1 /**************************************************************************** 2 * 3 * ftdrv.h 4 * 5 * FreeType internal font driver interface (specification). 6 * 7 * Copyright 1996-2018 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 #ifndef FTDRV_H_ 20 #define FTDRV_H_ 21 22 23 #include <ft2build.h> 24 #include FT_MODULE_H 25 26 27 FT_BEGIN_HEADER 28 29 30 typedef FT_Error 31 (*FT_Face_InitFunc)( FT_Stream stream, 32 FT_Face face, 33 FT_Int typeface_index, 34 FT_Int num_params, 35 FT_Parameter* parameters ); 36 37 typedef void 38 (*FT_Face_DoneFunc)( FT_Face face ); 39 40 41 typedef FT_Error 42 (*FT_Size_InitFunc)( FT_Size size ); 43 44 typedef void 45 (*FT_Size_DoneFunc)( FT_Size size ); 46 47 48 typedef FT_Error 49 (*FT_Slot_InitFunc)( FT_GlyphSlot slot ); 50 51 typedef void 52 (*FT_Slot_DoneFunc)( FT_GlyphSlot slot ); 53 54 55 typedef FT_Error 56 (*FT_Size_RequestFunc)( FT_Size size, 57 FT_Size_Request req ); 58 59 typedef FT_Error 60 (*FT_Size_SelectFunc)( FT_Size size, 61 FT_ULong size_index ); 62 63 typedef FT_Error 64 (*FT_Slot_LoadFunc)( FT_GlyphSlot slot, 65 FT_Size size, 66 FT_UInt glyph_index, 67 FT_Int32 load_flags ); 68 69 70 typedef FT_Error 71 (*FT_Face_GetKerningFunc)( FT_Face face, 72 FT_UInt left_glyph, 73 FT_UInt right_glyph, 74 FT_Vector* kerning ); 75 76 77 typedef FT_Error 78 (*FT_Face_AttachFunc)( FT_Face face, 79 FT_Stream stream ); 80 81 82 typedef FT_Error 83 (*FT_Face_GetAdvancesFunc)( FT_Face face, 84 FT_UInt first, 85 FT_UInt count, 86 FT_Int32 flags, 87 FT_Fixed* advances ); 88 89 90 /************************************************************************** 91 * 92 * @struct: 93 * FT_Driver_ClassRec 94 * 95 * @description: 96 * The font driver class. This structure mostly contains pointers to 97 * driver methods. 98 * 99 * @fields: 100 * root :: 101 * The parent module. 102 * 103 * face_object_size :: 104 * The size of a face object in bytes. 105 * 106 * size_object_size :: 107 * The size of a size object in bytes. 108 * 109 * slot_object_size :: 110 * The size of a glyph object in bytes. 111 * 112 * init_face :: 113 * The format-specific face constructor. 114 * 115 * done_face :: 116 * The format-specific face destructor. 117 * 118 * init_size :: 119 * The format-specific size constructor. 120 * 121 * done_size :: 122 * The format-specific size destructor. 123 * 124 * init_slot :: 125 * The format-specific slot constructor. 126 * 127 * done_slot :: 128 * The format-specific slot destructor. 129 * 130 * 131 * load_glyph :: 132 * A function handle to load a glyph to a slot. 133 * This field is mandatory! 134 * 135 * get_kerning :: 136 * A function handle to return the unscaled 137 * kerning for a given pair of glyphs. Can be 138 * set to 0 if the format doesn't support 139 * kerning. 140 * 141 * attach_file :: 142 * This function handle is used to read 143 * additional data for a face from another 144 * file/stream. For example, this can be used to 145 * add data from AFM or PFM files on a Type 1 146 * face, or a CIDMap on a CID-keyed face. 147 * 148 * get_advances :: 149 * A function handle used to return advance 150 * widths of `count' glyphs (in font units), 151 * starting at `first'. The `vertical' flag must 152 * be set to get vertical advance heights. The 153 * `advances' buffer is caller-allocated. 