CTypefaceStore Class Reference

#include <gdi.h>

Link against: gdi.lib

class CTypefaceStore : public CBase

Inherits from

CTypefaceStore

Protected Attributes
CArrayFixFlat< TFontAccess > *	iFontAccess

Public Member Functions
	~CTypefaceStore()
IMPORT_C TInt	BaselineOffset(TInt, TFontPrintPosition)
pure virtual TInt	FontHeightInTwips(TInt, TInt)
pure virtual TInt	GetNearestFontInTwips(CFont *&, const TFontSpec &)
pure virtual TInt	GetNearestFontToDesignHeightInTwips(CFont *&, const TFontSpec &)
pure virtual TInt	GetNearestFontToMaxHeightInTwips(CFont *&, const TFontSpec &, TInt)
pure virtual TInt	NumTypefaces()
IMPORT_C void	ReleaseFont(CFont *)
IMPORT_C TInt	SuperSubHeight(TInt, TFontPrintPosition)
pure virtual void	TypefaceSupport(TTypefaceSupport &, TInt)

Protected Member Functions
	CTypefaceStore()
IMPORT_C void	AddFontL(CFont *)
IMPORT_C void	ConstructL()
IMPORT_C TBool	IncrementFontCount(const CFont *)

Inherited Functions
	CBase::CBase()
	CBase::Delete(CBase *)
	CBase::Extension_(TUint,TAny &,TAny )
	CBase::operator new(TUint)
	CBase::operator new(TUint,TAny *)
	CBase::operator new(TUint,TLeave)
	CBase::operator new(TUint,TLeave,TUint)
	CBase::operator new(TUint,TUint)
	CBase::~CBase()

Detailed Description

Typeface store abstract base interface.

This class provides the interface to a store for typefaces.

Member Attribute Documentation

iFontAccess

CArrayFixFlat< TFontAccess > *

iFontAccess

[protected]

A list of fonts accessed by clients of the typeface store, which pairs a font with a count of the number of clients accessing the font.

Implemented as an array of TFontAccess objects.

An object is added to this array for every font accessed. If the font is released by all clients, and the access count drops to zero, the font is removed from the list.

Constructor & Destructor Documentation

CTypefaceStore ( )

IMPORT_C

CTypefaceStore

(

)

[protected]

~CTypefaceStore ( )

IMPORT_C

~CTypefaceStore

(

)

Destroys the typeface store and reclaims the memory allocated to it.

Member Function Documentation

AddFontL ( CFont * )

IMPORT_C void

AddFontL

(

CFont *

aFont

)

[protected]

Adds a hold, by a client of the typeface store, on the specified font.

If the specified font is not currently accessed by any clients of the typeface store then the font is added to the font list and the access count set to 1. If it is currently accessed then the access count for the font is incremented by 1.

Parameter	Description
aFont	Pointer to the device specific font accessed.

BaselineOffset ( TInt, TFontPrintPosition )

IMPORT_C TInt	BaselineOffset	(	TInt	aHeight,
			TFontPrintPosition	aPos
		)	[static]

Gets the baseline offset, in twips, for any font in subscript or superscript form.

If the print position is normal then zero is returned. If it is superscript then the baseline offset returned is a percentage, KSuperscriptOffsetPercentage, of aHeight. If it is subscript then the baseline offset returned is a percentage, KSubscriptOffsetPercentage, of aHeight.

Parameter	Description
aHeight	The height of a font.
aPos	The print position of the required font: superscript, subscript or normal.

Returns: The baseline offset for the font.

ConstructL ( )

IMPORT_C void

ConstructL

(

)

[protected]

Second phase constructor.

FontHeightInTwips ( TInt, TInt )

TInt	FontHeightInTwips	(	TInt	aTypefaceIndex,
			TInt	aHeightIndex
		)	const [pure virtual]

Gets the height of the font with specified height and typeface indices, in twips.

The value returned is rounded up or down to the nearest font height in twips.

Parameter	Description
aTypefaceIndex	A typeface index number, in the range: 0 to (NumTypefaces() - 1).
aHeightIndex	A font height index number.

Returns: The height of the font, in twips.

GetNearestFontInTwips ( CFont *&, const TFontSpec & )

TInt	GetNearestFontInTwips	(	CFont *&	aFont,
			const TFontSpec &	aFontSpec
		)	[pure virtual]

Gets the font which is the nearest to the given font specification.

When the font is no longer needed, call ReleaseFont().

