1 /***************************************************************************/ 2 /* */ 3 /* aftypes.h */ 4 /* */ 5 /* Auto-fitter types (specification only). */ 6 /* */ 7 /* Copyright 2003-2018 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 /************************************************************************* 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 compartmentalized 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 #ifdef FT_DEBUG_AUTOFIT 45 #include FT_CONFIG_STANDARD_LIBRARY_H 46 #endif 47 48 49 FT_BEGIN_HEADER 50 51 /*************************************************************************/ 52 /*************************************************************************/ 53 /***** *****/ 54 /***** D E B U G G I N G *****/ 55 /***** *****/ 56 /*************************************************************************/ 57 /*************************************************************************/ 58 59 #ifdef FT_DEBUG_AUTOFIT 60 61 extern int _af_debug_disable_horz_hints; 62 extern int _af_debug_disable_vert_hints; 63 extern int _af_debug_disable_blue_hints; 64 extern void* _af_debug_hints; 65 66 #endif /* FT_DEBUG_AUTOFIT */ 67 68 69 /*************************************************************************/ 70 /*************************************************************************/ 71 /***** *****/ 72 /***** U T I L I T Y S T U F F *****/ 73 /***** *****/ 74 /*************************************************************************/ 75 /*************************************************************************/ 76 77 typedef struct AF_WidthRec_ 78 { 79 FT_Pos org; /* original position/width in font units */ 80 FT_Pos cur; /* current/scaled position/width in device sub-pixels */ 81 FT_Pos fit; /* current/fitted position/width in device sub-pixels */ 82 83 } AF_WidthRec, *AF_Width; 84 85 86 FT_LOCAL( void ) 87 af_sort_pos( FT_UInt count, 88 FT_Pos* table ); 89 90 FT_LOCAL( void ) 91 af_sort_and_quantize_widths( FT_UInt* count, 92 AF_Width widths, 93 FT_Pos threshold ); 94 95 96 /*************************************************************************/ 97 /*************************************************************************/ 98 /***** *****/ 99 /***** A N G L E T Y P E S *****/ 100 /***** *****/ 101 /*************************************************************************/ 102 /*************************************************************************/ 103 104 /* 105 * The auto-fitter doesn't need a very high angular accuracy; 106 * this allows us to speed up some computations considerably with a 107 * light Cordic algorithm (see afangles.c). 108 */ 109 110 typedef FT_Int AF_Angle; 111 112 113 #define AF_ANGLE_PI 256 114 #define AF_ANGLE_2PI ( AF_ANGLE_PI * 2 ) 115 #define AF_ANGLE_PI2 ( AF_ANGLE_PI / 2 ) 116 #define AF_ANGLE_PI4 ( AF_ANGLE_PI / 4 ) 117 118 119 #if 0 120 /* 121 * compute the angle of a given 2-D vector 122 */ 123 FT_LOCAL( AF_Angle ) 124 af_angle_atan( FT_Pos dx, 125 FT_Pos dy ); 126 127 128 /* 129 * compute `angle2 - angle1'; the result is always within 130 * the range [-AF_ANGLE_PI .. AF_ANGLE_PI - 1] 131 */ 132 FT_LOCAL( AF_Angle ) 133 af_angle_diff( AF_Angle angle1, 134 AF_Angle angle2 ); 135 #endif /* 0 */ 136 137 138 #define AF_ANGLE_DIFF( result, angle1, angle2 ) \ 139 FT_BEGIN_STMNT \ 140 AF_Angle _delta = (angle2) - (angle1); \ 141 \ 142 \ 143 while ( _delta <= -AF_ANGLE_PI ) \ 144 _delta += AF_ANGLE_2PI; \ 145 \ 146 while ( _delta > AF_ANGLE_PI ) \ 147 _delta -= AF_ANGLE_2PI; \ 148 \ 149 result = _delta; \ 150 FT_END_STMNT 151 152 153 /* opaque handle to glyph-specific hints -- see `afhints.h' for more 154 * details 155 */ 156 typedef struct AF_GlyphHintsRec_* AF_GlyphHints; 157 158 159 /*************************************************************************/ 160 /*************************************************************************/ 161 /***** *****/ 162 /***** S C A L E R S *****/ 163 /***** *****/ 164 /*************************************************************************/ 165 /*************************************************************************/ 166 167 /* 168 * A scaler models the target pixel device that will receive the 169 * auto-hinted glyph image. 