1 /***************************************************************************/ 2 /* */ 3 /* aftypes.h */ 4 /* */ 5 /* Auto-fitter types (specification only). */ 6 /* */ 7 /* Copyright 2003-2015 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 * The auto-fitter is a complete rewrite of the old auto-hinter. 22 * Its main feature is the ability to differentiate between different 23 * writing systems and scripts in order to apply specific rules. 24 * 25 * The code has also been compartmentized into several entities that 26 * should make algorithmic experimentation easier than with the old 27 * code. 28 * 29 *************************************************************************/ 30 31 32 #ifndef __AFTYPES_H__ 33 #define __AFTYPES_H__ 34 35 #include <ft2build.h> 36 37 #include FT_FREETYPE_H 38 #include FT_OUTLINE_H 39 #include FT_INTERNAL_OBJECTS_H 40 #include FT_INTERNAL_DEBUG_H 41 42 #include "afblue.h" 43 44 45 FT_BEGIN_HEADER 46 47 /*************************************************************************/ 48 /*************************************************************************/ 49 /***** *****/ 50 /***** D E B U G G I N G *****/ 51 /***** *****/ 52 /*************************************************************************/ 53 /*************************************************************************/ 54 55 #ifdef FT_DEBUG_AUTOFIT 56 57 #include FT_CONFIG_STANDARD_LIBRARY_H 58 59 extern int _af_debug_disable_horz_hints; 60 extern int _af_debug_disable_vert_hints; 61 extern int _af_debug_disable_blue_hints; 62 extern void* _af_debug_hints; 63 64 #endif /* FT_DEBUG_AUTOFIT */ 65 66 67 /*************************************************************************/ 68 /*************************************************************************/ 69 /***** *****/ 70 /***** U T I L I T Y S T U F F *****/ 71 /***** *****/ 72 /*************************************************************************/ 73 /*************************************************************************/ 74 75 typedef struct AF_WidthRec_ 76 { 77 FT_Pos org; /* original position/width in font units */ 78 FT_Pos cur; /* current/scaled position/width in device sub-pixels */ 79 FT_Pos fit; /* current/fitted position/width in device sub-pixels */ 80 81 } AF_WidthRec, *AF_Width; 82 83 84 FT_LOCAL( void ) 85 af_sort_pos( FT_UInt count, 86 FT_Pos* table ); 87 88 FT_LOCAL( void ) 89 af_sort_and_quantize_widths( FT_UInt* count, 90 AF_Width widths, 91 FT_Pos threshold ); 92 93 94 /*************************************************************************/ 95 /*************************************************************************/ 96 /***** *****/ 97 /***** A N G L E T Y P E S *****/ 98 /***** *****/ 99 /*************************************************************************/ 100 /*************************************************************************/ 101 102 /* 103 * The auto-fitter doesn't need a very high angular accuracy; 104 * this allows us to speed up some computations considerably with a 105 * light Cordic algorithm (see afangles.c). 106 */ 107 108 typedef FT_Int AF_Angle; 109 110 111 #define AF_ANGLE_PI 256 112 #define AF_ANGLE_2PI ( AF_ANGLE_PI * 2 ) 113 #define AF_ANGLE_PI2 ( AF_ANGLE_PI / 2 ) 114 #define AF_ANGLE_PI4 ( AF_ANGLE_PI / 4 ) 115 116 117 #if 0 118 /* 119 * compute the angle of a given 2-D vector 120 */ 121 FT_LOCAL( AF_Angle ) 122 af_angle_atan( FT_Pos dx, 123 FT_Pos dy ); 124 125 126 /* 127 * compute `angle2 - angle1'; the result is always within 128 * the range [-AF_ANGLE_PI .. AF_ANGLE_PI - 1] 129 */ 130 FT_LOCAL( AF_Angle ) 131 af_angle_diff( AF_Angle angle1, 132 AF_Angle angle2 ); 133 #endif /* 0 */ 134 135 136 #define