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qstatusbar.cpp

/****************************************************************************
**
** Copyright (C) 1992-2006 Trolltech AS. All rights reserved.
**
** This file is part of the QtGui module of the Qt Toolkit.
**
** This file may be used under the terms of the GNU General Public
** License version 2.0 as published by the Free Software Foundation
** and appearing in the file LICENSE.GPL included in the packaging of
** this file.  Please review the following information to ensure GNU
** General Public Licensing requirements will be met:
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** If you are unsure which license is appropriate for your use, please
** review the following information:
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** This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
** WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
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****************************************************************************/

#include "qstatusbar.h"
#ifndef QT_NO_STATUSBAR

#include "qlist.h"
#include "qevent.h"
#include "qlayout.h"
#include "qpainter.h"
#include "qtimer.h"
#include "qstyle.h"
#include "qstyleoption.h"
#include "qsizegrip.h"
#include <private/qlayoutengine_p.h>

#include <private/qwidget_p.h>

class QStatusBarPrivate : public QWidgetPrivate
{
    Q_DECLARE_PUBLIC(QStatusBar)
public:
    QStatusBarPrivate() {}

    struct SBItem {
        SBItem(QWidget* widget, int stretch, bool permanent)
            : s(stretch), w(widget), p(permanent) {}
        int s;
        QWidget * w;
        bool p;
    };

    QList<SBItem *> items;
    QString tempItem;

    QBoxLayout * box;
    QTimer * timer;

#ifndef QT_NO_SIZEGRIP
    QSizeGrip * resizer;
#endif

    int savedStrut;
};

/*!
    \class QStatusBar qstatusbar.h
    \brief The QStatusBar class provides a horizontal bar suitable for
    presenting status information.

    \ingroup application
    \ingroup helpsystem
    \mainclass

    Each status indicator falls into one of three categories:

    \list
    \i \e Temporary - briefly occupies most of the status bar. Used
        to explain tool tip texts or menu entries, for example.
    \i \e Normal - occupies part of the status bar and may be hidden
        by temporary messages. Used to display the page and line
        number in a word processor, for example.
    \i \e Permanent - is never hidden. Used for important mode
        indications, for example, some applications put a Caps Lock
        indicator in the status bar.
    \endlist

    QStatusBar lets you display all three types of indicators.

    To display a \e temporary message, call showMessage() (perhaps by
    connecting a suitable signal to it). To remove a temporary
    message, call clearMessage(), or set a time limit when calling
    showMessage():

    \code
        connect(loader, SIGNAL(progressMessage(QString)),
                 statusBar(), SLOT(showMessage(QString)));

        statusBar()->showMessage("Loading...");  // Initial message
        loader.loadStuff();                  // Emits progress messages
        statusBar()->showMessage("Done.", 2000); // Final message for 2 seconds
    \endcode

    \e Normal and \e Permanent messages are displayed by creating a
    small widget and then adding it to the status bar with addWidget()
    or addPermanentWidget(). Widgets like QLabel, QProgressBar or
    even QToolButton are useful for adding to status
    bars. removeWidget() is used to remove widgets.

    \code
        statusBar()->addWidget(new MyReadWriteIndication);
    \endcode

    By default QStatusBar provides a QSizeGrip in the lower-right
    corner. You can disable it with setSizeGripEnabled(false);

    \image plastique-statusbar.png A status bar shown in the Plastique widget style.

    \sa QToolBar, QMainWindow, QLabel, {fowler}{GUI Design Handbook: Status Bar}
*/

#ifdef QT3_SUPPORT
/*!
    Constructs a status bar called \a name with parent \a parent and
    with a size grip.

    \sa setSizeGripEnabled()
*/
QStatusBar::QStatusBar(QWidget * parent, const char *name)
    : QWidget(*new QStatusBarPrivate, parent, 0)
{
    Q_D(QStatusBar);
    setObjectName(QString::fromAscii(name));
    d->box = 0;
    d->timer = 0;

#ifndef QT_NO_SIZEGRIP
    d->resizer = 0;
    setSizeGripEnabled(true); // causes reformat()
#else
    reformat();
#endif
}


/*! \fn void QStatusBar::addWidget(QWidget * widget, int stretch, bool permanent)

   Use addWidget(\a widget, \a stretch) or addPermanentWidget(\a
   widget, \a stretch) instead, depending on \a permanent.
 */

#endif

/*!
    Constructs a status bar with a size grip with the given \a parent.

