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

**

** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies).

** Contact: Nokia Corporation (qt-info@nokia.com)

**

** This file is part of the examples 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 either Technology Preview License Agreement or the

** Beta Release License Agreement.

**

** 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 1.0, included in the file LGPL_EXCEPTION.txt in this

** package.

**

** GNU General Public License Usage

** Alternatively, this file may be used under the terms of the GNU

** General Public License version 3.0 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 the GNU General Public License version 3.0 requirements will be

** met: http://www.gnu.org/copyleft/gpl.html.

**

** If you are unsure which license is appropriate for your use, please

** contact the sales department at http://qt.nokia.com/contact.

** $QT_END_LICENSE$

**

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

#include <QGraphicsSceneResizeEvent>

#include <QGraphicsWidget>

#include <QDebug>

#include "abstractscrollarea.h"

#include "scrollbar.h"

AbstractScrollArea::AbstractScrollArea(QGraphicsWidget *parent)

    : GvbWidget(parent)

    , m_viewport(0)

    , m_horizontalScrollBar(0)

    , m_verticalScrollBar(0)

    , m_prevHorizontalValue(0.0)

    , m_prevVerticalValue(0.0)

{

    setSizePolicy(QSizePolicy::Expanding, QSizePolicy::Expanding);

    setContentsMargins(0, 0, 0, 0);     

    m_horizontalScrollBar = new ScrollBar(Qt::Horizontal, this);

    m_horizontalScrollBar->hide();

    m_horizontalScrollBar->setContentsMargins(0, 0, 0, 0); 

    m_horizontalScrollBarPolicy = Qt::ScrollBarAsNeeded;

    m_horizontalScrollBar->setZValue(zValue()+1); // Raise scroll bar to top

    m_horizontalScrollBar->setVisible(false);

    connect(m_horizontalScrollBar, SIGNAL(sliderPositionChange(qreal)),

            this, SLOT(horizontalScroll(qreal)));

    connect(m_horizontalScrollBar, SIGNAL(sliderPressed()),

            this, SLOT(horizontalScrollStart()));

    m_verticalScrollBar = new ScrollBar(Qt::Vertical, this);

    m_verticalScrollBar->hide();

    m_verticalScrollBar->setContentsMargins(0, 0, 0, 0); 

    m_verticalScrollBarPolicy = Qt::ScrollBarAsNeeded;

    m_verticalScrollBar->setZValue(zValue()+1); // Raise scroll bar to top

    m_verticalScrollBar->setVisible(false);

    connect(m_verticalScrollBar, SIGNAL(sliderPositionChange(qreal)),

            this, SLOT(verticalScroll(qreal)));

    connect(m_verticalScrollBar, SIGNAL(sliderPressed()),

            this, SLOT(verticalScrollStart()));

    QGraphicsWidget *viewport = new QGraphicsWidget;

    setViewport(viewport);

}

AbstractScrollArea::~AbstractScrollArea()

{

}

ScrollBar *AbstractScrollArea::verticalScrollBar() const

{

    return m_verticalScrollBar;

}

ScrollBar *AbstractScrollArea::horizontalScrollBar() const

{

    return m_horizontalScrollBar;

}

void AbstractScrollArea::setHorizontalScrollBarPolicy(Qt::ScrollBarPolicy policy)

{

    m_horizontalScrollBarPolicy = policy;

}

void AbstractScrollArea::setVerticalScrollBarPolicy(Qt::ScrollBarPolicy policy)

{

    m_verticalScrollBarPolicy = policy;

}

Qt::ScrollBarPolicy AbstractScrollArea::verticalScrollBarPolicy() const

{

    return m_verticalScrollBarPolicy;

}

Qt::ScrollBarPolicy AbstractScrollArea::horizontalScrollBarPolicy() const

{

    return m_horizontalScrollBarPolicy;

}

QGraphicsWidget *AbstractScrollArea::viewport() const

{

    return m_viewport;

}

void AbstractScrollArea::setViewport(QGraphicsWidget *viewport)

