/*

* 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