ftcglyph.h (11080B)
1 /**************************************************************************** 2 * 3 * ftcglyph.h 4 * 5 * FreeType abstract glyph cache (specification). 6 * 7 * Copyright (C) 2000-2025 by 8 * David Turner, Robert Wilhelm, and Werner Lemberg. 9 * 10 * This file is part of the FreeType project, and may only be used, 11 * modified, and distributed under the terms of the FreeType project 12 * license, LICENSE.TXT. By continuing to use, modify, or distribute 13 * this file you indicate that you have read the license and 14 * understand and accept it fully. 15 * 16 */ 17 18 19 /* 20 * 21 * FTC_GCache is an _abstract_ cache object optimized to store glyph 22 * data. It works as follows: 23 * 24 * - It manages FTC_GNode objects. Each one of them can hold one or more 25 * glyph `items'. Item types are not specified in the FTC_GCache but 26 * in classes that extend it. 27 * 28 * - Glyph attributes, like face ID, character size, render mode, etc., 29 * can be grouped into abstract `glyph families'. This avoids storing 30 * the attributes within the FTC_GCache, since it is likely that many 31 * FTC_GNodes will belong to the same family in typical uses. 32 * 33 * - Each FTC_GNode is thus an FTC_Node with two additional fields: 34 * 35 * * gindex: A glyph index, or the first index in a glyph range. 36 * * family: A pointer to a glyph `family'. 37 * 38 * - Family types are not fully specific in the FTC_Family type, but 39 * by classes that extend it. 40 * 41 * Note that both FTC_ImageCache and FTC_SBitCache extend FTC_GCache. 42 * They share an FTC_Family sub-class called FTC_BasicFamily which is 43 * used to store the following data: face ID, pixel/point sizes, load 44 * flags. For more details see the file `src/cache/ftcbasic.c'. 45 * 46 * Client applications can extend FTC_GNode with their own FTC_GNode 47 * and FTC_Family sub-classes to implement more complex caches (e.g., 48 * handling automatic synthesis, like obliquing & emboldening, colored 49 * glyphs, etc.). 50 * 51 * See also the FTC_ICache & FTC_SCache classes in `ftcimage.h' and 52 * `ftcsbits.h', which both extend FTC_GCache with additional 53 * optimizations. 54 * 55 * A typical FTC_GCache implementation must provide at least the 56 * following: 57 * 58 * - FTC_GNode sub-class, e.g. MyNode, with relevant methods: 59 * my_node_new (must call FTC_GNode_Init) 60 * my_node_free (must call FTC_GNode_Done) 61 * my_node_compare (must call ftc_gnode_compare) 62 * my_node_remove_faceid (must call ftc_gnode_unselect in case 63 * of match) 64 * 65 * - FTC_Family sub-class, e.g. MyFamily, with relevant methods: 66 * my_family_compare 67 * my_family_init 68 * my_family_done 69 * 70 * - FTC_GQuery sub-class, e.g. MyQuery, to hold cache-specific query 71 * data. 72 * 73 * - Constant structures for a FTC_GNodeClass. 74 * 75 * - MyCacheNew() can be implemented easily as a call to the convenience 76 * function FTC_GCache_New. 77 * 78 * - MyCacheLookup with a call to FTC_GCache_Lookup. This function will 79 * automatically: 80 * 81 * - Search for the corresponding family in the cache, or create 82 * a new one if necessary. Put it in FTC_GQUERY(myquery).family 83 * 84 * - Call FTC_Cache_Lookup. 85 * 86 * If it returns NULL, you should create a new node, then call 87 * ftc_cache_add as usual. 88 */ 89 90 91 /************************************************************************** 92 * 93 * Important: The functions defined in this file are only used to 94 * implement an abstract glyph cache class. You need to 95 * provide additional logic to implement a complete cache. 96 * 97 */ 98 99 100 /*************************************************************************/ 101 /*************************************************************************/ 102 /*************************************************************************/ 103 /*************************************************************************/ 104 /*************************************************************************/ 105 /********* *********/ 106 /********* WARNING, THIS IS BETA CODE. *********/ 107 /********* *********/ 108 /*************************************************************************/ 109 /*************************************************************************/ 110 /*************************************************************************/ 111 /*************************************************************************/ 112 /*************************************************************************/ 113 114 115 #ifndef FTCGLYPH_H_ 116 #define FTCGLYPH_H_ 117 118 119 #include "ftcmanag.h" 120 121 122 FT_BEGIN_HEADER 123 124 125 /* 126 * We can group glyphs into `families'. Each family correspond to a 127 * given face ID, character size, transform, etc. 128 * 129 * Families are implemented as MRU list nodes. They are 130 * reference-counted. 