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

**

** Copyright (C) 2008-2010 Nokia Corporation and/or its subsidiary(-ies).

** All rights reserved.

** Contact: Nokia Corporation (developer.feedback@nokia.com)

**

** This file is part of the HbCore module of the UI Extensions for Mobile.

**

** GNU Lesser General Public License Usage

** 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 developer.feedback@nokia.com.

**

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

#include "hbvgbceffect_p.h"

#include "hbvgbceffect_p_p.h"

#include <QPainter>

/*!

 * \class HbVgBcEffect

 *

 * \brief OpenVG-based brightness-contrast filter effect.

 *

 * \internal

 */

HbVgBcEffectPrivate::HbVgBcEffectPrivate()

    : brightness(0), contrast(1)

{

}

HbVgBcEffect::HbVgBcEffect(QObject *parent)

    : HbVgEffect(*new HbVgBcEffectPrivate, parent)

{

}

HbVgBcEffect::HbVgBcEffect(HbVgBcEffectPrivate &dd, QObject *parent)

    : HbVgEffect(dd, parent)

{

}

HbVgBcEffect::~HbVgBcEffect()

{

}

qreal HbVgBcEffect::brightness() const

{

    Q_D(const HbVgBcEffect);

    return d->brightness;

}

void HbVgBcEffect::setBrightness(qreal brightness)

{

    Q_D(HbVgBcEffect);

    if (d->brightness == brightness) {

        return;

    }

    d->brightness = brightness;

    updateEffect();

    emit brightnessChanged(brightness);

}

qreal HbVgBcEffect::contrast() const

{

    Q_D(const HbVgBcEffect);

    return d->contrast;

}

void HbVgBcEffect::setContrast(qreal contrast)

{

    Q_D(HbVgBcEffect);

    if (d->contrast == contrast) {

        return;

    }

    d->contrast = contrast;

    updateEffect();

    emit contrastChanged(contrast);

}

QRectF HbVgBcEffect::boundingRectFor(const QRectF &rect) const

{

    return rect;

}

void HbVgBcEffect::performEffect(QPainter *painter,

                                 const QPointF &offset,

                                 const QVariant &vgImage,

                                 const QSize &vgImageSize)

{

#ifdef HB_EFFECTS_OPENVG

    QPixmap cachedPm = cached(vgImageSize);

    if (!cachedPm.isNull()) {

        painter->drawPixmap(offset, cachedPm);

        return;

    }

    Q_D(HbVgBcEffect);

    VGImage srcImage = vgImage.value<VGImage>();

    VGImage dstImage = d->ensurePixmap(&d->dstPixmap, vgImageSize);

    qreal opacity = clamp(d->opacity, 0.0f, 1.0f);

    if (opacity > HBVG_EPSILON) {

        if (d->paramsChanged) {

            // brightness [-1, 1]

            const VGfloat offset_br = clamp(d->brightness, -1.0f, 1.0f);

            const VGfloat scale_br = 1.0f - 0.5f * ((offset_br < 0.0f) ? -offset_br : offset_br);

            // contrast [0, N]

            const VGfloat scale_con = clamp(d->contrast, 0.0f, 100.0f);

            const VGfloat offset_con = -0.5f * scale_con + 0.5f ;

            // combine the effects of brightness and contrast

            const VGfloat off = offset_br + offset_con;

            const VGfloat sc  = scale_br * scale_con;

            // take opacity into account

            const VGfloat o = (VGfloat) opacity;

            const VGfloat oOff = off * o;

            const VGfloat oSc  = (sc * o) + (1.0f - o);

            d->colorMatrix[0] = oSc;

            d->colorMatrix[1] = 0.0f;

            d->colorMatrix[2] = 0.0f;

            d->colorMatrix[3] = 0.0f;

            d->colorMatrix[4] = 0.0f;

            d->colorMatrix[5] = oSc;

            d->colorMatrix[6] = 0.0f;

            d->colorMatrix[7] = 0.0f;

            d->colorMatrix[8] = 0.0f;

            d->colorMatrix[9] = 0.0f;

            d->colorMatrix[10] = oSc;

            d->colorMatrix[11] = 0.0f;

            d->colorMatrix[12] = 0.0f;

            d->colorMatrix[13] = 0.0f;

            d->colorMatrix[14] = 0.0f;

            d->colorMatrix[15] = 1.0f;

            d->colorMatrix[16] = oOff;

            d->colorMatrix[17] = oOff;

            d->colorMatrix[18] = oOff;

            d->colorMatrix[19] = 0.0f;

        }

        vgColorMatrix(dstImage, srcImage, d->colorMatrix);

        painter->drawPixmap(offset, d->dstPixmap);

        tryCache(d->dstPixmap);

    } else {

        painter->drawPixmap(offset, d->srcPixmap);

    }

#else

    Q_UNUSED(painter);

    Q_UNUSED(offset);

    Q_UNUSED(vgImage);

    Q_UNUSED(vgImageSize);

#endif

}