qwhatsthis.cpp

奇趣公司比较新的qt/emd版本

    QPointer<QToolButton> button;
#endif
    static void say(QWidget *, const QString &, int x = 0, int y = 0);
    static void notifyToplevels(QEvent *e);
};

void QWhatsThisPrivate::notifyToplevels(QEvent *e)
{
    QWidgetList toplevels = QApplication::topLevelWidgets();
    for (int i = 0; i < toplevels.count(); ++i) {
        register QWidget *w = toplevels.at(i);
        QApplication::sendEvent(w, e);
    }
}

QWhatsThisPrivate *QWhatsThisPrivate::instance = 0;

QWhatsThisPrivate::QWhatsThisPrivate()
{
    instance = this;
    qApp->installEventFilter(this);

    QPoint pos = QCursor::pos();
    if (QWidget *w = QApplication::widgetAt(pos)) {
        QHelpEvent e(QEvent::QueryWhatsThis, w->mapFromGlobal(pos), pos);
        bool sentEvent = QApplication::sendEvent(w, &e);
#ifdef QT_NO_CURSOR
        Q_UNUSED(sentEvent);
#else
        QApplication::setOverrideCursor((!sentEvent || !e.isAccepted())?
                                        Qt::ForbiddenCursor:Qt::WhatsThisCursor);
    } else {
        QApplication::setOverrideCursor(Qt::WhatsThisCursor);
#endif
    }
#ifndef QT_NO_ACCESSIBILITY
    QAccessible::updateAccessibility(this, 0, QAccessible::ContextHelpStart);
#endif
}

QWhatsThisPrivate::~QWhatsThisPrivate()
{
    if (action)
        action->setChecked(false);
#ifdef QT3_SUPPORT
    if (button)
        button->setChecked(false);
#endif
#ifndef QT_NO_CURSOR
    QApplication::restoreOverrideCursor();
#endif
#ifndef QT_NO_ACCESSIBILITY
    QAccessible::updateAccessibility(this, 0, QAccessible::ContextHelpEnd);
#endif
    instance = 0;
}

bool QWhatsThisPrivate::eventFilter(QObject *o, QEvent *e)
{
    if (!o->isWidgetType())
        return false;
    QWidget * w = static_cast<QWidget *>(o);
    bool customWhatsThis = w->testAttribute(Qt::WA_CustomWhatsThis);
    switch (e->type()) {
    case QEvent::MouseButtonPress:
    {
        QMouseEvent *me = static_cast<QMouseEvent*>(e);
        if (me->button() == Qt::RightButton || customWhatsThis)
            return false;
        QHelpEvent e(QEvent::WhatsThis, me->pos(), me->globalPos());
        if (!QApplication::sendEvent(w, &e) || !e.isAccepted())
            QWhatsThis::leaveWhatsThisMode();

    } break;

    case QEvent::MouseMove:
    {
        QMouseEvent *me = static_cast<QMouseEvent*>(e);
        QHelpEvent e(QEvent::QueryWhatsThis, me->pos(), me->globalPos());
        bool sentEvent = QApplication::sendEvent(w, &e);
#ifdef QT_NO_CURSOR
        Q_UNUSED(sentEvent);
#else
        QApplication::changeOverrideCursor((!sentEvent || !e.isAccepted())?
                                           Qt::ForbiddenCursor:Qt::WhatsThisCursor);
#endif
    }
    // fall thorugh
    case QEvent::MouseButtonRelease:
    case QEvent::MouseButtonDblClick:
        if (static_cast<QMouseEvent*>(e)->button() == Qt::RightButton || customWhatsThis)
            return false; // ignore RMB release
        break;
    case QEvent::KeyPress:
    {
        QKeyEvent* kev = (QKeyEvent*)e;

