/*

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

* All rights reserved.

* This component and the accompanying materials are made available

* under the terms of "Eclipse Public License v1.0"

* which accompanies this distribution, and is available

* at the URL "http://www.eclipse.org/legal/epl-v10.html".

*

* Initial Contributors:

* Nokia Corporation - initial contribution.

*

* Contributors:

*

* Description:   

*

*/

#include "HuiFxVg10BrightnessContrastFilter.h"

#include "HuiFxConstants.h"

CHuiFxVg10BrightnessContrastFilter* CHuiFxVg10BrightnessContrastFilter::NewL()

    {

    CHuiFxVg10BrightnessContrastFilter* e = new (ELeave) CHuiFxVg10BrightnessContrastFilter();

    CleanupStack::PushL(e);

    e->ConstructL();

    CleanupStack::Pop(e);

    return e;

    }

void CHuiFxVg10BrightnessContrastFilter::ConstructL()

    {

    CHuiFxVg10ColorMatrixFilterBase::ConstructL();

    // neutral settings

    iBrightness = 0.0f;

    iContrast = 1.0f;

    RegisterParameterL(KLitBrightness, &iBrightness);

    RegisterParameterL(KLitContrast, &iContrast);

    }

CHuiFxVg10BrightnessContrastFilter *CHuiFxVg10BrightnessContrastFilter::CloneL() const

    {

    CHuiFxVg10BrightnessContrastFilter *filter = new(ELeave) CHuiFxVg10BrightnessContrastFilter;

    filter->CHuiFxVg10ColorMatrixFilterBase::CopyFromL(this);

    filter->iBrightness = iBrightness;

    filter->iContrast = iContrast;

    filter->CopyParameterL(KLitBrightness, &filter->iBrightness, this);

    filter->CopyParameterL(KLitContrast, &filter->iContrast, this);    

    return filter;

    }

void CHuiFxVg10BrightnessContrastFilter::UpdateColorMatrix(void)

    {

    // brightness [-1, 1]

    const VGfloat offset_br = clamp(iBrightness, -1.0f, 1.0f);

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

    // contrast [0, N]

    const VGfloat scale_con = clamp(iContrast, 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 opacity = clamp(iOpacity, 0.0f, 1.0f);

    const VGfloat oOff = off * opacity;

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

    iColorMatrix[0] = oSc;

    iColorMatrix[1] = 0.0f;

    iColorMatrix[2] = 0.0f;

    iColorMatrix[3] = 0.0f;

    iColorMatrix[4] = 0.0f;

    iColorMatrix[5] = oSc;

    iColorMatrix[6] = 0.0f;

    iColorMatrix[7] = 0.0f;

    iColorMatrix[8] = 0.0f;

    iColorMatrix[9] = 0.0f;

    iColorMatrix[10] = oSc;

    iColorMatrix[11] = 0.0f;

    iColorMatrix[12] = 0.0f;

    iColorMatrix[13] = 0.0f;

    iColorMatrix[14] = 0.0f;

    iColorMatrix[15] = 1.0f;

    iColorMatrix[16] = oOff;

    iColorMatrix[17] = oOff;

    iColorMatrix[18] = oOff;

    iColorMatrix[19] = 0.0f;

    }