/*

* Copyright (c) 2004 Nokia Corporation and/or its subsidiary(-ies).

* All rights reserved.

* This component and the accompanying materials are made available

* under the terms of the License "Symbian Foundation License v1.0" to Symbian Foundation members and "Symbian Foundation End User License Agreement v1.0" to non-members

* which accompanies this distribution, and is available

* at the URL "http://www.symbianfoundation.org/legal/licencesv10.html".

*

* Initial Contributors:

* Nokia Corporation - initial contribution.

*

* Contributors:

*

* Description:  ?Description

*

*/

#ifndef AKNSRLEFFECTCONTEXT_H

#define AKNSRLEFFECTCONTEXT_H

//  INCLUDES

#include <fbs.h>

#include <bitdev.h>

// CONSTANTS

/**

* Constant value indicating a rendering operation where the layer is not given 

* at all.

*

* @since 2.8

*/

const TInt KAknsRlLayerNone         = 0x1;

/**

* Constant value indicating a rendering operation where the layer has only an 

* RGB channel.

*

* @since 2.8

*/

const TInt KAknsRlLayerRGBOnly      = 0x2;

/**

* Constant value indicating a rendering operation where the layer has only an 

* alpha channel.

*

* @since 2.8

*/

const TInt KAknsRlLayerAlphaOnly    = 0x4;

/**

* Constant value indicating a rendering operation where the layer has both an

* RGB channel and an alpha channel.

*

* @since 2.8

*/

const TInt KAknsRlLayerRGBA         = 0x8;

// DATA TYPES

/**

* Structure that encapsulates information of a layer.

*

* @since 2.8

*/

struct TAknsRlLayerData 

    {

    /**

    * Default constructor initializes to zero.

    *

    * @since 2.8

    */

    inline TAknsRlLayerData() : iRGBBitmap(0), iRGBDevice(0), iRGBGc(0),

        iAlphaBitmap(0), iAlphaDevice(0), iAlphaGc(0) {};

    /**

    * Bitmap for RGB channel.

    *

    * @since 2.8

    */

    CFbsBitmap* iRGBBitmap;

    /**

    * Bitmap device for RGB channel.

    *

    * @since 2.8

    */

    CFbsBitmapDevice* iRGBDevice;

    /**

    * Bitmap graphics context for RGB channel.

    *

    * @since 2.8

    */

    CFbsBitGc* iRGBGc;

    /**

    * Bitmap for alpha channel.

    *

    * @since 2.8

    */

    CFbsBitmap* iAlphaBitmap;

    /**

    * Bitmap device for alpha channel.

    *

    * @since 2.8

    */

    CFbsBitmapDevice* iAlphaDevice;

    /**

    * Bitmap graphics context for alpha channel.

    *

    * @since 2.8

    */

    CFbsBitGc* iAlphaGc;

    };

// FORWARD DECLARATIONS

class RAknsSrvSession;

// CLASS DECLARATION

/**

* Interface to skin effect context.

* 

* Skin effect plugins receive a reference to their contexts upon activation.

* The context is then used to retrieve and manipulate layer data.

*

* The skin renderer sets the size of the layers of the particular skin

* item being rendered, and may initialize the content of one or more

* layers. Then the effects are executed, one at a time, to manipulate

* layer content. Finally, one or more layers are used as the content

* of the skin item being rendered.

*

* All the layers have the same size. All the RGB channels have the same

* color depth, and the color depth is either @c EColor64K or @c EColor16MU.

* All the alpha channels have color depth @c EGray256.

*

* @since 2.8

*/

class MAknsRlEffectContext

    {

    public: // Constructors and destructor

        /**

        * Destructor for internal use.

        *

        * Destructor is reserved for internal use. Client code must never

        * destroy effect contexts.

        */

        inline virtual ~MAknsRlEffectContext() {}

    public: // New functions - Layer support

        /**

        * Retrieves the size of the layers. Every layer has the same size.

        *

        * @since 2.8

        */

        virtual const TSize LayerSize() =0;

        /**

        * Retrieves the given layer data.

        *

        * Retrieves the required objects to manipulate layer content, and

        * optionally initializes the graphical content if the layer is

        * currently unused.

        *

        * The ownership of the objects included in @c aData structure stays

        * with the effect context. Calling code must not deactivate, close,

        * nor destroy any of the objects.

        *

        * Calling code must assume any initial brush, pen, or color 

        * configuration regarding the graphics devices. After rendering, 

        * the plugin must not leave any clipping configuration active in the 

        * graphics contexts. Brush, pen, and color configuration may be left 

        * in any state.

        *

        * Only the fields indicated by @c aLayerStatus parameter are

        * assigned. Other fields are set to @c NULL. For example, if only

        * the RGB channel is requested, fields for the alpha channel are

        * set to @c NULL.

        *

        * Note that both RGB and alpha channels are created, even if

        * the callers requests only one of them. Therefore it is strongly

        * recommended to use aInitialize parameter with @c ETrue value,

        * unless the caller knows that it will draw both the channels.

        *

        * @param aData Structure that will receive layer data. This is an 

        *   output parameter created and owned by the caller. Ownership of 

        *   the data objects themselves (i.e., the fields of the stucture)

        *   stays with the effect context.

        *

        * @param aLayerIndex Index of the layer to be retrieved.

        *

        * @param aLayerStatus One of the @c KAknsRlLayer constants

        *   indicating which channels of the layer are requested.

        *   This value must not be @c KAknsRlLayerNone nor a combination

        *   of constants.

        *

        * @param aInitialize @c ETrue if the context should initialize the

        *   layer content, @c EFalse otherwise. Regardless of this parameter,

        *   the objects included in layer data are always constructed and 

        *   drawable. If the layer is currently unused (i.e., no effect

        *   plugin or renderer has yet drawn to it), @c ETrue value

        *   instructs the context to perform the following initialization:

        *    - If RGB and alpha channels are requested, both of them are

        *       filled with black.

        *    - If only RGB channel is requested, it is filled with black.

        *       Alpha channel (not visible to the effect) is filled with

        *       white.

        *    - If only alpha channel is requested, it is filled with black.

        *       RGB channel (not visible to the effect) is filled with

        *       black.

        *   If @c EFalse is specified, the initial content of a previously

        *   unused layer is undefined. This also applies to the channel

        *   possibly not included in the request.

        *   Note that initialization is never done if the layer has been

        *   previously used by some effect or the renderer itself.

        *

        * @par Exceptions:

        * The method leaves with an error code if the layer can not be

        * retrieved or an invalid parameter is given. The result of the

        * subsequent GetLayerDataL calls is undefined. The plugin must

        * exit as soon as possible with an error code.

        */

        virtual void GetLayerDataL( TAknsRlLayerData& aData,

            const TInt aLayerIndex, const TInt aLayerStatus,

            const TBool aInitialize ) =0;

        /**

        * Retrieves current skin server session.

        *

        * @return Pointer to current skin server session. No ownership is

        *   transferred.

        *

        * @since 3.0 

        */

        virtual RAknsSrvSession* GetSkinSrvSession() = 0;

    };

#endif // AKNSRLEFFECTCONTEXT_H

// End of File