/src/qt/qtbase/src/widgets/widgets/qsplitter.cpp

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#include "qsplitter.h"
#ifndef QT_NO_SPLITTER

#include "qapplication.h"
#include "qcursor.h"
#include "qdrawutil.h"
#include "qevent.h"
#include "qlayout.h"
#include "qlist.h"
#include "qpainter.h"
#include "qrubberband.h"
#include "qstyle.h"
#include "qstyleoption.h"
#include "qtextstream.h"
#include "qvarlengtharray.h"
#include "qvector.h"
#include "private/qlayoutengine_p.h"
#include "private/qsplitter_p.h"
#include "qtimer.h"
#include "qdebug.h"

#include <ctype.h>

QT_BEGIN_NAMESPACE

//#define QSPLITTER_DEBUG

/*!
    \class QSplitterHandle
    \brief The QSplitterHandle class provides handle functionality for the splitter.

    \ingroup organizers
    \inmodule QtWidgets

    QSplitterHandle is typically what people think about when they think about
    a splitter. It is the handle that is used to resize the widgets.

    A typical developer using QSplitter will never have to worry about
    QSplitterHandle. It is provided for developers who want splitter handles
    that provide extra features, such as popup menus.

    The typical way one would create splitter handles is to subclass QSplitter and then
    reimplement QSplitter::createHandle() to instantiate the custom splitter
    handle. For example, a minimum QSplitter subclass might look like this:

    \snippet splitterhandle/splitter.h 0

    The \l{QSplitter::}{createHandle()} implementation simply constructs a
    custom splitter handle, called \c Splitter in this example:

    \snippet splitterhandle/splitter.cpp 1

    Information about a given handle can be obtained using functions like
    orientation() and opaqueResize(), and is retrieved from its parent splitter.
    Details like these can be used to give custom handles different appearances
    depending on the splitter's orientation.

    The complexity of a custom handle subclass depends on the tasks that it
    needs to perform. A simple subclass might only provide a paintEvent()
    implementation:

    \snippet splitterhandle/splitter.cpp 0

    In this example, a predefined gradient is set up differently depending on
    the orientation of the handle. QSplitterHandle provides a reasonable
    size hint for the handle, so the subclass does not need to provide a
    reimplementation of sizeHint() unless the handle has special size
    requirements.

    \sa QSplitter
*/

/*!
    Creates a QSplitter handle with the given \a orientation and
    \a parent.
*/
QSplitterHandle::QSplitterHandle(Qt::Orientation orientation, QSplitter *parent)
    : QWidget(*new QSplitterHandlePrivate, parent, 0)
{
    Q_D(QSplitterHandle);
    d->s = parent;
    setOrientation(orientation);
}

/*!
    Destructor.
*/
QSplitterHandle::~QSplitterHandle()
{
}

/*!
    Sets the orientation of the splitter handle to \a orientation.
    This is usually propagated from the QSplitter.

    \sa QSplitter::setOrientation()
*/
void QSplitterHandle::setOrientation(Qt::Orientation orientation)
{
    Q_D(QSplitterHandle);
    d->orient = orientation;
#ifndef QT_NO_CURSOR
    setCursor(orientation == Qt::Horizontal ? Qt::SplitHCursor : Qt::SplitVCursor);
#endif
}

/*!
   Returns the handle's orientation. This is usually propagated from the QSplitter.

   \sa QSplitter::orientation()
*/
Qt::Orientation QSplitterHandle::orientation() const
{
    Q_D(const QSplitterHandle);
    return d->orient;
}


/*!
    Returns \c true if widgets are resized dynamically (opaquely), otherwise
    returns \c false. This value is controlled by the QSplitter.

    \sa QSplitter::opaqueResize()

*/
bool QSplitterHandle::opaqueResize() const
{
    Q_D(const QSplitterHandle);
    return d->s->opaqueResize();
}


/*!
    Returns the splitter associated with this splitter handle.

    \sa QSplitter::handle()
*/
QSplitter *QSplitterHandle::splitter() const
{
    return d_func()->s;
}

/*!
    Tells the splitter to move this handle to position \a pos, which is
    the distance from the left or top edge of the widget.

    Note that \a pos is also measured from the left (or top) for
    right-to-left languages. This function will map \a pos to the
    appropriate position before calling QSplitter::moveSplitter().

    \sa QSplitter::moveSplitter(), closestLegalPosition()
*/
void QSplitterHandle::moveSplitter(int pos)
{
    Q_D(QSplitterHandle);
    if (d->s->isRightToLeft() && d->orient == Qt::Horizontal)
        pos = d->s->contentsRect().width() - pos;
    d->s->moveSplitter(pos, d->s->indexOf(this));
}

/*!
   Returns the closest legal position to \a pos of the splitter
   handle. The positions are measured from the left or top edge of
   the splitter, even for right-to-left languages.

   \sa QSplitter::closestLegalPosition(), moveSplitter()
*/

int QSplitterHandle::closestLegalPosition(int pos)
{
    Q_D(QSplitterHandle);
    QSplitter *s = d->s;
    if (s->isRightToLeft() && d->orient == Qt::Horizontal) {
        int w = s->contentsRect().width();
        return w - s->closestLegalPosition(w - pos, s->indexOf(this));
    }
    return s->closestLegalPosition(pos, s->indexOf(this));
}

/*!
    \reimp
*/
QSize QSplitterHandle::sizeHint() const
{
    Q_D(const QSplitterHandle);
    int hw = d->s->handleWidth();
    QStyleOption opt(0);
    opt.init(d->s);
    opt.state = QStyle::State_None;
    return parentWidget()->style()->sizeFromContents(QStyle::CT_Splitter, &opt, QSize(hw, hw), d->s)
        .expandedTo(QApplication::globalStrut());
}

/*!
    \reimp
*/
void QSplitterHandle::resizeEvent(QResizeEvent *event)
{
    Q_D(const QSplitterHandle);

    // When splitters are only 1 or 0 pixel large we increase the
    // actual grab area to five pixels

