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# Simple HTML Help Browser

This example implements a simple HTML help browser using Qt's richtext capabilities.

Header file:

    /****************************************************************************
    ** $Id: qt/helpwindow.h   3.2.1   edited May 13 09:08 $
    **
    ** Copyright (C) 1992-2000 Trolltech AS.  All rights reserved.
    **
    ** This file is part of an example program for Qt.  This example
    ** program may be used, distributed and modified without limitation.
    **
    *****************************************************************************/

    #ifndef HELPWINDOW_H
    #define HELPWINDOW_H

    #include <qmainwindow.h>
    #include <qtextbrowser.h>
    #include <qstringlist.h>
    #include <qmap.h>
    #include <qdir.h>

    class QComboBox;
    class QPopupMenu;

    class HelpWindow : public QMainWindow
    {
        Q_OBJECT
    public:
        HelpWindow( const QString& home_,  const QString& path, QWidget* parent = 0, const char *name=0 );
        ~HelpWindow();

    private slots:
        void setBackwardAvailable( bool );
        void setForwardAvailable( bool );

        void sourceChanged( const QString& );
        void about();
        void aboutQt();
        void openFile();
        void newWindow();
        void print();

        void pathSelected( const QString & );
        void histChosen( int );
        void bookmChosen( int );
        void addBookmark();

    private:
        void readHistory();
        void readBookmarks();

        QTextBrowser* browser;
        QComboBox *pathCombo;
        int backwardId, forwardId;
        QStringList history, bookmarks;
        QMap<int, QString> mHistory, mBookmarks;
        QPopupMenu *hist, *bookm;

    };

    #endif

Implementation:

    /****************************************************************************
    ** $Id: qt/helpwindow.cpp   3.2.1   edited Jul 16 13:14 $
    **
    ** Copyright (C) 1992-2002 Trolltech AS.  All rights reserved.
    **
    ** This file is part of an example program for Qt.  This example
    ** program may be used, distributed and modified without limitation.
    **
    *****************************************************************************/

    #include "helpwindow.h"
    #include <qstatusbar.h>
    #include <qpixmap.h>
    #include <qpopupmenu.h>
    #include <qmenubar.h>
    #include <qtoolbar.h>
    #include <qtoolbutton.h>
    #include <qiconset.h>
    #include <qfile.h>
    #include <qtextstream.h>
    #include <qstylesheet.h>
    #include <qmessagebox.h>
    #include <qfiledialog.h>
    #include <qapplication.h>
    #include <qcombobox.h>
    #include <qevent.h>
    #include <qlineedit.h>
    #include <qobjectlist.h>
    #include <qfileinfo.h>
    #include <qfile.h>
    #include <qdatastream.h>
    #include <qprinter.h>
    #include <qsimplerichtext.h>
    #include <qpainter.h>
    #include <qpaintdevicemetrics.h>

    #include <ctype.h>

    HelpWindow::HelpWindow( const QString& home_, const QString& _path,
                            QWidget* parent, const char *name )
        : QMainWindow( parent, name, WDestructiveClose ),
          pathCombo( 0 )
    {
        readHistory();
        readBookmarks();

        browser = new QTextBrowser( this );

        browser->mimeSourceFactory()->setFilePath( _path );
        browser->setFrameStyle( QFrame::Panel | QFrame::Sunken );
        connect( browser, SIGNAL( sourceChanged(const QString& ) ),
                 this, SLOT( sourceChanged( const QString&) ) );

        setCentralWidget( browser );

        if ( !home_.isEmpty() )
            browser->setSource( home_ );

        connect( browser, SIGNAL( highlighted( const QString&) ),
                 statusBar(), SLOT( message( const QString&)) );

        resize( 640,700 );

        QPopupMenu* file = new QPopupMenu( this );
        file->insertItem( tr("&New Window"), this, SLOT( newWindow() ), CTRL+Key_N );
        file->insertItem( tr("&Open File"), this, SLOT( openFile() ), CTRL+Key_O );
        file->insertItem( tr("&Print"), this, SLOT( print() ), CTRL+Key_P );
        file->insertSeparator();
        file->insertItem( tr("&Close"), this, SLOT( close() ), CTRL+Key_Q );
        file->insertItem( tr("E&xit"), qApp, SLOT( closeAllWindows() ), CTRL+Key_X );

        // The same three icons are used twice each.
        QIconSet icon_back( QPixmap("back.xpm") );
        QIconSet icon_forward( QPixmap("forward.xpm") );
        QIconSet icon_home( QPixmap("home.xpm") );

        QPopupMenu* go = new QPopupMenu( this );
        backwardId = go->insertItem( icon_back,
                                     tr("&Backward"), browser, SLOT( backward() ),
                                     CTRL+Key_Left );
        forwardId = go->insertItem( icon_forward,
                                    tr("&Forward"), browser, SLOT( forward() ),
                                    CTRL+Key_Right );
        go->insertItem( icon_home, tr("&Home"), browser, SLOT( home() ) );

