/****************************************************************************

**

** 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 "qlayout.h"

#include "qapplication.h"

#include "qlayoutengine_p.h"

#include "qmenubar.h"

#include "qtoolbar.h"

#include "qsizegrip.h"

#include "qevent.h"

#include "qstyle.h"

#include "qvariant.h"

#include "qwidget_p.h"

#include "qlayout_p.h"

#include "qformlayout.h"

QT_BEGIN_NAMESPACE

static int menuBarHeightForWidth(QWidget *menubar, int w)

{

    if (menubar && !menubar->isHidden() && !menubar->isWindow()) {

        int result = menubar->heightForWidth(qMax(w, menubar->minimumWidth()));

        if (result != -1)

            return result;

        result = menubar->sizeHint()

            .expandedTo(menubar->minimumSize())

            .expandedTo(menubar->minimumSizeHint())

            .boundedTo(menubar->maximumSize()).height();

        if (result != -1)

            return result;

    }

    return 0;

}

/*!

    \class QLayout

    \brief The QLayout class is the base class of geometry managers.

    \ingroup geomanagement

    This is an abstract base class inherited by the concrete classes

    QBoxLayout, QGridLayout, QFormLayout, and QStackedLayout.

    For users of QLayout subclasses or of QMainWindow there is seldom

    any need to use the basic functions provided by QLayout, such as

    setSizeConstraint() or setMenuBar(). See \l{Layout Management}

    for more information.

    To make your own layout manager, implement the functions

    addItem(), sizeHint(), setGeometry(), itemAt() and takeAt(). You

    should also implement minimumSize() to ensure your layout isn't

    resized to zero size if there is too little space. To support

    children whose heights depend on their widths, implement

    hasHeightForWidth() and heightForWidth(). See the

    \l{layouts/borderlayout}{Border Layout} and

    \l{layouts/flowlayout}{Flow Layout} examples for

    more information about implementing custom layout managers.

    Geometry management stops when the layout manager is deleted.

    \sa QLayoutItem, {Layout Management}, {Basic Layouts Example},

        {Border Layout Example}, {Flow Layout Example}

*/

/*!

    Constructs a new top-level QLayout, with parent \a parent.

    \a parent may not be 0.

    There can be only one top-level layout for a widget. It is

    returned by QWidget::layout().

*/

QLayout::QLayout(QWidget *parent)

    : QObject(*new QLayoutPrivate, parent)

{

    if (!parent)

        return;

    parent->setLayout(this);

}

/*!

    Constructs a new child QLayout.

    This layout has to be inserted into another layout before geometry

    management will work.

*/

QLayout::QLayout()

    : QObject(*new QLayoutPrivate, 0)

{

}

/*! \internal

 */

QLayout::QLayout(QLayoutPrivate &dd, QLayout *lay, QWidget *w)

    : QObject(dd, lay ? static_cast<QObject*>(lay) : static_cast<QObject*>(w))

{

    Q_D(QLayout);

    if (lay) {

        lay->addItem(this);

    } else if (w) {

        if (w->layout()) {

            qWarning("QLayout: Attempting to add QLayout \"%s\" to %s \"%s\", which"

                     " already has a layout",

                     qPrintable(QObject::objectName()), w->metaObject()->className(),

                     w->objectName().toLocal8Bit().data());

            setParent(0);

        } else {

            d->topLevel = true;

            w->d_func()->layout = this;

            QT_TRY {

                invalidate();

            } QT_CATCH(...) {

                w->d_func()->layout = 0;

                QT_RETHROW;

            }

        }

    }

}

QLayoutPrivate::QLayoutPrivate()

    : QObjectPrivate(), insideSpacing(-1), userLeftMargin(-1), userTopMargin(-1), userRightMargin(-1),

      userBottomMargin(-1), topLevel(false), enabled(true), activated(true), autoNewChild(false),

      constraint(QLayout::SetDefaultConstraint), menubar(0)

{

}

void QLayoutPrivate::getMargin(int *result, int userMargin, QStyle::PixelMetric pm) const

{

    if (!result)

        return;

    Q_Q(const QLayout);

    if (userMargin >= 0) {

        *result = userMargin;

    } else if (!topLevel) {

        *result = 0;

    } else if (QWidget *pw = q->parentWidget()) {

        *result = pw->style()->pixelMetric(pm, 0, pw);

    } else {

        *result = 0;

    }

}

// Static item factory functions that allow for hooking things in Designer

QLayoutPrivate::QWidgetItemFactoryMethod QLayoutPrivate::widgetItemFactoryMethod = 0;

QLayoutPrivate::QSpacerItemFactoryMethod QLayoutPrivate::spacerItemFactoryMethod = 0;

QWidgetItem *QLayoutPrivate::createWidgetItem(const QLayout *layout, QWidget *widget)

{

    if (widgetItemFactoryMethod)

        if (QWidgetItem *wi = (*widgetItemFactoryMethod)(layout, widget))

            return wi;

    return new QWidgetItemV2(widget);

}

QSpacerItem *QLayoutPrivate::createSpacerItem(const QLayout *layout, int w, int h, QSizePolicy::Policy hPolicy, QSizePolicy::Policy vPolicy)

{

    if (spacerItemFactoryMethod)

        if (QSpacerItem *si = (*spacerItemFactoryMethod)(layout, w, h, hPolicy, vPolicy))

            return si;

    return new QSpacerItem(w, h,  hPolicy, vPolicy);

}

#ifdef QT3_SUPPORT

/*!

