q3dragobject.cpp

奇趣公司比较新的qt/emd版本

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#include "qplatformdefs.h"

#ifndef QT_NO_MIME

#include "q3dragobject.h"
#include "qpixmap.h"
#include "qevent.h"
#include "qfile.h"
#include "qtextcodec.h"
#include "qapplication.h"
#include "qpoint.h"
#include "qwidget.h"
#include "qbuffer.h"
#include "qimagereader.h"
#include "qimagewriter.h"
#include "qimage.h"
#include "qregexp.h"
#include "qdir.h"
#include "qdrag.h"
#include "q3strlist.h"
#include "q3cstring.h"

#include <private/qobject_p.h>

#include <ctype.h>

static QWidget *last_target = 0;

class QDragMime;

class Q3DragObjectPrivate : public QObjectPrivate
{
    Q_DECLARE_PUBLIC(Q3DragObject)
public:
    Q3DragObjectPrivate(): hot(0,0),pm_cursor(0) {}
    QPixmap pixmap;
    QPoint hot;
    // store default cursors
    QPixmap *pm_cursor;
};

class Q3TextDragPrivate : public Q3DragObjectPrivate
{
    Q_DECLARE_PUBLIC(Q3TextDrag)
public:
    Q3TextDragPrivate() { setSubType(QLatin1String("plain")); }
    void setSubType(const QString & st) {
        subtype = st;
        fmt = QString(QLatin1String("text/")).toLatin1() + subtype.toLatin1();
    }

    QString txt;
    QString subtype;
    QByteArray fmt;
};

class Q3StoredDragPrivate : public Q3DragObjectPrivate
{
    Q_DECLARE_PUBLIC(Q3StoredDrag)
public:
    Q3StoredDragPrivate() {}
    const char* fmt;
    QByteArray enc;
};

class Q3ImageDragPrivate : public Q3DragObjectPrivate
{
    Q_DECLARE_PUBLIC(Q3ImageDrag)
public:
    QImage img;
    QList<QByteArray> ofmts;
};

class QDragMime : public QMimeData
{
public:
    QDragMime(Q3DragObject *parent) : QMimeData(), dragObject(parent) { }
    ~QDragMime();

    QByteArray data(const QString &mimetype) const;
    bool hasFormat(const QString &mimetype) const;
    QStringList formats() const;

    QPointer<Q3DragObject> dragObject;
};

QDragMime::~QDragMime()
{
    delete dragObject;
}
QByteArray QDragMime::data(const QString &mimetype) const
{
    return dragObject->encodedData(mimetype.latin1());
}

bool QDragMime::hasFormat(const QString &mimetype) const
{
    return dragObject->provides(mimetype.latin1());
}

QStringList QDragMime::formats() const
{
    int i = 0;
    const char *format;
    QStringList f;
    while ((format = dragObject->format(i))) {
        f.append(QLatin1String(format));
        ++i;
    }
    return f;
}

/*!
    Constructs a drag object called \a name with a parent \a
    dragSource.

    Note that the drag object will be deleted when the \a dragSource is
    deleted.
*/

Q3DragObject::Q3DragObject(QWidget * dragSource, const char * name)
    : QObject(*(new Q3DragObjectPrivate), dragSource)
{
    setObjectName(QLatin1String(name));
}

/*! \internal */
Q3DragObject::Q3DragObject(Q3DragObjectPrivate &dd, QWidget *dragSource)
    : QObject(dd, dragSource)
{
}

/*!
    Destroys the drag object, canceling any drag and drop operation in
    which it is involved.
*/

Q3DragObject::~Q3DragObject()
{
}

#ifndef QT_NO_DRAGANDDROP
/*!
    Set the pixmap, \a pm, to display while dragging the object. The
    platform-specific implementation will use this where it can - so
    provide a small masked pixmap, and do not assume that the user
    will actually see it. For example, cursors on Windows 95 are of
    limited size.

    The \a hotspot is the point on (or off) the pixmap that should be
    under the cursor as it is dragged. It is relative to the top-left
    pixel of the pixmap.