        if (kev->key() == Qt::Key_Escape) {
            QWhatsThis::leaveWhatsThisMode();
            return true;
        } else if (customWhatsThis) {
            return false;
        } else if (kev->key() == Qt::Key_Menu ||
                    (kev->key() == Qt::Key_F10 &&
                      kev->modifiers() == Qt::ShiftModifier)) {
            // we don't react to these keys, they are used for context menus
            return false;
        } else if (kev->key() != Qt::Key_Shift && kev->key() != Qt::Key_Alt // not a modifier key
                   && kev->key() != Qt::Key_Control && kev->key() != Qt::Key_Meta) {
            QWhatsThis::leaveWhatsThisMode();
        }
    } break;
    default:
        return false;
    }
    return true;
}

class QWhatsThisAction: public QAction
{
    Q_OBJECT

public:
    explicit QWhatsThisAction(QObject* parent = 0);

private slots:
    void actionTriggered();
};

QWhatsThisAction::QWhatsThisAction(QObject *parent) : QAction(tr("What's This?"), parent)
{
#ifndef QT_NO_IMAGEFORMAT_XPM
    QPixmap p((const char**)button_image);
    setIcon(p);
#endif
    setCheckable(true);
    connect(this, SIGNAL(triggered()), this, SLOT(actionTriggered()));
#ifndef QT_NO_SHORTCUT
    setShortcut(Qt::ShiftModifier + Qt::Key_F1);
#endif
}

void QWhatsThisAction::actionTriggered()
{
    if (isChecked()) {
        QWhatsThis::enterWhatsThisMode();
        QWhatsThisPrivate::instance->action = this;
    }
}

QWhatsThis::QWhatsThis()
{
}

#ifdef QT3_SUPPORT
/*!
    \obsolete

    Sets the What's This text \a s for the widget \a w.

    Use QWidget::setWhatsThis() or QAction::setWhatsThis() instead.
*/
void QWhatsThis::add(QWidget *w, const QString &s)
{
    w->setWhatsThis(s);
}

/*!
    \obsolete

    Remove's the What's This text for the widget \a w.

    Use QWidget::setWhatsThis() or QAction::setWhatsThis() instead.
*/
void QWhatsThis::remove(QWidget *w)
{
    w->setWhatsThis(QString());
}

class QWhatsThisButton : public QToolButton
{
    Q_OBJECT
public:
    QWhatsThisButton(QWidget *p) : QToolButton(p) {
        setCheckable(true);
        QPixmap pix( const_cast<const char**>(button_image) );
        setIcon( pix );
        QObject::connect(this, SIGNAL(toggled(bool)), this, SLOT(whatToggled(bool)));
        setAutoRaise(true);
        setFocusPolicy(Qt::NoFocus);
    }

public slots:
    void whatToggled(bool b) {
        if (b) {
            QWhatsThis::enterWhatsThisMode();
            QWhatsThisPrivate::instance->button = this;
        }
    }
};

/*!
    Returns a new "What's This?" QToolButton with the given \a
    parent. To do this now, create your own QToolButton and a
    QWhatsThis object and call the QWhatsThis object's showText()
    function when the QToolButton is invoked.

    Use createAction() instead.
*/
QToolButton * QWhatsThis::whatsThisButton(QWidget * parent)
{
    return new QWhatsThisButton(parent);
}
#endif

/*!
    This function switches the user interface into "What's This?"
    mode. The user interface can be switched back into normal mode by
    the user (e.g. by them clicking or pressing Esc), or
    programmatically by calling leaveWhatsThisMode().

    When entering "What's This?" mode, a QEvent of type
    Qt::EnterWhatsThisMode is sent to all toplevel widgets.

    \sa inWhatsThisMode() leaveWhatsThisMode()
*/
void QWhatsThis::enterWhatsThisMode()
{
    if (QWhatsThisPrivate::instance)
        return;
    (void) new QWhatsThisPrivate;
    QEvent e(QEvent::EnterWhatsThisMode);
    QWhatsThisPrivate::notifyToplevels(&e);
 }

/*!
    Returns true if the user interface is in "What's This?" mode;
    otherwise returns false.