131 */ 132 133 typedef struct FTC_FamilyRec_ 134 { 135 FTC_MruNodeRec mrunode; 136 FT_UInt num_nodes; /* current number of nodes in this family */ 137 FTC_Cache cache; 138 FTC_MruListClass clazz; 139 140 } FTC_FamilyRec, *FTC_Family; 141 142 #define FTC_FAMILY( x ) ( (FTC_Family)(x) ) 143 #define FTC_FAMILY_P( x ) ( (FTC_Family*)(x) ) 144 145 146 typedef struct FTC_GNodeRec_ 147 { 148 FTC_NodeRec node; 149 FTC_Family family; 150 FT_UInt gindex; 151 152 } FTC_GNodeRec, *FTC_GNode; 153 154 #define FTC_GNODE( x ) ( (FTC_GNode)(x) ) 155 #define FTC_GNODE_P( x ) ( (FTC_GNode*)(x) ) 156 157 158 typedef struct FTC_GQueryRec_ 159 { 160 FT_UInt gindex; 161 FTC_Family family; 162 163 } FTC_GQueryRec, *FTC_GQuery; 164 165 #define FTC_GQUERY( x ) ( (FTC_GQuery)(x) ) 166 167 168 /************************************************************************** 169 * 170 * These functions are exported so that they can be called from 171 * user-provided cache classes; otherwise, they are really part of the 172 * cache sub-system internals. 173 */ 174 175 /* must be called by derived FTC_Node_InitFunc routines */ 176 FT_LOCAL( void ) 177 FTC_GNode_Init( FTC_GNode node, 178 FT_UInt gindex, /* glyph index for node */ 179 FTC_Family family ); 180 181 /* call this function to clear a node's family -- this is necessary */ 182 /* to implement the `node_remove_faceid' cache method correctly */ 183 FT_LOCAL( void ) 184 FTC_GNode_UnselectFamily( FTC_GNode gnode, 185 FTC_Cache cache ); 186 187 /* must be called by derived FTC_Node_DoneFunc routines */ 188 FT_LOCAL( void ) 189 FTC_GNode_Done( FTC_GNode node, 190 FTC_Cache cache ); 191 192 193 FT_LOCAL( void ) 194 FTC_Family_Init( FTC_Family family, 195 FTC_Cache cache ); 196 197 typedef struct FTC_GCacheRec_ 198 { 199 FTC_CacheRec cache; 200 FTC_MruListRec families; 201 202 } FTC_GCacheRec, *FTC_GCache; 203 204 #define FTC_GCACHE( x ) ((FTC_GCache)(x)) 205 206 207 #if 0 208 /* can be used as @FTC_Cache_InitFunc */ 209 FT_LOCAL( FT_Error ) 210 FTC_GCache_Init( FTC_GCache cache ); 211 #endif 212 213 214 #if 0 215 /* can be used as @FTC_Cache_DoneFunc */ 216 FT_LOCAL( void ) 217 FTC_GCache_Done( FTC_GCache cache ); 218 #endif 219 220 221 /* the glyph cache class adds fields for the family implementation */ 222 typedef struct FTC_GCacheClassRec_ 223 { 224 FTC_CacheClassRec clazz; 225 FTC_MruListClass family_class; 226 227 } FTC_GCacheClassRec; 228 229 typedef const FTC_GCacheClassRec* FTC_GCacheClass; 230 231 #define FTC_GCACHE_CLASS( x ) ((FTC_GCacheClass)(x)) 232 233 #define FTC_CACHE_GCACHE_CLASS( x ) \ 234 FTC_GCACHE_CLASS( FTC_CACHE( x )->org_class ) 235 #define FTC_CACHE_FAMILY_CLASS( x ) \ 236 ( (FTC_MruListClass)FTC_CACHE_GCACHE_CLASS( x )->family_class ) 237 238 239 /* convenience function; use it instead of FTC_Manager_Register_Cache */ 240 FT_LOCAL( FT_Error ) 241 FTC_GCache_New( FTC_Manager manager, 242 FTC_GCacheClass clazz, 243 FTC_GCache *acache ); 244 245 #ifndef FTC_INLINE 246 FT_LOCAL( FT_Error ) 247 FTC_GCache_Lookup( FTC_GCache cache, 248 FT_Offset hash, 249 FT_UInt gindex, 250 FTC_GQuery query, 251 FTC_Node *anode ); 252 #endif 253 254 255 /* */ 256 257 258 #define FTC_FAMILY_FREE( family, cache ) \ 259 FTC_MruList_Remove( &FTC_GCACHE((cache))->families, \ 260 (FTC_MruNode)(family) ) 261 262 263 #ifdef FTC_INLINE 264 265 #define FTC_GCACHE_LOOKUP_CMP( cache, famcmp, nodecmp, hash, \ 266 gindex, query, node, error ) \ 267 FT_BEGIN_STMNT \ 268 FTC_GCache _gcache = FTC_GCACHE( cache ); \ 269 FTC_GQuery _gquery = (FTC_GQuery)( query ); \ 270 FTC_MruNode_CompareFunc _fcompare = (FTC_MruNode_CompareFunc)(famcmp); \ 271 FTC_MruNode _mrunode; \ 272 \ 273 \ 274 _gquery->gindex = (gindex); \ 275 \ 276 FTC_MRULIST_LOOKUP_CMP( &_gcache->families, _gquery, _fcompare, \ 277 _mrunode, error ); \ 278 _gquery->family = FTC_FAMILY( _mrunode ); \ 279 if ( !error ) \ 280 { \ 281 FTC_Family _gqfamily = _gquery->family; \ 282 \ 283 \ 284 _gqfamily->num_nodes++; \ 285 \ 286 FTC_CACHE_LOOKUP_CMP( cache, nodecmp, hash, query, node, error ); \ 287 \ 288 if ( --_gqfamily->num_nodes == 0 ) \ 289 FTC_FAMILY_FREE( _gqfamily, _gcache ); \ 290 } \ 291 FT_END_STMNT 292 /* */ 293 294 #else /* !FTC_INLINE */ 295 296 #define FTC_GCACHE_LOOKUP_CMP( cache, famcmp, nodecmp, hash, \ 297 gindex, query, node, error ) \ 298 FT_BEGIN_STMNT \ 299 \ 300 error = FTC_GCache_Lookup( FTC_GCACHE( cache ), hash, gindex, \ 301 FTC_GQUERY( query ), &node ); \ 302 \ 303 FT_END_STMNT 304 305 #endif /* !FTC_INLINE */ 306 307 308 FT_END_HEADER 309 310 311 #endif /* FTCGLYPH_H_ */ 312 313 314 /* END */