qpicture.cpp

奇趣公司比较新的qt/emd版本

    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.
*/

/*! \fn bool QPicture::isDetached() const
\internal
*/
void QPicture::detach_helper()
{
    Q_D(QPicture);
    QPicturePrivate *x = new QPicturePrivate;
    int pictsize = size();
    x->pictb.setData(data(), pictsize);
    if (d->pictb.isOpen()) {
        x->pictb.open(d->pictb.openMode());
        x->pictb.seek(d->pictb.pos());
    }
    x->trecs = d->trecs;
    x->formatOk = d->formatOk;
    x->formatMinor = d->formatMinor;
    x->brect = d->brect;
    x->override_rect = d->override_rect;
    x = qAtomicSetPtr(&d_ptr, x);
    if (!x->ref.deref())
        delete x;
}

/*!
    Assigns picture \a p to this picture and returns a reference to
    this picture.
*/
QPicture& QPicture::operator=(const QPicture &p)
{
    qAtomicAssign<QPicturePrivate>(d_ptr, p.d_ptr);
    return *this;
}

/*!
  \internal

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

void 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 QPicturePrivate::checkFormat()
{
    resetFormat();

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

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

    char mf_id[4];                                // picture header tag
    s.readRawData(mf_id, 4);                        // read actual tag
    if (memcmp(mf_id, qt_mfhdr_tag, 4) != 0) {         // wrong header id
        qWarning("QPicturePaintEngine::checkFormat: Incorrect header");
        pictb.close();
        return false;
    }

    int cs_start = sizeof(quint32);                // pos of checksum word
    int data_start = cs_start + sizeof(quint16);
    quint16 cs,ccs;
    QByteArray buf = pictb.buffer();        // pointer to data

    s >> cs;                                // read checksum
    ccs = (quint16) qChecksum(buf.constData() + data_start, buf.size() - data_start);
    if (ccs != cs) {
        qWarning("QPicturePaintEngine::checkFormat: Invalid checksum %x, %x expected",
                  ccs, cs);
        pictb.close();
        return false;
    }

    quint16 major, minor;
    s >> major >> minor;                        // read version number
    if (major > mfhdr_maj) {                // new, incompatible version
        qWarning("QPicturePaintEngine::checkFormat: Incompatible version %d.%d",
                  major, minor);
        pictb.close();
        return false;
    }
    s.setVersion(major != 4 ? major : 3);

    quint8  c, clen;
    s >> c >> clen;
    if (c == QPicturePrivate::PdcBegin) {
        if (!(major >= 1 && major <= 3)) {
            qint32 l, t, w, h;
            s >> l >> t >> w >> h;
            brect = QRect(l, t, w, h);
        }
    } else {
        qWarning("QPicturePaintEngine::checkFormat: Format error");
        pictb.close();
        return false;
    }
    pictb.close();

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

/*! \internal */
QPaintEngine *QPicture::paintEngine() const
{
    if (!d_func()->paintEngine)
        const_cast<QPicture*>(this)->d_func()->paintEngine = new QPicturePaintEngine;
    return d_func()->paintEngine;
}

/*****************************************************************************
  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)
{
    quint32 size = r.d_func()->pictb.buffer().size();
    s << size;
    // null picture ?
    if (size == 0)
        return s;
    // just write the whole buffer to the stream
    s.writeRawData (r.d_func()->pictb.buffer(), r.d_func()->pictb.buffer().size());
    return s;
}

/*!
    \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_func()->pictb);
    sr.setVersion(r.d_func()->formatMajor);
    quint32 len;
    s >> len;
    QByteArray data;
    if (len > 0) {
        data.resize(len);
        s.readRawData(data.data(), len);
    }

    r.d_func()->pictb.setData(data);
    r.d_func()->resetFormat();
    return s;
}


#ifndef QT_NO_PICTUREIO
#include "qregexp.h"
#include "qapplication.h"
#include "qpictureformatplugin.h"

/*!
    \obsolete

    Returns a string that specifies the picture format of the file \a
    fileName, or 0 if the file cannot be read or if the format is not
    recognized.