170 */ 171 172 #define AF_SCALER_FLAG_NO_HORIZONTAL 1U /* disable horizontal hinting */ 173 #define AF_SCALER_FLAG_NO_VERTICAL 2U /* disable vertical hinting */ 174 #define AF_SCALER_FLAG_NO_ADVANCE 4U /* disable advance hinting */ 175 #define AF_SCALER_FLAG_NO_WARPER 8U /* disable warper */ 176 177 178 typedef struct AF_ScalerRec_ 179 { 180 FT_Face face; /* source font face */ 181 FT_Fixed x_scale; /* from font units to 1/64th device pixels */ 182 FT_Fixed y_scale; /* from font units to 1/64th device pixels */ 183 FT_Pos x_delta; /* in 1/64th device pixels */ 184 FT_Pos y_delta; /* in 1/64th device pixels */ 185 FT_Render_Mode render_mode; /* monochrome, anti-aliased, LCD, etc. */ 186 FT_UInt32 flags; /* additional control flags, see above */ 187 188 } AF_ScalerRec, *AF_Scaler; 189 190 191 #define AF_SCALER_EQUAL_SCALES( a, b ) \ 192 ( (a)->x_scale == (b)->x_scale && \ 193 (a)->y_scale == (b)->y_scale && \ 194 (a)->x_delta == (b)->x_delta && \ 195 (a)->y_delta == (b)->y_delta ) 196 197 198 typedef struct AF_StyleMetricsRec_* AF_StyleMetrics; 199 200 /* This function parses an FT_Face to compute global metrics for 201 * a specific style. 202 */ 203 typedef FT_Error 204 (*AF_WritingSystem_InitMetricsFunc)( AF_StyleMetrics metrics, 205 FT_Face face ); 206 207 typedef void 208 (*AF_WritingSystem_ScaleMetricsFunc)( AF_StyleMetrics metrics, 209 AF_Scaler scaler ); 210 211 typedef void 212 (*AF_WritingSystem_DoneMetricsFunc)( AF_StyleMetrics metrics ); 213 214 typedef void 215 (*AF_WritingSystem_GetStdWidthsFunc)( AF_StyleMetrics metrics, 216 FT_Pos* stdHW, 217 FT_Pos* stdVW ); 218 219 220 typedef FT_Error 221 (*AF_WritingSystem_InitHintsFunc)( AF_GlyphHints hints, 222 AF_StyleMetrics metrics ); 223 224 typedef FT_Error 225 (*AF_WritingSystem_ApplyHintsFunc)( FT_UInt glyph_index, 226 AF_GlyphHints hints, 227 FT_Outline* outline, 228 AF_StyleMetrics metrics ); 229 230 231 /*************************************************************************/ 232 /*************************************************************************/ 233 /***** *****/ 234 /***** W R I T I N G S Y S T E M S *****/ 235 /***** *****/ 236 /*************************************************************************/ 237 /*************************************************************************/ 238 239 /* 240 * For the auto-hinter, a writing system consists of multiple scripts that 241 * can be handled similarly *in a typographical way*; the relationship is 242 * not based on history. For example, both the Greek and the unrelated 243 * Armenian scripts share the same features like ascender, descender, 244 * x-height, etc. Essentially, a writing system is covered by a 245 * submodule of the auto-fitter; it contains 246 * 247 * - a specific global analyzer that computes global metrics specific to 248 * the script (based on script-specific characters to identify ascender 249 * height, x-height, etc.), 250 * 251 * - a specific glyph analyzer that computes segments and edges for each 252 * glyph covered by the script, 253 * 254 * - a specific grid-fitting algorithm that distorts the scaled glyph 255 * outline according to the results of the glyph analyzer. 256 */ 257 258 #define AFWRTSYS_H_ /* don't load header files */ 259 #undef WRITING_SYSTEM 260 #define WRITING_SYSTEM( ws, WS ) \ 261 AF_WRITING_SYSTEM_ ## WS, 262 263 /* The list of known writing systems. */ 264 typedef enum AF_WritingSystem_ 265 { 266 267 #include "afwrtsys.h" 268 269 AF_WRITING_SYSTEM_MAX /* do not remove */ 270 271 } AF_WritingSystem; 272 273 #undef AFWRTSYS_H_ 274 275 276 typedef struct AF_WritingSystemClassRec_ 277 { 278 AF_WritingSystem writing_system; 279 280 FT_Offset style_metrics_size; 281 AF_WritingSystem_InitMetricsFunc style_metrics_init; 282 AF_WritingSystem_ScaleMetricsFunc style_metrics_scale; 283 AF_WritingSystem_DoneMetricsFunc style_metrics_done; 284 AF_WritingSystem_GetStdWidthsFunc