Note that this deprecated function is replaced by the new GetNearestFontToDesignHeightInTwips() yielding (virtually) the same result. However clients are strongly encouraged to use the new GetNearestFontToMaxHeightInTwips() function instead. This will guarantee that every character within any given text string will fit within the given amount of twips, whereas the design height is an aesthetic unit decided by the font designer without strict physical meaning, which may result in cropped characters.

DeprecatedUse GetNearestFontToDesignHeightInTwips

Parameter	Description
aFont	On return, contains a pointer to the nearest font.
aFontSpec	The specification of the font to be matched.

Returns: KErrNone if successful; a system-wide error code otherwise.

GetNearestFontToDesignHeightInTwips ( CFont *&, const TFontSpec & )

TInt	GetNearestFontToDesignHeightInTwips	(	CFont *&	aFont,
			const TFontSpec &	aFontSpec
		)	[pure virtual]

Gets the font which is the nearest to the given font specification.

When the font is no longer needed, call ReleaseFont().

This new function replaces the deprecated GetNearestFontInTwips() yielding (virtually) the same result. However clients are strongly encouraged to use the new GetNearestFontToMaxHeightInTwips() function instead. This will guarantee that every character within any given text string will fit within the given amount of twips, whereas the design height is an aesthetic unit decided by the font designer without strict physical meaning, which may result in cropped characters.

Parameter	Description
aFont	On return, contains a pointer to the nearest font.
aFontSpec	The specification of the font to be matched.

Returns: KErrNone if successful; a system-wide error code otherwise.

GetNearestFontToMaxHeightInTwips ( CFont *&, const TFontSpec &, TInt )

TInt	GetNearestFontToMaxHeightInTwips	(	CFont *&	aFont,
			const TFontSpec &	aFontSpec,
			TInt	aMaxHeight
		)	[pure virtual]

Gets the font which is the nearest to the given font specification.

When the font is no longer needed, call ReleaseFont().

The font and bitmap server returns a pointer to the nearest matching font from those available. Matches to max height of font - this does its best to return a font that will fit within the maximum height specified (but note that variations due to hinting algorithms may rarely result in this height being exceeded by up to one pixel). Problems can also be encountered with bitmap fonts where the typeface exists but doesn't have a font small enough.

Parameter	Description
aFont	On return, contains a pointer to the nearest font.
aFontSpec	The specification of the font to be matched.
aMaxHeight	The maximum height within which the font must fit.

Returns: KErrNone if successful; a system-wide error code otherwise.

IncrementFontCount ( const CFont * )

IMPORT_C TBool

IncrementFontCount

(

const CFont *

aFont

)

[protected]

Search for the font in iFontAccess and increment its count.

Parameter	Description
aFont	Font to search for.

Returns: ETrue if the specified font is found, EFalse otherwise.

NumTypefaces ( )

TInt

NumTypefaces

(

)

const [pure virtual]

Gets the number of typefaces supported by the typeface store.

Returns: The number of supported typefaces.

ReleaseFont ( CFont * )

IMPORT_C void

ReleaseFont

(

CFont *

aFont

)

Releases the hold of a typeface store client on a specified font.

Decrements the access-count for the specified font by one. If this reduces the access-count to zero then the font is no longer needed by any client, and is deleted from the typeface store list.

Parameter	Description
aFont	The font to be released by the client.

SuperSubHeight ( TInt, TFontPrintPosition )

IMPORT_C TInt	SuperSubHeight	(	TInt	aHeight,
			TFontPrintPosition	aPos
		)	[static]

Gets the height for a font in subscript or superscript form.

If the print position is normal then aHeight is returned unchanged. If it is superscript or subscript then the height returned is a percentage, KSuperSubScalingPercentage, of aHeight.

Parameter	Description
aHeight	The height of a font.
aPos	The print position of the font: superscript, subscript or normal.

Returns: The required height of the font.

TypefaceSupport ( TTypefaceSupport &, TInt )

void	TypefaceSupport	(	TTypefaceSupport &	aTypefaceSupport,
			TInt	aTypefaceIndex
		)	const [pure virtual]

Gets typeface information for a specified typeface index.

This information is returned in aTypefaceSupport, and includes the typeface name and typeface attributes, the number of font heights, the maximum and minimum font heights, and whether it is a scaleable typeface.

Parameter	Description
aTypefaceSupport	On return, if the function executed successfully, this object contains the typeface information.
aTypefaceIndex	A typeface index number, in the range: zero to (NumTypefaces() - 1).