qlayout.cpp

qt-x11-opensource-src-4.1.4.tar.gz源码

/****************************************************************************
**
** Copyright (C) 1992-2006 Trolltech ASA. All rights reserved.
**
** This file is part of the QtGui module of the Qt Toolkit.
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** License version 2.0 as published by the Free Software Foundation
** and appearing in the file LICENSE.GPL included in the packaging of
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#include "qlayout.h"

#include "qapplication.h"
#include "qlayoutengine_p.h"
#include "qmenubar.h"
#include "qtoolbar.h"
#include "qevent.h"
#include "qstyle.h"
#include "qvariant.h"
#include "qwidget_p.h"
#include "qlayout_p.h"

static int menuBarHeightForWidth(QWidget *menubar, int w)
{
    if (menubar && !menubar->isHidden() && !menubar->isWindow())
        return menubar->heightForWidth(qMax(w, menubar->minimumWidth()));
    return 0;
}

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

    \ingroup appearance
    \ingroup geomanagement

    This is an abstract base class inherited by the concrete classes
    QBoxLayout, QGridLayout, 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 Classes}
    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 Classes}
*/


/*!
    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("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;
            invalidate();
        }
    }
}

QLayoutPrivate::QLayoutPrivate()
    : QObjectPrivate(), insideSpacing(-1), outsideBorder(-1), topLevel(false), enabled(true),
      activated(true), autoNewChild(false), constraint(QLayout::SetDefaultConstraint)
      , menubar(0)
{
}




#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));
    d->outsideBorder = 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;
            invalidate();
        }
    }
}

/*!
    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.

    The ownership of \a item is transferred to the layout, and it's
    the layout's responsibility to delete it.
*/

/*!
    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(new QWidgetItem(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 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

    The margin default is provided by the style. The default margin
    most Qt styles specify is 9 for child widgets and 11 for windows.

    \sa spacing
*/

/*!
    \property QLayout::spacing
    \brief the spacing between widgets inside the layout

    The default value is -1, which signifies that the layout's
    spacing is inherited from the parent layout, or from the style
    settings for the parent widget.

    \sa margin
*/

int QLayout::margin() const
{
    Q_D(const QLayout);
    if ( d->outsideBorder >= 0 )
        return d->outsideBorder;
    if (!d->topLevel)
        return 0;
    QWidget *pw = parentWidget();
    if (pw)
        return pw->style()->pixelMetric(
            (pw->isWindow() || (pw->windowType() == Qt::SubWindow))
            ? QStyle::PM_DefaultTopLevelMargin
            : QStyle::PM_DefaultChildMargin
            );
    return 0;
}


int QLayout::spacing() const
{
    Q_D(const QLayout);
    if (d->insideSpacing >=0) {
        return d->insideSpacing;
    } else if (d->topLevel) {
        QWidget *pw = parentWidget();
        if (pw)
            return pw->style()->pixelMetric(QStyle::PM_DefaultLayoutSpacing);
        else
            return QApplication::style()->pixelMetric(QStyle::PM_DefaultLayoutSpacing);
    } else if (parent()) {
        return static_cast<QLayout*>(parent())->spacing();
    } else {
        return -1; //this is a layout that hasn't been inserted yet
    }
}

#ifdef QT3_SUPPORT
bool QLayout::isTopLevel() const
{
    Q_D(const QLayout);
    return d->topLevel;
}
#endif

void QLayout::setMargin(int margin)
{
    Q_D(QLayout);
    d->outsideBorder = margin;
    invalidate();
}


void QLayout::setSpacing(int spacing)
{
    Q_D(QLayout);
    d->insideSpacing = spacing;
    invalidate();
}

/*!
    Returns the parent widget of this layout, or 0 if this layout is
    not installed on any widget.

    If the layout is a sub-layout, this function returns the parent
    widget of the parent layout.

    \sa parent()
*/
QWidget *QLayout::parentWidget() const
{
    Q_D(const QLayout);
    if (!d->topLevel) {
        if (parent()) {
            QLayout *parentLayout = ::qobject_cast<QLayout*>(parent());
            Q_ASSERT(parentLayout);
            return parentLayout->parentWidget();
        } else {
            return 0;
        }
    } else {
        Q_ASSERT(parent() && parent()->isWidgetType());
        return static_cast<QWidget *>(parent());
    }
}

/*!
    \reimp
*/
bool QLayout::isEmpty() const
{
    int i = 0;
    QLayoutItem *item = itemAt(i);
    while (item) {
        if (!item->isEmpty())
            return false;
        ++i;
        item = itemAt(i);
    }
    return true;
}

/*!
    \reimp
*/
void QLayout::setGeometry(const QRect &r)
{
    Q_D(QLayout);
    d->rect = r;
}

/*!
    \reimp
*/
QRect QLayout::geometry() const
{
    Q_D(const QLayout);
    return d->rect;
}

/*!
    \reimp
*/
void QLayout::invalidate()
{
    Q_D(QLayout);
    d->rect = QRect();
    update();
}

static bool removeWidgetRecursively(QLayoutItem *li, QWidget *w)
{
    QLayout *lay = li->layout();
    if (!lay)