    // Note that QSplitter uses contentsRect for layouting
    // and ensures that handles are drawn on top of widgets
    // We simply use the contents margins for draggin and only
    // paint the mask area
    bool useTinyMode = (d->s->handleWidth() <= 1);
    setAttribute(Qt::WA_MouseNoMask, useTinyMode);
    if (useTinyMode) {
        if (orientation() == Qt::Horizontal)
            setContentsMargins(2, 0, 2, 0);
        else
            setContentsMargins(0, 2, 0, 2);
        setMask(QRegion(contentsRect()));
    }

    QWidget::resizeEvent(event);
}

/*!
    \reimp
*/
bool QSplitterHandle::event(QEvent *event)
{
    Q_D(QSplitterHandle);
    switch(event->type()) {
    case QEvent::HoverEnter:
        d->hover = true;
        update();
        break;
    case QEvent::HoverLeave:
        d->hover = false;
        update();
        break;
    default:
        break;
    }
    return QWidget::event(event);
}

/*!
    \reimp
*/
void QSplitterHandle::mouseMoveEvent(QMouseEvent *e)
{
    Q_D(QSplitterHandle);
    if (!(e->buttons() & Qt::LeftButton))
        return;
    int pos = d->pick(parentWidget()->mapFromGlobal(e->globalPos()))
                 - d->mouseOffset;
    if (opaqueResize()) {
        moveSplitter(pos);
    } else {
        d->s->setRubberBand(closestLegalPosition(pos));
    }
}

/*!
   \reimp
*/
void QSplitterHandle::mousePressEvent(QMouseEvent *e)
{
    Q_D(QSplitterHandle);
    if (e->button() == Qt::LeftButton) {
        d->mouseOffset = d->pick(e->pos());
        d->pressed = true;
        update();
    }
}

/*!
   \reimp
*/
void QSplitterHandle::mouseReleaseEvent(QMouseEvent *e)
{
    Q_D(QSplitterHandle);
    if (!opaqueResize() && e->button() == Qt::LeftButton) {
        int pos = d->pick(parentWidget()->mapFromGlobal(e->globalPos()))
                     - d->mouseOffset;
        d->s->setRubberBand(-1);
        moveSplitter(pos);
    }
    if (e->button() == Qt::LeftButton) {
        d->pressed = false;
        update();
    }
}

/*!
   \reimp
*/
void QSplitterHandle::paintEvent(QPaintEvent *)
{
    Q_D(QSplitterHandle);
    QPainter p(this);
    QStyleOption opt(0);
    opt.rect = contentsRect();
    opt.palette = palette();
    if (orientation() == Qt::Horizontal)
        opt.state = QStyle::State_Horizontal;
    else
        opt.state = QStyle::State_None;
    if (d->hover)
        opt.state |= QStyle::State_MouseOver;
    if (d->pressed)
        opt.state |= QStyle::State_Sunken;
    if (isEnabled())
        opt.state |= QStyle::State_Enabled;
    parentWidget()->style()->drawControl(QStyle::CE_Splitter, &opt, &p, d->s);
}


int QSplitterLayoutStruct::getWidgetSize(Qt::Orientation orient)
{
    if (sizer == -1) {
        QSize s = widget->sizeHint();
        const int presizer = pick(s, orient);
        const int realsize = pick(widget->size(), orient);
        if (!s.isValid() || (widget->testAttribute(Qt::WA_Resized) && (realsize > presizer))) {
            sizer = pick(widget->size(), orient);
        } else {
            sizer = presizer;
        }
        QSizePolicy p = widget->sizePolicy();
        int sf = (orient == Qt::Horizontal) ? p.horizontalStretch() : p.verticalStretch();
        if (sf > 1)
            sizer *= sf;
    }
    return sizer;
}

int QSplitterLayoutStruct::getHandleSize(Qt::Orientation orient)
{
    return pick(handle->sizeHint(), orient);
}

void QSplitterPrivate::init()
{
    Q_Q(QSplitter);
    QSizePolicy sp(QSizePolicy::Expanding, QSizePolicy::Preferred);
    if (orient == Qt::Vertical)
        sp.transpose();
    q->setSizePolicy(sp);
    q->setAttribute(Qt::WA_WState_OwnSizePolicy, false);
}

void QSplitterPrivate::recalc(bool update)
{
    Q_Q(QSplitter);
    int n = list.count();
    /*
      Splitter handles before the first visible widget or right
      before a hidden widget must be hidden.
    */
    bool first = true;
    bool allInvisible = n != 0;
    for (int i = 0; i < n ; ++i) {
        QSplitterLayoutStruct *s = list.at(i);
        bool widgetHidden = s->widget->isHidden();
        if (allInvisible && !widgetHidden && !s->collapsed)
            allInvisible = false;
        s->handle->setHidden(first || widgetHidden);
        if (!widgetHidden)
            first = false;
    }

    if (allInvisible)
        for (int i = 0; i < n ; ++i) {
            QSplitterLayoutStruct *s = list.at(i);
            if (!s->widget->isHidden()) {
                s->collapsed = false;
                break;
            }
        }

    int fi = 2 * q->frameWidth();
    int maxl = fi;
    int minl = fi;
    int maxt = QWIDGETSIZE_MAX;
    int mint = fi;
    /*
      calculate min/max sizes for the whole splitter
    */
    bool empty = true;
    for (int j = 0; j < n; j++) {
        QSplitterLayoutStruct *s = list.at(j);

        if (!s->widget->isHidden()) {
            empty = false;
            if (!s->handle->isHidden()) {
                minl += s->getHandleSize(orient);
                maxl += s->getHandleSize(orient);
            }