        QPopupMenu* help = new QPopupMenu( this );
        help->insertItem( tr("&About"), this, SLOT( about() ) );
        help->insertItem( tr("About &Qt"), this, SLOT( aboutQt() ) );

        hist = new QPopupMenu( this );
        QStringList::Iterator it = history.begin();
        for ( ; it != history.end(); ++it )
            mHistory[ hist->insertItem( *it ) ] = *it;
        connect( hist, SIGNAL( activated( int ) ),
                 this, SLOT( histChosen( int ) ) );

        bookm = new QPopupMenu( this );
        bookm->insertItem( tr( "Add Bookmark" ), this, SLOT( addBookmark() ) );
        bookm->insertSeparator();

        QStringList::Iterator it2 = bookmarks.begin();
        for ( ; it2 != bookmarks.end(); ++it2 )
            mBookmarks[ bookm->insertItem( *it2 ) ] = *it2;
        connect( bookm, SIGNAL( activated( int ) ),
                 this, SLOT( bookmChosen( int ) ) );

        menuBar()->insertItem( tr("&File"), file );
        menuBar()->insertItem( tr("&Go"), go );
        menuBar()->insertItem( tr( "History" ), hist );
        menuBar()->insertItem( tr( "Bookmarks" ), bookm );
        menuBar()->insertSeparator();
        menuBar()->insertItem( tr("&Help"), help );

        menuBar()->setItemEnabled( forwardId, FALSE);
        menuBar()->setItemEnabled( backwardId, FALSE);
        connect( browser, SIGNAL( backwardAvailable( bool ) ),
                 this, SLOT( setBackwardAvailable( bool ) ) );
        connect( browser, SIGNAL( forwardAvailable( bool ) ),
                 this, SLOT( setForwardAvailable( bool ) ) );

        QToolBar* toolbar = new QToolBar( this );
        addToolBar( toolbar, "Toolbar");
        QToolButton* button;

        button = new QToolButton( icon_back, tr("Backward"), "", browser, SLOT(backward()), toolbar );
        connect( browser, SIGNAL( backwardAvailable(bool) ), button, SLOT( setEnabled(bool) ) );
        button->setEnabled( FALSE );
        button = new QToolButton( icon_forward, tr("Forward"), "", browser, SLOT(forward()), toolbar );
        connect( browser, SIGNAL( forwardAvailable(bool) ), button, SLOT( setEnabled(bool) ) );
        button->setEnabled( FALSE );
        button = new QToolButton( icon_home, tr("Home"), "", browser, SLOT(home()), toolbar );

        toolbar->addSeparator();

        pathCombo = new QComboBox( TRUE, toolbar );
        connect( pathCombo, SIGNAL( activated( const QString & ) ),
                 this, SLOT( pathSelected( const QString & ) ) );
        toolbar->setStretchableWidget( pathCombo );
        setRightJustification( TRUE );
        setDockEnabled( DockLeft, FALSE );
        setDockEnabled( DockRight, FALSE );

        pathCombo->insertItem( home_ );
        browser->setFocus();

    }

    void HelpWindow::setBackwardAvailable( bool b)
    {
        menuBar()->setItemEnabled( backwardId, b);
    }

    void HelpWindow::setForwardAvailable( bool b)
    {
        menuBar()->setItemEnabled( forwardId, b);
    }

    void HelpWindow::sourceChanged( const QString& url )
    {
        if ( browser->documentTitle().isNull() )
            setCaption( "Qt Example - Helpviewer - " + url );
        else
            setCaption( "Qt Example - Helpviewer - " + browser->documentTitle() ) ;

        if ( !url.isEmpty() && pathCombo ) {
            bool exists = FALSE;
            int i;
            for ( i = 0; i < pathCombo->count(); ++i ) {
                if ( pathCombo->text( i ) == url ) {
                    exists = TRUE;
                    break;
                }
            }
            if ( !exists ) {
                pathCombo->insertItem( url, 0 );
                pathCombo->setCurrentItem( 0 );
                mHistory[ hist->insertItem( url ) ] = url;
            } else
                pathCombo->setCurrentItem( i );
        }
    }

    HelpWindow::~HelpWindow()
    {
        history =  mHistory.values();

        QFile f( QDir::currentDirPath() + "/.history" );
        f.open( IO_WriteOnly );
        QDataStream s( &f );
        s << history;
        f.close();

        bookmarks = mBookmarks.values();

