/*

* Copyright (c) 2006 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:   

*	CDCIETD 

*		Display specific color contrast enhancement, 

*		Image Enhancement for Transflective Displays version 2,

*		IETD 2.

*

*/

//  Include Files  

#include <e32std.h>	// The basic definitions

#include <fbs.h>	// For FBS bitmap

#include "DCIetd.h"	// The DCIetd class

//  MEMBER FUNCTIONS

//=============================================================================

/*

-----------------------------------------------------------------------------

  CDCIetd

  Constructor

  Default constructor, initializes member variables to initial values

  Return Values:  none

-----------------------------------------------------------------------------

*/

CDCIetd::CDCIetd()

{

	// Set default values for parameters (from init file)

	iParameters.aWhitePixels = WhitePixels;

	iParameters.aBlackPixels = BlackPixels;

	iParameters.aStretchLimit = StretchLimit;

	iParameters.aSaturationGain = SaturationGain;

	iParameters.aBitLimit = BitLimit;

	iParameters.aWBC = WBC;

	iParameters.aDBC = DBC;

}

/*

-----------------------------------------------------------------------------

  CDCIetd

  NewLC

  Factory function to instantiate the class.

  This function leaves the class pointer to the cleanup stack

  May leave with KErrNoMemory if no memory available

  Return Values:  CDCIetd* self:  pointer to the class instance

-----------------------------------------------------------------------------

*/

CDCIetd* CDCIetd::NewLC()

{

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

    CleanupStack::PushL(self);

    self->ConstructL();

    return self;

}

/*

-----------------------------------------------------------------------------

  CDCIetd

  NewL

  Factory function to instantiate the class.

  May leave with KErrNoMemory if no memory available

  Return Values:  CDCIetd* self:  pointer to the class instance

-----------------------------------------------------------------------------

*/

CDCIetd* CDCIetd::NewL()

{

    CDCIetd* self = CDCIetd::NewLC();

    CleanupStack::Pop();

    return self;

}

/*

-----------------------------------------------------------------------------

  CDCIetd

  ConstructL

  Second phase constructor. Does nothing at the moment

  Return Values:  none

 -----------------------------------------------------------------------------

*/

void CDCIetd::ConstructL()

{

    // This function is intentionally left blank.

}

/*

-----------------------------------------------------------------------------

  CDCIetd

  Destructor

  Return Values:  none

-----------------------------------------------------------------------------

*/

CDCIetd::~CDCIetd()

{

    // This function is intentionally left blank.

}

/*

-----------------------------------------------------------------------------

  CDCIetd

  Analyze

  Analyze image referenced by aBPtr 

  Return Values:  none

-----------------------------------------------------------------------------

*/

// Analyze image referenced by aBPtr

void CDCIetd::Analyze(CFbsBitmap& aBPtr)

{

	//EColor16M image is needed

	if (aBPtr.DisplayMode() != EColor16M) return;

	//Do analysis

	GatherHistograms(aBPtr);

	MakeMappings();

}

/*

-----------------------------------------------------------------------------

  CDCIetd

  ProcessL

  Process image referenced by aImage (modify aImage).

  May leave with KErrNoMemory if no memory available

  Return Values:  none

-----------------------------------------------------------------------------

*/

void CDCIetd::ProcessL (CFbsBitmap& aImage)  // image reference

{

	TUint	r, g, b;	// Color components

	TUint	lum;		// Brightness estimate

	TInt	dr, dg, db;	// Differences to brightness

	TUint8*	dataPtr;	// Pointer to data

	//EColor16M image is needed

	if (aImage.DisplayMode() != EColor16M) return;

	//Line Buffer and pointer to the data

	TUint imageWidth = aImage.SizeInPixels().iWidth;

	TUint scanLineLengthInBytes = aImage.ScanLineLength(imageWidth, aImage.DisplayMode());

	//Allocate buffer for scanline

	iScanLineBuffer = HBufC8::NewMaxL(scanLineLengthInBytes);

	//Pointer to scanline

	TPtr8 linePtr = iScanLineBuffer->Des();

	//Step through image pixels and do stretching

	//and saturation increase

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

	//Read all lines

	for (TInt lineNo=0; lineNo<aImage.SizeInPixels().iHeight; ++lineNo)

	{

		//Get line

		aImage.GetScanLine(linePtr, TPoint(0, lineNo), imageWidth, aImage.DisplayMode());

		//CHECK! CONST_CAST not used in every algorithm which way is better?