    \warning We have seen problems with drag cursors on different
    graphics hardware and driver software on Windows. Setting the
    graphics acceleration in the display settings down one tick solved
    the problems in all cases.
*/
void Q3DragObject::setPixmap(QPixmap pm, const QPoint& hotspot)
{
    Q_D(Q3DragObject);
    d->pixmap = pm;
    d->hot = hotspot;
#if 0
    QDragManager *manager = QDragManager::self();
    if (manager && manager->object == d->data)
        manager->updatePixmap();
#endif
}

/*!
    \overload

    Uses a hotspot that positions the pixmap below and to the right of
    the mouse pointer. This allows the user to clearly see the point
    on the window where they are dragging the data.
*/
void Q3DragObject::setPixmap(QPixmap pm)
{
    setPixmap(pm,QPoint(-10, -10));
}

/*!
    Returns the currently set pixmap, or a null pixmap if none is set.

    \sa QPixmap::isNull()
*/
QPixmap Q3DragObject::pixmap() const
{
    return d_func()->pixmap;
}

/*!
    Returns the currently set pixmap hotspot.

    \sa setPixmap()
*/
QPoint Q3DragObject::pixmapHotSpot() const
{
    return d_func()->hot;
}

/*!
    Starts a drag operation using the contents of this object, using
    DragDefault mode.

    The function returns true if the caller should delete the original
    copy of the dragged data (but see target()); otherwise returns
    false.

    If the drag contains \e references to information (e.g. file names
    in a Q3UriDrag are references) then the return value should always
    be ignored, as the target is expected to directly manipulate the
    content referred to by the drag object. On X11 the return value should
    always be correct anyway, but on Windows this is not necessarily
    the case; e.g. the file manager starts a background process to
    move files, so the source \e{must not} delete the files!

    Note that on Windows the drag operation will start a blocking modal
    event loop that will not dispatch any QTimers.
*/
bool Q3DragObject::drag()
{
    return drag(DragDefault);
}

/*!
    After the drag completes, this function will return the QWidget
   which received the drop, or 0 if the data was dropped on another
    application.

    This can be useful for detecting the case where drag and drop is
    to and from the same widget.
*/
QWidget *Q3DragObject::target()
{
    return last_target;
}

/*!
    Starts a drag operation using the contents of this object, using
    \c DragMove mode. Be sure to read the constraints described in
    drag().

    Returns true if the data was dragged as a \e move, indicating that
    the caller should remove the original source of the data (the drag
    object must continue to have a copy); otherwise returns false.

    \sa drag() dragCopy() dragLink()
*/
bool Q3DragObject::dragMove()
{
    return drag(DragMove);
}


/*!
    Starts a drag operation using the contents of this object, using
    \c DragCopy mode. Be sure to read the constraints described in
    drag().

    \sa drag() dragMove() dragLink()
*/
void Q3DragObject::dragCopy()
{
    (void)drag(DragCopy);
}

/*!
    Starts a drag operation using the contents of this object, using
    \c DragLink mode. Be sure to read the constraints described in
    drag().

    \sa drag() dragCopy() dragMove()
*/
void Q3DragObject::dragLink()
{
    (void)drag(DragLink);
}


/*!
    \enum Q3DragObject::DragMode

    This enum describes the possible drag modes.

    \value DragDefault     The mode is determined heuristically.
    \value DragCopy        The data is copied.
    \value DragMove        The data is moved.
    \value DragLink        The data is linked.
    \value DragCopyOrMove  The user chooses the mode by using the
                           \key{Shift} key to switch from the default
                           copy mode to move mode.
*/


/*!
    \overload
    Starts a drag operation using the contents of this object.

    At this point, the object becomes owned by Qt, not the
    application. You should not delete the drag object or anything it
    references. The actual transfer of data to the target application
    will be done during future event processing - after that time the
    drag object will be deleted.

    Returns true if the dragged data was dragged as a \e move,
    indicating that the caller should remove the original source of
    the data (the drag object must continue to have a copy); otherwise
    returns false.