            QSize minS = qSmartMinSize(s->widget);
            minl += pick(minS);
            maxl += pick(s->widget->maximumSize());
            mint = qMax(mint, trans(minS));
            int tm = trans(s->widget->maximumSize());
            if (tm > 0)
                maxt = qMin(maxt, tm);
        }
    }

    if (empty) {
        if (qobject_cast<QSplitter *>(parent)) {
            // nested splitters; be nice
            maxl = maxt = 0;
        } else {
            // QSplitter with no children yet
            maxl = QWIDGETSIZE_MAX;
        }
    } else {
        maxl = qMin<int>(maxl, QWIDGETSIZE_MAX);
    }
    if (maxt < mint)
        maxt = mint;

    if (update) {
        if (orient == Qt::Horizontal) {
            q->setMaximumSize(maxl, maxt);
            if (q->isWindow())
                q->setMinimumSize(minl,mint);
        } else {
            q->setMaximumSize(maxt, maxl);
            if (q->isWindow())
                q->setMinimumSize(mint,minl);
        }
        doResize();
        q->updateGeometry();
    } else {
        firstShow = true;
    }
}

void QSplitterPrivate::doResize()
{
    Q_Q(QSplitter);
    QRect r = q->contentsRect();
    int n = list.count();
    QVector<QLayoutStruct> a(n*2);
    int i;

    bool noStretchFactorsSet = true;
    for (i = 0; i < n; ++i) {
        QSizePolicy p = list.at(i)->widget->sizePolicy();
        int sf = orient == Qt::Horizontal ? p.horizontalStretch() : p.verticalStretch();
        if (sf != 0) {
            noStretchFactorsSet = false;
            break;
        }
    }

    int j=0;
    for (i = 0; i < n; ++i) {
        QSplitterLayoutStruct *s = list.at(i);
#ifdef QSPLITTER_DEBUG
        qDebug("widget %d hidden: %d collapsed: %d handle hidden: %d", i, s->widget->isHidden(),
               s->collapsed, s->handle->isHidden());
#endif

        a[j].init();
        if (s->handle->isHidden()) {
            a[j].maximumSize = 0;
        } else {
            a[j].sizeHint = a[j].minimumSize = a[j].maximumSize = s->getHandleSize(orient);
            a[j].empty = false;
        }
        ++j;

        a[j].init();
        if (s->widget->isHidden() || s->collapsed) {
            a[j].maximumSize = 0;
        } else {
            a[j].minimumSize = pick(qSmartMinSize(s->widget));
            a[j].maximumSize = pick(s->widget->maximumSize());
            a[j].empty = false;

            bool stretch = noStretchFactorsSet;
            if (!stretch) {
                QSizePolicy p = s->widget->sizePolicy();
                int sf = orient == Qt::Horizontal ? p.horizontalStretch() : p.verticalStretch();
                stretch = (sf != 0);
            }
            if (stretch) {
                a[j].stretch = s->getWidgetSize(orient);
                a[j].sizeHint = a[j].minimumSize;
                a[j].expansive = true;
            } else {
                a[j].sizeHint = qMax(s->getWidgetSize(orient), a[j].minimumSize);
            }
        }
        ++j;
    }

    qGeomCalc(a, 0, n*2, pick(r.topLeft()), pick(r.size()), 0);

#ifdef QSPLITTER_DEBUG
    for (i = 0; i < n*2; ++i) {
        qDebug("%*s%d: stretch %d, sh %d, minS %d, maxS %d, exp %d, emp %d -> %d, %d",
               i, "", i,
               a[i].stretch,
               a[i].sizeHint,
               a[i].minimumSize,
               a[i].maximumSize,
               a[i].expansive,
               a[i].empty,
               a[i].pos,
               a[i].size);
    }
#endif

    for (i = 0; i < n; ++i) {
        QSplitterLayoutStruct *s = list.at(i);
        setGeo(s, a[i*2+1].pos, a[i*2+1].size, false);
    }
}

void QSplitterPrivate::storeSizes()
{
    for (int i = 0; i < list.size(); ++i) {
        QSplitterLayoutStruct *sls = list.at(i);
        sls->sizer = pick(sls->rect.size());
    }
}

void QSplitterPrivate::addContribution(int index, int *min, int *max, bool mayCollapse) const
{
    QSplitterLayoutStruct *s = list.at(index);
    if (!s->widget->isHidden()) {
        if (!s->handle->isHidden()) {
            *min += s->getHandleSize(orient);
            *max += s->getHandleSize(orient);
        }
        if (mayCollapse || !s->collapsed)
            *min += pick(qSmartMinSize(s->widget));

        *max += pick(s->widget->maximumSize());
    }
}

int QSplitterPrivate::findWidgetJustBeforeOrJustAfter(int index, int delta, int &collapsibleSize) const
{
    if (delta < 0)
        index += delta;
    do {
        QWidget *w = list.at(index)->widget;
        if (!w->isHidden()) {
            if (collapsible(list.at(index)))
                collapsibleSize = pick(qSmartMinSize(w));
            return index;
        }
        index += delta;
    } while (index >= 0 && index < list.count());

    return -1;
}

/*
  For the splitter handle with index \a index, \a min and \a max give the range without collapsing any widgets,
  and \a farMin and farMax give the range with collapsing included.
*/
void QSplitterPrivate::getRange(int index, int *farMin, int *min, int *max, int *farMax) const
{
    Q_Q(const QSplitter);
    int n = list.count();
    if (index <= 0 || index >= n)
        return;

    int collapsibleSizeBefore = 0;
    int idJustBefore = findWidgetJustBeforeOrJustAfter(index, -1, collapsibleSizeBefore);

    int collapsibleSizeAfter = 0;
    int idJustAfter = findWidgetJustBeforeOrJustAfter(index, +1, collapsibleSizeAfter);

    int minBefore = 0;
    int minAfter = 0;
    int maxBefore = 0;
    int maxAfter = 0;
    int i;

    for (i = 0; i < index; ++i)
        addContribution(i, &minBefore, &maxBefore, i == idJustBefore);
    for (i = index; i < n; ++i)
        addContribution(i, &minAfter, &maxAfter, i == idJustAfter);