    \sa load() save()
*/

const char* QPicture::pictureFormat(const QString &fileName)
{
    return QPictureIO::pictureFormat(fileName);
}

/*!
    \obsolete

    Returns a list of picture formats that are supported for picture
    input.

    \sa outputFormats() inputFormatList() QPictureIO
*/
QList<QByteArray> QPicture::inputFormats()
{
    return QPictureIO::inputFormats();
}

static QStringList qToStringList(const QList<QByteArray> arr)
{
    QStringList list;
    for (int i = 0; i < arr.count(); ++i)
        list.append(QString::fromLatin1(arr.at(i)));
    return list;
}

/*!
    \obsolete

    Returns a list of picture formats that are supported for picture
    input.

    Note that if you want to iterate over the list, you should iterate
    over a copy, e.g.
    \quotefromfile snippets/picture/picture.cpp
    \skipto FORMATS
    \skipto QStringList
    \printuntil myProcessing

    \sa outputFormatList() inputFormats() QPictureIO
*/
QStringList QPicture::inputFormatList()
{
    return qToStringList(QPictureIO::inputFormats());
}


/*!
    \obsolete

    Returns a list of picture formats that are supported for picture
    output.

    Note that if you want to iterate over the list, you should iterate
    over a copy, e.g.
    \quotefromfile snippets/picture/picture.cpp
    \skipto OUTPUT
    \skipto QStringList
    \printuntil myProcessing

    \sa inputFormatList() outputFormats() QPictureIO
*/
QStringList QPicture::outputFormatList()
{
    return qToStringList(QPictureIO::outputFormats());
}

/*!
    \obsolete

    Returns a list of picture formats that are supported for picture
    output.

    \sa inputFormats() outputFormatList() QPictureIO
*/
QList<QByteArray> QPicture::outputFormats()
{
    return QPictureIO::outputFormats();
}

/*****************************************************************************
  QPictureIO member functions
 *****************************************************************************/

/*!
    \obsolete

    \class QPictureIO qpicture.h

    \brief The QPictureIO class contains parameters for loading and
    saving pictures.

    \ingroup multimedia
    \ingroup io

    QPictureIO contains a QIODevice object that is used for picture data
    I/O. The programmer can install new picture file formats in addition
    to those that Qt provides.

    You don't normally need to use this class; QPicture::load(),
    QPicture::save().

    \sa QPicture QPixmap QFile
*/

struct QPictureIOData
{
    QPicture        pi;                                // picture
    int                iostat;                                // IO status
    QByteArray        frmt;                                // picture format
    QIODevice  *iodev;                                // IO device
    QString        fname;                                // file name
    QString     descr;                                // picture description
    const char *parameters;
    int quality;
    float gamma;
};

/*!
    Constructs a QPictureIO object with all parameters set to zero.
*/

QPictureIO::QPictureIO()
{
    init();
}

/*!
    Constructs a QPictureIO object with the I/O device \a ioDevice and a
    \a format tag.
*/

QPictureIO::QPictureIO(QIODevice *ioDevice, const char *format)
{
    init();
    d->iodev = ioDevice;
    d->frmt = format;
}

/*!
    Constructs a QPictureIO object with the file name \a fileName and a
    \a format tag.
*/

QPictureIO::QPictureIO(const QString &fileName, const char* format)
{
    init();
    d->frmt = format;
    d->fname = fileName;
}

/*!
    Contains initialization common to all QPictureIO constructors.
*/

void QPictureIO::init()
{
    d = new QPictureIOData();
    d->parameters = 0;
    d->quality = -1; // default quality of the current format
    d->gamma=0.0f;
    d->iostat = 0;
    d->iodev  = 0;
}

