src/gui/kernel/qwhatsthis.cpp
changeset 0 1918ee327afb
child 4 3b1da2848fc7
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/gui/kernel/qwhatsthis.cpp	Mon Jan 11 14:00:40 2010 +0000
@@ -0,0 +1,777 @@
+/****************************************************************************
+**
+** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies).
+** All rights reserved.
+** Contact: Nokia Corporation (qt-info@nokia.com)
+**
+** This file is part of the QtGui module of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** No Commercial Usage
+** This file contains pre-release code and may not be distributed.
+** You may use this file in accordance with the terms and conditions
+** contained in the Technology Preview License Agreement accompanying
+** this package.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 2.1 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPL included in the
+** packaging of this file.  Please review the following information to
+** ensure the GNU Lesser General Public License version 2.1 requirements
+** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
+**
+** In addition, as a special exception, Nokia gives you certain additional
+** rights.  These rights are described in the Nokia Qt LGPL Exception
+** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
+**
+** If you have questions regarding the use of this file, please contact
+** Nokia at qt-info@nokia.com.
+**
+**
+**
+**
+**
+**
+**
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#include "qwhatsthis.h"
+#ifndef QT_NO_WHATSTHIS
+#include "qpointer.h"
+#include "qapplication.h"
+#include "qdesktopwidget.h"
+#include "qevent.h"
+#include "qpixmap.h"
+#include "qpainter.h"
+#include "qtimer.h"
+#include "qhash.h"
+#include "qaction.h"
+#include "qcursor.h"
+#include "qbitmap.h"
+#include "qtextdocument.h"
+#include "../text/qtextdocumentlayout_p.h"
+#include "qtoolbutton.h"
+#include "qdebug.h"
+#ifndef QT_NO_ACCESSIBILITY
+#include "qaccessible.h"
+#endif
+#if defined(Q_WS_WIN)
+#include "qt_windows.h"
+#ifndef SPI_GETDROPSHADOW
+#define SPI_GETDROPSHADOW                   0x1024
+#endif
+#endif
+#if defined(Q_WS_X11)
+#include "qx11info_x11.h"
+#include <qwidget.h>
+#endif
+
+QT_BEGIN_NAMESPACE
+
+/*!
+    \class QWhatsThis
+    \brief The QWhatsThis class provides a simple description of any
+    widget, i.e. answering the question "What's This?".
+
+    \ingroup helpsystem
+
+
+    "What's This?" help is part of an application's online help
+    system, and provides users with information about the
+    functionality and usage of a particular widget. "What's This?"
+    help texts are typically longer and more detailed than \link
+    QToolTip tooltips\endlink, but generally provide less information
+    than that supplied by separate help windows.
+
+    QWhatsThis provides a single window with an explanatory text that
+    pops up when the user asks "What's This?". The default way for
+    users to ask the question is to move the focus to the relevant
+    widget and press Shift+F1. The help text appears immediately; it
+    goes away as soon as the user does something else.
+    (Note that if there is a shortcut for Shift+F1, this mechanism
+    will not work.) Some dialogs provide a "?" button that users can
+    click to enter "What's This?" mode; they then click the relevant
+    widget to pop up the "What's This?" window. It is also possible to
+    provide a a menu option or toolbar button to switch into "What's
+    This?" mode.
+
+    To add "What's This?" text to a widget or an action, you simply
+    call QWidget::setWhatsThis() or QAction::setWhatsThis().
+
+    The text can be either rich text or plain text. If you specify a
+    rich text formatted string, it will be rendered using the default
+    stylesheet, making it possible to embed images in the displayed
+    text. To be as fast as possible, the default stylesheet uses a
+    simple method to determine whether the text can be rendered as
+    plain text. See Qt::mightBeRichText() for details.
+
+    \snippet doc/src/snippets/whatsthis/whatsthis.cpp 0
+
+    An alternative way to enter "What's This?" mode is to call
+    createAction(), and add the returned QAction to either a menu or
+    a tool bar. By invoking this context help action (in the picture
+    below, the button with the arrow and question mark icon) the user
+    switches into "What's This?" mode. If they now click on a widget
+    the appropriate help text is shown. The mode is left when help is
+    given or when the user presses Esc.
+
+    \img whatsthis.png
+
+    You can enter "What's This?" mode programmatically with
+    enterWhatsThisMode(), check the mode with inWhatsThisMode(), and
+    return to normal mode with leaveWhatsThisMode().
+
+    If you want to control the "What's This?" behavior of a widget
+    manually see Qt::WA_CustomWhatsThis.
+
+    It is also possible to show different help texts for different
+    regions of a widget, by using a QHelpEvent of type
+    QEvent::WhatsThis. Intercept the help event in your widget's
+    QWidget::event() function and call QWhatsThis::showText() with the
+    text you want to display for the position specified in
+    QHelpEvent::pos(). If the text is rich text and the user clicks
+    on a link, the widget also receives a QWhatsThisClickedEvent with
+    the link's reference as QWhatsThisClickedEvent::href(). If a
+    QWhatsThisClickedEvent is handled (i.e. QWidget::event() returns
+    true), the help window remains visible. Call
+    QWhatsThis::hideText() to hide it explicitly.