    QRect r = q->contentsRect();
    int farMinVal;
    int minVal;
    int maxVal;
    int farMaxVal;

    int smartMinBefore = qMax(minBefore, pick(r.size()) - maxAfter);
    int smartMaxBefore = qMin(maxBefore, pick(r.size()) - minAfter);

    minVal = pick(r.topLeft()) + smartMinBefore;
    maxVal = pick(r.topLeft()) + smartMaxBefore;

    farMinVal = minVal;
    if (minBefore - collapsibleSizeBefore >= pick(r.size()) - maxAfter)
        farMinVal -= collapsibleSizeBefore;
    farMaxVal = maxVal;
    if (pick(r.size()) - (minAfter - collapsibleSizeAfter) <= maxBefore)
        farMaxVal += collapsibleSizeAfter;

    if (farMin)
        *farMin = farMinVal;
    if (min)
        *min = minVal;
    if (max)
        *max = maxVal;
    if (farMax)
        *farMax = farMaxVal;
}

int QSplitterPrivate::adjustPos(int pos, int index, int *farMin, int *min, int *max, int *farMax) const
{
    const int Threshold = 40;

    getRange(index, farMin, min, max, farMax);

    if (pos >= *min) {
        if (pos <= *max) {
            return pos;
        } else {
            int delta = pos - *max;
            int width = *farMax - *max;

            if (delta > width / 2 && delta >= qMin(Threshold, width)) {
                return *farMax;
            } else {
                return *max;
            }
        }
    } else {
        int delta = *min - pos;
        int width = *min - *farMin;

        if (delta > width / 2 && delta >= qMin(Threshold, width)) {
            return *farMin;
        } else {
            return *min;
        }
    }
}

bool QSplitterPrivate::collapsible(QSplitterLayoutStruct *s) const
{
    if (s->collapsible != Default) {
        return (bool)s->collapsible;
    } else {
        return childrenCollapsible;
    }
}

void QSplitterPrivate::updateHandles()
{
    Q_Q(QSplitter);
    recalc(q->isVisible());
}

void QSplitterPrivate::setSizes_helper(const QList<int> &sizes, bool clampNegativeSize)
{
    int j = 0;

    for (int i = 0; i < list.size(); ++i) {
        QSplitterLayoutStruct *s = list.at(i);

        s->collapsed = false;
        s->sizer = sizes.value(j++);
        if (clampNegativeSize && s->sizer < 0)
            s->sizer = 0;
        int smartMinSize = pick(qSmartMinSize(s->widget));

        // Make sure that we reset the collapsed state.
        if (s->sizer == 0) {
            if (collapsible(s) && smartMinSize > 0) {
                s->collapsed = true;
            } else {
                s->sizer = smartMinSize;
            }
        } else {
            if (s->sizer < smartMinSize)
                s->sizer = smartMinSize;
        }
    }
    doResize();
}

void QSplitterPrivate::setGeo(QSplitterLayoutStruct *sls, int p, int s, bool allowCollapse)
{
    Q_Q(QSplitter);
    QWidget *w = sls->widget;
    QRect r;
    QRect contents = q->contentsRect();
    if (orient == Qt::Horizontal) {
        r.setRect(p, contents.y(), s, contents.height());
    } else {
        r.setRect(contents.x(), p, contents.width(), s);
    }
    sls->rect = r;

    int minSize = pick(qSmartMinSize(w));

    if (orient == Qt::Horizontal && q->isRightToLeft())
        r.moveRight(contents.width() - r.left());

    if (allowCollapse)
        sls->collapsed = s <= 0 && minSize > 0 && !w->isHidden();

    //   Hide the child widget, but without calling hide() so that
    //   the splitter handle is still shown.
    if (sls->collapsed)
        r.moveTopLeft(QPoint(-r.width()-1, -r.height()-1));

    w->setGeometry(r);

    if (!sls->handle->isHidden()) {
        QSplitterHandle *h = sls->handle;
        QSize hs = h->sizeHint();
        int left, top, right, bottom;
        h->getContentsMargins(&left, &top, &right, &bottom);
        if (orient==Qt::Horizontal) {
            if (q->isRightToLeft())
                p = contents.width() - p + hs.width();
            h->setGeometry(p-hs.width() - left, contents.y(), hs.width() + left + right, contents.height());
        } else {
            h->setGeometry(contents.x(), p-hs.height() - top, contents.width(), hs.height() + top + bottom);
        }
    }
}

void QSplitterPrivate::doMove(bool backwards, int hPos, int index, int delta, bool mayCollapse,
                              int *positions, int *widths)
{
    if (index < 0 || index >= list.count())
        return;

#ifdef QSPLITTER_DEBUG
    qDebug() << "QSplitterPrivate::doMove" << backwards << hPos << index << delta << mayCollapse;
#endif

    QSplitterLayoutStruct *s = list.at(index);
    QWidget *w = s->widget;

    int nextId = backwards ? index - delta : index + delta;

    if (w->isHidden()) {
        doMove(backwards, hPos, nextId, delta, collapsible(nextId), positions, widths);
    } else {
        int hs =s->handle->isHidden() ? 0 : s->getHandleSize(orient);

        int  ws = backwards ? hPos - pick(s->rect.topLeft())
                 : pick(s->rect.bottomRight()) - hPos -hs + 1;
        if (ws > 0 || (!s->collapsed && !mayCollapse)) {
            ws = qMin(ws, pick(w->maximumSize()));
            ws = qMax(ws, pick(qSmartMinSize(w)));
        } else {
            ws = 0;
        }
        positions[index] = backwards ? hPos - ws : hPos + hs;
        widths[index] = ws;
        doMove(backwards, backwards ? hPos - ws - hs : hPos + hs + ws, nextId, delta,
               collapsible(nextId), positions, widths);
    }

}

QSplitterLayoutStruct *QSplitterPrivate::findWidget(QWidget *w) const
{
    for (int i = 0; i < list.size(); ++i) {
        if (list.at(i)->widget == w)
            return list.at(i);
    }
    return 0;
}


/*!
    \internal
*/
void QSplitterPrivate::insertWidget_helper(int index, QWidget *widget, bool show)
{
    Q_Q(QSplitter);
    QBoolBlocker b(blockChildAdd);
    bool needShow = show && q->isVisible() &&
                    !(widget->isHidden() && widget->testAttribute(Qt::WA_WState_ExplicitShowHide));
    if (widget->parentWidget() != q)
        widget->setParent(q);
    if (needShow)
        widget->show();
    insertWidget(index, widget);
    recalc(q->isVisible());
}

/*
    Inserts the widget \a w at position \a index in the splitter's list of widgets.

