/*

 * 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: 

 *   Interface for Series 60 font type, incorporating principles of series 60 layout

 *

 *

 */

 #ifndef AKNLAYOUTFONT_H

 #define AKNLAYOUTFONT_H

 #include <gdi.h>

 #include <fbs.h>

 #include <AknFontSpecification.h>

 #include <AknTextDecorationMetrics.h>

 class CBitmapDevice;

 /**

 * This abstract class is a CFbsFont that can update itself (re-bind a font) and has standard

 * Series 60 layout API available.

 * 

 * Concrete classes derived from this implement constructors and Update methods that

 * supply the specification required for the initially, and newly bound font, respectively. 

 * Derived classes must also implement the CreateFont framework method in order to

 * implement the font binding itself.

 * 

 *  @lib avkon.dll

 *  @since 2.8

 *

 *  @internal

 */

 NONSHARABLE_CLASS(CAknLayoutFont) : public CFbsFont

     {

 public:

     /**

     * C++ Destructor.

     */

     virtual ~CAknLayoutFont();

 public: // New functions

     /**  

     * Update this object's binding to a CFbsFont, using the member data of the derived class.

     * This method only needs to be called if the client owns the CAknLayoutFont

     * object, and there has been a layout switch that may affect the font. 

     * 

     * It is functionally equivalent to deleting the CAknLayoutFont object, and 

     * reconstructing it with the same parameters.

     */

     IMPORT_C void Update();

     /**

     * Return the maximum extent of any pixel in the font upwards from the baseline

     * Measured up, so therefore it is a positive value.

     * 

     * @return maximum ascent of the font

     */ 

     IMPORT_C TInt MaxAscent() const;

     /**

     * Return the maximum extent of any pixel in the font down the baseline

     * Measured down, so therefore it is usually a positive value.

     * 

     * @return maximum descent of the font

     */ 

     IMPORT_C TInt MaxDescent() const;

     /*

     * Position of the baseline measured down from the Series 60 layout text pane top

     *

     * @return distance from text pane top to baseline

     */

     IMPORT_C TInt TextPaneTopToBaseline() const;

     /*

     * Position of the text pane bottom measured down from the baseline

     *

     * @return distance from text pane top to baseline

     */

     IMPORT_C TInt BaselineToTextPaneBottom() const;

     /*

     * Series 60 text pane height. 

     * Always equal to TextPaneTopToBaseline() + BaselineToTextPaneBottom()

     *

     * @return text pane height

     */

     IMPORT_C TInt TextPaneHeight() const;

     /**

     * This provides the baseline relative to the top of the combined font for a specific 

     * character code. This value does not include any TopShortfall.

     **/

     TInt AscentForCharacter( TChar aCharacter ) const; 

     /**

     * Returns if a font pointer cast to this type if the actual type conforms to this type. 

     * 

     * @returns NULL if the font does not conform to CAknLayoutFont.

     */

     IMPORT_C static const CAknLayoutFont* AsCAknLayoutFontOrNull( const CFont* aFont );

     /**

     * Returns an object describing how the text with this font is to be decorated

     * 

     * @return   text decoration metrics for the font

     */

     IMPORT_C TAknTextDecorationMetrics TextDecorationMetrics() const;

     /**

     * Returns the Avkon font category (EAknFontCategoryPrimary, EAknFontCategorySecondary...)

     * that was used to generate this font.

     * 

     * @return   font category

     */

     IMPORT_C TAknFontCategory FontCategory() const;

     /**

     * This API allows the font to provide the metrics under which the font was requested.

     * 

     * @return   the font specification for which the font has been supplied

     */

     IMPORT_C TAknFontSpecification FontSpecification() const;

 public: // Functions from CFont

 public:// Functions from CFbsFont

     TFontSpec DoFontSpecInTwips() const;

 protected:

     /**

     * C++ Constructor.

     */

     CAknLayoutFont( CBitmapDevice& aScreenDevice );

     CBitmapDevice& BitmapDevice() const;

 protected: // Internal methods

     void SetExcessAscent( TInt aExcessAscent );

     void SetExcessDescent( TInt aExcessDescent );

     void SetBottomShortfall( TInt aBottomShortfall );

     void SetTextPaneHeight( TInt aTextPaneHeight );

 private: // New Framework methods

     virtual CFbsFont* SupplyFont() = 0;

     virtual TInt DoAscentForCharacter( TChar aCharacter ) const;

     virtual TAknTextDecorationMetrics DoTextDecorationMetrics() const = 0;

     virtual TAknFontSpecification DoFontSpecification() const = 0;

     virtual void CAknLayoutFont_Reserved_1();

 private:

     void Register();

     void Deregister();

 private:

     CFbsFont* iNonDynamicFont;

     CBitmapDevice& iScreenDevice;

     TInt iExcessAscent;

     TInt iExcessDescent;

     TInt iBottomShortfall;

     TInt iTextPaneHeight;

     TInt iSpare;

     };

 #endif  //AKNLAYOUTFONT_H