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# main.cpp Example File
demos/spreadsheet/main.cpp

        /****************************************************************************
        **
        ** Copyright (C) 2004-2006 Trolltech ASA. 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::number(row + 1);
        }

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

        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(); }

        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 actually 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();
            int firstRow, firstCol, secondRow, secondCol;
            decode_pos(list.at(1), &firstRow, &firstCol);
            decode_pos(list.at(2), &secondRow, &secondCol);

            const QTableWidgetItem *start = tableWidget()->item(firstRow, firstCol);
            const QTableWidgetItem *end = tableWidget()->item(secondRow, secondCol);

            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 = formula;
            }

            isResolving = false;
            return result;
        }

        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->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)
        {

            QStringList rows, cols;
            for (int c = 0; c < table->columnCount(); ++c)
                cols << QChar('A' + c);
            for (int r = 0; r < table->rowCount(); ++r)
                rows << QString::number(1 + r);

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

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

            QLabel cell1Label(c1Text, &group);
            QComboBox cell1RowInput(&group);
            int c1Row, c1Col;
            decode_pos(*cell1, &c1Row, &c1Col);
            cell1RowInput.addItems(rows);
            cell1RowInput.setCurrentIndex(c1Row);
            QComboBox cell1ColInput(&group);
            cell1ColInput.addItems(cols);
            cell1ColInput.setCurrentIndex(c1Col);

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

            QLabel cell2Label(c2Text, &group);
            QComboBox cell2RowInput(&group);
            int c2Row, c2Col;
            decode_pos(*cell2, &c2Row, &c2Col);
            cell2RowInput.addItems(rows);
            cell2RowInput.setCurrentIndex(c2Row);
            QComboBox cell2ColInput(&group);
            cell2ColInput.addItems(cols);
            cell2ColInput.setCurrentIndex(c2Col);

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

            QLabel outLabel(outText, &group);
            QComboBox outRowInput(&group);
            int outRow, outCol;
            decode_pos(*outCell, &outRow, &outCol);
            outRowInput.addItems(rows);
            outRowInput.setCurrentIndex(outRow);
            QComboBox outColInput(&group);
            outColInput.addItems(cols);
            outColInput.setCurrentIndex(outCol);

            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 = encode_pos(table->currentRow(), table->currentColumn());

            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("* B2 D2"));
            table->setItem(2, 4, new SpreadSheetItem("* B3 D3"));
            table->setItem(3, 4, new SpreadSheetItem("* B4 D4"));
            table->setItem(4, 4, new SpreadSheetItem("* B5 D5"));
            table->setItem(5, 4, new SpreadSheetItem("* B6 D6"));
            table->setItem(6, 4, new SpreadSheetItem("* B7 D7"));
            table->setItem(7, 4, new SpreadSheetItem("* B8 D8"));
            table->setItem(8, 4, new SpreadSheetItem("* B9 D9"));
            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"