetItem("* B5 D5"));
        table->setItem(6, 4, new SpreadSheetItem("* B6 D6"));
        table->setItem(7, 4, new SpreadSheetItem("* B7 D7"));
        table->setItem(8, 4, new SpreadSheetItem("* B8 D8"));
        table->setItem(9, 4, new SpreadSheetItem("sum E2 E9"));
        table->item(9,4)->setBackgroundColor(Qt::lightGray);

    }

    const char *htmlText =
    "<HTML>"
    "<p><b>This demo shows use of <c>QTableWidget</c> with custom handling for"
    " individual cells.</b></p>"
    "<p>Using a customized table item we make it possible to have dynamic"
    " output in different cells. The content that is implemented for this"
    " particular demo is:"
    "<ul>"
    "<li>Addition two cells.</li>"
    "<li>Subtracting one cell from another.</li>"
    "<li>Multiplying two cells.</li>"
    "<li>Dividing one cell with another.</li>"
    "<li>Summing the contents of an arbitrary number of cells.</li>"
    "</HTML>";

    void SpreadSheet::showAbout()
    {
        QMessageBox::about(this, "About Spread Sheet", htmlText);
    }

    int main(int argc, char** argv) {
        Q_INIT_RESOURCE(spreadsheet);
        QApplication app(argc, argv);
        SpreadSheet sheet(10, 5);
        sheet.setWindowIcon(QPixmap(":/images/interview.png"));
        sheet.resize(600, 400);
        sheet.show();
        return app.exec();
    }

    #include "main.moc"