    If \a w is already in the splitter, it will be moved to the new position.
*/

QSplitterLayoutStruct *QSplitterPrivate::insertWidget(int index, QWidget *w)
{
    Q_Q(QSplitter);
    QSplitterLayoutStruct *sls = 0;
    int i;
    int last = list.count();
    for (i = 0; i < list.size(); ++i) {
        QSplitterLayoutStruct *s = list.at(i);
        if (s->widget == w) {
            sls = s;
            --last;
            break;
        }
    }
    if (index < 0 || index > last)
        index = last;

    if (sls) {
        list.move(i,index);
    } else {
        QSplitterHandle *newHandle = 0;
        sls = new QSplitterLayoutStruct;
        QString tmp = QLatin1String("qt_splithandle_");
        tmp += w->objectName();
        newHandle = q->createHandle();
        newHandle->setObjectName(tmp);
        sls->handle = newHandle;
        sls->widget = w;
        w->lower();
        list.insert(index,sls);

        if (newHandle && q->isVisible())
            newHandle->show(); // will trigger sending of post events

    }
    return sls;
}

/*!
    \class QSplitter
    \brief The QSplitter class implements a splitter widget.

    \ingroup organizers
    \inmodule QtWidgets


    A splitter lets the user control the size of child widgets by dragging the
    boundary between them. Any number of widgets may be controlled by a
    single splitter. The typical use of a QSplitter is to create several
    widgets and add them using insertWidget() or addWidget().

    The following example will show a QListView, QTreeView, and
    QTextEdit side by side, with two splitter handles:

    \snippet splitter/splitter.cpp 0

    If a widget is already inside a QSplitter when insertWidget() or
    addWidget() is called, it will move to the new position. This can be used
    to reorder widgets in the splitter later. You can use indexOf(),
    widget(), and count() to get access to the widgets inside the splitter.

    A default QSplitter lays out its children horizontally (side by side); you
    can use setOrientation(Qt::Vertical) to lay its
    children out vertically.

    By default, all widgets can be as large or as small as the user
    wishes, between the \l minimumSizeHint() (or \l minimumSize())
    and \l maximumSize() of the widgets.

    QSplitter resizes its children dynamically by default. If you
    would rather have QSplitter resize the children only at the end of
    a resize operation, call setOpaqueResize(false).

    The initial distribution of size between the widgets is determined by
    multiplying the initial size with the stretch factor.
    You can also use setSizes() to set the sizes
    of all the widgets. The function sizes() returns the sizes set by the user.
    Alternatively, you can save and restore the sizes of the widgets from a
    QByteArray using saveState() and restoreState() respectively.

    When you hide() a child, its space will be distributed among the
    other children. It will be reinstated when you show() it again.

    \note Adding a QLayout to a QSplitter is not supported (either through
    setLayout() or making the QSplitter a parent of the QLayout); use addWidget()
    instead (see example above).

    \sa QSplitterHandle, QHBoxLayout, QVBoxLayout, QTabWidget
*/


/*!
    Constructs a horizontal splitter with the \a parent
    argument passed on to the QFrame constructor.

    \sa setOrientation()
*/
QSplitter::QSplitter(QWidget *parent)
    : QFrame(*new QSplitterPrivate, parent)
{
    Q_D(QSplitter);
    d->orient = Qt::Horizontal;
    d->init();
}


/*!
    Constructs a splitter with the given \a orientation and \a parent.

    \sa setOrientation()
*/
QSplitter::QSplitter(Qt::Orientation orientation, QWidget *parent)
    : QFrame(*new QSplitterPrivate, parent)
{
    Q_D(QSplitter);
    d->orient = orientation;
    d->init();
}


/*!
    Destroys the splitter. All children are deleted.
*/

QSplitter::~QSplitter()
{
    Q_D(QSplitter);
    delete d->rubberBand;
    while (!d->list.isEmpty())
        delete d->list.takeFirst();
}

/*!
    Updates the splitter's state. You should not need to call this
    function.
*/
void QSplitter::refresh()
{
    Q_D(QSplitter);
    d->recalc(true);
}

/*!
    \property QSplitter::orientation
    \brief the orientation of the splitter

    By default, the orientation is horizontal (i.e., the widgets are
    laid out side by side). The possible orientations are
    Qt::Horizontal and Qt::Vertical.

    \sa QSplitterHandle::orientation()
*/

void QSplitter::setOrientation(Qt::Orientation orientation)
{
    Q_D(QSplitter);
    if (d->orient == orientation)
        return;

    if (!testAttribute(Qt::WA_WState_OwnSizePolicy)) {
        QSizePolicy sp = sizePolicy();
        sp.transpose();
        setSizePolicy(sp);
        setAttribute(Qt::WA_WState_OwnSizePolicy, false);
    }

    d->orient = orientation;

    for (int i = 0; i < d->list.size(); ++i) {
        QSplitterLayoutStruct *s = d->list.at(i);
        s->handle->setOrientation(orientation);
    }
    d->recalc(isVisible());
}

Qt::Orientation QSplitter::orientation() const
{
    Q_D(const QSplitter);
    return d->orient;
}

/*!
    \property QSplitter::childrenCollapsible
    \brief whether child widgets can be resized down to size 0 by the user

    By default, children are collapsible. It is possible to enable
    and disable the collapsing of individual children using
    setCollapsible().

    \sa setCollapsible()
*/

void QSplitter::setChildrenCollapsible(bool collapse)
{
    Q_D(QSplitter);
    d->childrenCollapsible = collapse;
}

bool QSplitter::childrenCollapsible() const
{
    Q_D(const QSplitter);
    return d->childrenCollapsible;
}

/*!
    Sets whether the child widget at \a index is collapsible to \a collapse.

    By default, children are collapsible, meaning that the user can
    resize them down to size 0, even if they have a non-zero
    minimumSize() or minimumSizeHint(). This behavior can be changed
    on a per-widget basis by calling this function, or globally for
    all the widgets in the splitter by setting the \l
    childrenCollapsible property.

