source: trunk/src/kernel/qpicture.cpp@ 94

/****************************************************************************
** $Id: qpicture.cpp 2 2005-11-16 15:49:26Z dmik $
**
** Implementation of QPicture class
**
** Created : 940802
**
** Copyright (C) 1992-2000 Trolltech AS.  All rights reserved.
**
** This file is part of the kernel module of the Qt GUI Toolkit.
**
** This file may be distributed under the terms of the Q Public License
** as defined by Trolltech AS of Norway and appearing in the file
** LICENSE.QPL included in the packaging of this file.
**
** This file may be distributed and/or modified under the terms of the
** GNU General Public License version 2 as published by the Free Software
** Foundation and appearing in the file LICENSE.GPL included in the
** packaging of this file.
**
** Licensees holding valid Qt Enterprise Edition or Qt Professional Edition
** licenses may use this file in accodrance with the Qt Commercial License
** Agreement provided with the Software.
**
** This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
** WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
**
** See http://www.trolltech.com/pricing.html or email sales@trolltech.com for
**   information about Qt Commercial License Agreements.
** See http://www.trolltech.com/qpl/ for QPL licensing information.
** See http://www.trolltech.com/gpl/ for GPL licensing information.
**
** Contact info@trolltech.com if any conditions of this licensing are
** not clear to you.
**
**********************************************************************/

#include "qpicture.h"

#ifndef QT_NO_PICTURE

#include "qpainter.h"
#include "qpixmap.h"
#include "qimage.h"
#include "qfile.h"
#include "qdatastream.h"
#include "qpaintdevicemetrics.h"

#ifndef QT_NO_SVG
#include "private/qsvgdevice_p.h"
#endif

/*!
    \class QPicture qpicture.h
    \brief The QPicture class is a paint device that records and
    replays QPainter commands.

    \ingroup graphics
    \ingroup images
    \ingroup shared

    A picture serializes painter commands to an IO device in a
    platform-independent format. For example, a picture created under
    Windows can be read on a Sun SPARC.

    Pictures are called meta-files on some platforms.

    Qt pictures use a proprietary binary format. Unlike native picture
    (meta-file) formats on many window systems, Qt pictures have no
    limitations regarding their contents. Everything that can be
    painted can also be stored in a picture, e.g. fonts, pixmaps,
    regions, transformed graphics, etc.

    QPicture is an \link shclass.html implicitly shared\endlink class.

    Example of how to record a picture:
    \code
    QPicture  pic;
    QPainter  p;
    p.begin( &pic );               // paint in picture
    p.drawEllipse( 10,20, 80,70 ); // draw an ellipse
    p.end();                       // painting done
    pic.save( "drawing.pic" );     // save picture
    \endcode

    Example of how to replay a picture:
    \code
    QPicture  pic;
    pic.load( "drawing.pic" );     // load picture
    QPainter  p;
    p.begin( &myWidget );          // paint in myWidget
    p.drawPicture( pic );          // draw the picture
    p.end();                       // painting done
    \endcode

    Pictures can also be drawn using play(). Some basic data about a
    picture is available, for example, size(), isNull() and
    boundingRect().

*/


static const char  *mfhdr_tag = "QPIC";         // header tag
static const Q_UINT16 mfhdr_maj = 5;            // major version #
static const Q_UINT16 mfhdr_min = 0;            // minor version #


/*!
    Constructs an empty picture.

    The \a formatVersion parameter may be used to \e create a QPicture
    that can be read by applications that are compiled with earlier
    versions of Qt.
    \list
    \i \a formatVersion == 1 is binary compatible with Qt 1.x and later.
    \i \a formatVersion == 2 is binary compatible with Qt 2.0.x and later.
    \i \a formatVersion == 3 is binary compatible with Qt 2.1.x and later.
    \i \a formatVersion == 4 is binary compatible with Qt 3.0.x and later.
    \i \a formatVersion == 5 is binary compatible with Qt 3.1.
    \endlist

    Note that the default formatVersion is -1 which signifies the
    current release, i.e. for Qt 3.1 a formatVersion of 5 is the same
    as the default formatVersion of -1.

