/*+
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* Copyright (c) 2004 Nokia Corporation and/or its subsidiary(-ies).+
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* All rights reserved.+
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* This component and the accompanying materials are made available+
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* under the terms of "Eclipse Public License v1.0"+
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* which accompanies this distribution, and is available+
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* at the URL "http://www.eclipse.org/legal/epl-v10.html".+
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*+
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* Initial Contributors:+
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* Nokia Corporation - initial contribution.+
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*+
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* Contributors:+
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*+
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* Description:    Image Transforms subsystem.+
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*+
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*/+
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#ifndef CVTIMAGESCALERIMPL_H+
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#define CVTIMAGESCALERIMPL_H+
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+
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// INCLUDE FILES+
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+
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#include <e32base.h>+
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#include <bitmaptransforms.h>+
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+
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// FORWARD DECLARATIONS+
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+
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class CVtImage;+
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+
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// CLASS DECLARATIONS+
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+
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/**+
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*  Image scaler implementation.+
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*+
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*  @lib videosource.lib+
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*/+
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class CVtImageScalerImpl : public CActive+
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    {+
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    protected:+
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+
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        /**+
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         * Constructor.+
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         */+
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        CVtImageScalerImpl();+
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+
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    public:+
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+
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        /**+
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         * Destructor.+
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         */+
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        ~CVtImageScalerImpl();+
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+
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        /**+
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        * Sets scaler params.+
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        * @param "aParams" Scaling params, including source and target images.+
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        * @exception In error situation leaves with one of the system wide+
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        * error codes.+
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        */+
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        void SetSourceTargetL( const CVtImage& aSource, CVtImage& aTarget );+
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+
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        /**+
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        * Method to check whether bitmap heap locking is needed or not during+
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        * scaling process.+
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        * @exception In error situation leaves with one of the system wide+
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        * error codes.+
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        * @return ETrue if bitmap heap lock is needed, EFalse otherwise.+
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        */+
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        TBool NeedHeapLock() const;+
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+
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        /**+
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        * Pure virtual scaling method.+
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        * @param "aContinue" When method returns, this parameter will contain+
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        * ETrue if new call is needed (i.e. scaling is not yet finished) or+
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        * EFalse if scaling is complete.+
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        * @return KErrNone or one of the system wide error codes.+
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        */+
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        virtual TInt Scale( TBool& aContinue ) = 0;+
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+
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    protected:+
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+
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        /**+
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         * Scales using CBitmapScaler, which is slow but works with any+
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         * Symbian color mode.+
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         * @param aQuality Scaling quality @see CBitmapScaler::TQualityAlgorithm+
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         * @exception In error situation leaves with one of the system wide+
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         * error codes.+
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         */+
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        void ScaleWithBitmapScalerL(+
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            const CBitmapScaler::TQualityAlgorithm aQuality );+
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+
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    private:+
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+
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        /**+
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        * Pure virtual source and target image validation method.+
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        * @param "aSource" Constant reference to source image.+
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        * @param "aTarget" Constant reference to target image.+
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        * @exception If source or target is not valid, this method leaves+
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        * with KErrNotSupported.+
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        */+
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        virtual void ValidateSourceTargetL(+
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            const CVtImage& aSource,+
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            CVtImage& aTarget ) = 0;+
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+
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        /**+
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        * Method for validating image size.+
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        * @param "aSize" Size to be validated.+
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        * @param "aMinSize" Minimum allowed size. If this is not given a default+
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        * size of TSize( 1, 1 ) is used.+
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        * @exception If size is not valid within given parameters, this+
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        * method leaves with KErrNotSupported.+
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        */+
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        void LeaveIfNotValidSizeL(+
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            const TSize& aSize,+
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            const TSize aMinSize = TSize( 1, 1 ) );+
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+
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    private: // from CActive+
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+
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        /**+
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         * @see CActive::RunL+
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         */+
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        void RunL();+
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+
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        /**+
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         * @see CActive::DoCancel+
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         */+
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        void DoCancel();+
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+
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    protected:+
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+
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        // Source for scaling+
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        const CVtImage* iSource; // not owned+
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+
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        // Target image (will hold scaled source)+
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        CVtImage* iTarget; // not owned+
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+
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        // Bitmap scaler instance+
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        CBitmapScaler* iScaler;+
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+
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        // Active scheduler waiter object+
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        CActiveSchedulerWait iActiveSchedulerWait;+
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+
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    };+
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+
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#endif // CVTIMAGESCALERIMPL_H+
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+
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// End of File+
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