    Constructs a new top-level QLayout called \a name, with parent

    widget \a parent. \a parent may not be 0.

    The \a margin is the number of pixels between the edge of the

    widget and the managed children. The \a spacing sets the value of

    spacing(), which gives the spacing between the managed widgets. If

    \a spacing is -1 (the default), spacing is set to the value of \a

    margin.

    There can be only one top-level layout for a widget. It is

    returned by QWidget::layout()

    \sa QWidget::setLayout()

*/

QLayout::QLayout(QWidget *parent, int margin, int spacing, const char *name)

    : QObject(*new QLayoutPrivate,parent)

{

    Q_D(QLayout);

    setObjectName(QString::fromAscii(name));

    setMargin(margin);

    if (spacing < 0)

        d->insideSpacing = margin;

    else

        d->insideSpacing = spacing;

    if (parent) {

        if (parent->layout()) {

            qWarning("QLayout \"%s\" added to %s \"%s\", which already has a layout",

                     QObject::objectName().toLocal8Bit().data(), parent->metaObject()->className(),

                     parent->objectName().toLocal8Bit().data());

            parent->layout()->setParent(0);

        } else {

            d->topLevel = true;

            parent->d_func()->layout = this;

            QT_TRY {

                invalidate();

            } QT_CATCH(...) {

                parent->d_func()->layout = 0;

                QT_RETHROW;

            }

        }

    }

}

/*!

    Constructs a new child QLayout called \a name, and places it

    inside \a parentLayout by using the default placement defined by

    addItem().

    If \a spacing is -1, this QLayout inherits \a parentLayout's

    spacing(), otherwise the value of \a spacing is used.

*/

QLayout::QLayout(QLayout *parentLayout, int spacing, const char *name)

    : QObject(*new QLayoutPrivate,parentLayout)

{

    Q_D(QLayout);

    setObjectName(QString::fromAscii(name));

    d->insideSpacing = spacing;

    parentLayout->addItem(this);

}

/*!

    Constructs a new child QLayout called \a name. If \a spacing is

    -1, this QLayout inherits its parent's spacing(); otherwise the

    value of \a spacing is used.

    This layout has to be inserted into another layout before geometry

    management will work.

*/

QLayout::QLayout(int spacing, const char *name)

    : QObject(*new QLayoutPrivate, 0)

{

    Q_D(QLayout);

    setObjectName(QString::fromAscii(name));

    d->insideSpacing = spacing;

}

/*!

    Automatically adding widgets is deprecated. Use addWidget() or

    addLayout() instead.

*/

void QLayout::setAutoAdd(bool a) { Q_D(QLayout); d->autoNewChild = a; }

/*!

    Automatically adding widgets is deprecated. Use addWidget() or

    addLayout() instead.

*/

bool QLayout::autoAdd() const { Q_D(const QLayout); return d->autoNewChild; }

#endif

/*!

    \fn void QLayout::addItem(QLayoutItem *item)

    Implemented in subclasses to add an \a item. How it is added is

    specific to each subclass.

    This function is not usually called in application code. To add a widget

    to a layout, use the addWidget() function; to add a child layout, use the

    addLayout() function provided by the relevant QLayout subclass.

    \bold{Note:} The ownership of \a item is transferred to the layout, and it's

    the layout's responsibility to delete it.

    \sa addWidget(), QBoxLayout::addLayout(), QGridLayout::addLayout()

*/

/*!

    Adds widget \a w to this layout in a manner specific to the

    layout. This function uses addItem().

*/

void QLayout::addWidget(QWidget *w)

{

    addChildWidget(w);

    addItem(QLayoutPrivate::createWidgetItem(this, w));

}

/*!

    Sets the alignment for widget \a w to \a alignment and returns

    true if \a w is found in this layout (not including child

    layouts); otherwise returns false.

*/

bool QLayout::setAlignment(QWidget *w, Qt::Alignment alignment)

{

    int i = 0;

    QLayoutItem *item = itemAt(i);

    while (item) {

        if (item->widget() == w) {

            item->setAlignment(alignment);

            invalidate();

            return true;

        }

        ++i;

        item = itemAt(i);

    }

    return false;

}

/*!

  \overload

  Sets the alignment for the layout \a l to \a alignment and

  returns true if \a l is found in this layout (not including child

  layouts); otherwise returns false.