/*!
    Destroys the object and all related data.
*/

QPictureIO::~QPictureIO()
{
    if (d->parameters)
        delete [] (char*)d->parameters;
    delete d;
}


/*****************************************************************************
  QPictureIO picture handler functions
 *****************************************************************************/

class QPictureHandler
{
public:
    QPictureHandler(const char *f, const char *h, const QByteArray& fl,
                     picture_io_handler r, picture_io_handler w);
    QByteArray              format;                        // picture format
    QRegExp              header;                        // picture header pattern
    enum TMode { Untranslated=0, TranslateIn, TranslateInOut } text_mode;
    picture_io_handler  read_picture;                // picture read function
    picture_io_handler  write_picture;                // picture write function
    bool              obsolete;                        // support not "published"
};

QPictureHandler::QPictureHandler(const char *f, const char *h, const QByteArray& fl,
                              picture_io_handler r, picture_io_handler w)
    : format(f), header(QString::fromLatin1(h))
{
    text_mode = Untranslated;
    if (fl.contains('t'))
        text_mode = TranslateIn;
    else if (fl.contains('T'))
        text_mode = TranslateInOut;
    obsolete = fl.contains('O');
    read_picture  = r;
    write_picture = w;
}

typedef QList<QPictureHandler *> QPHList;
static QPHList pictureHandlers;

#ifndef QT_NO_LIBRARY
Q_GLOBAL_STATIC(QMutex, mutex)
Q_GLOBAL_STATIC_WITH_ARGS(QFactoryLoader, loader,
                          (QPictureFormatInterface_iid,
                           QCoreApplication::libraryPaths(),
                           QLatin1String("/pictureformats")))
#endif
void qt_init_picture_plugins()
{
#ifndef QT_NO_LIBRARY
    QMutexLocker locker(mutex());
    QFactoryLoader *loader = ::loader();
    QStringList keys = loader->keys();
    for (int i = 0; i < keys.count(); ++i)
        if (QPictureFormatInterface *format = qobject_cast<QPictureFormatInterface*>(loader->instance(keys.at(i))))
            format->installIOHandler(keys.at(i));
#endif
}

static void cleanup()
{
    // make sure that picture handlers are delete before plugin manager
    while (!pictureHandlers.isEmpty())
        delete pictureHandlers.takeFirst();
}

void qt_init_picture_handlers()                // initialize picture handlers
{
    static bool done = false;
    if (done) return;
    done = true;

    qAddPostRoutine(cleanup);
}

static QPictureHandler *get_picture_handler(const char *format)
{                                                // get pointer to handler
    qt_init_picture_handlers();
    qt_init_picture_plugins();
    for (int i = 0; i < pictureHandlers.size(); ++i) {
        if (pictureHandlers.at(i)->format == format)
            return pictureHandlers.at(i);
    }
    return 0;                                        // no such handler
}


/*!
    Defines a picture I/O handler for the picture format called \a
    format, which is recognized using the regular
    expression defined in \a header, read using \a readPicture and
    written using \a writePicture.

    \a flags is a string of single-character flags for this format.
    The only flag defined currently is T (upper case), so the only
    legal value for \a flags are "T" and the empty string. The "T"
    flag means that the picture file is a text file, and Qt should treat
    all newline conventions as equivalent. (XPM files and some PPM
    files are text files for example.)

    \a format is used to select a handler to write a QPicture; \a header
    is used to select a handler to read an picture file.

    If \a readPicture is a null pointer, the QPictureIO will not be able
    to read pictures in \a format. If \a writePicture is a null pointer,
    the QPictureIO will not be able to write pictures in \a format. If
    both are null, the QPictureIO object is valid but useless.

    Example:
    \quotefromfile snippets/picture/picture.cpp
    \skipto SVG READ
    \skipto readSVG
    \printuntil }
    \skipto SVG WRITE
    \skipto writeSVG
    \printuntil }