    Reading pictures generated by earlier versions of Qt is supported
    and needs no special coding; the format is automatically detected.
*/

QPicture::QPicture( int formatVersion )
    : QPaintDevice( QInternal::Picture | QInternal::ExternalDevice )
    // set device type
{
    d = new QPicturePrivate;

#if defined(QT_CHECK_RANGE)
    if ( formatVersion == 0 )
        qWarning( "QPicture: invalid format version 0" );
#endif

    // still accept the 0 default from before Qt 3.0.
    if ( formatVersion > 0 && formatVersion != (int)mfhdr_maj ) {
        d->formatMajor = formatVersion;
        d->formatMinor = 0;
        d->formatOk = FALSE;
    }
    else {
        d->resetFormat();
    }
}

/*!
    Constructs a \link shclass.html shallow copy\endlink of \a pic.
*/

QPicture::QPicture( const QPicture &pic )
    : QPaintDevice( QInternal::Picture | QInternal::ExternalDevice )
{
    d = pic.d;
    d->ref();
}

/*!
    Destroys the picture.
*/
QPicture::~QPicture()
{
    if ( d->deref() )
        delete d;
}


/*!
    \fn bool QPicture::isNull() const

    Returns TRUE if the picture contains no data; otherwise returns
    FALSE.
*/

/*!
    \fn uint QPicture::size() const

    Returns the size of the picture data.

    \sa data()
*/

/*!
    \fn const char* QPicture::data() const

    Returns a pointer to the picture data. The pointer is only valid
    until the next non-const function is called on this picture. The
    returned pointer is 0 if the picture contains no data.

    \sa size(), isNull()
*/

/*!
    Sets the picture data directly from \a data and \a size. This
    function copies the input data.

    \sa data(), size()
*/

void QPicture::setData( const char* data, uint size )
{
    detach();
    QByteArray a( size );
    memcpy( a.data(), data, size );
    d->pictb.setBuffer( a );                    // set byte array in buffer
    d->resetFormat();                           // we'll have to check
}


/*!
    Loads a picture from the file specified by \a fileName and returns
    TRUE if successful; otherwise returns FALSE.

    By default, the file will be interpreted as being in the native
    QPicture format. Specifying the \a format string is optional and
    is only needed for importing picture data stored in a different
    format.

    Currently, the only external format supported is the \link
    http://www.w3.org/Graphics/SVG/ W3C SVG \endlink format which
    requires the \link xml.html Qt XML module \endlink. The
    corresponding \a format string is "svg".

    \sa save()
*/

bool QPicture::load( const QString &fileName, const char *format )
{
    QFile f( fileName );
    if ( !f.open(IO_ReadOnly) )
        return FALSE;
    return load( &f, format );
}

/*!
    \overload

    \a dev is the device to use for loading.
*/

bool QPicture::load( QIODevice *dev, const char *format )
{
#ifndef QT_NO_SVG
    if ( qstrcmp( format, "svg" ) == 0 ) {
        QSvgDevice svg;
        if ( !svg.load( dev ) )
            return FALSE;
        QPainter p( this );
        bool b = svg.play( &p );
        d->brect = svg.boundingRect();
        return b;
    }
#endif
    if ( format ) {
        qWarning( "QPicture::load: No such picture format: %s", format );
        return FALSE;
    }

    detach();
    QByteArray a = dev->readAll();
    d->pictb.setBuffer( a );                    // set byte array in buffer
    return d->checkFormat();
}

/*!
    Saves a picture to the file specified by \a fileName and returns
    TRUE if successful; otherwise returns FALSE.

    Specifying the file \a format string is optional. It's not
    recommended unless you intend to export the picture data for
    use by a third party reader. By default the data will be saved in
    the native QPicture file format.

    Currently, the only external format supported is the \link
    http://www.w3.org/Graphics/SVG/ W3C SVG \endlink format which
    requires the \link xml.html Qt XML module \endlink. The
    corresponding \a format string is "svg".

    \sa load()
*/

bool QPicture::save( const QString &fileName, const char *format )
{
    if ( paintingActive() ) {
#if defined(QT_CHECK_STATE)
        qWarning( "QPicture::save: still being painted on. "
                  "Call QPainter::end() first" );
#endif
        return FALSE;
    }

#ifndef QT_NO_SVG
    // identical to QIODevice* code below but the file name
    // makes a difference when it comes to saving pixmaps
    if ( qstricmp( format, "svg" ) == 0 ) {
        QSvgDevice svg;
        QPainter p( &svg );
        if ( !play( &p ) )
            return FALSE;
        svg.setBoundingRect( boundingRect() );
        return svg.save( fileName );
    }
#endif

    QFile f( fileName );
    if ( !f.open(IO_WriteOnly) )
        return FALSE;
    return save( &f, format );
}

