/*

 * 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 "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:  ?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