    \sa setSizeGripEnabled()
*/
00159 QStatusBar::QStatusBar(QWidget * parent)
    : QWidget(*new QStatusBarPrivate, parent, 0)
{
    Q_D(QStatusBar);
    d->box = 0;
    d->timer = 0;

#ifndef QT_NO_SIZEGRIP
    d->resizer = 0;
    setSizeGripEnabled(true); // causes reformat()
#else
    reformat();
#endif
}

/*!
    Destroys the status bar and frees any allocated resources and
    child widgets.
*/
00178 QStatusBar::~QStatusBar()
{
    Q_D(QStatusBar);
    while (!d->items.isEmpty())
        delete d->items.takeFirst();
}


/*!
    Adds \a widget to this status bar. \a widget is reparented if it
    isn't already a child of the QStatusBar.

    The widget is located to the far left of the first permanent
    widget (see addPermanentWidget()) and may be obscured by temporary
    messages.

    \a stretch is used to compute a suitable size for \a widget as the
    status bar grows and shrinks. The default of 0 uses a minimum of
    space.

    This function may cause some flicker.

    \sa removeWidget(), addPermanentWidget()
*/

00203 void QStatusBar::addWidget(QWidget * widget, int stretch)
{
    if (!widget)
        return;

    Q_D(QStatusBar);
    QStatusBarPrivate::SBItem* item = new QStatusBarPrivate::SBItem(widget, stretch, false);

    int i = d->items.size() - 1;
    for (; i>=0; --i)
        if (!(d->items.at(i) && d->items.at(i)->p))
            break;
    d->items.insert(i >= 0 ? i + 1 : 0, item);

    if (!d->tempItem.isEmpty())
        widget->hide();

    reformat();
    if (!widget->isHidden() || !widget->testAttribute(Qt::WA_WState_ExplicitShowHide))
        widget->show();
}

/*!
    Adds \a widget permanently to this status bar. \a widget is
    reparented if it isn't already a child of the QStatusBar.

    Permanently means that the widget may not be obscured by temporary
    messages. It is is located at the far right of the status bar.

    \a stretch is used to compute a suitable size for \a widget as the
    status bar grows and shrinks. The default of 0 uses a minimum of
    space.

    This function may cause some flicker.

    \sa removeWidget(), addWidget()
*/

00241 void QStatusBar::addPermanentWidget(QWidget * widget, int stretch)
{
    if (!widget)
        return;

    Q_D(QStatusBar);
    QStatusBarPrivate::SBItem* item = new QStatusBarPrivate::SBItem(widget, stretch, true);

    int i = d->items.size() - 1;
    d->items.insert(i >= 0 ? i + 1 : 0, item);

    reformat();
    if (!widget->isHidden() || !widget->testAttribute(Qt::WA_WState_ExplicitShowHide))
        widget->show();
}


/*!
    Removes \a widget from the status bar.

    This function may cause some flicker.

    Note that \a widget is not deleted.

    \sa addWidget()
*/

00268 void QStatusBar::removeWidget(QWidget* widget)
{
    if (!widget)
        return;

    Q_D(QStatusBar);
    bool found = false;
    QStatusBarPrivate::SBItem* item;
    for (int i=0; i<d->items.size(); ++i) {
        item = d->items.at(i);
        if (!item)
            break;
        if (item->w == widget) {
            d->items.removeAt(i);
            delete item;
            found = true;
            break;
        }
    }

    if (found)
        reformat();
#if defined(QT_DEBUG)
    else
        qDebug("QStatusBar::removeWidget(): Widget not found.");
#endif
}

/*!
    \property QStatusBar::sizeGripEnabled
    \brief whether the QSizeGrip in the bottom-right of the status bar is enabled