/*!
    \overload

    \a dev is the device to use for saving.
*/

bool QPicture::save( QIODevice *dev, const char *format )
{
    if ( paintingActive() ) {
#if defined(QT_CHECK_STATE)
        qWarning( "QPicture::save: still being painted on. "
                  "Call QPainter::end() first" );
#endif
        return FALSE;
    }

#ifndef QT_NO_SVG
    if ( qstricmp( format, "svg" ) == 0 ) {
        QSvgDevice svg;
        QPainter p( &svg );
        if ( !play( &p ) )
            return FALSE;
        svg.setBoundingRect( boundingRect() );
        return svg.save( dev );
    }
#endif
    if ( format ) {
        qWarning( "QPicture::save: No such picture format: %s", format );
        return FALSE;
    }

    dev->writeBlock( d->pictb.buffer().data(), d->pictb.buffer().size() );
    return TRUE;
}

/*!
    Returns the picture's bounding rectangle or an invalid rectangle
    if the picture contains no data.
*/

QRect QPicture::boundingRect() const
{
    if ( !d->formatOk )
        d->checkFormat();
    return d->brect;
}

/*!
    Sets the picture's bounding rectangle to \a r. The automatically
    calculated value is overriden.
*/

void QPicture::setBoundingRect( const QRect &r )
{
    if ( !d->formatOk )
        d->checkFormat();
    d->brect = r;
}

/*!
    Replays the picture using \a painter, and returns TRUE if
    successful; otherwise returns FALSE.

    This function does exactly the same as QPainter::drawPicture()
    with (x, y) = (0, 0).
*/

bool QPicture::play( QPainter *painter )
{
    if ( d->pictb.size() == 0 )                 // nothing recorded
        return TRUE;

    if ( !d->formatOk && !d->checkFormat() )
        return FALSE;

    d->pictb.open( IO_ReadOnly );               // open buffer device
    QDataStream s;
    s.setDevice( &d->pictb );                   // attach data stream to buffer
    s.device()->at( 10 );                       // go directly to the data
    s.setVersion( d->formatMajor == 4 ? 3 : d->formatMajor );

    Q_UINT8  c, clen;
    Q_UINT32 nrecords;
    s >> c >> clen;
    Q_ASSERT( c == PdcBegin );
    // bounding rect was introduced in ver 4. Read in checkFormat().
    if ( d->formatMajor >= 4 ) {
        Q_INT32 dummy;
        s >> dummy >> dummy >> dummy >> dummy;
    }
    s >> nrecords;
    if ( !exec( painter, s, nrecords ) ) {
#if defined(QT_CHECK_RANGE)
        qWarning( "QPicture::play: Format error" );
#endif
        d->pictb.close();
        return FALSE;
    }
    d->pictb.close();
    return TRUE;                                // no end-command
}


/*!
  \internal
  Iterates over the internal picture data and draws the picture using
  \a painter.
*/

bool QPicture::exec( QPainter *painter, QDataStream &s, int nrecords )
{
#if defined(QT_DEBUG)
    int         strm_pos;
#endif
    Q_UINT8     c;                              // command id
    Q_UINT8     tiny_len;                       // 8-bit length descriptor
    Q_INT32     len;                            // 32-bit length descriptor
    Q_INT16     i_16, i1_16, i2_16;             // parameters...
    Q_INT8      i_8;
    Q_UINT32    ul;
    QCString    str1;
    QString     str;
    QPoint      p, p1, p2;
    QRect       r;
    QPointArray a;
    QColor      color;
    QFont       font;
    QPen        pen;
    QBrush      brush;
    QRegion     rgn;
#ifndef QT_NO_TRANSFORMATIONS
    QWMatrix    matrix;
#endif