{

    if (m_viewport) {

        m_viewport->setParentItem(0);

        QList<QGraphicsItem*> children = m_viewport->childItems();

        foreach (QGraphicsItem *child, children)

            child->setParentItem(0);

        delete m_viewport;

    }

    m_viewport = viewport;

    if (viewport) {

        m_viewport->setParentItem(this);

        m_viewport->setContentsMargins(0, 0, 0, 0);

        adjustScrollBars();

    }

    emit viewportChanged(viewport);

}

bool AbstractScrollArea::event(QEvent *e)

{

    if (e->type() == QEvent::ApplicationLayoutDirectionChange

       || e->type() == QEvent::LayoutDirectionChange) {

    } else if (e->type() == QEvent::GraphicsSceneResize) {        

        QGraphicsSceneResizeEvent *event = 

            static_cast<QGraphicsSceneResizeEvent*>(e);

        QSizeF newSize = event->newSize();

        QRectF hrect = m_horizontalScrollBar->boundingRect();

        QRectF vrect = m_verticalScrollBar->boundingRect();

        QSizeF vpSize = newSize;

        if (m_horizontalScrollBarPolicy != Qt::ScrollBarAlwaysOff)

            vpSize.setHeight(newSize.height() - hrect.height());

        if (m_verticalScrollBarPolicy != Qt::ScrollBarAlwaysOff)

            vpSize.setWidth(newSize.width() - vrect.width());

        m_viewport->resize(vpSize);

        adjustScrollBars();

    }

    return QGraphicsWidget::event(e);

}

void AbstractScrollArea::scrollContentsBy(qreal dx, qreal dy)

{

    Q_UNUSED(dx)

    Q_UNUSED(dy)

    prepareGeometryChange();

}

void AbstractScrollArea::verticalScrollStart()

{

    m_prevVerticalValue = m_verticalScrollBar->sliderPosition(); 

}

void AbstractScrollArea::verticalScroll(qreal value)

{

    qreal dy = value - m_prevVerticalValue;

    if (!qFuzzyCompare(dy,qreal(0.0))) {

        scrollContentsBy(0.0, dy);

        m_prevVerticalValue = value;

    }

}

void AbstractScrollArea::horizontalScrollStart()

{

    m_prevHorizontalValue = m_horizontalScrollBar->sliderPosition(); 

}

void AbstractScrollArea::horizontalScroll(qreal value)

{

    qreal dx = value - m_prevHorizontalValue;

    if (!qFuzzyCompare(dx,qreal(0.0))) {

        scrollContentsBy(dx, 0.0);

        m_prevHorizontalValue = value;

    }

}

void AbstractScrollArea::adjustScrollBars()

{

    if (m_horizontalScrollBarPolicy == Qt::ScrollBarAlwaysOff) {

        m_horizontalScrollBar->hide();

    } else {

        m_horizontalScrollBar->show();

        QRectF sbgeom = boundingRect();

        sbgeom.setTop(sbgeom.bottom() - m_horizontalScrollBar->boundingRect().height());

        sbgeom.setRight(sbgeom.right() - m_verticalScrollBar->boundingRect().width());

        m_horizontalScrollBar->setGeometry(sbgeom);

    }

    if (m_verticalScrollBarPolicy == Qt::ScrollBarAlwaysOff) {

        m_verticalScrollBar->hide();

        QRectF sbgeom = boundingRect();

        sbgeom.setLeft(sbgeom.right());

        sbgeom.setBottom(sbgeom.bottom());

        m_verticalScrollBar->setGeometry(sbgeom);

    } else {

        m_verticalScrollBar->show();

        QRectF sbgeom = boundingRect();

        sbgeom.setLeft(sbgeom.right() - m_verticalScrollBar->boundingRect().width());

        if (m_horizontalScrollBarPolicy != Qt::ScrollBarAlwaysOff)

            sbgeom.setBottom(sbgeom.bottom() - m_horizontalScrollBar->boundingRect().height());

        m_verticalScrollBar->setGeometry(sbgeom);

    }

}