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CFontCache Class Reference

class CFontCache : public CBase

Font cache.

When a CFont* needs to be found for a particular TFontSpec, the cache can be searched to see if the TFontSpec is already in the cache. If the TFontSpec is in the cache, its corresponding CFont* can be returned. Otherwise GetNearestFontInTwips() must be used to search all of the available fonts for the nearest CFont- a procedure which takes much longer than a simple cache search.

The current font cache should be destroyed and a new cache created whenever the zoom factor or device map changes, as these changes break the relation between CFont and TFontSpec.

Inherits from

CFontCache
- CBase

Nested Classes and Structures

CFontCache::CFontCacheEntry

Public Member Functions
	CFontCache()
	CFontCache(TInt)
	~CFontCache()
IMPORT_C CFont *	AddEntryL(CFont *, const TFontSpec &)
IMPORT_C CFont *	RemoveFirstEntry()
IMPORT_C CFont *	Search(const TFontSpec &)

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()

Public Attributes
TInt	iNumHits
TInt	iNumMisses

Private Attributes
CFontCacheEntry *	iFirst
TInt	iMaxEntries
TInt	iNumEntries

Constructor & Destructor Documentation

CFontCache()

IMPORT_C

CFontCache

(

)

Default constructor.

This constructs a CFontCache of size KMaxFontCacheEntries.

CFontCache(TInt)

IMPORT_C

CFontCache

(

TInt

aMaxEntries

)

Constructor specifying the number of cache entries.

Parameters

TInt aMaxEntries

Number of entries for this cache. You must ensure this is less than or equal to KMaxFontCacheEntries.

~CFontCache()

IMPORT_C

~CFontCache

(

)

Destructor.

This destroys the cashe and releases its allocated memory.

Member Functions Documentation

AddEntryL(CFont *, const TFontSpec &)

IMPORT_C CFont *	AddEntryL	(	CFont *	aFont,
			const TFontSpec &	aFontSpec
		)

Adds a font entry to the cache.

The font, and the font specification required to extract it from the cache, are both specified. If the cache is already full, the font replaces the oldest entry already in the cache, which is returned.

Parameters

CFont * aFont	The font to be stored in the cache.
const TFontSpec & aFontSpec	The font's corresponding font specification.

RemoveFirstEntry()

IMPORT_C CFont *

RemoveFirstEntry

(

)

Removes the first entry from the font cache and returns it.

Search(const TFontSpec &)

IMPORT_C CFont *

(

const TFontSpec &

aFontSpec

)

Searches the cache for a specified font.

The CFont returned is that which corresponds to the font specification aFontSpec.

Parameters

const TFontSpec & aFontSpec

The specification of the font to be searched for.

Member Data Documentation

CFontCacheEntry * iFirst

CFontCacheEntry *

iFirst

[private]

TInt iMaxEntries

TInt

iMaxEntries

[private]

TInt iNumEntries

TInt

iNumEntries

[private]

TInt iNumHits

TInt

iNumHits

The number of cache hits since the font cache was created i.e. successful results from CFontCache::Search().

TInt iNumMisses

TInt	iNumMisses

The number of cache misses since the font cache was created i.e. unsuccessful results from CFontCache::Search().