    while ( nrecords-- && !s.eof() ) {
        s >> c;                                 // read cmd
        s >> tiny_len;                          // read param length
        if ( tiny_len == 255 )                  // longer than 254 bytes
            s >> len;
        else
            len = tiny_len;
#if defined(QT_DEBUG)
        strm_pos = s.device()->at();
#endif
        switch ( c ) {                          // exec cmd
            case PdcNOP:
                break;
            case PdcDrawPoint:
                s >> p;
                painter->drawPoint( p );
                break;
            case PdcMoveTo:
                s >> p;
                painter->moveTo( p );
                break;
            case PdcLineTo:
                s >> p;
                painter->lineTo( p );
                break;
            case PdcDrawLine:
                s >> p1 >> p2;
                painter->drawLine( p1, p2 );
                break;
            case PdcDrawRect:
                s >> r;
                painter->drawRect( r );
                break;
            case PdcDrawRoundRect:
                s >> r >> i1_16 >> i2_16;
                painter->drawRoundRect( r, i1_16, i2_16 );
                break;
            case PdcDrawEllipse:
                s >> r;
                painter->drawEllipse( r );
                break;
            case PdcDrawArc:
                s >> r >> i1_16 >> i2_16;
                painter->drawArc( r, i1_16, i2_16 );
                break;
            case PdcDrawPie:
                s >> r >> i1_16 >> i2_16;
                painter->drawPie( r, i1_16, i2_16 );
                break;
            case PdcDrawChord:
                s >> r >> i1_16 >> i2_16;
                painter->drawChord( r, i1_16, i2_16 );
                break;
            case PdcDrawLineSegments:
                s >> a;
                painter->drawLineSegments( a );
                break;
            case PdcDrawPolyline:
                s >> a;
                painter->drawPolyline( a );
                break;
            case PdcDrawPolygon:
                s >> a >> i_8;
                painter->drawPolygon( a, i_8 );
                break;
            case PdcDrawCubicBezier:
                s >> a;
#ifndef QT_NO_BEZIER
                painter->drawCubicBezier( a );
#endif
                break;
            case PdcDrawText:
                s >> p >> str1;
                painter->drawText( p, str1 );
                break;
            case PdcDrawTextFormatted:
                s >> r >> i_16 >> str1;
                painter->drawText( r, i_16, str1 );
                break;
            case PdcDrawText2:
                s >> p >> str;
                painter->drawText( p, str );
                break;
            case PdcDrawText2Formatted:
                s >> r >> i_16 >> str;
                painter->drawText( r, i_16, str );
                break;
            case PdcDrawPixmap: {
                QPixmap pixmap;
                if ( d->formatMajor < 4 ) {
                    s >> p >> pixmap;
                    painter->drawPixmap( p, pixmap );
                } else {
                    s >> r >> pixmap;
                    painter->drawPixmap( r, pixmap );
                }
                        }
                break;
            case PdcDrawImage: {
                QImage image;
                if ( d->formatMajor < 4 ) {
                    s >> p >> image;
                    painter->drawImage( p, image );
                } else {
                    s >> r >> image;
                    painter->drawImage( r, image );
                }
                }
                break;
            case PdcBegin:
                s >> ul;                        // number of records
                if ( !exec( painter, s, ul ) )
                    return FALSE;
                break;
            case PdcEnd:
                if ( nrecords == 0 )
                    return TRUE;
                break;
            case PdcSave:
                painter->save();
                break;
            case PdcRestore:
                painter->restore();
                break;
            case PdcSetBkColor:
                s >> color;
                painter->setBackgroundColor( color );
                break;
            case PdcSetBkMode:
                s >> i_8;
                painter->setBackgroundMode( (Qt::BGMode)i_8 );
                break;
            case PdcSetROP:
                s >> i_8;
                painter->setRasterOp( (Qt::RasterOp)i_8 );
                break;
            case PdcSetBrushOrigin:
                s >> p;
                painter->setBrushOrigin( p );
                break;
            case PdcSetFont:
                s >> font;
                painter->setFont( font );
                break;
            case PdcSetPen:
                s >> pen;
                painter->setPen( pen );
                break;
            case PdcSetBrush:
                s >> brush;
                painter->setBrush( brush );
                break;
            case PdcSetTabStops:
                s >> i_16;
                painter->setTabStops( i_16 );
                break;
            case PdcSetTabArray:
                s >> i_16;
                if ( i_16 == 0 ) {
                    painter->setTabArray( 0 );
                } else {
                    int *ta = new int[i_16];
                    Q_CHECK_PTR( ta );
                    for ( int i=0; i<i_16; i++ ) {
                        s >> i1_16;
                        ta[i] = i1_16;
                    }
                    painter->setTabArray( ta );
                    delete [] ta;
                }
                break;
            case PdcSetVXform:
                s >> i_8;
#ifndef QT_NO_TRANSFORMATIONS
                painter->setViewXForm( i_8 );
#endif
                break;
            case PdcSetWindow:
                s >> r;
#ifndef QT_NO_TRANSFORMATIONS
                painter->setWindow( r );
#endif
                break;
            case PdcSetViewport:
                s >> r;
#ifndef QT_NO_TRANSFORMATIONS
                painter->setViewport( r );
#endif
                break;
            case PdcSetWXform:
                s >> i_8;
#ifndef QT_NO_TRANSFORMATIONS
                painter->setWorldXForm( i_8 );
#endif
                break;
            case PdcSetWMatrix:
#ifndef QT_NO_TRANSFORMATIONS   // #### fix me!
                s >> matrix >> i_8;
                painter->setWorldMatrix( matrix, i_8 );
#endif
                break;
#ifndef QT_NO_TRANSFORMATIONS
            case PdcSaveWMatrix:
                painter->saveWorldMatrix();
                break;
            case PdcRestoreWMatrix:
                painter->restoreWorldMatrix();
                break;
#endif
            case PdcSetClip:
                s >> i_8;
                painter->setClipping( i_8 );
                break;
            case PdcSetClipRegion:
                s >> rgn >> i_8;
                painter->setClipRegion( rgn, (QPainter::CoordinateMode)i_8 );
                break;
            default:
#if defined(QT_CHECK_RANGE)
                qWarning( "QPicture::play: Invalid command %d", c );
#endif
                if ( len )                      // skip unknown command
                    s.device()->at( s.device()->at()+len );
        }
#if defined(QT_DEBUG)
        //qDebug( "device->at(): %i, strm_pos: %i len: %i", s.device()->at(), strm_pos, len );
        Q_ASSERT( Q_INT32(s.device()->at() - strm_pos) == len );
#endif
    }
    return FALSE;
}


