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# A simple demonstration of QFont member functions

This example demonstrates the use of various QFont member functions.

It is covered in detail by a walkthrough.

The main window API (viewer.h):

    /* $Id$ */

    #ifndef VIEWER_H
    #define VIEWER_H

    #include <qwidget.h>
    #include <qfont.h>

    class QTextView;
    class QPushButton;

    class Viewer : public QWidget
    {
    Q_OBJECT

    public:
        Viewer();

    private slots:
        void setDefault();
        void setSansSerif();
        void setItalics();

    private:
        void setFontSubstitutions();
        void layout();
        void showFontInfo( QFont & );

        QTextView * greetings;
        QTextView * fontInfo;

        QPushButton * defaultButton;
        QPushButton * sansSerifButton;
        QPushButton * italicsButton;
    };

    #endif

The main window implementation (viewer.cpp):

    /* $Id$ */

    #include "viewer.h"
    #include <qstring.h>
    #include <qstringlist.h>
    #include <qtextview.h>
    #include <qpushbutton.h>
    #include <qlayout.h>

    Viewer::Viewer()
           :QWidget()
    {
        setFontSubstitutions();

        QString greeting_heb = QString::fromUtf8( "\327\251\327\234\327\225\327\235" );
        QString greeting_ru = QString::fromUtf8( "\320\227\320\264\321\200\320\260\320\262\321\201\321\202\320\262\321\203\320\271\321\202\320\265" );
        QString greeting_en( "Hello" );

        greetings = new QTextView( this, "textview" );

        greetings->setText( greeting_en + "\n" +
                           greeting_ru + "\n" +
                           greeting_heb );

        fontInfo = new QTextView( this, "fontinfo" );

        setDefault();

        defaultButton = new QPushButton( "Default", this,
                                                       "pushbutton1" );
        defaultButton->setFont( QFont( "times" ) );
        connect( defaultButton, SIGNAL( clicked() ),
                 this, SLOT( setDefault() ) );

        sansSerifButton = new QPushButton( "Sans Serif", this,
                                                         "pushbutton2" );
        sansSerifButton->setFont( QFont( "Helvetica", 12 ) );
        connect( sansSerifButton, SIGNAL( clicked() ),
                 this, SLOT( setSansSerif() ) );

        italicsButton = new QPushButton( "Italics", this,
                                                       "pushbutton3" );
        italicsButton->setFont( QFont( "lucida", 12, QFont::Bold, TRUE ) );
        connect( italicsButton, SIGNAL( clicked() ),
                 this, SLOT( setItalics() ) );

        layout();
    }

    void Viewer::setDefault()
    {
        QFont font( "Bavaria" );
        font.setPointSize( 24 );

        font.setWeight( QFont::Bold );
        font.setUnderline( TRUE );

        greetings->setFont( font );

        showFontInfo( font );
    }

    void Viewer::setSansSerif()
    {
        QFont font( "Newyork", 18 );
        font.setStyleHint( QFont::SansSerif );
        greetings->setFont( font );

        showFontInfo( font );
    }

    void Viewer::setItalics()
    {
        QFont font( "Tokyo" );
        font.setPointSize( 32 );
        font.setWeight( QFont::Bold );
        font.setItalic( TRUE );

        greetings->setFont( font );

        showFontInfo( font );
    }

    void Viewer::showFontInfo( QFont & font )
    {
        QFontInfo info( font );

        QString messageText;
        messageText = "Font requested: \"" +
                      font.family() + "\" " +
                      QString::number( font.pointSize() ) + "pt<BR>" +
                      "Font used: \"" +
                      info.family() + "\" " +
                      QString::number( info.pointSize() ) + "pt<P>";

        QStringList substitutions = QFont::substitutes( font.family() );

        if ( ! substitutions.isEmpty() ){
            messageText += "The following substitutions exist for " + \
                           font.family() + ":<UL>";

            QStringList::Iterator i = substitutions.begin();
            while ( i != substitutions.end() ){
                messageText += "<LI>\"" + (* i) + "\"";
                i++;
            }
             messageText += "</UL>";
        } else {
            messageText += "No substitutions exist for " + \
                           font.family() + ".";
        }

        fontInfo->setText( messageText );
    }

    void Viewer::setFontSubstitutions()
    {
        QStringList substitutes;
        substitutes.append( "Times" );
        substitutes +=  "Mincho",
        substitutes << "Arabic Newspaper" << "crox";

        QFont::insertSubstitutions( "Bavaria", substitutes );

        QFont::insertSubstitution( "Tokyo", "Lucida" );
    }

    // For those who prefer to use Qt Designer for creating GUIs
    // the following function might not be of particular interest:
    // all it does is creating the widget layout.

    void Viewer::layout()
    {
        QHBoxLayout * textViewContainer = new QHBoxLayout();
        textViewContainer->addWidget( greetings );
        textViewContainer->addWidget( fontInfo );

        QHBoxLayout * buttonContainer = new QHBoxLayout();

        buttonContainer->addWidget( defaultButton );
        buttonContainer->addWidget( sansSerifButton );
        buttonContainer->addWidget( italicsButton );

        int maxButtonHeight = defaultButton->height();

        if ( sansSerifButton->height() > maxButtonHeight )
            maxButtonHeight = sansSerifButton->height();
        if ( italicsButton->height() > maxButtonHeight )
            maxButtonHeight = italicsButton->height();

        defaultButton->setFixedHeight( maxButtonHeight );
        sansSerifButton->setFixedHeight( maxButtonHeight );
        italicsButton->setFixedHeight( maxButtonHeight );

        QVBoxLayout * container = new QVBoxLayout( this );
        container->addLayout( textViewContainer );
        container->addLayout( buttonContainer );

        resize( 700, 250 );
    }

main() program (simple-qfont-demo.cpp):

    /* $Id$ */

    #include "viewer.h"

    #include <qapplication.h>

    int main( int argc, char **argv )
    {
        QApplication app( argc, argv );
        Viewer * textViewer = new Viewer();
        textViewer->setCaption( "Qt Example - Simple QFont Demo" );
        app.setMainWidget( textViewer );
        textViewer->show();
        return app.exec();
    }

See also QFont Examples.