qpicture.cpp

qt-x11-opensource-src-4.1.4.tar.gz源码

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**
** Copyright (C) 1992-2006 Trolltech ASA. All rights reserved.
**
** This file is part of the QtGui module of the Qt Toolkit.
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#include "qpicture.h"
#include <private/qpicture_p.h>

#ifndef QT_NO_PICTURE

#include <private/qfactoryloader_p.h>
#include <private/qpaintengine_pic_p.h>

#include "qdatastream.h"
#include "qfile.h"
#include "qimage.h"
#include "qmutex.h"
#include "qpainter.h"
#include "qpainterpath.h"
#include "qpixmap.h"
#include "qregion.h"
#include "qdebug.h"

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

    \ingroup multimedia
    \ingroup shared
    \mainclass

    A picture serializes painter commands to an IO device in a
    platform-independent format. They are sometimes referred to as meta-files.

    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 on a widget or pixmap (e.g., fonts, pixmaps, regions,
    transformed graphics, etc.)  can also be stored in a picture.

    QPicture is resolution independent, i.e. a QPicture can be
    displayed on different devices (for example svg, pdf, ps, printer
    and screen) looking the same. This is, for instance, needed for
    WYSIWYG print preview. QPicture runs in the default system dpi,
    and scales the painter to match differences in resolution
    depending on the window system.

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

    Example of how to record a picture:
    \quotefromfile snippets/picture/picture.cpp
    \skipto RECORD
    \skipto QPicture
    \printuntil save

    Example of how to replay a picture:
    \quotefromfile snippets/picture/picture.cpp
    \skipto REPLAY
    \skipto QPicture
    \printuntil end();

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

    \sa QMovie
*/

const char  *qt_mfhdr_tag = "QPIC"; // header tag
static const quint16 mfhdr_maj = 8; // major version #
static const quint16 mfhdr_min = 0; // minor version #
extern int qt_defaultDpi();

/*!
    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.

    Note that the default formatVersion is -1 which signifies the
    current release, i.e. for Qt 4.0 a formatVersion of 7 is the same
    as the default formatVersion of -1.

    Reading pictures generated by earlier versions of Qt is not
    supported in Qt 4.0.
*/

QPicture::QPicture(int formatVersion)
    : QPaintDevice(),
      d_ptr(new QPicturePrivate)
{
    Q_D(QPicture);
    d_ptr->q_ptr = this;
    d->paintEngine = 0;

    if (formatVersion == 0)
        qWarning("QPicture: invalid format version 0");

    // 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(), d_ptr(pic.d_ptr)
{
    d_func()->ref.ref();
}

/*! \internal */
QPicture::QPicture(QPicturePrivate &dptr)
    : QPaintDevice(),
      d_ptr(&dptr)
{
    d_ptr->q_ptr = this;
}

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

/*!
  \internal
*/
int QPicture::devType() const
{
    return QInternal::Picture;
}

/*!
    \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()
*/


bool QPicture::isNull() const
{
    return d_func()->pictb.buffer().isNull();
}

uint QPicture::size() const
{
    return d_func()->pictb.buffer().size();
}

const char* QPicture::data() const
{
    return d_func()->pictb.buffer();
}

void QPicture::detach()
{
    if (d_func()->ref != 1)
        detach_helper();
}

bool QPicture::isDetached() const
{
    return d_func()->ref == 1;
}

/*!
    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();
    d_func()->pictb.setData(data, size);
    d_func()->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.

    \sa save()
*/

bool QPicture::load(const QString &fileName, const char *format)
{
    QFile f(fileName);
    if (!f.open(QIODevice::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)
{
    if(format) {
#ifndef QT_NO_PICTUREIO
        QPictureIO io(dev, format);
        bool result = io.read();
        if (result) {
            operator=(io.picture());

        } else if (format)
#else
            bool result = false;
#endif
        {
            qWarning("QPicture::load: No such picture format: %s", format);
        }
        return result;
    }

    detach();
    QByteArray a = dev->readAll();

    d_func()->pictb.setData(a);                        // set byte array in buffer
    return d_func()->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. By default the
    data will be saved in the native QPicture file format.

    \sa load()
*/

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


    if(format) {
#ifndef QT_NO_PICTUREIO
        QPictureIO io(fileName, format);
        bool result = io.write();
        if (result) {
            operator=(io.picture());
        } else if (format)
#else
        bool result = false;
#endif
        {
            qWarning("QPicture::save: No such picture format: %s", format);
        }
        return result;
    }

    QFile f(fileName);
    if (!f.open(QIODevice::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()) {
        qWarning("QPicture::save: still being painted on. "
                  "Call QPainter::end() first");
        return false;
    }

    if(format) {
#ifndef QT_NO_PICTUREIO
        QPictureIO io(dev, format);
        bool result = io.write();
        if (result) {
            operator=(io.picture());
        } else if (format)
#else
        bool result = false;
#endif
        {
            qWarning("QPicture::save: No such picture format: %s", format);
        }
        return result;
    }

    dev->write(d_func()->pictb.buffer(), d_func()->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
{
    Q_D(const QPicture);
    // Use override rect where possible.
    if (!d->override_rect.isEmpty())
        return d->override_rect;

    if (!d->formatOk)
        d_ptr->checkFormat();

    return d->brect;
}

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

void QPicture::setBoundingRect(const QRect &r)
{
    d_func()->override_rect = 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)
{
    Q_D(QPicture);

    if (d->pictb.size() == 0)                        // nothing recorded
        return true;

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

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

    quint8  c, clen;
    quint32 nrecords;
    s >> c >> clen;
    Q_ASSERT(c == QPicturePrivate::PdcBegin);
    // bounding rect was introduced in ver 4. Read in checkFormat().
    if (d->formatMajor >= 4) {
        qint32 dummy;
        s >> dummy >> dummy >> dummy >> dummy;
    }
    s >> nrecords;
    if (!exec(painter, s, nrecords)) {
        qWarning("QPicture::play: Format error");
        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)