/*!
  \internal
  Records painter commands and stores them in the pictb buffer.
*/

bool QPicture::cmd( int c, QPainter *pt, QPDevCmdParam *p )
{
    detach();
    return d->cmd( c, pt, p );
}

/*!
  \internal
  Implementation of the function forwarded above to the internal data struct.
*/

bool QPicture::QPicturePrivate::cmd( int c, QPainter *pt, QPDevCmdParam *p )
{
    QDataStream s;
    s.setDevice( &pictb );
    // when moving up to 4 the QDataStream version remained at 3
    s.setVersion( formatMajor != 4 ? formatMajor : 3 );
    if ( c ==  PdcBegin ) {                     // begin; write header
        QByteArray empty( 0 );
        pictb.setBuffer( empty );               // reset byte array in buffer
        pictb.open( IO_WriteOnly );
        s.writeRawBytes( mfhdr_tag, 4 );
        s << (Q_UINT16)0 << (Q_UINT16)formatMajor << (Q_UINT16)formatMinor;
        s << (Q_UINT8)c << (Q_UINT8)sizeof(Q_INT32);
        brect = QRect();
        if ( formatMajor >= 4 ) {
            s << (Q_INT32)brect.left() << (Q_INT32)brect.top()
              << (Q_INT32)brect.width() << (Q_INT32)brect.height();
        }
        trecs = 0;
        s << (Q_UINT32)trecs;                   // total number of records
        formatOk = FALSE;
        return TRUE;
    } else if ( c == PdcEnd ) {         // end; calc checksum and close
        trecs++;
        s << (Q_UINT8)c << (Q_UINT8)0;
        QByteArray buf = pictb.buffer();
        int cs_start = sizeof(Q_UINT32);                // pos of checksum word
        int data_start = cs_start + sizeof(Q_UINT16);
        int brect_start = data_start + 2*sizeof(Q_INT16) + 2*sizeof(Q_UINT8);
        int pos = pictb.at();
        pictb.at( brect_start );
        if ( formatMajor >= 4 ) { // bounding rectangle
            s << (Q_INT32)brect.left() << (Q_INT32)brect.top()
              << (Q_INT32)brect.width() << (Q_INT32)brect.height();
        }
        s << (Q_UINT32)trecs;                   // write number of records
        pictb.at( cs_start );
        Q_UINT16 cs = (Q_UINT16)qChecksum( buf.data()+data_start, pos-data_start );
        s << cs;                                // write checksum
        pictb.close();
        return TRUE;
    }
    trecs++;
    s << (Q_UINT8)c;                            // write cmd to stream
    s << (Q_UINT8)0;                            // write dummy length info
    int pos = (int)pictb.at();                  // save position
    QRect br;                                   // bounding rect addition
    bool corr = FALSE;                          // correction for pen width

