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/****************************************************************************
*
* ftcglyph.h
*
* FreeType abstract glyph cache (specification).
*
* Copyright (C) 2000-2024 by
* David Turner, Robert Wilhelm, and Werner Lemberg.
*
* This file is part of the FreeType project, and may only be used,
* modified, and distributed under the terms of the FreeType project
* license, LICENSE.TXT. By continuing to use, modify, or distribute
* this file you indicate that you have read the license and
* understand and accept it fully.
*
*/
/*
*
* FTC_GCache is an _abstract_ cache object optimized to store glyph
* data. It works as follows:
*
* - It manages FTC_GNode objects. Each one of them can hold one or more
* glyph `items'. Item types are not specified in the FTC_GCache but
* in classes that extend it.
*
* - Glyph attributes, like face ID, character size, render mode, etc.,
* can be grouped into abstract `glyph families'. This avoids storing
* the attributes within the FTC_GCache, since it is likely that many
* FTC_GNodes will belong to the same family in typical uses.
*
* - Each FTC_GNode is thus an FTC_Node with two additional fields:
*
* * gindex: A glyph index, or the first index in a glyph range.
* * family: A pointer to a glyph `family'.
*
* - Family types are not fully specific in the FTC_Family type, but
* by classes that extend it.
*
* Note that both FTC_ImageCache and FTC_SBitCache extend FTC_GCache.
* They share an FTC_Family sub-class called FTC_BasicFamily which is
* used to store the following data: face ID, pixel/point sizes, load
* flags. For more details see the file `src/cache/ftcbasic.c'.
*
* Client applications can extend FTC_GNode with their own FTC_GNode
* and FTC_Family sub-classes to implement more complex caches (e.g.,
* handling automatic synthesis, like obliquing & emboldening, colored
* glyphs, etc.).
*
* See also the FTC_ICache & FTC_SCache classes in `ftcimage.h' and
* `ftcsbits.h', which both extend FTC_GCache with additional
* optimizations.
*
* A typical FTC_GCache implementation must provide at least the
* following:
*
* - FTC_GNode sub-class, e.g. MyNode, with relevant methods:
* my_node_new (must call FTC_GNode_Init)
* my_node_free (must call FTC_GNode_Done)
* my_node_compare (must call ftc_gnode_compare)
* my_node_remove_faceid (must call ftc_gnode_unselect in case
* of match)
*
* - FTC_Family sub-class, e.g. MyFamily, with relevant methods:
* my_family_compare
* my_family_init
* my_family_done
*
* - FTC_GQuery sub-class, e.g. MyQuery, to hold cache-specific query
* data.
*
* - Constant structures for a FTC_GNodeClass.
*
* - MyCacheNew() can be implemented easily as a call to the convenience
* function FTC_GCache_New.
*
* - MyCacheLookup with a call to FTC_GCache_Lookup. This function will
* automatically:
*
* - Search for the corresponding family in the cache, or create
* a new one if necessary. Put it in FTC_GQUERY(myquery).family
*
* - Call FTC_Cache_Lookup.
*
* If it returns NULL, you should create a new node, then call
* ftc_cache_add as usual.
*/
/**************************************************************************
*
* Important: The functions defined in this file are only used to
* implement an abstract glyph cache class. You need to
* provide additional logic to implement a complete cache.
*
*/
/*************************************************************************/
/*************************************************************************/
/*************************************************************************/
/*************************************************************************/
/*************************************************************************/
/********* *********/
/********* WARNING, THIS IS BETA CODE. *********/
/********* *********/
/*************************************************************************/
/*************************************************************************/
/*************************************************************************/
/*************************************************************************/
/*************************************************************************/
#ifndef FTCGLYPH_H_
#define FTCGLYPH_H_
#include "ftcmanag.h"
FT_BEGIN_HEADER
/*
* We can group glyphs into `families'. Each family correspond to a
* given face ID, character size, transform, etc.
*
* Families are implemented as MRU list nodes. They are
* reference-counted.
*/
typedef struct FTC_FamilyRec_
{
FTC_MruNodeRec mrunode;
FT_UInt num_nodes; /* current number of nodes in this family */
FTC_Cache cache;
FTC_MruListClass clazz;
} FTC_FamilyRec, *FTC_Family;
#define FTC_FAMILY( x ) ( (FTC_Family)(x) )
#define FTC_FAMILY_P( x ) ( (FTC_Family*)(x) )
typedef struct FTC_GNodeRec_
{
FTC_NodeRec node;
FTC_Family family;
FT_UInt gindex;
} FTC_GNodeRec, *FTC_GNode;
#define FTC_GNODE( x ) ( (FTC_GNode)(x) )
#define FTC_GNODE_P( x ) ( (FTC_GNode*)(x) )
typedef struct FTC_GQueryRec_
{
FT_UInt gindex;
FTC_Family family;
} FTC_GQueryRec, *FTC_GQuery;
#define FTC_GQUERY( x ) ( (FTC_GQuery)(x) )
/**************************************************************************
*
* These functions are exported so that they can be called from
* user-provided cache classes; otherwise, they are really part of the
* cache sub-system internals.