    \sa childrenCollapsible
*/

void QSplitter::setCollapsible(int index, bool collapse)
{
    Q_D(QSplitter);

    if (index < 0 || index >= d->list.size()) {
        qWarning("QSplitter::setCollapsible: Index %d out of range", index);
        return;
    }
    d->list.at(index)->collapsible = collapse ? 1 : 0;
}

/*!
    Returns \c true if the widget at \a index is collapsible, otherwise returns \c false.
*/
bool QSplitter::isCollapsible(int index) const
{
    Q_D(const QSplitter);
    if (index < 0 || index >= d->list.size()) {
        qWarning("QSplitter::isCollapsible: Index %d out of range", index);
        return false;
    }
    return d->list.at(index)->collapsible;
}

/*!
    \reimp
*/
void QSplitter::resizeEvent(QResizeEvent *)
{
    Q_D(QSplitter);
    d->doResize();
}

/*!
    Adds the given \a widget to the splitter's layout after all the other
    items.

    If \a widget is already in the splitter, it will be moved to the new position.

    \sa insertWidget(), widget(), indexOf()
*/
void QSplitter::addWidget(QWidget *widget)
{
    Q_D(QSplitter);
    insertWidget(d->list.count(), widget);
}

/*!
    Inserts the \a widget specified into the splitter's layout at the
    given \a index.

    If \a widget is already in the splitter, it will be moved to the new position.

    if \a index is an invalid index, then the widget will be inserted at the end.

    \sa addWidget(), indexOf(), widget()
*/
void QSplitter::insertWidget(int index, QWidget *widget)
{
    Q_D(QSplitter);
    d->insertWidget_helper(index, widget, true);
}

/*!
    \fn int QSplitter::indexOf(QWidget *widget) const

    Returns the index in the splitter's layout of the specified \a widget. This
    also works for handles.

    Handles are numbered from 0. There are as many handles as there
    are child widgets, but the handle at position 0 is always hidden.


    \sa count(), widget()
*/
int QSplitter::indexOf(QWidget *w) const
{
    Q_D(const QSplitter);
    for (int i = 0; i < d->list.size(); ++i) {
        QSplitterLayoutStruct *s = d->list.at(i);
        if (s->widget == w || s->handle == w)
            return i;
    }
    return -1;
}

/*!
    Returns a new splitter handle as a child widget of this splitter.
    This function can be reimplemented in subclasses to provide support
    for custom handles.

    \sa handle(), indexOf()
*/
QSplitterHandle *QSplitter::createHandle()
{
    Q_D(QSplitter);
    return new QSplitterHandle(d->orient, this);
}

/*!
    Returns the handle to the left (or above) for the item in the
    splitter's layout at the given \a index. The handle at index 0 is
    always hidden.

    For right-to-left languages such as Arabic and Hebrew, the layout
    of horizontal splitters is reversed. The handle will be to the
    right of the widget at \a index.

    \sa count(), widget(), indexOf(), createHandle(), setHandleWidth()
*/
QSplitterHandle *QSplitter::handle(int index) const
{
    Q_D(const QSplitter);
    if (index < 0 || index >= d->list.size())
        return 0;
    return d->list.at(index)->handle;
}

/*!
    Returns the widget at the given \a index in the splitter's layout.

    \sa count(), handle(), indexOf(), insertWidget()
*/
QWidget *QSplitter::widget(int index) const
{
    Q_D(const QSplitter);
    if (index < 0 || index >= d->list.size())
        return 0;
    return d->list.at(index)->widget;
}

/*!
    Returns the number of widgets contained in the splitter's layout.

    \sa widget(), handle()
*/
int QSplitter::count() const
{
    Q_D(const QSplitter);
    return d->list.count();
}

/*!
    \reimp

    Tells the splitter that the child widget described by \a c has been
    inserted or removed.

    This method is also used to handle the situation where a widget is created
    with the splitter as a parent but not explicitly added with insertWidget()
    or addWidget(). This is for compatibility and not the recommended way of
    putting widgets into a splitter in new code. Please use insertWidget() or
    addWidget() in new code.

    \sa addWidget(), insertWidget()
*/

void QSplitter::childEvent(QChildEvent *c)
{
    Q_D(QSplitter);
    if (!c->child()->isWidgetType()) {
        if (c->type() == QEvent::ChildAdded && qobject_cast<QLayout *>(c->child()))
            qWarning("Adding a QLayout to a QSplitter is not supported.");
        return;
    }
    QWidget *w = static_cast<QWidget*>(c->child());
    if (c->added() && !d->blockChildAdd && !w->isWindow() && !d->findWidget(w)) {
        d->insertWidget_helper(d->list.count(), w, false);
    } else if (c->polished() && !d->blockChildAdd) {
        if (isVisible() && !(w->isHidden() && w->testAttribute(Qt::WA_WState_ExplicitShowHide)))
            w->show();
    } else if (c->type() == QEvent::ChildRemoved) {
        for (int i = 0; i < d->list.size(); ++i) {
            QSplitterLayoutStruct *s = d->list.at(i);
            if (s->widget == w) {
                d->list.removeAt(i);
                delete s;
                d->recalc(isVisible());
                return;
            }
        }
    }
}


/*!
    Displays a rubber band at position \a pos. If \a pos is negative, the
    rubber band is removed.
*/

void QSplitter::setRubberBand(int pos)
{
    Q_D(QSplitter);
    if (pos < 0) {
        if (d->rubberBand)
            d->rubberBand->deleteLater();
        return;
    }
    QRect r = contentsRect();
    const int rBord = 3; // customizable?
    int hw = handleWidth();
    if (!d->rubberBand) {
        QBoolBlocker b(d->blockChildAdd);
        d->rubberBand = new QRubberBand(QRubberBand::Line, this);
        // For accessibility to identify this special widget.
        d->rubberBand->setObjectName(QLatin1String("qt_rubberband"));
    }

    const QRect newGeom = d->orient == Qt::Horizontal ? QRect(QPoint(pos + hw / 2 - rBord, r.y()), QSize(2 * rBord, r.height()))
                                                      : QRect(QPoint(r.x(), pos + hw / 2 - rBord), QSize(r.width(), 2 * rBord));
    d->rubberBand->setGeometry(newGeom);
    d->rubberBand->show();
}

/*!
    \reimp
*/

bool QSplitter::event(QEvent *e)
{
    Q_D(QSplitter);
    switch (e->type()) {
    case QEvent::Hide:
        // Reset firstShow to false here since things can be done to the splitter in between
        if (!d->firstShow)
            d->firstShow = true;
        break;
    case QEvent::Show:
        if (!d->firstShow)
            break;
        d->firstShow = false;
        // fall through
    case QEvent::HideToParent:
    case QEvent::ShowToParent:
    case QEvent::LayoutRequest:
        d->recalc(isVisible());
        break;
    default:
        ;
    }
    return QWidget::event(e);
}

/*!
    \fn QSplitter::splitterMoved(int pos, int index)

    This signal is emitted when the splitter handle at a particular \a
    index has been moved to position \a pos.