    switch ( c ) {
        case PdcDrawPoint:
        case PdcMoveTo:
        case PdcLineTo:
        case PdcSetBrushOrigin:
            s << *p[0].point;
            br = QRect( *p[0].point, QSize( 1, 1 ) );
            corr = TRUE;
            break;
        case PdcDrawLine:
            s << *p[0].point << *p[1].point;
            br = QRect( *p[0].point, *p[1].point ).normalize();
            corr = TRUE;
            break;
        case PdcDrawRect:
        case PdcDrawEllipse:
            s << *p[0].rect;
            br = *p[0].rect;
            corr = TRUE;
            break;
        case PdcDrawRoundRect:
        case PdcDrawArc:
        case PdcDrawPie:
        case PdcDrawChord:
            s << *p[0].rect << (Q_INT16)p[1].ival << (Q_INT16)p[2].ival;
            br = *p[0].rect;
            corr = TRUE;
            break;
        case PdcDrawLineSegments:
        case PdcDrawPolyline:
            s << *p[0].ptarr;
            br = p[0].ptarr->boundingRect();
            corr = TRUE;
            break;
#ifndef QT_NO_BEZIER
        case PdcDrawCubicBezier:
            s << *p[0].ptarr;
            br = p[0].ptarr->cubicBezier().boundingRect();
            corr = TRUE;
            break;
#endif
        case PdcDrawPolygon:
            s << *p[0].ptarr << (Q_INT8)p[1].ival;
            br = p[0].ptarr->boundingRect();
            corr = TRUE;
            break;
        case PdcDrawText2:
            if ( formatMajor == 1 ) {
                pictb.at( pos - 2 );
                s << (Q_UINT8)PdcDrawText << (Q_UINT8)0;
                QCString str1( (*p[1].str).latin1() );
                s << *p[0].point << str1;
            }
            else {
                s << *p[0].point << *p[1].str;
            }
            br = pt->fontMetrics().boundingRect( *p[1].str );
            br.moveBy( p[0].point->x(), p[0].point->y() );
            break;
        case PdcDrawText2Formatted:
            if ( formatMajor == 1 ) {
                pictb.at( pos - 2 );
                s << (Q_UINT8)PdcDrawTextFormatted << (Q_UINT8)0;
                QCString str1( (*p[2].str).latin1() );
                s << *p[0].rect << (Q_INT16)p[1].ival << str1;
            }
            else {
                s << *p[0].rect << (Q_INT16)p[1].ival << *p[2].str;
            }
            br = *p[0].rect;
            break;
        case PdcDrawPixmap:
            if ( formatMajor < 4 ) {
                s << *p[0].point;
                s << *p[1].pixmap;
                br = QRect( *p[0].point, p[1].pixmap->size() );
            } else {
                s << *p[0].rect;
                s << *p[1].pixmap;
                br = *p[0].rect;
            }
            break;
        case PdcDrawImage:
            if ( formatMajor < 4 ) {
                QPoint pt( p[0].point->x(), p[0].point->y() );
                s << pt;
                s << *p[1].image;
                br = QRect( *p[0].point, p[1].image->size() );
            } else {
                s << *p[0].rect;
                s << *p[1].image;
                br = *p[0].rect;
            }
            break;
        case PdcSave:
        case PdcRestore:
            break;
        case PdcSetBkColor:
            s << *p[0].color;
            break;
        case PdcSetBkMode:
        case PdcSetROP:
            s << (Q_INT8)p[0].ival;
            break;
        case PdcSetFont:
            s << *p[0].font;
            break;
        case PdcSetPen:
            s << *p[0].pen;
            break;
        case PdcSetBrush:
            s << *p[0].brush;
            break;
        case PdcSetTabStops:
            s << (Q_INT16)p[0].ival;
            break;
        case PdcSetTabArray:
            s << (Q_INT16)p[0].ival;
            if ( p[0].ival ) {
                int *ta = p[1].ivec;
                for ( int i=0; i<p[0].ival; i++ )
                    s << (Q_INT16)ta[i];
            }
            break;
        case PdcSetUnit:
        case PdcSetVXform:
        case PdcSetWXform:
        case PdcSetClip:
            s << (Q_INT8)p[0].ival;
            break;
#ifndef QT_NO_TRANSFORMATIONS
        case PdcSetWindow:
        case PdcSetViewport:
            s << *p[0].rect;
            break;
        case PdcSetWMatrix:
            s << *p[0].matrix << (Q_INT8)p[1].ival;
            break;
#endif
        case PdcSetClipRegion:
            s << *p[0].rgn;
            s << (Q_INT8)p[1].ival;
            break;
#if defined(QT_CHECK_RANGE)
        default:
            qWarning( "QPicture::cmd: Command %d not recognized", c );
#endif
    }
    int newpos = (int)pictb.at();               // new position
    int length = newpos - pos;
    if ( length < 255 ) {                       // write 8-bit length
        pictb.at(pos - 1);                      // position to right index
        s << (Q_UINT8)length;
    } else {                                    // write 32-bit length
        s << (Q_UINT32)0;                               // extend the buffer
        pictb.at(pos - 1);                      // position to right index
        s << (Q_UINT8)255;                      // indicate 32-bit length
        char *p = pictb.buffer().data();
        memmove( p+pos+4, p+pos, length );      // make room for 4 byte
        s << (Q_UINT32)length;
        newpos += 4;
    }
    pictb.at( newpos );                         // set to new position

