/*

* Copyright (c) 2006-2007 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:   Implementation of CHuiMatrixStack. CHuiMatrixStack is a stack 

*                of 2D transformation matrices.

*

*/

#include "HuiMatrixStack.h"

#include "uiacceltk/HuiPanic.h"

EXPORT_C CHuiMatrixStack::TMatrix::TMatrix()

        : iIsIdentity(ETrue)

    {

    // First column.

    iMatrix[0] = 1;

    iMatrix[1] = 0;

    iMatrix[2] = 0;

    // Second column.

    iMatrix[3] = 0;

    iMatrix[4] = 1;

    iMatrix[5] = 0;

    // Third column.

    iMatrix[6] = 0;

    iMatrix[7] = 0;

    iMatrix[8] = 1;

    }

#define HUI_MATRIX_INDEX(aRow, aColumn) (aColumn*3 + aRow)

void CHuiMatrixStack::TMatrix::Multiply(const TMatrix& aOther)

    {

    TMatrix result;

    // Clear the result.

    Mem::FillZ(result.iMatrix, sizeof(result.iMatrix));

    // It could still be an identity matrix, but probably not.

    result.iIsIdentity = EFalse;

    for(TInt i = 0; i < 3; ++i) // Row.

        {

        for(TInt j = 0; j < 3; ++j) // Column.

            {

            for(TInt k = 0; k < 3; ++k)

                {

                result.iMatrix[ HUI_MATRIX_INDEX(i, j) ] +=

                    iMatrix[ HUI_MATRIX_INDEX(i, k) ] * aOther.iMatrix[ HUI_MATRIX_INDEX(k, j) ];

                }

            }

        }

    *this = result;

    }

EXPORT_C void CHuiMatrixStack::TMatrix::Multiply(THuiRealPoint& aPoint) const

    {

    if(iIsIdentity)

        {

        // No need to do anything.

        return;

        }

    TReal32 wPoint[3] =

        {

        aPoint.iX,

        aPoint.iY,

        1.0f

        };

    TReal32 result[3] =

        {

        0, 0, 0

        };

    for(TInt i = 0; i < 3; ++i)

        {

        for(TInt j = 0; j < 3; ++j)

            {

            result[i] += wPoint[j] * iMatrix[ HUI_MATRIX_INDEX(i, j) ];

            }

        }

    if(result[2] != 0)

        {

        // Normalize.

        result[0] /= result[2];

        result[1] /= result[2];

        }

    else

        {

        // Completely zero.

        result[0] = 0;

        result[1] = 0;

        }

    aPoint.iX = result[0];

    aPoint.iY = result[1];

    }

EXPORT_C CHuiMatrixStack* CHuiMatrixStack::NewL()

    {

    CHuiMatrixStack* self = CHuiMatrixStack::NewLC();

    CleanupStack::Pop(self);

    return self;

    }

CHuiMatrixStack* CHuiMatrixStack::NewLC()

    {

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

    CleanupStack::PushL(self);

    self->ConstructL();

    return self;

    }

CHuiMatrixStack::~CHuiMatrixStack()

    {

    iStack.Close();    

    }

CHuiMatrixStack::CHuiMatrixStack()

    {

    }

void CHuiMatrixStack::ConstructL()

    {

    // Append one identity matrix as the default contents of the stack.

    User::LeaveIfError( iStack.Append(TMatrix()) );

    }

EXPORT_C TInt CHuiMatrixStack::Count() const

    {

    return iStack.Count();

    }

EXPORT_C CHuiMatrixStack::TMatrix& CHuiMatrixStack::Current()

    {

    // There is always at least one matrix in the stack.

    return iStack[iStack.Count() - 1];

    }

EXPORT_C TInt CHuiMatrixStack::Push()

    {

    // Make a copy of the topmost item.

    return iStack.Append(Current());

    }

EXPORT_C void CHuiMatrixStack::Pop()

    {

    if(iStack.Count() <= 1)

        {

        // Invalid operation.

        THuiPanic::Panic(THuiPanic::EMatrixStackPopFromEmpty);

        }

    iStack.Remove(iStack.Count() - 1);

    }

EXPORT_C void CHuiMatrixStack::LoadIdentity()

    {

    Current() = TMatrix();

    }    

EXPORT_C void CHuiMatrixStack::Multiply(const TMatrix& aMatrix)

    {

    Current().Multiply(aMatrix);

    }