/*

* Copyright (c) 2009 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:  Text recognition algorithm implementation.

*

*/

#ifndef __HTI_TEXT_RCG_

#define __HTI_TEXT_RCG_

#include <fbs.h>

#include <gulfont.h>

#include <e32math.h>

const TInt KDefaultAvgDiffMin = 50;

const TInt KDefaultFgSSMin = 50;

const TInt KDefaultFgAvgDiffMin = 5; //in "pure" (not AA) pixels

const TInt KWorstCase = 0xFF;

const TInt KSuccessThresold = 50;

const TInt KNormCoefAcc = 2;

const TInt KDefaultFGAAmount = 5;

const TInt KDefaultBGAAmount = 10;

const TInt KFgPatternColor = 0x00; //black

const TInt KBgPatternColor = 0xff; //white

TInt CompareTPoint(const TPoint& aP1,const TPoint& aP2);

enum THtiTextRecgHints

    {

    EHintNone = 0,

    EHintEdge = 1

    };

/**

* The class implements text recognition algorithm on screenshots

* based on system fonts

*

*/

class CHtiTextRcg : public CBase

{

public:

    CHtiTextRcg();

    virtual ~CHtiTextRcg();

    void SetHint(TInt aHint);

    TBool RecognizeTextL(CFbsBitmap* aScreenshot,

                        const TDesC& aText,

                        const CFont* aFont,

                        TRect& aResult);

    /**

    * aResult will contain the coordinates of the found text

    *  Return 0 if match is perfect, 255 if text was not found

    * return value from 0 to 255 means some error, the lower it is the better match

    *

    */

    //brute force optim

    TInt RecognizeAAL(CFbsBitmap* aScreenshot,const TDesC& aText, const CFont* aFont, TRect& aResult);

    //brute force clean optim

    TInt RecognizeBinL(CFbsBitmap* aScreenshot,const TDesC& aText, const CFont* aFont, TRect& aResult);

    //static image processing routines

    //convert image to 256-greyscale

    static CFbsBitmap* ColorDownL(CFbsBitmap * aBitmap);

    //generates bitmap of the text using the font given

    static CFbsBitmap* GetTextBitmapL( const TDesC& aText,

                            const CFont* fontUsed,

                            const TInt aLength = KMaxTInt );

    static CFbsBitmap* GetTextBitmapL( const TDesC& aText,

                            const CFont* fontUsed,

                            TRgb aForeground,

                            TRgb aBackground,

                            TDisplayMode aDisplayMode,

                            const TInt aLength = KMaxTInt );

    //calculates min max of a greyscale bitmap in question

    static void MinMax(CFbsBitmap * aBitmap, TInt& aMin, TInt& aMax);

    /**

    * use FGA and BGA to speed-up comparation

    * this function only returns 255 or 0

    * Analyses only min and max colors

    */

    TInt ImageDiffBinSampleL(CFbsBitmap * aBitmap1, TPoint aOrigin1,

                 CFbsBitmap * aBitmap2);

    /**

    * Iterations like in Diff5 but metrics from Diff6

    * Used for full word checking if Diff6 is 0 for a letter

    * this function only returns 255 or 0

    */

    TInt ImageDiffBinFullL(CFbsBitmap * aBitmap1, TPoint aOrigin1,

                 CFbsBitmap * aBitmap2);

    /**

    * use FGA and BGA to speed-up comparation and AA pixels

    */

    TInt ImageDiffAASampleL(CFbsBitmap * aBitmap1, TPoint aOrigin1,

                 CFbsBitmap * aBitmap2);

    /**

    * Iterations like in Diff5 but metrics from Diff6/DiffAASample

    * Used for full word checking if Diff6 is 0 for a letter

    */

    TInt ImageDiffAAFullL(CFbsBitmap * aBitmap1, TPoint aOrigin1,

                 CFbsBitmap * aBitmap2);

    /*

    * Analyze pattern and fills in FGA and BGA sets

    * Return ETrue if pattern is valid (non empty)

    */

    TBool AnalyzePatternL(CFbsBitmap * aPattern);

private:

    //algorithm parameters

    //minimal abs avarage difference beetwen foreground and background

    TInt iAvgDiffMin;

    //minimal SS for foreground, with plain color should be 0

    TInt iFgSSMin;

    /**

    * minimal avg diff for foreground, used in Diff3

    */

    TInt iFgAvgDiffMin;

    //TInt64 iSeed;

    //following vars set by AnalyzePatternL

    TInt iFGAAmount;

    TInt iBGAAmount;

    //foreground assesment point set

    RArray<TPoint> iFGASet;

    //background assesment point set

    RArray<TPoint> iBGASet;

    //font color in reference image

    TInt iMaskFgColor;//

    //background color in reference image

    TInt iMaskBgColor;//

    //used for AA algorithm

    //set in Sample function and used in Full function

    //for optimization

    TInt iTestFgColor;

    TInt iTestBgColor;

    // normalization coeff to compare test image with mask directly

    // |iMaskFgColor-iMaskBgColor|*NormCoefAcc)/|iTestFgColor-iTestBgColor|

    // where NormCoefAcc multiplyer is used to increase accuracy (all ints)

    // and is implemented as shif by KNormCoefAcc bits

    // back shift is performed after color is multiplied by iTestNormCoef

    TInt iTestNormCoef;

    /**

    * Current recognition method

    * Changed by SetHint

    */

    TInt iCurrentStrategy;

};

#endif //__HTI_TEXT_RCG_

// End of file