154 * The idea of this function is to be able to 155 * perform device-independent text layout without 156 * loading a single glyph image. 157 * 158 * request_size :: 159 * A handle to a function used to request the new 160 * character size. Can be set to 0 if the 161 * scaling done in the base layer suffices. 162 * 163 * select_size :: 164 * A handle to a function used to select a new 165 * fixed size. It is used only if 166 * @FT_FACE_FLAG_FIXED_SIZES is set. Can be set 167 * to 0 if the scaling done in the base layer 168 * suffices. 169 * @note: 170 * Most function pointers, with the exception of `load_glyph', can be 171 * set to 0 to indicate a default behaviour. 172 */ 173 typedef struct FT_Driver_ClassRec_ 174 { 175 FT_Module_Class root; 176 177 FT_Long face_object_size; 178 FT_Long size_object_size; 179 FT_Long slot_object_size; 180 181 FT_Face_InitFunc init_face; 182 FT_Face_DoneFunc done_face; 183 184 FT_Size_InitFunc init_size; 185 FT_Size_DoneFunc done_size; 186 187 FT_Slot_InitFunc init_slot; 188 FT_Slot_DoneFunc done_slot; 189 190 FT_Slot_LoadFunc load_glyph; 191 192 FT_Face_GetKerningFunc get_kerning; 193 FT_Face_AttachFunc attach_file; 194 FT_Face_GetAdvancesFunc get_advances; 195 196 /* since version 2.2 */ 197 FT_Size_RequestFunc request_size; 198 FT_Size_SelectFunc select_size; 199 200 } FT_Driver_ClassRec, *FT_Driver_Class; 201 202 203 /************************************************************************** 204 * 205 * @macro: 206 * FT_DECLARE_DRIVER 207 * 208 * @description: 209 * Used to create a forward declaration of an FT_Driver_ClassRec 210 * struct instance. 211 * 212 * @macro: 213 * FT_DEFINE_DRIVER 214 * 215 * @description: 216 * Used to initialize an instance of FT_Driver_ClassRec struct. 217 * 218 * `ftinit.c' (ft_create_default_module_classes) already contains a 219 * mechanism to call these functions for the default modules 220 * described in `ftmodule.h'. 221 * 222 * The struct will be allocated in the global scope (or the scope 223 * where the macro is used). 224 */ 225 #define FT_DECLARE_DRIVER( class_ ) \ 226 FT_CALLBACK_TABLE \ 227 const FT_Driver_ClassRec class_; 228 229 #define FT_DEFINE_DRIVER( \ 230 class_, \ 231 flags_, \ 232 size_, \ 233 name_, \ 234 version_, \ 235 requires_, \ 236 interface_, \ 237 init_, \ 238 done_, \ 239 get_interface_, \ 240 face_object_size_, \ 241 size_object_size_, \ 242 slot_object_size_, \ 243 init_face_, \ 244 done_face_, \ 245 init_size_, \ 246 done_size_, \ 247 init_slot_, \ 248 done_slot_, \ 249 load_glyph_, \ 250 get_kerning_, \ 251 attach_file_, \ 252 get_advances_, \ 253 request_size_, \ 254 select_size_ ) \ 255 FT_CALLBACK_TABLE_DEF \ 256 const FT_Driver_ClassRec class_ = \ 257 { \ 258 FT_DEFINE_ROOT_MODULE( flags_, \ 259 size_, \ 260 name_, \ 261 version_, \ 262 requires_, \ 263 interface_, \ 264 init_, \ 265 done_, \ 266 get_interface_ ) \ 267 \ 268 face_object_size_, \ 269 size_object_size_, \ 270 slot_object_size_, \ 271 \ 272 init_face_, \ 273 done_face_, \ 274 \ 275 init_size_, \ 276 done_size_, \ 277 \ 278 init_slot_, \ 279 done_slot_, \ 280 \ 281 load_glyph_, \ 282 \ 283 get_kerning_, \ 284 attach_file_, \ 285 get_advances_, \ 286 \ 287 request_size_, \ 288 select_size_ \ 289 }; 290 291 292 FT_END_HEADER 293 294 #endif /* FTDRV_H_ */ 295 296 297 /* END */ 298
