source: trunk/src/gui/kernel/qtooltip.cpp@ 284

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#ifdef Q_WS_MAC
# include <private/qcore_mac_p.h>
#endif

#include <qapplication.h>
#include <qdesktopwidget.h>
#include <qevent.h>
#include <qhash.h>
#include <qlabel.h>
#include <qpointer.h>
#include <qstyle.h>
#include <qstyleoption.h>
#include <qstylepainter.h>
#include <qtimer.h>
#include <qtooltip.h>
#include <private/qeffects_p.h>
#include <qtextdocument.h>
#include <qdebug.h>
#include <private/qstylesheetstyle_p.h>
#ifndef QT_NO_TOOLTIP

#ifdef Q_WS_MAC
# include <private/qcore_mac_p.h>
#include <private/qt_cocoa_helpers_mac_p.h>
#endif

QT_BEGIN_NAMESPACE

/*!
    \class QToolTip

    \brief The QToolTip class provides tool tips (balloon help) for any
    widget.

    \ingroup helpsystem
    \mainclass

    The tip is a short piece of text reminding the user of the
    widget's function. It is drawn immediately below the given
    position in a distinctive black-on-yellow color combination. The
    tip can be any \l{QTextEdit}{rich text} formatted string.

    Rich text displayed in a tool tip is implicitly word-wrapped unless
    specified differently with \c{<p style='white-space:pre'>}.

    The simplest and most common way to set a widget's tool tip is by
    calling its QWidget::setToolTip() function.

    It is also possible to show different tool tips for different
    regions of a widget, by using a QHelpEvent of type
    QEvent::ToolTip. Intercept the help event in your widget's \l
    {QWidget::}{event()} function and call QToolTip::showText() with
    the text you want to display. The \l{widgets/tooltips}{Tooltips}
    example illustrates this technique.

    If you are calling QToolTip::hideText(), or QToolTip::showText()
    with an empty string, as a result of a \l{QEvent::}{ToolTip}-event you
    should also call \l{QEvent::}{ignore()} on the event, to signal
    that you don't want to start any tooltip specific modes.

    Note that, if you want to show tooltips in an item view, the
    model/view architecture provides functionality to set an item's
    tool tip; e.g., the QTableWidgetItem::setToolTip() function.
    However, if you want to provide custom tool tips in an item view,
    you must intercept the help event in the
    QAbstractItemView::viewportEvent() function and handle it yourself.

    The default tool tip color and font can be customized with
    setPalette() and setFont(). When a tooltip is currently on
    display, isVisible() returns true and text() the currently visible
    text.

    \note Tool tips use the inactive color group of QPalette, because tool
    tips are not active windows.

    \sa QWidget::toolTip, QAction::toolTip, {Tool Tips Example}
*/

class QTipLabel : public QLabel
{
    Q_OBJECT
public:
    QTipLabel(const QString &text, QWidget *w);
    ~QTipLabel();
    static QTipLabel *instance;

    bool eventFilter(QObject *, QEvent *);

    QBasicTimer hideTimer;
    bool fadingOut;

    void reuseTip(const QString &text);
    void hideTip();
    void hideTipImmediately();
    void setTipRect(QWidget *w, const QRect &r);
    void restartHideTimer();
    bool tipChanged(const QPoint &pos, const QString &text, QObject *o);
    void placeTip(const QPoint &pos, QWidget *w);

    static int getTipScreen(const QPoint &pos, QWidget *w);
protected:
    void timerEvent(QTimerEvent *e);
    void paintEvent(QPaintEvent *e);
    void mouseMoveEvent(QMouseEvent *e);
    void resizeEvent(QResizeEvent *e);

#ifndef QT_NO_STYLE_STYLESHEET
public slots:
    /** \internal
      Cleanup the _q_stylesheet_parent propery.
     */
    void styleSheetParentDestroyed() {
        setProperty("_q_stylesheet_parent", QVariant());
        styleSheetParent = 0;
    }

private:
    QWidget *styleSheetParent;
#endif

private:
    QWidget *widget;
    QRect rect;
};

QTipLabel *QTipLabel::instance = 0;

QTipLabel::QTipLabel(const QString &text, QWidget *w)
#ifndef QT_NO_STYLE_STYLESHEET
    : QLabel(w, Qt::ToolTip), styleSheetParent(0), widget(0)
#else
    : QLabel(w, Qt::ToolTip), widget(0)
#endif
{
    delete instance;
    instance = this;
    setForegroundRole(QPalette::ToolTipText);
    setBackgroundRole(QPalette::ToolTipBase);
    setPalette(QToolTip::palette());
    ensurePolished();
    setMargin(1 + style()->pixelMetric(QStyle::PM_ToolTipLabelFrameWidth, 0, this));
    setFrameStyle(QFrame::NoFrame);
    setAlignment(Qt::AlignLeft);
    setIndent(1);
    setWordWrap(Qt::mightBeRichText(text));
    qApp->installEventFilter(this);
    setWindowOpacity(style()->styleHint(QStyle::SH_ToolTipLabel_Opacity, 0, this) / 255.0);
    setMouseTracking(true);
    fadingOut = false;
    reuseTip(text);
}

void QTipLabel::restartHideTimer()
{
    int time = 10000 + 40 * qMax(0, text().length()-100);
    hideTimer.start(time, this);
}