AF_ANGLE_DIFF( result, angle1, angle2 ) \ 137 FT_BEGIN_STMNT \ 138 AF_Angle _delta = (angle2) - (angle1); \ 139 \ 140 \ 141 while ( _delta <= -AF_ANGLE_PI ) \ 142 _delta += AF_ANGLE_2PI; \ 143 \ 144 while ( _delta > AF_ANGLE_PI ) \ 145 _delta -= AF_ANGLE_2PI; \ 146 \ 147 result = _delta; \ 148 FT_END_STMNT 149 150 151 /* opaque handle to glyph-specific hints -- see `afhints.h' for more 152 * details 153 */ 154 typedef struct AF_GlyphHintsRec_* AF_GlyphHints; 155 156 157 /*************************************************************************/ 158 /*************************************************************************/ 159 /***** *****/ 160 /***** S C A L E R S *****/ 161 /***** *****/ 162 /*************************************************************************/ 163 /*************************************************************************/ 164 165 /* 166 * A scaler models the target pixel device that will receive the 167 * auto-hinted glyph image. 168 */ 169 170 #define AF_SCALER_FLAG_NO_HORIZONTAL 1U /* disable horizontal hinting */ 171 #define AF_SCALER_FLAG_NO_VERTICAL 2U /* disable vertical hinting */ 172 #define AF_SCALER_FLAG_NO_ADVANCE 4U /* disable advance hinting */ 173 #define AF_SCALER_FLAG_NO_WARPER 8U /* disable warper */ 174 175 176 typedef struct AF_ScalerRec_ 177 { 178 FT_Face face; /* source font face */ 179 FT_Fixed x_scale; /* from font units to 1/64th device pixels */ 180 FT_Fixed y_scale; /* from font units to 1/64th device pixels */ 181 FT_Pos x_delta; /* in 1/64th device pixels */ 182 FT_Pos y_delta; /* in 1/64th device pixels */ 183 FT_Render_Mode render_mode; /* monochrome, anti-aliased, LCD, etc. */ 184 FT_UInt32 flags; /* additional control flags, see above */ 185 186 } AF_ScalerRec, *AF_Scaler; 187 188 189 #define AF_SCALER_EQUAL_SCALES( a, b ) \ 190 ( (a)->x_scale == (b)->x_scale && \ 191 (a)->y_scale == (b)->y_scale && \ 192 (a)->x_delta == (b)->x_delta && \ 193 (a)->y_delta == (b)->y_delta ) 194 195 196 typedef struct AF_StyleMetricsRec_* AF_StyleMetrics; 197 198 /* This function parses an FT_Face to compute global metrics for 199 * a specific style. 200 */ 201 typedef FT_Error 202 (*AF_WritingSystem_InitMetricsFunc)( AF_StyleMetrics metrics, 203 FT_Face face ); 204 205 typedef void 206 (*AF_WritingSystem_ScaleMetricsFunc)( AF_StyleMetrics metrics, 207 AF_Scaler scaler ); 208 209 typedef void 210 (*AF_WritingSystem_DoneMetricsFunc)( AF_StyleMetrics metrics ); 211 212 213 typedef FT_Error 214 (*AF_WritingSystem_InitHintsFunc)( AF_GlyphHints hints, 215 AF_StyleMetrics metrics ); 216 217 typedef void 218 (*AF_WritingSystem_ApplyHintsFunc)( AF_GlyphHints hints, 219 FT_Outline* outline, 220 AF_StyleMetrics metrics ); 221 222 223 /*************************************************************************/ 224 /*************************************************************************/ 225 /***** *****/ 226 /***** W R I T I N G S Y S T E M S *****/ 227 /***** *****/ 228 /*************************************************************************/ 229 /*************************************************************************/ 230 231 /* 232 * For the auto-hinter, a writing system consists of multiple scripts that 233 * can be handled similarly *in a typographical way*; the relationship is 234 * not based on history. For example, both the Greek and the unrelated 235 * Armenian scripts share the same features like ascender, descender, 236 * x-height, etc. Essentially, a writing system is covered by a 237 * submodule of the auto-fitter; it contains 238 * 239 * - a specific global analyzer that computes global metrics specific to 240 * the script (based on script-specific characters to identify ascender 241 * height, x-height, etc.), 242 * 243 * - a specific glyph analyzer that computes segments and edges for each 244 * glyph covered by the script, 245 * 246 * - a specific grid-fitting algorithm that distorts the scaled glyph 247 * outline according to the results of the glyph analyzer. 