        QFile f2( QDir::currentDirPath() + "/.bookmarks" );
        f2.open( IO_WriteOnly );
        QDataStream s2( &f2 );
        s2 << bookmarks;
        f2.close();
    }

    void HelpWindow::about()
    {
        QMessageBox::about( this, "HelpViewer Example",
                            "<p>This example implements a simple HTML help viewer "
                            "using Qt's rich text capabilities</p>"
                            "<p>It's just about 400 lines of C++ code, so don't expect too much :-)</p>"
                            );
    }

    void HelpWindow::aboutQt()
    {
        QMessageBox::aboutQt( this, "QBrowser" );
    }

    void HelpWindow::openFile()
    {
    #ifndef QT_NO_FILEDIALOG
        QString fn = QFileDialog::getOpenFileName( QString::null, QString::null, this );
        if ( !fn.isEmpty() )
            browser->setSource( fn );
    #endif
    }

    void HelpWindow::newWindow()
    {
        ( new HelpWindow(browser->source(), "qbrowser") )->show();
    }

    void HelpWindow::print()
    {
    #ifndef QT_NO_PRINTER
        QPrinter printer( QPrinter::HighResolution );
        printer.setFullPage(TRUE);
        if ( printer.setup( this ) ) {
            QPainter p( &printer );
            if( !p.isActive() ) // starting printing failed
                return;
            QPaintDeviceMetrics metrics(p.device());
            int dpiy = metrics.logicalDpiY();
            int margin = (int) ( (2/2.54)*dpiy ); // 2 cm margins
            QRect body( margin, margin, metrics.width() - 2*margin, metrics.height() - 2*margin );
            QSimpleRichText richText( browser->text(),
                                      QFont(),
                                      browser->context(),
                                      browser->styleSheet(),
                                      browser->mimeSourceFactory(),
                                      body.height() );
            richText.setWidth( &p, body.width() );
            QRect view( body );
            int page = 1;
            do {
                richText.draw( &p, body.left(), body.top(), view, colorGroup() );
                view.moveBy( 0, body.height() );
                p.translate( 0 , -body.height() );
                p.drawText( view.right() - p.fontMetrics().width( QString::number(page) ),
                            view.bottom() + p.fontMetrics().ascent() + 5, QString::number(page) );
                if ( view.top()  >= richText.height() )
                    break;
                printer.newPage();
                page++;
            } while (TRUE);
        }
    #endif
    }

    void HelpWindow::pathSelected( const QString &_path )
    {
        browser->setSource( _path );
        if ( mHistory.values().contains(_path) )
            mHistory[ hist->insertItem( _path ) ] = _path;
    }

    void HelpWindow::readHistory()
    {
        if ( QFile::exists( QDir::currentDirPath() + "/.history" ) ) {
            QFile f( QDir::currentDirPath() + "/.history" );
            f.open( IO_ReadOnly );
            QDataStream s( &f );
            s >> history;
            f.close();
            while ( history.count() > 20 )
                history.remove( history.begin() );
        }
    }

    void HelpWindow::readBookmarks()
    {
        if ( QFile::exists( QDir::currentDirPath() + "/.bookmarks" ) ) {
            QFile f( QDir::currentDirPath() + "/.bookmarks" );
            f.open( IO_ReadOnly );
            QDataStream s( &f );
            s >> bookmarks;
            f.close();
        }
    }

    void HelpWindow::histChosen( int i )
    {
        if ( mHistory.contains( i ) )
            browser->setSource( mHistory[ i ] );
    }

    void HelpWindow::bookmChosen( int i )
    {
        if ( mBookmarks.contains( i ) )
            browser->setSource( mBookmarks[ i ] );
    }

    void HelpWindow::addBookmark()
    {
        mBookmarks[ bookm->insertItem( caption() ) ] = browser->context();
    }

Main:

    /****************************************************************************
    ** $Id: qt/main.cpp   3.2.1   edited Jul 9 13:58 $
    **
    ** Copyright (C) 1992-2000 Trolltech AS.  All rights reserved.
    **
    ** This file is part of an example program for Qt.  This example
    ** program may be used, distributed and modified without limitation.
    **
    *****************************************************************************/

    #include "helpwindow.h"
    #include <qapplication.h>
    #include <qdir.h>
    #include <stdlib.h>

    int main( int argc, char ** argv )
    {
        QApplication::setColorSpec( QApplication::ManyColor );
        QApplication a(argc, argv);

        QString home;
        if (argc > 1) {
            home = argv[1];
        } else {
            // Use a hard coded path. It is only an example.
            home = QDir( "../../doc/html/index.html" ).absPath();
        }

        HelpWindow *help = new HelpWindow(home, ".", 0, "help viewer");
        help->setCaption("Qt Example - Helpviewer");
        if ( QApplication::desktop()->width() > 400
             && QApplication::desktop()->height() > 500 )
            help->show();
        else
            help->showMaximized();

        QObject::connect( &a, SIGNAL(lastWindowClosed()),
                          &a, SLOT(quit()) );

        return a.exec();
    }

See also Examples.