		dataPtr = CONST_CAST(TUint8*, linePtr.Ptr());

		//Step through pixels in line

		for (TUint x=0; x < imageWidth; ++x)

		{

			// Map color componets according to mapping LUTs

			b = iMap[2][*dataPtr++];

			g = iMap[1][*dataPtr++];

			r = iMap[0][*dataPtr++];

			//Compute brightness estimate

			//lum=0.299r+0.587g+0.114b; //true Y

			//lum=(32768+19595*r+38470*g+7471*b)>>16; //Y

			//lum = (r+g+b)/3; //Simple approximation

			lum=(r+(g<<1)+b)>>2; //More effective simple approximation

			//Compute componentwise differences to luminance

			dr = r-lum;

			dg = g-lum;

			db = b-lum;

			//Increase differences => saturation increases.

			//Use gain parameter for adjusting the strength of the effect.

			b += iParameters.aSaturationGain*db/32;

			g += iParameters.aSaturationGain*dg/32;

			r += iParameters.aSaturationGain*dr/32;

			//Save data to same image & same pixels

			dataPtr -= 3;

			//Limit to available dynamic range [0,255].

			*dataPtr++ = Limit255(b);

			*dataPtr++ = Limit255(g);

			*dataPtr++ = Limit255(r);

		}

		//Save line

		aImage.SetScanLine(linePtr, lineNo);

	}

	//Free memory

	delete(iScanLineBuffer);

	iScanLineBuffer = 0;

}

/*

-----------------------------------------------------------------------------

  CDCIetd

  GatherHistograms

  Gather histograms and make cumulative histogram.

  Return Values:  none

-----------------------------------------------------------------------------

*/

void CDCIetd::GatherHistograms (const CFbsBitmap& aImage)  // Pointer to the image bitmap

{

	const TUint8* dataPtr; //Pointer to data

	TInt lineNo; //Line number

	TUint x;	 //Pixel index	

	TUint color; //Color index

	TUint count; // Number of colors in each component

	//Compute image width & allocate scan line memory

	TUint imageWidth = aImage.SizeInPixels().iWidth;

	TUint histScanLineLengthInBytes = aImage.ScanLineLength(imageWidth, aImage.DisplayMode());

	iScanLineBuffer = HBufC8::NewMaxL(histScanLineLengthInBytes);

	//Pointer to line

	TPtr8 linePtr = iScanLineBuffer->Des();

	//Clear histograms

	Mem::FillZ(iHistogram, sizeof(iHistogram));

	// Read all lines and gather histograms

	for (lineNo=0; lineNo<aImage.SizeInPixels().iHeight; lineNo++)

	{

		//Get line

		aImage.GetScanLine(linePtr, TPoint(0, lineNo), imageWidth, aImage.DisplayMode());

		dataPtr = linePtr.Ptr();

		//Step through pixels

		for (x=imageWidth; x != 0; --x)

		{

			++iHistogram[2][*dataPtr++]; // Increase Blue bin value

			++iHistogram[1][*dataPtr++]; // Increase Green bin value

			++iHistogram[0][*dataPtr++]; // Increase Red bin value

		}

	}

	//Make cumulative histograms & count colors in each histogram

	for (color=0; color<3; ++color)

	{

		 // Count used colors

		count=0;

		for (x=0; x<256; ++x)

		{

			if (iHistogram[color][x]>0) count++;

		}

		// Compute increased stretch limit if a color component has less colors than iBitLimit.

		// Otherwise use predetermined stretch limit.

		if (count<iParameters.aBitLimit)

			iReducedStretchLimit[color] = (TUint8)(iParameters.aStretchLimit*count/iParameters.aBitLimit+255-255*count/iParameters.aBitLimit);

		else

			iReducedStretchLimit[color] = iParameters.aStretchLimit;

		//Make cumulative histogram

		for (x=1; x<256; ++x)

			iHistogram[color][x] += iHistogram[color][x-1];

	}

	//Free memory

	delete(iScanLineBuffer);

	iScanLineBuffer = 0;

}

/*

-----------------------------------------------------------------------------

  CDCIetd

  MakeMappings

  Make mapping function look-up table (LUT).