    The \a mode specifies the drag mode (see
    \l{Q3DragObject::DragMode}.) Normally one of the simpler drag(),
    dragMove(), or dragCopy() functions would be used instead.
*/
bool Q3DragObject::drag(DragMode mode)
{
    Q_D(Q3DragObject);
    QDragMime *data = new QDragMime(this);
    int i = 0;
    const char *fmt;
    while ((fmt = format(i))) {
        data->setData(QLatin1String(fmt), encodedData(fmt));
        ++i;
    }

    QDrag *drag = new QDrag(qobject_cast<QWidget *>(parent()));
    drag->setMimeData(data);
    drag->setPixmap(d->pixmap);
    drag->setHotSpot(d->hot);

    Qt::DropActions op;
    switch(mode) {
    case DragDefault:
    case DragCopyOrMove:
        op = Qt::CopyAction|Qt::MoveAction;
        break;
    case DragCopy:
        op = Qt::CopyAction;
        break;
    case DragMove:
        op = Qt::MoveAction;
        break;
    case DragLink:
        op = Qt::LinkAction;
        break;
    }
    bool retval = (drag->start(op) == Qt::MoveAction);
    last_target = drag->target();

    return retval;
}

#endif


/*!
    Returns a pointer to the widget where this object originated (the drag
    source).
*/

QWidget * Q3DragObject::source()
{
    if (parent() && parent()->isWidgetType())
        return (QWidget *)parent();
    else
        return 0;
}


/*!
    \class Q3DragObject qdragobject.h

    \brief The Q3DragObject class encapsulates MIME-based data
    transfer.

    \compat

    Q3DragObject is the base class for all data that needs to be
    transferred between and within applications, both for drag and
    drop and for the clipboard.

    See the \link dnd.html Drag and drop documentation\endlink for an
    overview of how to provide drag and drop in your application.

    See the QClipboard documentation for an overview of how to provide
    cut and paste in your application.

    The drag() function is used to start a drag operation. You can
    specify the \l DragMode in the call or use one of the convenience
    functions dragCopy(), dragMove(), or dragLink(). The drag source
    where the data originated is retrieved with source(). If the data
    was dropped on a widget within the application, target() will
    return a pointer to that widget. Specify the pixmap to display
    during the drag with setPixmap().
*/

static
void stripws(QByteArray& s)
{
    int f;
    while ((f = s.indexOf(' ')) >= 0)
        s.remove(f,1);
}

/*!
    \class Q3TextDrag qdragobject.h

    \brief The Q3TextDrag class is a drag and drop object for
    transferring plain and Unicode text.

    \compat

    Plain text is passed in a QString which may contain multiple lines
    (i.e. may contain newline characters). The drag target will receive
    the newlines according to the runtime environment, e.g. LF on Unix,
    and CRLF on Windows.

    Qt provides no built-in mechanism for delivering only a single-line.

    For more information about drag and drop, see the Q3DragObject class
    and the \link dnd.html drag and drop documentation\endlink.
*/


/*!
    Constructs a text drag object with the given \a name, and sets its data
    to \a text. The \a dragSource is the widget that the drag operation started
    from.
*/

Q3TextDrag::Q3TextDrag(const QString &text, QWidget * dragSource, const char * name)
    : Q3DragObject(*new Q3TextDragPrivate, dragSource)
{
    setObjectName(QLatin1String(name));
    setText(text);
}


/*!
    Constructs a default text drag object with the given \a name.
    The \a dragSource is the widget that the drag operation started from.
*/

Q3TextDrag::Q3TextDrag(QWidget * dragSource, const char * name)
    : Q3DragObject(*(new Q3TextDragPrivate), dragSource)
{
    setObjectName(QLatin1String(name));
}

/*! \internal */
Q3TextDrag::Q3TextDrag(Q3TextDragPrivate &dd, QWidget *dragSource)
    : Q3DragObject(dd, dragSource)
{

}

/*!
    Destroys the text drag object.
*/
Q3TextDrag::~Q3TextDrag()
{

}

/*!
    \fn void Q3TextDrag::setSubtype(const QString &subtype)

    Sets the MIME \a subtype of the text being dragged. The default subtype
    is "plain", so the default MIME type of the text is "text/plain".
    You might use this to declare that the text is "text/html" by calling
    setSubtype("html").
*/
void Q3TextDrag::setSubtype(const QString & st)
{
    d_func()->setSubType(st);
}

/*!
    Sets the \a text to be dragged. You will need to call this if you did
    not pass the text during construction.
*/
void Q3TextDrag::setText(const QString &text)
{
    d_func()->txt = text;
}


/*!
    \reimp
*/