248 */ 249 250 #define __AFWRTSYS_H__ /* don't load header files */ 251 #undef WRITING_SYSTEM 252 #define WRITING_SYSTEM( ws, WS ) \ 253 AF_WRITING_SYSTEM_ ## WS, 254 255 /* The list of known writing systems. */ 256 typedef enum AF_WritingSystem_ 257 { 258 259 #include "afwrtsys.h" 260 261 AF_WRITING_SYSTEM_MAX /* do not remove */ 262 263 } AF_WritingSystem; 264 265 #undef __AFWRTSYS_H__ 266 267 268 typedef struct AF_WritingSystemClassRec_ 269 { 270 AF_WritingSystem writing_system; 271 272 FT_Offset style_metrics_size; 273 AF_WritingSystem_InitMetricsFunc style_metrics_init; 274 AF_WritingSystem_ScaleMetricsFunc style_metrics_scale; 275 AF_WritingSystem_DoneMetricsFunc style_metrics_done; 276 277 AF_WritingSystem_InitHintsFunc style_hints_init; 278 AF_WritingSystem_ApplyHintsFunc style_hints_apply; 279 280 } AF_WritingSystemClassRec; 281 282 typedef const AF_WritingSystemClassRec* AF_WritingSystemClass; 283 284 285 /*************************************************************************/ 286 /*************************************************************************/ 287 /***** *****/ 288 /***** S C R I P T S *****/ 289 /***** *****/ 290 /*************************************************************************/ 291 /*************************************************************************/ 292 293 /* 294 * Each script is associated with a set of Unicode ranges that gets used 295 * to test whether the font face supports the script. 296 * 297 * We use four-letter script tags from the OpenType specification, 298 * extended by `NONE', which indicates `no script'. 299 */ 300 301 #undef SCRIPT 302 #define SCRIPT( s, S, d, h, sc1, sc2, sc3 ) \ 303 AF_SCRIPT_ ## S, 304 305 /* The list of known scripts. */ 306 typedef enum AF_Script_ 307 { 308 309 #include "afscript.h" 310 311 AF_SCRIPT_MAX /* do not remove */ 312 313 } AF_Script; 314 315 316 typedef struct AF_Script_UniRangeRec_ 317 { 318 FT_UInt32 first; 319 FT_UInt32 last; 320 321 } AF_Script_UniRangeRec; 322 323 #define AF_UNIRANGE_REC( a, b ) { (FT_UInt32)(a), (FT_UInt32)(b) } 324 325 typedef const AF_Script_UniRangeRec* AF_Script_UniRange; 326 327 328 typedef struct AF_ScriptClassRec_ 329 { 330 AF_Script script; 331 332 AF_Script_UniRange script_uni_ranges; /* last must be { 0, 0 } */ 333 334 FT_UInt32 standard_char1; /* for default width and height */ 335 FT_UInt32 standard_char2; /* ditto */ 336 FT_UInt32 standard_char3; /* ditto */ 337 338 } AF_ScriptClassRec; 339 340 typedef const AF_ScriptClassRec* AF_ScriptClass; 341 342 343 /*************************************************************************/ 344 /*************************************************************************/ 345 /***** *****/ 346 /***** C O V E R A G E S *****/ 347 /***** *****/ 348 /*************************************************************************/ 349 /*************************************************************************/ 350 351 /* 352 * Usually, a font contains more glyphs than can be addressed by its 353 * character map. 354 * 355 * In the PostScript font world, encoding vectors specific to a given 356 * task are used to select such glyphs, and these glyphs can be often 357 * recognized by having a suffix in its glyph names. For example, a 358 * superscript glyph `A' might be called `A.sup'. Unfortunately, this 359 * naming scheme is not standardized and thus unusable for us. 360 * 361 * In the OpenType world, a better solution was invented, namely 362 * `features', which cleanly separate a character's input encoding from 363 * the corresponding glyph's appearance, and which don't use glyph names 364 * at all. For our purposes, and slightly generalized, an OpenType 365 * feature is a name of a mapping that maps character codes to 366 * non-standard glyph indices (features get used for other things also). 