    Enables or disables the QSizeGrip in the bottom-right of the
    status bar. By default, the size grip is enabled.
*/

bool QStatusBar::isSizeGripEnabled() const
{
#ifdef QT_NO_SIZEGRIP
    return false;
#else
    Q_D(const QStatusBar);
    return !!d->resizer;
#endif
}

void QStatusBar::setSizeGripEnabled(bool enabled)
{
#ifndef QT_NO_SIZEGRIP
    Q_D(QStatusBar);
    if (!enabled != !d->resizer) {
        if (enabled) {
            d->resizer = new QSizeGrip(this);
        } else {
            delete d->resizer;
            d->resizer = 0;
        }
        reformat();
        if (d->resizer && isVisible())
            d->resizer->show();
    }
#endif
}


/*!
    Changes the status bar's appearance to account for item changes.
    Special subclasses may need this, but geometry management will
    usually take care of any necessary rearrangements.
*/
00338 void QStatusBar::reformat()
{
    Q_D(QStatusBar);
    if (d->box)
        delete d->box;

    QBoxLayout *vbox;
#ifndef QT_NO_SIZEGRIP
    if (d->resizer) {
        d->box = new QHBoxLayout(this);
        d->box->setMargin(0);
        vbox = new QVBoxLayout;
        d->box->addLayout(vbox);
    } else
#endif
    {
        vbox = d->box = new QVBoxLayout(this);
        d->box->setMargin(0);
    }
    vbox->addSpacing(3);
    QBoxLayout* l = new QHBoxLayout;
    vbox->addLayout(l);
    l->addSpacing(3);
    l->setSpacing(4);

    int maxH = fontMetrics().height();

    int i;
    QStatusBarPrivate::SBItem* item;
    for (i=0,item=0; i<d->items.size(); ++i) {
        item = d->items.at(i);
        if (!item || item->p)
            break;
        l->addWidget(item->w, item->s);
        int itemH = qMin(qSmartMinSize(item->w).height(), item->w->maximumHeight());
        maxH = qMax(maxH, itemH);
    }

    l->addStretch(0);

    for (item=0; i<d->items.size(); ++i) {
        item = d->items.at(i);
        if (!item)
            break;
        l->addWidget(item->w, item->s);
        int itemH = qMin(qSmartMinSize(item->w).height(), item->w->maximumHeight());
        maxH = qMax(maxH, itemH);
    }
    l->addSpacing(4);
#ifndef QT_NO_SIZEGRIP
    if (d->resizer) {
        maxH = qMax(maxH, d->resizer->sizeHint().height());
        d->box->addSpacing(1);
        d->box->addWidget(d->resizer, 0, Qt::AlignBottom);
    }
#endif
    l->addStrut(maxH);
    d->savedStrut = maxH;
    vbox->addSpacing(2);
    d->box->activate();
    repaint();
}

/*!
    Hides the normal status indications and displays \a message for \a
    timeout milli-seconds (if non-zero), or until clearMessage() or
    another showMessage() is called, whichever occurs first.
*/
00406 void QStatusBar::showMessage(const QString &message, int timeout)
{
    Q_D(QStatusBar);
    if (d->tempItem == message)
        return;

    d->tempItem = message;

    if (timeout > 0) {
        if (!d->timer) {
            d->timer = new QTimer(this);
            connect(d->timer, SIGNAL(timeout()), this, SLOT(clearMessage()));
        }
        d->timer->start(timeout);
    } else if (d->timer) {
        delete d->timer;
        d->timer = 0;
    }

    hideOrShow();
}

/*!
    Removes any temporary message being shown.

    \sa showMessage()
*/

00434 void QStatusBar::clearMessage()
{
    Q_D(QStatusBar);
    if (d->tempItem.isEmpty())
        return;
    if (d->timer) {
        delete d->timer;
        d->timer = 0;
    }
    d->tempItem.clear();
    hideOrShow();
}

/*!
    Returns the temporary message currently shown,
    or an empty string if there is no such message.
*/
00451 QString QStatusBar::currentMessage() const
{
    Q_D(const QStatusBar);
    return d->tempItem;
}

/*!
    \fn void QStatusBar::message(const QString &message, int timeout)

    Hides the normal status indications and displays \a message for \a
    timeout milli-seconds or until clearMessage() or another showMessage() is called,
    whichever occurs first.
*/

/*!
    \fn void QStatusBar::clear()

    Removes any temporary message being shown.
*/

/*!
    \fn QStatusBar::messageChanged(const QString &message)

    This signal is emitted when the temporary status messages
    changes. \a message is the new temporary message, and is a
    null-string when the message has been removed.

