CFontCache Class Reference

#include <gdi.h>

Link against: gdi.lib

class CFontCache : public CBase

Inherits from

  • CFontCache
    Public Attributes
    TInt iNumHits
    TInt iNumMisses
    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()

    Detailed Description

    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.

    Member Attribute Documentation

    iNumHits

    TInt iNumHits

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

    iNumMisses

    TInt iNumMisses

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

    Constructor & Destructor Documentation

    CFontCache ( )

    IMPORT_CCFontCache()

    Default constructor.

    This constructs a CFontCache of size KMaxFontCacheEntries.

    CFontCache ( TInt )

    IMPORT_CCFontCache(TIntaMaxEntries)

    Constructor specifying the number of cache entries.

    ParameterDescription
    aMaxEntriesNumber 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 Function 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.

    ParameterDescription
    aFontThe font to be stored in the cache.
    aFontSpecThe font's corresponding font specification.

    Returns: If the cache isn't full, NULL is returned. If the cache is full, the displaced cache entry is returned.

    RemoveFirstEntry ( )

    IMPORT_C CFont *RemoveFirstEntry()

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

    Returns: The entry removed from the font cache. If the cache is empty, NULL is returned.

    Search ( const TFontSpec & )

    IMPORT_C CFont *Search(const TFontSpec &aFontSpec)

    Searches the cache for a specified font.

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

    ParameterDescription
    aFontSpecThe specification of the font to be searched for.

    Returns: If an entry for the font specification is found in the cache, the pointer to the font corresponding to the font specification is returned. Otherwise NULL is returned.

    © Nokia 2011.