+
+    \sa QToolTip
+*/
+
+extern void qDeleteInEventHandler(QObject *o);
+
+class QWhatsThat : public QWidget
+{
+    Q_OBJECT
+
+public:
+    QWhatsThat(const QString& txt, QWidget* parent, QWidget *showTextFor);
+    ~QWhatsThat() ;
+
+    static QWhatsThat *instance;
+
+protected:
+    void showEvent(QShowEvent *e);
+    void mousePressEvent(QMouseEvent*);
+    void mouseReleaseEvent(QMouseEvent*);
+    void mouseMoveEvent(QMouseEvent*);
+    void keyPressEvent(QKeyEvent*);
+    void paintEvent(QPaintEvent*);
+
+private:
+    QPointer<QWidget>widget;
+    bool pressed;
+    QString text;
+    QTextDocument* doc;
+    QString anchor;
+    QPixmap background;
+};
+
+QWhatsThat *QWhatsThat::instance = 0;
+
+// shadowWidth not const, for XP drop-shadow-fu turns it to 0
+static int shadowWidth = 6;   // also used as '5' and '6' and even '8' below
+static const int vMargin = 8;
+static const int hMargin = 12;
+
+QWhatsThat::QWhatsThat(const QString& txt, QWidget* parent, QWidget *showTextFor)
+    : QWidget(parent, Qt::Popup),
+      widget(showTextFor), pressed(false), text(txt)
+{
+    delete instance;
+    instance = this;
+    setAttribute(Qt::WA_DeleteOnClose, true);
+    setAttribute(Qt::WA_NoSystemBackground, true);
+    if (parent)
+        setPalette(parent->palette());
+    setMouseTracking(true);
+    setFocusPolicy(Qt::StrongFocus);
+#ifndef QT_NO_CURSOR
+    setCursor(Qt::ArrowCursor);
+#endif
+    QRect r;
+    doc = 0;
+    ensurePolished(); // Ensures style sheet font before size calc
+    if (Qt::mightBeRichText(text)) {
+        doc = new QTextDocument();
+        doc->setUndoRedoEnabled(false);
+        doc->setDefaultFont(QApplication::font(this));
+#ifdef QT_NO_TEXTHTMLPARSER
+        doc->setPlainText(text);
+#else
+        doc->setHtml(text);
+#endif
+        doc->setUndoRedoEnabled(false);
+        doc->adjustSize();
+        r.setTop(0);
+        r.setLeft(0);
+        r.setSize(doc->size().toSize());
+    }
+    else
+    {
+        int sw = QApplication::desktop()->width() / 3;
+        if (sw < 200)
+            sw = 200;
+        else if (sw > 300)
+            sw = 300;
+
+        r = fontMetrics().boundingRect(0, 0, sw, 1000,
+                                        Qt::AlignLeft + Qt::AlignTop
+                                        + Qt::TextWordWrap + Qt::TextExpandTabs,
+                                        text);
+    }
+#if defined(Q_WS_WIN)
+    if ((QSysInfo::WindowsVersion >= QSysInfo::WV_XP
+        && QSysInfo::WindowsVersion < QSysInfo::WV_NT_based))
+    {
+        BOOL shadow;
+        SystemParametersInfo(SPI_GETDROPSHADOW, 0, &shadow, 0);
+        shadowWidth = shadow ? 0 : 6;
+    }
+#endif
+    resize(r.width() + 2*hMargin + shadowWidth, r.height() + 2*vMargin + shadowWidth);
+}
+
+QWhatsThat::~QWhatsThat()
+{
+    instance = 0;
+    if (doc)
+        delete doc;
+}
+
+void QWhatsThat::showEvent(QShowEvent *)
+{
+    background = QPixmap::grabWindow(QApplication::desktop()->internalWinId(),
+                                     x(), y(), width(), height());
+}
+
+void QWhatsThat::mousePressEvent(QMouseEvent* e)
+{
+    pressed = true;
+    if (e->button() == Qt::LeftButton && rect().contains(e->pos())) {
+        if (doc)
+            anchor = doc->documentLayout()->anchorAt(e->pos() -  QPoint(hMargin, vMargin));
+        return;
+    }
+    close();
+}
+
+void QWhatsThat::mouseReleaseEvent(QMouseEvent* e)
+{
+    if (!pressed)
+        return;
+    if (widget && e->button() == Qt::LeftButton && doc && rect().contains(e->pos())) {
+        QString a = doc->documentLayout()->anchorAt(e->pos() -  QPoint(hMargin, vMargin));
+        QString href;
+        if (anchor == a)
+            href = a;
+        anchor.clear();
+        if (!href.isEmpty()) {
+            QWhatsThisClickedEvent e(href);
+            if (QApplication::sendEvent(widget, &e))
+                return;
+        }
+    }
+    close();
+}
+
+void QWhatsThat::mouseMoveEvent(QMouseEvent* e)
+{
+#ifdef QT_NO_CURSOR
+    Q_UNUSED(e);
+#else
+    if (!doc)
+        return;