    \sa enterWhatsThisMode()
*/
bool QWhatsThis::inWhatsThisMode()
{
    return (QWhatsThisPrivate::instance != 0);
}

/*!
    If the user interface is in "What's This?" mode, this function
    switches back to normal mode; otherwise it does nothing.

    When leaving "What's This?" mode, a QEvent of type
    Qt::LeaveWhatsThisMode is sent to all toplevel widgets.

    \sa enterWhatsThisMode() inWhatsThisMode()
*/
void QWhatsThis::leaveWhatsThisMode()
{
    delete QWhatsThisPrivate::instance;
    QEvent e(QEvent::LeaveWhatsThisMode);
    QWhatsThisPrivate::notifyToplevels(&e);
}

void QWhatsThisPrivate::say(QWidget * widget, const QString &text, int x, int y)
{
    if (text.size() == 0)
        return;
    // make a fresh widget, and set it up
    QWhatsThat *whatsThat = new QWhatsThat(
        text,
#if defined(Q_WS_X11)
        QApplication::desktop()->screen(widget ? widget->x11Info().screen() : QCursor::x11Screen()),
#else
        0,
#endif
        widget
       );


    // okay, now to find a suitable location

    int scr = (widget ?
                QApplication::desktop()->screenNumber(widget) :
#if defined(Q_WS_X11)
                QCursor::x11Screen()
#else
                QApplication::desktop()->screenNumber(QPoint(x,y))
#endif // Q_WS_X11
               );
    QRect screen = QApplication::desktop()->screenGeometry(scr);

    int w = whatsThat->width();
    int h = whatsThat->height();
    int sx = screen.x();
    int sy = screen.y();

    // first try locating the widget immediately above/below,
    // with nice alignment if possible.
    QPoint pos;
    if (widget)
        pos = widget->mapToGlobal(QPoint(0,0));

    if (widget && w > widget->width() + 16)
        x = pos.x() + widget->width()/2 - w/2;
    else
        x = x - w/2;

        // squeeze it in if that would result in part of what's this
        // being only partially visible
    if (x + w  + shadowWidth > sx+screen.width())
        x = (widget? (qMin(screen.width(),
                           pos.x() + widget->width())
                     ) : screen.width())
            - w;

    if (x < sx)
        x = sx;

    if (widget && h > widget->height() + 16) {
        y = pos.y() + widget->height() + 2; // below, two pixels spacing
        // what's this is above or below, wherever there's most space
        if (y + h + 10 > sy+screen.height())
            y = pos.y() + 2 - shadowWidth - h; // above, overlap
    }
    y = y + 2;

        // squeeze it in if that would result in part of what's this
        // being only partially visible
    if (y + h + shadowWidth > sy+screen.height())
        y = (widget ? (qMin(screen.height(),
                             pos.y() + widget->height())
                       ) : screen.height())
            - h;
    if (y < sy)
        y = sy;

    whatsThat->move(x, y);
    whatsThat->show();
    whatsThat->grabKeyboard();
}

/*!
    Shows \a text as a "What's This?" window, at global position \a
    pos. The optional widget argument, \a w, is used to determine the
    appropriate screen on multi-head systems.

    \sa hideText()
*/
void QWhatsThis::showText(const QPoint &pos, const QString &text, QWidget *w)
{
    leaveWhatsThisMode();
    QWhatsThisPrivate::say(w, text, pos.x(), pos.y());
}

/*!
    If a "What's This?" window is showing, this destroys it.

    \sa showText()
*/
void QWhatsThis::hideText()
{
    delete QWhatsThat::instance;
}

/*!
    Returns a ready-made QAction, used to invoke "What's This?" context
    help, with the given \a parent.

    The returned QAction provides a convenient way to let users enter
    "What's This?" mode.
*/
QAction *QWhatsThis::createAction(QObject *parent)
{
    return new QWhatsThisAction(parent);
}

#include "qwhatsthis.moc"
#endif