367 * For example, the `sups' feature provides superscript glyphs, thus 368 * mapping character codes like `A' or `B' to superscript glyph 369 * representation forms. How this mapping happens is completely 370 * uninteresting to us. 371 * 372 * For the auto-hinter, a `coverage' represents all glyphs of an OpenType 373 * feature collected in a set (as listed below) that can be hinted 374 * together. To continue the above example, superscript glyphs must not 375 * be hinted together with normal glyphs because the blue zones 376 * completely differ. 377 * 378 * Note that FreeType itself doesn't compute coverages; it only provides 379 * the glyphs addressable by the default Unicode character map. Instead, 380 * we use the HarfBuzz library (if available), which has many functions 381 * exactly for this purpose. 382 * 383 * AF_COVERAGE_DEFAULT is special: It should cover everything that isn't 384 * listed separately (including the glyphs addressable by the character 385 * map). In case HarfBuzz isn't available, it exactly covers the glyphs 386 * addressable by the character map. 387 * 388 */ 389 390 #undef COVERAGE 391 #define COVERAGE( name, NAME, description, \ 392 tag1, tag2, tag3, tag4 ) \ 393 AF_COVERAGE_ ## NAME, 394 395 396 typedef enum AF_Coverage_ 397 { 398 #include "afcover.h" 399 400 AF_COVERAGE_DEFAULT 401 402 } AF_Coverage; 403 404 405 /*************************************************************************/ 406 /*************************************************************************/ 407 /***** *****/ 408 /***** S T Y L E S *****/ 409 /***** *****/ 410 /*************************************************************************/ 411 /*************************************************************************/ 412 413 /* 414 * The topmost structure for modelling the auto-hinter glyph input data 415 * is a `style class', grouping everything together. 416 */ 417 418 #undef STYLE 419 #define STYLE( s, S, d, ws, sc, ss, c ) \ 420 AF_STYLE_ ## S, 421 422 /* The list of known styles. */ 423 typedef enum AF_Style_ 424 { 425 426 #include "afstyles.h" 427 428 AF_STYLE_MAX /* do not remove */ 429 430 } AF_Style; 431 432 433 typedef struct AF_StyleClassRec_ 434 { 435 AF_Style style; 436 437 AF_WritingSystem writing_system; 438 AF_Script script; 439 AF_Blue_Stringset blue_stringset; 440 AF_Coverage coverage; 441 442 } AF_StyleClassRec; 443 444 typedef const AF_StyleClassRec* AF_StyleClass; 445 446 447 /*************************************************************************/ 448 /*************************************************************************/ 449 /***** *****/ 450 /***** S T Y L E M E T R I C S *****/ 451 /***** *****/ 452 /*************************************************************************/ 453 /*************************************************************************/ 454 455 typedef struct AF_FaceGlobalsRec_* AF_FaceGlobals; 456 457 /* This is the main structure that combines everything. Autofit modules */ 458 /* specific to writing systems derive their structures from it, for */ 459 /* example `AF_LatinMetrics'. */ 460 461 typedef struct AF_StyleMetricsRec_ 462 { 463 AF_StyleClass style_class; 464 AF_ScalerRec scaler; 465 FT_Bool digits_have_same_width; 466 467 