    if ( br.isValid() ) {
        if ( corr ) {                           // widen bounding rect
            int w2 = pt->pen().width() / 2;
            br.setCoords( br.left() - w2, br.top() - w2,
                          br.right() + w2, br.bottom() + w2 );
        }
#ifndef QT_NO_TRANSFORMATIONS
        br = pt->worldMatrix().map( br );
#endif
        if ( pt->hasClipping() ) {
            QRect cr = pt->clipRegion().boundingRect();
            br &= cr;
        }
        if ( br.isValid() )
            brect |= br;                        // merge with existing rect
    }

    return TRUE;
}


/*!
    Internal implementation of the virtual QPaintDevice::metric()
    function.

    Use the QPaintDeviceMetrics class instead.

    A picture has the following hard-coded values: dpi=72,
    numcolors=16777216 and depth=24.

    \a m is the metric to get.
*/

int QPicture::metric( int m ) const
{
    int val;
    switch ( m ) {
        // ### hard coded dpi and color depth values !
        case QPaintDeviceMetrics::PdmWidth:
            val = d->brect.width();
            break;
        case QPaintDeviceMetrics::PdmHeight:
            val = d->brect.height();
            break;
        case QPaintDeviceMetrics::PdmWidthMM:
            val = int(25.4/72.0*d->brect.width());
            break;
        case QPaintDeviceMetrics::PdmHeightMM:
            val = int(25.4/72.0*d->brect.height());
            break;
        case QPaintDeviceMetrics::PdmDpiX:
        case QPaintDeviceMetrics::PdmPhysicalDpiX:
            val = 72;
            break;
        case QPaintDeviceMetrics::PdmDpiY:
        case QPaintDeviceMetrics::PdmPhysicalDpiY:
            val = 72;
            break;
        case QPaintDeviceMetrics::PdmNumColors:
            val = 16777216;
            break;
        case QPaintDeviceMetrics::PdmDepth:
            val = 24;
            break;
        default:
            val = 0;
#if defined(QT_CHECK_RANGE)
            qWarning( "QPicture::metric: Invalid metric command" );
#endif
    }
    return val;
}

/*!
    Detaches from shared picture data and makes sure that this picture
    is the only one referring to the data.

    If multiple pictures share common data, this picture makes a copy
    of the data and detaches itself from the sharing mechanism.
    Nothing is done if there is just a single reference.
*/

void QPicture::detach()
{
    if ( d->count != 1 )
        *this = copy();
}

/*!
    Returns a \link shclass.html deep copy\endlink of the picture.
*/

QPicture QPicture::copy() const
{
    QPicture p;
    QByteArray a( size() );
    memcpy( a.data(), data(), size() );
    p.d->pictb.setBuffer( a );                  // set byte array in buffer
    if ( d->pictb.isOpen() ) {                  // copy buffer state
        p.d->pictb.open( d->pictb.mode() );
        p.d->pictb.at( d->pictb.at() );
    }
    p.d->trecs = d->trecs;
    p.d->formatOk = d->formatOk;
    p.d->formatMinor = d->formatMajor;
    p.d->brect = boundingRect();
    return p;
}

/*****************************************************************************
  QPainter member functions
 *****************************************************************************/

/*!
    Replays the picture \a pic translated by (\a x, \a y).

    This function does exactly the same as QPicture::play() when
    called with (\a x, \a y) = (0, 0).
*/

void QPainter::drawPicture( int x, int y, const QPicture &pic )
{
    save();
    translate( x, y );
    ((QPicture*)&pic)->play( (QPainter*)this );
    restore();
}

/*!
    \overload void QPainter::drawPicture( const QPoint &p, const QPicture &pic )

    Draws picture \a pic at point \a p.
*/

void QPainter::drawPicture( const QPoint &p, const QPicture &pic )
{
    drawPicture( p.x(), p.y(), pic );
}

