/*

* Copyright (c) 2004-2008 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:  PolySpline.

*

*/

#include "AknsAlPolyLine1D.h"

// -----------------------------------------------------------------------------

// C++ constructor.

// -----------------------------------------------------------------------------

//

CAknsAlPolyLine1D::CAknsAlPolyLine1D()

    {

    }

// -----------------------------------------------------------------------------

// Destructor.

// -----------------------------------------------------------------------------

//

CAknsAlPolyLine1D::~CAknsAlPolyLine1D()

    {

    }

// -----------------------------------------------------------------------------

// Symbian 1st phase constructor.

// -----------------------------------------------------------------------------

//

CAknsAlPolyLine1D* CAknsAlPolyLine1D::NewL()

    { // static

    CAknsAlPolyLine1D* self=new(ELeave) CAknsAlPolyLine1D();

    return self;

    }

// -----------------------------------------------------------------------------

// Gets poly point.

// -----------------------------------------------------------------------------

//

TPoint CAknsAlPolyLine1D::GetPolyPoint( const TUint32 aPosition )

    {

    // linepoints have x-coordinates between 0...16bit,

    // so we only need to use upper 16 bits from aPosition

    TInt pos = aPosition >> 16;

    // find the line, where pos is pointing

    TInt i = 0; // first index

    TInt j = iPointCount-1; // last index

    TInt k;

    while ( i < j )

        {

        k = (i + j)/2;

        if ( pos < iPoints[k].iX )

            {

            j = k;

            }

        else

            {

            i = k + 1;

            }

        }

    // i = j = wanted line's end point index

    TUint32 deltaX = iPoints[i].iX - iPoints[i-1].iX; // always positive, 16 bits

    TUint32 deltaY; // might be negative, so use flag to get correct results

    TBool negativeY = EFalse;

    if ((iPoints[i].iY - iPoints[i-1].iY) < 0)

        {

        deltaY = iPoints[i-1].iY - iPoints[i].iY;

        negativeY = ETrue;

        }

    else

        {

        deltaY = iPoints[i].iY - iPoints[i-1].iY;

        }

    pos -= iPoints[i-1].iX;

    if (pos == 0) // we are in line's first pixel

        {

        return TPoint((iPoints[i-1].iX * iAreaSize.iWidth) >> 16,

                  (iPoints[i-1].iY * iAreaSize.iHeight) >> 16);

        }

    TUint32 calculatedY = (deltaY * pos) / deltaX; // first get delta from start point

    if (negativeY)

        {

        calculatedY = iPoints[i-1].iY - calculatedY; // line going downwards

        }

    else

        {

        calculatedY = iPoints[i-1].iY + calculatedY; // line going upwards

        }

    return CalculateScaledPoint(TPoint(aPosition >> 16,calculatedY));

    }

// End of file