/****************************************************************************
**
** Copyright (C) 2012 Digia Plc and/or its subsidiary(-ies).
** Contact: http://www.qt-project.org/legal
**
** This file is part of the examples of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:LGPL$
** Commercial License Usage
** Licensees holding valid commercial Qt licenses may use this file in
** accordance with the commercial license agreement provided with the
** Software or, alternatively, in accordance with the terms contained in
** a written agreement between you and Digia.  For licensing terms and
** conditions see http://qt.digia.com/licensing.  For further information
** use the contact form at http://qt.digia.com/contact-us.
**
** 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, Digia gives you certain additional
** rights.  These rights are described in the Digia Qt LGPL Exception
** version 1.1, 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.
**
**
** $QT_END_LICENSE$
**
****************************************************************************/

#include <QGraphicsItem>
#include <QPainter>
#include <QDebug>
#include "listitemcache.h"

ListItemCache::ListItemCache()
{
}

ListItemCache::~ListItemCache()
{
    QPixmapCache::remove(m_cacheKey);
}

void ListItemCache::draw(QPainter * painter) 
{
    QRectF irect = sourceBoundingRect(Qt::LogicalCoordinates);
    QRectF vrect = painter->clipPath().boundingRect();

    if (vrect.intersects(irect)) {
        QRectF newVisibleRect = irect.intersected(vrect);
        QPixmap pixmap;

        if (!QPixmapCache::find(m_cacheKey, &pixmap) ||
            m_visibleRect.toRect() != newVisibleRect.toRect()) {
            //qDebug() << "ListItemCache: caching" << m_visibleRect
            //    << "->" << newVisibleRect;

            pixmap = QPixmap(sourceBoundingRect().toRect().size());
            pixmap.fill(Qt::transparent);

            QPainter pixmapPainter(&pixmap);
            drawSource(&pixmapPainter);
            pixmapPainter.end();
            m_cacheKey = QPixmapCache::insert(pixmap);

            m_visibleRect = newVisibleRect;
        }

        //qDebug() << "ListItemCache: blitting" << m_visibleRect;
        painter->drawPixmap(0, 0, pixmap);
    } 
}

void ListItemCache::sourceChanged(ChangeFlags)
{
    QPixmapCache::remove(m_cacheKey);
}