/*!
  \obsolete

  Use one of the other QPainter::drawPicture() functions with a (0, 0)
  offset instead.
*/

void QPainter::drawPicture( const QPicture &pic )
{
    drawPicture( 0, 0, pic );
}

/*!
    Assigns a \link shclass.html shallow copy\endlink of \a p to this
    picture and returns a reference to this picture.
*/

QPicture& QPicture::operator= (const QPicture& p)
{
    p.d->ref();                         // avoid 'x = x'
    if ( d->deref() )
        delete d;
    d = p.d;
    return *this;
}


/*!
  \internal

  Sets formatOk to FALSE and resets the format version numbers to default
*/

void QPicture::QPicturePrivate::resetFormat()
{
    formatOk = FALSE;
    formatMajor = mfhdr_maj;
    formatMinor = mfhdr_min;
}

/*!
  \internal

  Checks data integrity and format version number. Set formatOk to TRUE
  on success, to FALSE otherwise. Returns the resulting formatOk value.
*/

bool QPicture::QPicturePrivate::checkFormat()
{
    resetFormat();

    // can't check anything in an empty buffer
    if ( pictb.size() == 0 )
        return FALSE;

    pictb.open( IO_ReadOnly );                  // open buffer device
    QDataStream s;
    s.setDevice( &pictb );                      // attach data stream to buffer

    char mf_id[4];                              // picture header tag
    s.readRawBytes( mf_id, 4 );                 // read actual tag
    if ( memcmp(mf_id, mfhdr_tag, 4) != 0 ) {   // wrong header id
#if defined(QT_CHECK_RANGE)
        qWarning( "QPicture::checkFormat: Incorrect header" );
#endif
        pictb.close();
        return FALSE;
    }

    int cs_start = sizeof(Q_UINT32);            // pos of checksum word
    int data_start = cs_start + sizeof(Q_UINT16);
    Q_UINT16 cs,ccs;
    QByteArray buf = pictb.buffer();    // pointer to data
    s >> cs;                            // read checksum
    ccs = qChecksum( buf.data() + data_start, buf.size() - data_start );
    if ( ccs != cs ) {
#if defined(QT_CHECK_STATE)
        qWarning( "QPicture::checkFormat: Invalid checksum %x, %x expected",
                  ccs, cs );
#endif
        pictb.close();
        return FALSE;
    }

    Q_UINT16 major, minor;
    s >> major >> minor;                        // read version number
    if ( major > mfhdr_maj ) {          // new, incompatible version
#if defined(QT_CHECK_RANGE)
        qWarning( "QPicture::checkFormat: Incompatible version %d.%d",
                  major, minor);
#endif
        pictb.close();
        return FALSE;
    }
    s.setVersion( major != 4 ? major : 3 );

    Q_UINT8  c, clen;
    s >> c >> clen;
    if ( c == PdcBegin ) {
        if ( !( major >= 1 && major <= 3 )) {
            Q_INT32 l, t, w, h;
            s >> l >> t >> w >> h;
            brect = QRect( l, t, w, h );
        }
    } else {
#if defined(QT_CHECK_RANGE)
        qWarning( "QPicture::checkFormat: Format error" );
#endif
        pictb.close();
        return FALSE;
    }
    pictb.close();

    formatOk = TRUE;                    // picture seems to be ok
    formatMajor = major;
    formatMinor = minor;
    return TRUE;
}

/*****************************************************************************
  QPicture stream functions
 *****************************************************************************/

/*!
    \relates QPicture

    Writes picture \a r to the stream \a s and returns a reference to
    the stream.
*/

QDataStream &operator<<( QDataStream &s, const QPicture &r )
{
    Q_UINT32 size = r.d->pictb.buffer().size();
    s << size;
    // null picture ?
    if ( size == 0 )
        return s;
    // just write the whole buffer to the stream
    return s.writeRawBytes ( r.d->pictb.buffer().data(),
                             r.d->pictb.buffer().size() );
}

/*!
    \relates QPicture

    Reads a picture from the stream \a s into picture \a r and returns
    a reference to the stream.
*/

QDataStream &operator>>( QDataStream &s, QPicture &r )
{
    QDataStream sr;

    // "init"; this code is similar to the beginning of QPicture::cmd()
    sr.setDevice( &r.d->pictb );
    sr.setVersion( r.d->formatMajor );
    Q_UINT32 len;
    s >> len;
    QByteArray data( len );
    if ( len > 0 )
        s.readRawBytes( data.data(), len );

    r.d->pictb.setBuffer( data );
    r.d->resetFormat();

    return s;
}

#endif // QT_NO_PICTURE