AF_FaceGlobals globals; /* to access properties */ 468 469 } AF_StyleMetricsRec; 470 471 472 /* Declare and define vtables for classes */ 473 #ifndef FT_CONFIG_OPTION_PIC 474 475 #define AF_DECLARE_WRITING_SYSTEM_CLASS( writing_system_class ) \ 476 FT_CALLBACK_TABLE const AF_WritingSystemClassRec \ 477 writing_system_class; 478 479 #define AF_DEFINE_WRITING_SYSTEM_CLASS( \ 480 writing_system_class, \ 481 system, \ 482 m_size, \ 483 m_init, \ 484 m_scale, \ 485 m_done, \ 486 h_init, \ 487 h_apply ) \ 488 FT_CALLBACK_TABLE_DEF \ 489 const AF_WritingSystemClassRec writing_system_class = \ 490 { \ 491 system, \ 492 \ 493 m_size, \ 494 \ 495 m_init, \ 496 m_scale, \ 497 m_done, \ 498 \ 499 h_init, \ 500 h_apply \ 501 }; 502 503 504 #define AF_DECLARE_SCRIPT_CLASS( script_class ) \ 505 FT_CALLBACK_TABLE const AF_ScriptClassRec \ 506 script_class; 507 508 #define AF_DEFINE_SCRIPT_CLASS( \ 509 script_class, \ 510 script, \ 511 ranges, \ 512 std_char1, \ 513 std_char2, \ 514 std_char3 ) \ 515 FT_CALLBACK_TABLE_DEF \ 516 const AF_ScriptClassRec script_class = \ 517 { \ 518 script, \ 519 ranges, \ 520 std_char1, \ 521 std_char2, \ 522 std_char3 \ 523 }; 524 525 526 #define AF_DECLARE_STYLE_CLASS( style_class ) \ 527 FT_CALLBACK_TABLE const AF_StyleClassRec \ 528 style_class; 529 530 #define AF_DEFINE_STYLE_CLASS( \ 531 style_class, \ 532 style, \ 533 writing_system, \ 534 script, \ 535 blue_stringset, \ 536 coverage ) \ 537 FT_CALLBACK_TABLE_DEF \ 538 const AF_StyleClassRec style_class = \ 539 { \ 540 style, \ 541 writing_system, \ 542 script, \ 543 blue_stringset, \ 544 coverage \ 545 }; 546 547 #else /* FT_CONFIG_OPTION_PIC */ 548 549 #define AF_DECLARE_WRITING_SYSTEM_CLASS( writing_system_class ) \ 550 FT_LOCAL( void ) \ 551 FT_Init_Class_ ## writing_system_class( AF_WritingSystemClassRec* ac ); 552 553 #define AF_DEFINE_WRITING_SYSTEM_CLASS( \ 554 writing_system_class, \ 555 system, \ 556 m_size, \ 557 m_init, \ 558 m_scale, \ 559 m_done, \ 560 h_init, \ 561 h_apply ) \ 562 FT_LOCAL_DEF( void ) \ 563 FT_Init_Class_ ## writing_system_class( AF_WritingSystemClassRec* ac ) \ 564 { \ 565 ac->writing_system = system; \ 566 \ 567 ac->style_metrics_size = m_size; \ 568 \ 569 ac->style_metrics_init = m_init; \ 570 ac->style_metrics_scale = m_scale; \ 571 ac->style_metrics_done = m_done; \ 572 \ 573 ac->style_hints_init = h_init; \ 574 ac->style_hints_apply = h_apply; \ 575 } 576 577 578 #define AF_DECLARE_SCRIPT_CLASS( script_class ) \ 579 FT_LOCAL( void ) \ 580 FT_Init_Class_ ## script_class( AF_ScriptClassRec* ac ); 581 582 #define AF_DEFINE_SCRIPT_CLASS( \ 583 script_class, \ 584 script_, \ 585 ranges, \ 586 std_char1, \ 587 std_char2, \ 588 std_char3 ) \ 589 FT_LOCAL_DEF( void ) \ 590 FT_Init_Class_ ## script_class( AF_ScriptClassRec* ac ) \ 591 { \ 592 ac->script = script_; \ 593 ac->script_uni_ranges = ranges; \ 594 ac->standard_char1 = std_char1; \ 595 ac->standard_char2 = std_char2; \ 596 ac->standard_char3 = std_char3; \ 597 } 598 599 600 #define AF_DECLARE_STYLE_CLASS( style_class ) \ 601 FT_LOCAL( void ) \ 602 FT_Init_Class_ ## style_class( AF_StyleClassRec* ac ); 603 604 #define AF_DEFINE_STYLE_CLASS( \ 605 style_class, \ 606 style_, \ 607 writing_system_, \ 608 script_, \ 609 blue_stringset_, \ 610 coverage_ ) \ 611 FT_LOCAL_DEF( void ) \ 612 FT_Init_Class_ ## style_class( AF_StyleClassRec* ac ) \ 613 { \ 614 ac->style = style_; \ 615 ac->writing_system = writing_system_; \ 616 ac->script = script_; \ 617 ac->blue_stringset = blue_stringset_; \ 618 ac->coverage = coverage_; \ 619 } 620 621 #endif /* FT_CONFIG_OPTION_PIC */ 622 623 624 /* */ 625 626 FT_END_HEADER 627 628 #endif /* __AFTYPES_H__ */ 629 630 631 /* END */ 632