Movies or the Story of the Animated GIF file

The Movies example displays animated GIF files using the QMovie and QLabel classes.
Main:
/****************************************************************************
** $Id: qt/main.cpp   3.1.2   edited Jan 22 08:38 $
**
** 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 <qapplication.h>
#include <qfiledialog.h>
#include <qpushbutton.h>
#include <qlabel.h>
#include <qpainter.h>
#include <qmessagebox.h>
#include <qmovie.h>
#include <qvbox.h>


class MovieScreen : public QFrame {
    Q_OBJECT
    QMovie movie;
    QString filename;
    QSize sh;

public:
    MovieScreen(const char* fname, QMovie m, QWidget* p=0, const char* name=0, WFlags f=0) :
        QFrame(p, name, f),
        sh(100,100)
    {
        setCaption(fname);
        filename = fname;
        movie = m;

        // Set a frame around the movie.
        setFrameStyle(QFrame::WinPanel|QFrame::Sunken);

        // No background needed, since we draw on the whole widget.
        movie.setBackgroundColor(backgroundColor());
        setBackgroundMode(NoBackground);

        // Get the movie to tell use when interesting things happen.
        movie.connectUpdate(this, SLOT(movieUpdated(const QRect&)));
        movie.connectResize(this, SLOT(movieResized(const QSize&)));
        movie.connectStatus(this, SLOT(movieStatus(int)));

        setSizePolicy(QSizePolicy(QSizePolicy::Expanding,QSizePolicy::Expanding));
    }

    QSize sizeHint() const
    {
        return sh;
    }

protected:

    // Draw the contents of the QFrame - the movie and on-screen-display
    void drawContents(QPainter* p)
    {
        // Get the current movie frame.
        QPixmap pm = movie.framePixmap();

        // Get the area we have to draw in.
        QRect r = contentsRect();

        if ( !pm.isNull() ) {
            // Only rescale is we need to - it can take CPU!
            if ( r.size() != pm.size() ) {
                QWMatrix m;
                m.scale((double)r.width()/pm.width(),
                        (double)r.height()/pm.height());
                pm = pm.xForm(m);
            }

            // Draw the [possibly scaled] frame.  movieUpdated() below calls
            // repaint with only the changed area, so clipping will ensure we
            // only do the minimum amount of rendering.
            //
            p->drawPixmap(r.x(), r.y(), pm);
        }


        // The on-screen display

        const char* message = 0;

        if (movie.paused()) {
            message = "PAUSED";
        } else if (movie.finished()) {
            message = "THE END";
        } else if (movie.steps() > 0) {
            message = "FF >>";
        }

        if (message) {
            // Find a good font size...
            p->setFont(QFont("Helvetica", 24));

            QFontMetrics fm = p->fontMetrics();
            if ( fm.width(message) > r.width()-10 )
                p->setFont(QFont("Helvetica", 18));

            fm = p->fontMetrics();
            if ( fm.width(message) > r.width()-10 )
                p->setFont(QFont("Helvetica", 14));

            fm = p->fontMetrics();
            if ( fm.width(message) > r.width()-10 )
                p->setFont(QFont("Helvetica", 12));

            fm = p->fontMetrics();
            if ( fm.width(message) > r.width()-10 )
                p->setFont(QFont("Helvetica", 10));

            // "Shadow" effect.
            p->setPen(black);
            p->drawText(1, 1, width()-1, height()-1, AlignCenter, message);
            p->setPen(white);
            p->drawText(0, 0, width()-1, height()-1, AlignCenter, message);
        }
    }

public slots:
    void restart()
    {
        movie.restart();
        repaint();
    }

    void togglePause()
    {
        if ( movie.paused() )
            movie.unpause();
        else
            movie.pause();
        repaint();
    }

    void step()
    {
        movie.step();
        repaint();
    }

    void step10()
    {
        movie.step(10);
        repaint();
    }

private slots:
    void movieUpdated(const QRect& area)
    {
        if (!isVisible())
            show();

        // The given area of the movie has changed.