  Return Values:  none

-----------------------------------------------------------------------------

*/

void CDCIetd::MakeMappings()

{

	TUint    MinBins[3];// Smallest existing values in histogram

	TUint    MaxBins[3];// Largest existing values in histogram

	TUint    minBin;    // Minimum of smallest existing values

	TUint    maxBin;    // Maximum of largest existing values

	TUint    x;         // Index

	// Stretching limit variables

	TUint    minShift;

	TUint    maxShift;

	TUint    totalShift;

	TUint    color; //Color index

	//Step through colors

	for (color=0; color<3; ++color)

	{

		// Find smallest existing values in histograms, discard darkest pixels

		// according to blackpixels parameter

		x = 0; // Start from fist bin

		MinBins[color] = iParameters.aBlackPixels * iHistogram[color][255]/1000; // Compute value to be found

		while (x < 255 && (TUint)iHistogram[color][x] < MinBins[color])

			++x; // Find from histogram

		MinBins[color] = x; // Save bin index = start of stretching part of LUT

		// Find largest existing values in histograms, discard brightest pixels

		// according to whitepixels parameter

		x = 255;  // Start from last bin

		//Compute value to be found

		MaxBins[color] = iHistogram[color][255] - iParameters.aWhitePixels * iHistogram[color][255]/1000;

		while (x > 0 && (TUint)iHistogram[color][x] > MaxBins[color])

			--x; // Find from histogram

		MaxBins[color] = x; // Save bin index = end of stretching part of LUT

	}

	//Find minimum of all colors

	minBin=255;

	for (color=0; color<3; color++)

	{

		if (minBin>MinBins[color]) minBin=MinBins[color];

	}

	//Find maximum of all colors

	maxBin=0;

	for (color=0; color<3; color++)

	{

		if (maxBin<MaxBins[color]) maxBin=MaxBins[color];

	}

	//Adjust white and dark balance within limits given in parameters (maximum correction).

	//0 means that largest(or smallest) of all values is used => no WBC(or DBC).

	for (color=0; color<3; color++)

	{

		if(maxBin-MaxBins[color]>iParameters.aWBC) MaxBins[color]=maxBin-iParameters.aWBC;

		if((MinBins[color]-minBin) > iParameters.aDBC) MinBins[color]=minBin+iParameters.aDBC;

	}

	//Step through color components

	for (color=0; color<3; color++)

	{

		// If histogram has only one nonzero bin maxBin can be less than minBin.

		// In that case change maxBin value to minBin.

		if(MaxBins[color]<MinBins[color]) MaxBins[color]=MinBins[color];

		// Limit stretching to narrovest histogram that can be stretched

		if (MaxBins[color]-MinBins[color] < iReducedStretchLimit[color])

		{

			// Compute limiting shifts to measured values.

			// Compute shifts for dark and bright end in relation

			// to coresponding available space in dynamic range.

			totalShift = iReducedStretchLimit[color]-(MaxBins[color]-MinBins[color]);

			maxShift = totalShift*(255-MaxBins[color])/(255-(MaxBins[color]-MinBins[color]));

			minShift = totalShift*MinBins[color]/(255-(MaxBins[color]-MinBins[color]));

			// Check that dynamic range is not exceeded

			// (Should happen only with faulty parameter values)

			if(minShift > MinBins[color])

				MinBins[color]=0;

			else

			// Shift measured values, so that stretching is limited 

			MinBins[color] -= minShift;

			// Shift measured values, so that stretching is limited 

			MaxBins[color] += maxShift;

			// Check that dynamic range is not exceeded

			// (Should happen only with faulty parameter values)

			if (MaxBins[color]>255)

				MaxBins[color]=255;

		}

		// Set 0 mapping part of the LUT

		for (x=0; x<=MinBins[color]; ++x)

			iMap[color][x] = 0;

		// Set 255 mapping part of the LUT

		for (x=MaxBins[color]; x<=255; ++x)

			iMap[color][x] = 255;

		// Compute linear stretching part of the LUT

		for (x=MinBins[color]+1; x<MaxBins[color]; x++)

			iMap[color][x] = (TUint8)(255*(x-MinBins[color])/(MaxBins[color]-MinBins[color]));

	}

}

/*

-----------------------------------------------------------------------------

  CDCIetd

  SetParams

  Set processing parameters

  Return Values:  none

-----------------------------------------------------------------------------

*/

void CDCIetd::SetParams(DCIetdParameters* params)

{

	iParameters = *params;

}

/*

-----------------------------------------------------------------------------

  CDCIetd

  GetParams

  Get current processing parameters

  Return Values:  none

-----------------------------------------------------------------------------

*/

void CDCIetd::GetParams(DCIetdParameters* params)

{

	*params = iParameters;

}

//----IMAAMI----