*/
/* must be called by derived FTC_Node_InitFunc routines */
FT_LOCAL( void )
FTC_GNode_Init( FTC_GNode node,
FT_UInt gindex, /* glyph index for node */
FTC_Family family );
/* call this function to clear a node's family -- this is necessary */
/* to implement the `node_remove_faceid' cache method correctly */
FT_LOCAL( void )
FTC_GNode_UnselectFamily( FTC_GNode gnode,
FTC_Cache cache );
/* must be called by derived FTC_Node_DoneFunc routines */
FT_LOCAL( void )
FTC_GNode_Done( FTC_GNode node,
FTC_Cache cache );
FT_LOCAL( void )
FTC_Family_Init( FTC_Family family,
FTC_Cache cache );
typedef struct FTC_GCacheRec_
{
FTC_CacheRec cache;
FTC_MruListRec families;
} FTC_GCacheRec, *FTC_GCache;
#define FTC_GCACHE( x ) ((FTC_GCache)(x))
#if 0
/* can be used as @FTC_Cache_InitFunc */
FT_LOCAL( FT_Error )
FTC_GCache_Init( FTC_GCache cache );
#endif
#if 0
/* can be used as @FTC_Cache_DoneFunc */
FT_LOCAL( void )
FTC_GCache_Done( FTC_GCache cache );
#endif
/* the glyph cache class adds fields for the family implementation */
typedef struct FTC_GCacheClassRec_
{
FTC_CacheClassRec clazz;
FTC_MruListClass family_class;
} FTC_GCacheClassRec;
typedef const FTC_GCacheClassRec* FTC_GCacheClass;
#define FTC_GCACHE_CLASS( x ) ((FTC_GCacheClass)(x))
#define FTC_CACHE_GCACHE_CLASS( x ) \
FTC_GCACHE_CLASS( FTC_CACHE( x )->org_class )
#define FTC_CACHE_FAMILY_CLASS( x ) \
( (FTC_MruListClass)FTC_CACHE_GCACHE_CLASS( x )->family_class )
/* convenience function; use it instead of FTC_Manager_Register_Cache */
FT_LOCAL( FT_Error )
FTC_GCache_New( FTC_Manager manager,
FTC_GCacheClass clazz,
FTC_GCache *acache );
#ifndef FTC_INLINE
FT_LOCAL( FT_Error )
FTC_GCache_Lookup( FTC_GCache cache,
FT_Offset hash,
FT_UInt gindex,
FTC_GQuery query,
FTC_Node *anode );
#endif
/* */
#define FTC_FAMILY_FREE( family, cache ) \
FTC_MruList_Remove( &FTC_GCACHE((cache))->families, \
(FTC_MruNode)(family) )
#ifdef FTC_INLINE
#define FTC_GCACHE_LOOKUP_CMP( cache, famcmp, nodecmp, hash, \
gindex, query, node, error ) \
FT_BEGIN_STMNT \
FTC_GCache _gcache = FTC_GCACHE( cache ); \
FTC_GQuery _gquery = (FTC_GQuery)( query ); \
FTC_MruNode_CompareFunc _fcompare = (FTC_MruNode_CompareFunc)(famcmp); \
FTC_MruNode _mrunode; \
\
\
_gquery->gindex = (gindex); \
\
FTC_MRULIST_LOOKUP_CMP( &_gcache->families, _gquery, _fcompare, \
_mrunode, error ); \
_gquery->family = FTC_FAMILY( _mrunode ); \
if ( !error ) \
{ \
FTC_Family _gqfamily = _gquery->family; \
\
\
_gqfamily->num_nodes++; \
\
FTC_CACHE_LOOKUP_CMP( cache, nodecmp, hash, query, node, error ); \
\
if ( --_gqfamily->num_nodes == 0 ) \
FTC_FAMILY_FREE( _gqfamily, _gcache ); \
} \
FT_END_STMNT
/* */
#else /* !FTC_INLINE */
#define FTC_GCACHE_LOOKUP_CMP( cache, famcmp, nodecmp, hash, \
gindex, query, node, error ) \
FT_BEGIN_STMNT \
\
error = FTC_GCache_Lookup( FTC_GCACHE( cache ), hash, gindex, \
FTC_GQUERY( query ), &node ); \
\
FT_END_STMNT
#endif /* !FTC_INLINE */
FT_END_HEADER
#endif /* FTCGLYPH_H_ */
/* END */