        QRect r = contentsRect();

        if ( r.size() != movie.framePixmap().size() ) {
            // Need to scale - redraw whole frame.
            repaint( r );
        } else {
            // Only redraw the changed area of the frame
            repaint( area.x()+r.x(), area.y()+r.x(),
                     area.width(), area.height() );
        }
    }

    void movieResized(const QSize& size)
    {
        // The movie changed size, probably from its initial zero size.

        int fw = frameWidth();
        sh = QSize( size.width() + fw*2, size.height() + fw*2 );
        updateGeometry();
        if ( parentWidget() && parentWidget()->isHidden() )
            parentWidget()->show();
    }

    void movieStatus(int status)
    {
        // The movie has sent us a status message.

        if (status < 0) {
            QString msg;
            msg.sprintf("Could not play movie \"%s\"", (const char*)filename);
            QMessageBox::warning(this, "movies", msg);
            parentWidget()->close();
        } else if (status == QMovie::Paused || status == QMovie::EndOfMovie) {
            repaint(); // Ensure status text is displayed
        }
    }
};

class MoviePlayer : public QVBox {
    MovieScreen* movie;
public:
    MoviePlayer(const char* fname, QMovie m, QWidget* p=0, const char* name=0, WFlags f=0) :
        QVBox(p,name,f)
    {
        movie = new MovieScreen(fname, m, this);
        QHBox* hb = new QHBox(this);
        QPushButton* btn;
        btn = new QPushButton("<<", hb);
        connect(btn, SIGNAL(clicked()), movie, SLOT(restart()));
        btn = new QPushButton("||", hb);
        connect(btn, SIGNAL(clicked()), movie, SLOT(togglePause()));
        btn = new QPushButton(">|", hb);
        connect(btn, SIGNAL(clicked()), movie, SLOT(step()));
        btn = new QPushButton(">>|", hb);
        connect(btn, SIGNAL(clicked()), movie, SLOT(step10()));
    }
};


// A QFileDialog that chooses movies.
//
class MovieStarter: public QFileDialog {
    Q_OBJECT
public:
    MovieStarter(const char *dir);

public slots:
    void startMovie(const QString& filename);
    // QDialog's method - normally closes the file dialog.
    // We want it left open, and we want Cancel to quit everything.
    void done( int r );
};


MovieStarter::MovieStarter(const char *dir)
    : QFileDialog(dir, "*.gif *.mng")
{
    //behave as in getOpenFilename
    setMode( ExistingFile );
    // When a file is selected, show it as a movie.
    connect(this, SIGNAL(fileSelected(const QString&)),
            this, SLOT(startMovie(const QString&)));
}


void MovieStarter::startMovie(const QString& filename)
{
    if ( filename ) { // Start a new movie - have it delete when closed.
#ifdef Q_WS_MAC
        (new MoviePlayer( filename, QMovie(filename), this, 0, WDestructiveClose|WMacDrawer|WType_TopLevel))->show();
#else
        (new MoviePlayer( filename, QMovie(filename), 0, 0, WDestructiveClose))->show();
#endif
    }
}

void MovieStarter::done( int r )
{
    if (r != Accepted)
        qApp->quit(); // end on Cancel
    setResult( r );

    // And don't hide.
}


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

    if (argc > 1) {
        // Commandline mode - show movies given on the command line
        //
        bool gui=TRUE;
        for (int arg=1; arg<argc; arg++) {
            if ( QString(argv[arg]) == "-i" )
                gui = !gui;
            else if ( gui )
                (void)new MoviePlayer(argv[arg], QMovie(argv[arg]), 0, 0,
                                      Qt::WDestructiveClose);
            else
                (void)new MovieScreen(argv[arg], QMovie(argv[arg]), 0, 0,
                                      Qt::WDestructiveClose);
        }
        QObject::connect(qApp, SIGNAL(lastWindowClosed()), qApp, SLOT(quit()));
    } else {
        // "GUI" mode - open a chooser for movies
        //
        MovieStarter* fd = new MovieStarter(".");
        fd->show();
    }

    // Go!
    return a.exec();
}

#include "main.moc"