    For right-to-left languages such as Arabic and Hebrew, the layout
    of horizontal splitters is reversed. \a pos is then the
    distance from the right edge of the widget.

    \sa moveSplitter()
*/

/*!
    Moves the left or top edge of the splitter handle at \a index as
    close as possible to position \a pos, which is the distance from the
    left or top edge of the widget.

    For right-to-left languages such as Arabic and Hebrew, the layout
    of horizontal splitters is reversed. \a pos is then the distance
    from the right edge of the widget.

    \sa splitterMoved(), closestLegalPosition(), getRange()
*/
void QSplitter::moveSplitter(int pos, int index)
{
    Q_D(QSplitter);
    QSplitterLayoutStruct *s = d->list.at(index);
    int farMin;
    int min;
    int max;
    int farMax;

#ifdef QSPLITTER_DEBUG
    int debugp = pos;
#endif

    pos = d->adjustPos(pos, index, &farMin, &min, &max, &farMax);
    int oldP = d->pick(s->rect.topLeft());
#ifdef QSPLITTER_DEBUG
    qDebug() << "QSplitter::moveSplitter" << debugp << index << "adjusted" << pos << "oldP" << oldP;
#endif

    QVarLengthArray<int, 32> poss(d->list.count());
    QVarLengthArray<int, 32> ws(d->list.count());
    bool upLeft;

    d->doMove(false, pos, index, +1, (d->collapsible(s) && (pos > max)), poss.data(), ws.data());
    d->doMove(true, pos, index - 1, +1, (d->collapsible(index - 1) && (pos < min)), poss.data(), ws.data());
    upLeft = (pos < oldP);

    int wid, delta, count = d->list.count();
    if (upLeft) {
        wid = 0;
        delta = 1;
    } else {
        wid = count - 1;
        delta = -1;
    }
    for (; wid >= 0 && wid < count; wid += delta) {
        QSplitterLayoutStruct *sls = d->list.at( wid );
        if (!sls->widget->isHidden())
            d->setGeo(sls, poss[wid], ws[wid], true);
    }
    d->storeSizes();

    emit splitterMoved(pos, index);
}


/*!
    Returns the valid range of the splitter at \a index in
    *\a{min} and *\a{max} if \a min and \a max are not 0.
*/

void QSplitter::getRange(int index, int *min, int *max) const
{
    Q_D(const QSplitter);
    d->getRange(index, min, 0, 0, max);
}


/*!
    Returns the closest legal position to \a pos of the widget at \a index.

    For right-to-left languages such as Arabic and Hebrew, the layout
    of horizontal splitters is reversed. Positions are then measured
    from the right edge of the widget.

    \sa getRange()
*/

int QSplitter::closestLegalPosition(int pos, int index)
{
    Q_D(QSplitter);
    int x, i, n, u;
    return d->adjustPos(pos, index, &u, &n, &i, &x);
}

/*!
    \property QSplitter::opaqueResize
    \brief whether resizing is opaque

    The default resize behavior is style dependent (determined by the
    SH_Splitter_OpaqueResize style hint). However, you can override it
    by calling setOpaqueResize()

    \sa QStyle::StyleHint
*/

bool QSplitter::opaqueResize() const
{
    Q_D(const QSplitter);
    return d->opaqueResizeSet ? d->opaque : style()->styleHint(QStyle::SH_Splitter_OpaqueResize, 0, this);
}


void QSplitter::setOpaqueResize(bool on)
{
    Q_D(QSplitter);
    d->opaqueResizeSet = true;
    d->opaque = on;
}


/*!
    \reimp
*/
QSize QSplitter::sizeHint() const
{
    Q_D(const QSplitter);
    ensurePolished();
    int l = 0;
    int t = 0;
    for (int i = 0; i < d->list.size(); ++i) {
        QWidget *w = d->list.at(i)->widget;
        if (w->isHidden())
            continue;
        QSize s = w->sizeHint();
        if (s.isValid()) {
            l += d->pick(s);
            t = qMax(t, d->trans(s));
        }
    }
    return orientation() == Qt::Horizontal ? QSize(l, t) : QSize(t, l);
}


/*!
    \reimp
*/

QSize QSplitter::minimumSizeHint() const
{
    Q_D(const QSplitter);
    ensurePolished();
    int l = 0;
    int t = 0;

    for (int i = 0; i < d->list.size(); ++i) {
        QSplitterLayoutStruct *s = d->list.at(i);
        if (!s || !s->widget)
            continue;
        if (s->widget->isHidden())
            continue;
        QSize widgetSize = qSmartMinSize(s->widget);
        if (widgetSize.isValid()) {
            l += d->pick(widgetSize);
            t = qMax(t, d->trans(widgetSize));
        }
        if (!s->handle || s->handle->isHidden())
            continue;
        QSize splitterSize = s->handle->sizeHint();
        if (splitterSize.isValid()) {
            l += d->pick(splitterSize);
            t = qMax(t, d->trans(splitterSize));
        }
    }
    return orientation() == Qt::Horizontal ? QSize(l, t) : QSize(t, l);
}


/*!
    Returns a list of the size parameters of all the widgets in this splitter.

