/*

* Copyright (c)  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:   Declares alftextureautosizeparams texture class.

*

*/

#ifndef C_ALFTEXTUREAUTOSIZEPARAMS_H

#define C_ALFTEXTUREAUTOSIZEPARAMS_H

#include <e32std.h>

/**

 * Texture auto size parameters. These can be used to control texture 

 * resizing when automatic size calculation is enabled. Actual behaviour

 * of parameters may depend also on the used renderer, e.g. texture

 * resizing algorithm may be more aggressive in BitGdi than in 

 * OpenGLES renderer.

 * 

 * Example of use 

 * @code

 * TAlfTextureAutoSizeParams newparams = texture->AutoSizeParams();

 * newparams.SetSizeLowerThreshold(TAlfTextureAutoSizeParams::EHigh);

 * newparams.SetSizeUpperThreshold(TAlfTextureAutoSizeParams::ELow);

 * texture->SetAutoSizeParams(newparams);

 * @endcode

 *

 */

NONSHARABLE_CLASS( TAlfTextureAutoSizeParams )

    {

public:

    enum

        {

        EVeryLow = -20,

        ELow = -10,

        EMedium = 0,

        EHigh = 10,

        EVeryHigh = 20

        };

    /**

     * Constructor.

     */

    IMPORT_C TAlfTextureAutoSizeParams();

    /** 

     * Gets a size threshold which defines how much required size may

     * decrease before it is considered to be small enough to 

     * cause texture resizing.

     *

     * Possible values are e.g:

     *   EVeryHigh

     *   EHigh

     *   EMedium

     *   ELow

     *   EVeryLow            

     * but more values may be added in the future.            

     * 

     * @return Texture downsize threshold

     */  

    IMPORT_C TInt SizeLowerThreshold() const;

    /** 

     * Sets a size threshold which defines how much required size may

     * decrease before it is considered to be small enough to 

     * cause texture resizing.

     * 

     * Exmple: Setting value to EVeryLow causes texture to be 

     * very easily resized to a smaller size if needed. 

     * 

     * Possible values are e.g:

     *   EVeryHigh

     *   EHigh

     *   EMedium

     *   ELow

     *   EVeryLow            

     * but more values may be added in the future.            

     *

     * @param aSizeLowerThreshold Texture downscale threshold

     */  

    IMPORT_C void SetSizeLowerThreshold(TInt aSizeLowerThreshold);

    /** 

     * Gets a size threshold which defines how much required size may

     * increase before it is considered to be big enough to 

     * cause texture resizing.

     *

     * Possible values are e.g:

     *   EVeryHigh

     *   EHigh

     *   EMedium

     *   ELow

     *   EVeryLow            

     * but more values may be added in the future.            

     *

     * @return Texture upscale threshold

     */  

    IMPORT_C TInt SizeUpperThreshold() const;

    /** 

     * Sets a size threshold which defines how much required size may

     * increase before it is considered to be big enough to 

     * cause texture resizing.

     *

     * Exmple: Setting value to EVeryLow causes texture to be 

     * very easily resized to a larger size if needed. 

     *

     * Possible values are e.g:

     *   EVeryHigh

     *   EHigh

     *   EMedium

     *   ELow

     *   EVeryLow            

     * but more values may be added in the future.            

     *

     * @param aSizeUpperThreshold Texture upscale threshold

     */  

    IMPORT_C void SetSizeUpperThreshold(TInt aSizeUpperThreshold);

    /**

     * Gets the minumum amount of resize. If height or width difference 

     * between current size and required size is smaller than threshold

     * specified by this value, resizing is not done 

     * (except if the current texture size is zero).

     *

     * Possible values are e.g:

     *   EVeryHigh

     *   EHigh

     *   EMedium

     *   ELow

     *   EVeryLow            

     * but more values may be added in the future.            

     *

     * @return aMinSizeChange 

     */

     IMPORT_C TInt MinSizeChange() const;   

    /**

     * Sets the minumum amount of resize. If height or width difference 

     * between current size and required size is smaller than threshold

     * specified by this value, resizing is not done 

     * (except if the current texture size is zero).

     *

     * Exmple: Setting value to EHigh can be used to prevent unnecessary

     * size changes if the required size varies often but changes are small.

     *

     * Possible values are e.g:

     *   EVeryHigh

     *   EHigh

     *   EMedium

     *   ELow

     *   EVeryLow            

     * but more values may be added in the future.            

     *

     * @param aMinSizeChange 

     */

     IMPORT_C void SetMinSizeChange(TInt aMinSizeChange);   

    /**

     * Gets size threshold under which relative resizing calculations are

     * settled to be less aggressive than specified. This is used to avoid unnecessary

     * resizing when texture size is very small (small pixel changes may be large

     * relative changes)

     *

     * Possible values are e.g:

     *   EVeryHigh

     *   EHigh

     *   EMedium

     *   ELow

     *   EVeryLow            

     * but more values may be added in the future.            

     *

     * @return Size threshold.

     */

    IMPORT_C TInt DownsizeSettleThreshold() const;

    /**

     * Sets size threshold under which relative resizing calculations are

     * settled to be less aggressive than specified. This is used to avoid unnecessary

     * resizing when texture size is very small (small pixel changes may be large

     * relative changes)

     *

     * Possible values are e.g:

     *   EVeryHigh

     *   EHigh

     *   EMedium

     *   ELow

     *   EVeryLow

     * but more values may be added in the future.            

     *

     * @param aDownsizeSettleThreshold Size threshold.

     */

    IMPORT_C void SetDownsizeSettleThreshold(TInt aDownsizeSettleThreshold);

private:

    /** Lower size threshold */

    TInt iSizeLowerThreshold;

    /** Higher size threshold */

    TInt iSizeUpperThreshold;

    /** Min resize amount that makes sense to do */

    TInt iMinSizeChange;            

    /** Size when texture is so small that relative lower/upper thresholds are no more followed strictly */

    TInt iDownsizeSettleThreshold;

    /** Reserved for future use */

    TInt iSpare[10];

    };

#endif