*/

bool QLayout::setAlignment(QLayout *l, Qt::Alignment alignment)

{

    int i = 0;

    QLayoutItem *item = itemAt(i);

    while (item) {

        if (item->layout() == l) {

            item->setAlignment(alignment);

            invalidate();

            return true;

        }

        ++i;

        item = itemAt(i);

    }

    return false;

}

/*!

    \fn void QLayout::setAlignment(Qt::Alignment alignment)

    Sets the alignment of this item to \a alignment.

    \sa QLayoutItem::setAlignment()

*/

/*!

    \fn bool QLayout::isTopLevel() const

    Returns true if this layout is a top-level layout, i.e. not a

    child of another layout; otherwise returns false.

*/

/*!

    \property QLayout::margin

    \brief the width of the outside border of the layout

    \obsolete

    Use setContentsMargins() and getContentsMargins() instead.

    \sa contentsRect(), spacing

*/

/*!

    \obsolete

*/

int QLayout::margin() const

{

    int left, top, right, bottom;

    getContentsMargins(&left, &top, &right, &bottom);

    if (left == top && top == right && right == bottom) {

        return left;

    } else {

        return -1;

    }

}

/*!

    \property QLayout::spacing

    \brief the spacing between widgets inside the layout

    If no value is explicitly set, the layout's spacing is inherited

    from the parent layout, or from the style settings for the parent

    widget.

    For QGridLayout and QFormLayout, it is possible to set different horizontal and

    vertical spacings using \l{QGridLayout::}{setHorizontalSpacing()}

    and \l{QGridLayout::}{setVerticalSpacing()}. In that case,

    spacing() returns -1.

    \sa contentsRect(), getContentsMargins(), QStyle::layoutSpacing(),

        QStyle::pixelMetric()

*/

int QLayout::spacing() const

{

    if (const QBoxLayout* boxlayout = qobject_cast<const QBoxLayout*>(this)) {

        return boxlayout->spacing();

    } else if (const QGridLayout* gridlayout = qobject_cast<const QGridLayout*>(this)) {

        return gridlayout->spacing();

    } else if (const QFormLayout* formlayout = qobject_cast<const QFormLayout*>(this)) {

        return formlayout->spacing();

    } else {

        Q_D(const QLayout);

        if (d->insideSpacing >=0) {

            return d->insideSpacing;

        } else {

            // arbitrarily prefer horizontal spacing to vertical spacing

            return qSmartSpacing(this, QStyle::PM_LayoutHorizontalSpacing);

        }

    }

}

/*!

    \obsolete

*/

void QLayout::setMargin(int margin)

{

    setContentsMargins(margin, margin, margin, margin);

}

void QLayout::setSpacing(int spacing)

{

    if (QBoxLayout* boxlayout = qobject_cast<QBoxLayout*>(this)) {

        boxlayout->setSpacing(spacing);

    } else if (QGridLayout* gridlayout = qobject_cast<QGridLayout*>(this)) {

        gridlayout->setSpacing(spacing);

    } else if (QFormLayout* formlayout = qobject_cast<QFormLayout*>(this)) {

        formlayout->setSpacing(spacing);

    } else {

        Q_D(QLayout);

        d->insideSpacing = spacing;

        invalidate();

    }

}

/*!

    \since 4.3

    Sets the \a left, \a top, \a right, and \a bottom margins to use

    around the layout.

    By default, QLayout uses the values provided by the style. On

    most platforms, the margin is 11 pixels in all directions.

    \sa getContentsMargins(), QStyle::pixelMetric(),

        {QStyle::}{PM_LayoutLeftMargin},

        {QStyle::}{PM_LayoutTopMargin},

        {QStyle::}{PM_LayoutRightMargin},

        {QStyle::}{PM_LayoutBottomMargin}

*/

void QLayout::setContentsMargins(int left, int top, int right, int bottom)

{

    Q_D(QLayout);

    if (d->userLeftMargin == left && d->userTopMargin == top &&

        d->userRightMargin == right && d->userBottomMargin == bottom)

        return;

    d->userLeftMargin = left;

    d->userTopMargin = top;

    d->userRightMargin = right;

    d->userBottomMargin = bottom;

    invalidate();

}

/*!

    \since 4.3

    Extracts the left, top, right, and bottom margins used around the

    layout, and assigns them to *\a left, *\a top, *\a right, and *\a

    bottom (unless they are null pointers).

    By default, QLayout uses the values provided by the style. On

    most platforms, the margin is 11 pixels in all directions.

    \sa setContentsMargins(), QStyle::pixelMetric(),

        {QStyle::}{PM_LayoutLeftMargin},

        {QStyle::}{PM_LayoutTopMargin},

        {QStyle::}{PM_LayoutRightMargin},

        {QStyle::}{PM_LayoutBottomMargin}