    If the splitter's orientation is horizontal, the list contains the
    widgets width in pixels, from left to right; if the orientation is
    vertical, the list contains the widgets' heights in pixels,
    from top to bottom.

    Giving the values to another splitter's setSizes() function will
    produce a splitter with the same layout as this one.

    Note that invisible widgets have a size of 0.

    \sa setSizes()
*/

QList<int> QSplitter::sizes() const
{
    Q_D(const QSplitter);
    ensurePolished();

    QList<int> list;
    for (int i = 0; i < d->list.size(); ++i) {
        QSplitterLayoutStruct *s = d->list.at(i);
        list.append(d->pick(s->rect.size()));
    }
    return list;
}

/*!
    Sets the child widgets' respective sizes to the values given in the \a list.

    If the splitter is horizontal, the values set the width of each
    widget in pixels, from left to right. If the splitter is vertical, the
    height of each widget is set, from top to bottom.

    Extra values in the \a list are ignored. If \a list contains too few
    values, the result is undefined, but the program will still be well-behaved.

    The overall size of the splitter widget is not affected.
    Instead, any additional/missing space is distributed amongst the
    widgets according to the relative weight of the sizes.

    If you specify a size of 0, the widget will be invisible. The size policies
    of the widgets are preserved. That is, a value smaller than the minimal size
    hint of the respective widget will be replaced by the value of the hint.

    \sa sizes()
*/

void QSplitter::setSizes(const QList<int> &list)
{
    Q_D(QSplitter);
    d->setSizes_helper(list, true);
}

/*!
    \property QSplitter::handleWidth
    \brief the width of the splitter handles

    By default, this property contains a value that depends on the user's platform
    and style preferences.

    If you set handleWidth to 1 or 0, the actual grab area will grow to overlap a
    few pixels of its respective widgets.
*/

int QSplitter::handleWidth() const
{
    Q_D(const QSplitter);
    if (d->handleWidth >= 0) {
        return d->handleWidth;
    } else {
        return style()->pixelMetric(QStyle::PM_SplitterWidth, 0, this);
    }
}

void QSplitter::setHandleWidth(int width)
{
    Q_D(QSplitter);
    d->handleWidth = width;
    d->updateHandles();
}

/*!
    \reimp
*/
void QSplitter::changeEvent(QEvent *ev)
{
    Q_D(QSplitter);
    if(ev->type() == QEvent::StyleChange)
        d->updateHandles();
    QFrame::changeEvent(ev);
}

static const qint32 SplitterMagic = 0xff;

/*!
    Saves the state of the splitter's layout.

    Typically this is used in conjunction with QSettings to remember the size
    for a future session. A version number is stored as part of the data.
    Here is an example:

    \snippet splitter/splitter.cpp 1

    \sa restoreState()
*/
QByteArray QSplitter::saveState() const
{
    Q_D(const QSplitter);
    int version = 1;
    QByteArray data;
    QDataStream stream(&data, QIODevice::WriteOnly);

    stream << qint32(SplitterMagic);
    stream << qint32(version);
    QList<int> list;
    for (int i = 0; i < d->list.size(); ++i) {
        QSplitterLayoutStruct *s = d->list.at(i);
        list.append(s->sizer);
    }
    stream << list;
    stream << childrenCollapsible();
    stream << qint32(handleWidth());
    stream << opaqueResize();
    stream << qint32(orientation());
    stream << d->opaqueResizeSet;
    return data;
}

/*!
    Restores the splitter's layout to the \a state specified.
    Returns \c true if the state is restored; otherwise returns \c false.

    Typically this is used in conjunction with QSettings to restore the size
    from a past session. Here is an example:

    Restore the splitter's state:

    \snippet splitter/splitter.cpp 2

    A failure to restore the splitter's layout may result from either
    invalid or out-of-date data in the supplied byte array.

    \sa saveState()
*/
bool QSplitter::restoreState(const QByteArray &state)
{
    Q_D(QSplitter);
    int version = 1;
    QByteArray sd = state;
    QDataStream stream(&sd, QIODevice::ReadOnly);
    QList<int> list;
    bool b;
    qint32 i;
    qint32 marker;
    qint32 v;

    stream >> marker;
    stream >> v;
    if (marker != SplitterMagic || v > version)
        return false;

    stream >> list;
    d->setSizes_helper(list, false);

    stream >> b;
    setChildrenCollapsible(b);

    stream >> i;
    setHandleWidth(i);

    stream >> b;
    setOpaqueResize(b);

    stream >> i;
    setOrientation(Qt::Orientation(i));
    d->doResize();

    if (v >= 1)
        stream >> d->opaqueResizeSet;

    return true;
}

/*!
    Updates the size policy of the widget at position \a index to
    have a stretch factor of \a stretch.

    \a stretch is not the effective stretch factor; the effective
    stretch factor is calculated by taking the initial size of the
    widget and multiplying it with \a stretch.

    This function is provided for convenience. It is equivalent to

    \snippet code/src_gui_widgets_qsplitter.cpp 0

    \sa setSizes(), widget()
*/
void QSplitter::setStretchFactor(int index, int stretch)
{
    Q_D(QSplitter);
    if (index <= -1 || index >= d->list.count())
        return;

    QWidget *widget = d->list.at(index)->widget;
    QSizePolicy sp = widget->sizePolicy();
    sp.setHorizontalStretch(stretch);
    sp.setVerticalStretch(stretch);
    widget->setSizePolicy(sp);
}


/*!
    \relates QSplitter
    \obsolete

    Use \a ts << \a{splitter}.saveState() instead.
*/

QTextStream& operator<<(QTextStream& ts, const QSplitter& splitter)
{
    ts << splitter.saveState() << endl;
    return ts;
}

/*!
    \relates QSplitter
    \obsolete

    Use \a ts >> \a{splitter}.restoreState() instead.
*/

QTextStream& operator>>(QTextStream& ts, QSplitter& splitter)
{
    QString line = ts.readLine();
    line = line.simplified();
    line.replace(QLatin1Char(' '), QString());
    line = line.toUpper();

    splitter.restoreState(line.toLatin1());
    return ts;
}

QT_END_NAMESPACE

#endif // QT_NO_SPLITTER