+    QString a = doc->documentLayout()->anchorAt(e->pos() -  QPoint(hMargin, vMargin));
+    if (!a.isEmpty())
+        setCursor(Qt::PointingHandCursor);
+    else
+        setCursor(Qt::ArrowCursor);
+#endif
+}
+
+void QWhatsThat::keyPressEvent(QKeyEvent*)
+{
+    close();
+}
+
+void QWhatsThat::paintEvent(QPaintEvent*)
+{
+    bool drawShadow = true;
+#if defined(Q_WS_WIN)
+    if ((QSysInfo::WindowsVersion >= QSysInfo::WV_XP
+        && QSysInfo::WindowsVersion < QSysInfo::WV_NT_based))
+    {
+        BOOL shadow;
+        SystemParametersInfo(SPI_GETDROPSHADOW, 0, &shadow, 0);
+        drawShadow = !shadow;
+    }
+#elif defined(Q_WS_MAC) || defined(Q_WS_QWS)
+    drawShadow = false; // never draw it on OS X or QWS, as we get it for free
+#endif
+
+    QRect r = rect();
+    r.adjust(0, 0, -1, -1);
+    if (drawShadow)
+        r.adjust(0, 0, -shadowWidth, -shadowWidth);
+    QPainter p(this);
+    p.drawPixmap(0, 0, background);
+    p.setPen(QPen(palette().toolTipText(), 0));
+    p.setBrush(palette().toolTipBase());
+    p.drawRect(r);
+    int w = r.width();
+    int h = r.height();
+    p.setPen(palette().brush(QPalette::Dark).color());
+    p.drawRect(1, 1, w-2, h-2);
+    if (drawShadow) {
+        p.setPen(palette().shadow().color());
+        p.drawPoint(w + 5, 6);
+        p.drawLine(w + 3, 6, w + 5, 8);
+        p.drawLine(w + 1, 6, w + 5, 10);
+        int i;
+        for(i=7; i < h; i += 2)
+            p.drawLine(w, i, w + 5, i + 5);
+        for(i = w - i + h; i > 6; i -= 2)
+            p.drawLine(i, h, i + 5, h + 5);
+        for(; i > 0 ; i -= 2)
+            p.drawLine(6, h + 6 - i, i + 5, h + 5);
+    }
+    r.adjust(0, 0, 1, 1);
+    p.setPen(palette().toolTipText().color());
+    r.adjust(hMargin, vMargin, -hMargin, -vMargin);
+
+    if (doc) {
+        p.translate(r.x(), r.y());
+        QRect rect = r;
+        rect.translate(-r.x(), -r.y());
+        p.setClipRect(rect);
+        QAbstractTextDocumentLayout::PaintContext context;
+        context.palette.setBrush(QPalette::Text, context.palette.toolTipText());
+        doc->documentLayout()->draw(&p, context);
+    }
+    else
+    {
+        p.drawText(r, Qt::AlignLeft + Qt::AlignTop + Qt::TextWordWrap + Qt::TextExpandTabs, text);
+    }
+}
+
+static const char * const button_image[] = {
+"16 16 3 1",
+"         c None",
+"o        c #000000",
+"a        c #000080",
+"o        aaaaa  ",
+"oo      aaa aaa ",
+"ooo    aaa   aaa",
+"oooo   aa     aa",
+"ooooo  aa     aa",
+"oooooo  a    aaa",
+"ooooooo     aaa ",
+"oooooooo   aaa  ",
+"ooooooooo aaa   ",
+"ooooo     aaa   ",
+"oo ooo          ",
+"o  ooo    aaa   ",
+"    ooo   aaa   ",
+"    ooo         ",
+"     ooo        ",
+"     ooo        "};
+
+class QWhatsThisPrivate : public QObject
+{
+ public:
+    QWhatsThisPrivate();
+    ~QWhatsThisPrivate();
+    static QWhatsThisPrivate *instance;
+    bool eventFilter(QObject *, QEvent *);
+    QPointer<QAction> action;
+#ifdef QT3_SUPPORT
+    QPointer<QToolButton> button;
+#endif
+    static void say(QWidget *, const QString &, int x = 0, int y = 0);
+    static void notifyToplevels(QEvent *e);
+    bool leaveOnMouseRelease;
+};
+
+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()
+    : leaveOnMouseRelease(false)
+{
+    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())
+            leaveOnMouseRelease = true;
+
+    } 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 through
+    case QEvent::MouseButtonRelease:
+    case QEvent::MouseButtonDblClick:
+        if (leaveOnMouseRelease && e->type() == QEvent::MouseButtonRelease)
+            QWhatsThis::leaveWhatsThisMode();
+        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) && !defined(QT_NO_CURSOR)
+        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) && !defined(QT_NO_CURSOR)
+                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()
+{
+    qDeleteInEventHandler(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);
+}
+
+QT_END_NAMESPACE
+
+#include "qwhatsthis.moc"
+
+#endif // QT_NO_WHATSTHIS