void QTipLabel::reuseTip(const QString &text)
{
#ifndef QT_NO_STYLE_STYLESHEET
    if (styleSheetParent) {
        disconnect(styleSheetParent, SIGNAL(destroyed()),
                   QTipLabel::instance, SLOT(styleSheetParentDestroyed()));
        styleSheetParent = 0;
    }
#endif

    setText(text);
    QFontMetrics fm(font());
    QSize extra(1, 0);
    // Make it look good with the default ToolTip font on Mac, which has a small descent.
    if (fm.descent() == 2 && fm.ascent() >= 11)
        ++extra.rheight();
    resize(sizeHint() + extra);
    restartHideTimer();
}

void QTipLabel::paintEvent(QPaintEvent *ev)
{
    QStylePainter p(this);
    QStyleOptionFrame opt;
    opt.init(this);
    p.drawPrimitive(QStyle::PE_PanelTipLabel, opt);
    p.end();

    QLabel::paintEvent(ev);
}

void QTipLabel::resizeEvent(QResizeEvent *e)
{
    QStyleHintReturnMask frameMask;
    QStyleOption option;
    option.init(this);
    if (style()->styleHint(QStyle::SH_ToolTip_Mask, &option, this, &frameMask))
        setMask(frameMask.region);

    QLabel::resizeEvent(e);
}

void QTipLabel::mouseMoveEvent(QMouseEvent *e)
{
    if (rect.isNull())
        return;
    QPoint pos = e->globalPos();
    if (widget)
        pos = widget->mapFromGlobal(pos);
    if (!rect.contains(pos))
        hideTip();
    QLabel::mouseMoveEvent(e);
}

QTipLabel::~QTipLabel()
{
    instance = 0;
}

void QTipLabel::hideTip()
{
    hideTimer.start(300, this);
}

void QTipLabel::hideTipImmediately()
{
    close(); // to trigger QEvent::Close which stops the animation
    deleteLater();
}

void QTipLabel::setTipRect(QWidget *w, const QRect &r)
{
    if (!rect.isNull() && !w)
        qWarning("QToolTip::setTipRect: Cannot pass null widget if rect is set");
    else{
        widget = w;
        rect = r;
    }
}

void QTipLabel::timerEvent(QTimerEvent *e)
{
    if (e->timerId() == hideTimer.timerId()){
        hideTimer.stop();
#if defined(Q_WS_MAC) && !defined(QT_NO_EFFECTS)
        if (QApplication::isEffectEnabled(Qt::UI_FadeTooltip)){
            // Fade out tip on mac (makes it invisible).
            // The tip will not be deleted until a new tip is shown.

                        // DRSWAT - Cocoa
                        macWindowFade(qt_mac_window_for(this));
            QTipLabel::instance->fadingOut = true; // will never be false again.
        }
        else
            hideTipImmediately();
#else
        hideTipImmediately();
#endif
    }
}

bool QTipLabel::eventFilter(QObject *o, QEvent *e)
{
    switch (e->type()) {
#ifdef Q_WS_MAC
    case QEvent::KeyPress:
    case QEvent::KeyRelease: {
        int key = static_cast<QKeyEvent *>(e)->key();
        Qt::KeyboardModifiers mody = static_cast<QKeyEvent *>(e)->modifiers();
        if (!(mody & Qt::KeyboardModifierMask)
            && key != Qt::Key_Shift && key != Qt::Key_Control
            && key != Qt::Key_Alt && key != Qt::Key_Meta)
            hideTip();
        break;
    }
#endif
    case QEvent::Leave:
        hideTip();
        break;
    case QEvent::WindowActivate:
    case QEvent::WindowDeactivate:
    case QEvent::MouseButtonPress:
    case QEvent::MouseButtonRelease:
    case QEvent::MouseButtonDblClick:
    case QEvent::FocusIn:
    case QEvent::FocusOut:
    case QEvent::Wheel:
        hideTipImmediately();
        break;

    case QEvent::MouseMove:
        if (o == widget && !rect.isNull() && !rect.contains(static_cast<QMouseEvent*>(e)->pos()))
            hideTip();
    default:
        break;
    }
    return false;
}

int QTipLabel::getTipScreen(const QPoint &pos, QWidget *w)
{
    if (QApplication::desktop()->isVirtualDesktop())
        return QApplication::desktop()->screenNumber(pos);
    else
        return QApplication::desktop()->screenNumber(w);
}

void QTipLabel::placeTip(const QPoint &pos, QWidget *w)
{
#ifndef QT_NO_STYLE_STYLESHEET
    if (testAttribute(Qt::WA_StyleSheet) || (w && qobject_cast<QStyleSheetStyle *>(w->style()))) {
        //the stylesheet need to know the real parent
        QTipLabel::instance->setProperty("_q_stylesheet_parent", qVariantFromValue(w));
        //we force the style to be the QStyleSheetStyle, and force to clear the cache as well.
        QTipLabel::instance->setStyleSheet(QLatin1String("/* */"));

        // Set up for cleaning up this later...
        QTipLabel::instance->styleSheetParent = w;
        if (w) {
            connect(w, SIGNAL(destroyed()),
                QTipLabel::instance, SLOT(styleSheetParentDestroyed()));
        }
    }
#endif //QT_NO_STYLE_STYLESHEET


#ifdef Q_WS_MAC
    QRect screen = QApplication::desktop()->availableGeometry(getTipScreen(pos, w));
#else
    QRect screen = QApplication::desktop()->screenGeometry(getTipScreen(pos, w));
#endif