    \sa showMessage(), clearMessage()
*/

/*!
    Ensures that the right widgets are visible. Used by showMessage() and
    clearMessage().
*/
00485 void QStatusBar::hideOrShow()
{
    Q_D(QStatusBar);
    bool haveMessage = !d->tempItem.isEmpty();

    QStatusBarPrivate::SBItem* item = 0;
    for (int i=0; i<d->items.size(); ++i) {
        item = d->items.at(i);
        if (!item || item->p)
            break;
        if (haveMessage)
            item->w->hide();
        else
            item->w->show();
    }

    emit messageChanged(d->tempItem);
    repaint();
}


/*!
    \fn void QStatusBar::paintEvent(QPaintEvent *event)

    Shows the temporary message, if appropriate, in response to the
    paint \a event.
*/
00512 void QStatusBar::paintEvent(QPaintEvent *)
{
    Q_D(QStatusBar);
    bool haveMessage = !d->tempItem.isEmpty();

    QPainter p(this);
    QStatusBarPrivate::SBItem* item = 0;

    bool rtl = layoutDirection() == Qt::RightToLeft;

    int left = 6;
    int right = width() - 12;

#ifndef QT_NO_SIZEGRIP
    if (d->resizer && d->resizer->isVisible()) {
        if (rtl)
            left = d->resizer->x() + d->resizer->width();
        else
            right = d->resizer->x();
    }
#endif

    for (int i=0; i<d->items.size(); ++i) {
        item = d->items.at(i);
        if (!item)
            break;
        if (!haveMessage || item->p)
            if (item->w->isVisible()) {
                if (item->p) {
                    if (rtl)
                        left = qMax(left, item->w->x() + item->w->width() + 2);
                    else
                        right = qMin(right, item->w->x()-1);
                }
                QStyleOption opt(0);
                opt.rect.setRect(item->w->x() - 1, item->w->y() - 1,
                                 item->w->width() + 2, item->w->height() + 2);
                opt.palette = palette();
                opt.state = QStyle::State_None;
                style()->drawPrimitive(QStyle::PE_FrameStatusBar, &opt, &p, item->w);
            }
    }
    if (haveMessage) {
        p.setPen(palette().foreground().color());
        p.drawText(left, 0, right-left, height(), Qt::AlignLeading | Qt::AlignVCenter | Qt::TextSingleLine, d->tempItem);
    }
}

/*!
    \reimp
*/
00563 void QStatusBar::resizeEvent(QResizeEvent * e)
{
    QWidget::resizeEvent(e);
}

/*!
    \reimp
*/

00572 bool QStatusBar::event(QEvent *e)
{
    Q_D(QStatusBar);

    if (e->type() == QEvent::LayoutRequest
#ifdef QT3_SUPPORT
        || e->type() == QEvent::LayoutHint
#endif
        ) {
        // Calculate new strut height and call reformat() if it has changed
        int maxH = fontMetrics().height();

        QStatusBarPrivate::SBItem* item = 0;
        for (int i=0; i<d->items.size(); ++i) {
            item = d->items.at(i);
            if (!item)
                break;
            int itemH = qMin(qSmartMinSize(item->w).height(), item->w->maximumHeight());
            maxH = qMax(maxH, itemH);
        }

#ifndef QT_NO_SIZEGRIP
        if (d->resizer)
            maxH = qMax(maxH, d->resizer->sizeHint().height());
#endif

        if (maxH != d->savedStrut)
            reformat();
        else
            update();
    }
    if (e->type() == QEvent::ChildRemoved) {
        QStatusBarPrivate::SBItem* item = 0;
        for (int i=0; i<d->items.size(); ++i) {
            item = d->items.at(i);
            if (!item)
                break;
            if (item->w == ((QChildEvent*)e)->child()) {
                d->items.removeAt(i);
                delete item;
            }
        }
    }
    return QWidget::event(e);
}

#endif

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