/* This file is part of the KDE project
 * Copyright (C) 2008 Jan Hambrecht <jaham@gmx.net>
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Library General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Library General Public License for more details.
 *
 * You should have received a copy of the GNU Library General Public License
 * along with this library; see the file COPYING.LIB.  If not, write to
 * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
 * Boston, MA 02110-1301, USA.
 */

#include "BarnDoorWipeStrategy.h"
#include "BarnDoorWipeEffectFactory.h"
#include <QtGui/QWidget>
#include <QtGui/QPainter>

const int StepCount = 250;

BarnDoorWipeStrategy::BarnDoorWipeStrategy( int subtype, const char *smilSubType, bool reverse )
    : KPrPageEffectStrategy( subtype, "barnDoorWipe", smilSubType, reverse )
{
}

BarnDoorWipeStrategy::~BarnDoorWipeStrategy()
{
}

void BarnDoorWipeStrategy::setup( const KPrPageEffect::Data &data, QTimeLine &timeLine )
{
    Q_UNUSED( data );
    timeLine.setFrameRange( 0, StepCount );
}

void BarnDoorWipeStrategy::paintStep( QPainter &p, int currPos, const KPrPageEffect::Data &data )
{
    p.drawPixmap( QPoint( 0, 0 ), data.m_oldPage, data.m_widget->rect() );
    p.setClipPath( clipPath( currPos, data.m_widget->rect() ) );
    p.drawPixmap( QPoint( 0, 0 ), data.m_newPage, data.m_widget->rect() );
}

void BarnDoorWipeStrategy::next( const KPrPageEffect::Data &data )
{
    data.m_widget->update();
}

QPainterPath BarnDoorWipeStrategy::clipPath( int step, const QRect &area )
{
    qreal percent = static_cast<qreal>(step) / static_cast<qreal>(StepCount);
    if( reverse() )
        percent = static_cast<qreal>(StepCount-step) / static_cast<qreal>(StepCount);

    int stepx = static_cast<int>( area.width() * percent );
    int stepy = static_cast<int>( area.height() * percent );

    int width_2 = area.width() >> 1;
    int height_2 = area.height() >> 1;

    QPainterPath path;

    switch( subType() )
    {
        case BarnDoorWipeEffectFactory::Vertical:
        case BarnDoorWipeEffectFactory::VerticalReverse:
        {
            stepx = static_cast<int>( width_2 * percent );
            QPoint top( width_2, 0 );
            QPoint bottom( width_2, area.height() );
            path.moveTo( top - QPoint( stepx, 0 ) );
            path.lineTo( top + QPoint( stepx, 0 ) );
            path.lineTo( bottom + QPoint( stepx, 0 ) );
            path.lineTo( bottom - QPoint( stepx, 0 ) );
            break;
        }
        case BarnDoorWipeEffectFactory::Horizontal:
        case BarnDoorWipeEffectFactory::HorizontalReverse:
        {
            stepy = static_cast<int>( height_2 * percent );
            QPoint left( 0, height_2 );
            QPoint right( area.width(), height_2 );
            path.moveTo( left + QPoint( 0, stepy ) );
            path.lineTo( left - QPoint( 0, stepy ) );
            path.lineTo( right - QPoint( 0, stepy ) );
            path.lineTo( right + QPoint( 0, stepy ) );
            break;
        }
        case BarnDoorWipeEffectFactory::DiagonalBottomLeft:
        case BarnDoorWipeEffectFactory::DiagonalBottomLeftReverse:
        {
            path.moveTo( area.bottomLeft() + QPoint( stepx, 0 ) );
            path.lineTo( area.bottomLeft() );
            path.lineTo( area.bottomLeft() - QPoint( 0, stepy ) );
            path.lineTo( area.topRight() - QPoint( stepx, 0 ) );
            path.lineTo( area.topRight() );
            path.lineTo( area.topRight() + QPoint( 0, stepy ) );
            break;
        }
        case BarnDoorWipeEffectFactory::DiagonalTopLeft:
        case BarnDoorWipeEffectFactory::DiagonalTopLeftReverse:
        {
            path.moveTo( area.topLeft() + QPoint( 0, stepy ) );
            path.lineTo( area.topLeft() );
            path.lineTo( area.topLeft() + QPoint( stepx, 0 ) );
            path.lineTo( area.bottomRight() - QPoint( 0, stepy ) );
            path.lineTo( area.bottomRight() );
            path.lineTo( area.bottomRight() - QPoint( stepx, 0 ) );
            break;
        }
        default:
            return QPainterPath();
    }

    path.closeSubpath();

    if( reverse() )
    {
        QPainterPath areaPath;
        areaPath.addRect( area );
        path = areaPath.subtracted( path );
    }

    return path;
}