style_metrics_getstdw; 285 286 AF_WritingSystem_InitHintsFunc style_hints_init; 287 AF_WritingSystem_ApplyHintsFunc style_hints_apply; 288 289 } AF_WritingSystemClassRec; 290 291 typedef const AF_WritingSystemClassRec* AF_WritingSystemClass; 292 293 294 /*************************************************************************/ 295 /*************************************************************************/ 296 /***** *****/ 297 /***** S C R I P T S *****/ 298 /***** *****/ 299 /*************************************************************************/ 300 /*************************************************************************/ 301 302 /* 303 * Each script is associated with two sets of Unicode ranges to test 304 * whether the font face supports the script, and which non-base 305 * characters the script contains. 306 * 307 * We use four-letter script tags from the OpenType specification, 308 * extended by `NONE', which indicates `no script'. 309 */ 310 311 #undef SCRIPT 312 #define SCRIPT( s, S, d, h, H, ss ) \ 313 AF_SCRIPT_ ## S, 314 315 /* The list of known scripts. */ 316 typedef enum AF_Script_ 317 { 318 319 #include "afscript.h" 320 321 AF_SCRIPT_MAX /* do not remove */ 322 323 } AF_Script; 324 325 326 typedef struct AF_Script_UniRangeRec_ 327 { 328 FT_UInt32 first; 329 FT_UInt32 last; 330 331 } AF_Script_UniRangeRec; 332 333 #define AF_UNIRANGE_REC( a, b ) { (FT_UInt32)(a), (FT_UInt32)(b) } 334 335 typedef const AF_Script_UniRangeRec* AF_Script_UniRange; 336 337 338 typedef struct AF_ScriptClassRec_ 339 { 340 AF_Script script; 341 342 /* last element in the ranges must be { 0, 0 } */ 343 AF_Script_UniRange script_uni_ranges; 344 AF_Script_UniRange script_uni_nonbase_ranges; 345 346 FT_Bool top_to_bottom_hinting; 347 348 const char* standard_charstring; /* for default width and height */ 349 350 } AF_ScriptClassRec; 351 352 typedef const AF_ScriptClassRec* AF_ScriptClass; 353 354 355 /*************************************************************************/ 356 /*************************************************************************/ 357 /***** *****/ 358 /***** C O V E R A G E S *****/ 359 /***** *****/ 360 /*************************************************************************/ 361 /*************************************************************************/ 362 363 /* 364 * Usually, a font contains more glyphs than can be addressed by its 365 * character map. 366 * 367 * In the PostScript font world, encoding vectors specific to a given 368 * task are used to select such glyphs, and these glyphs can be often 369 * recognized by having a suffix in its glyph names. For example, a 370 * superscript glyph `A' might be called `A.sup'. Unfortunately, this 371 * naming scheme is not standardized and thus unusable for us. 372 * 373 * In the OpenType world, a better solution was invented, namely 374 * `features', which cleanly separate a character's input encoding from 375 * the corresponding glyph's appearance, and which don't use glyph names 376 * at all. For our purposes, and slightly generalized, an OpenType 377 * feature is a name of a mapping that maps character codes to 378 * non-standard glyph indices (features get used for other things also). 379 * For example, the `sups' feature provides superscript glyphs, thus 380 * mapping character codes like `A' or `B' to superscript glyph 381 * representation forms. How this mapping happens is completely 382 * uninteresting to us. 383 * 384 * For the auto-hinter, a `coverage' represents all glyphs of an OpenType 385 * feature collected in a set (as listed below) that can be hinted 386 * together. To continue the above example, superscript glyphs must not 387 * be hinted together with normal glyphs because the blue zones 388 * completely differ. 389 * 390 * Note that FreeType itself doesn't compute coverages; it only provides 391 * the glyphs addressable by the default Unicode character map. Instead, 392 * we use the HarfBuzz library (if available), which has many functions 393 * exactly for this purpose. 394 * 395 * AF_COVERAGE_DEFAULT is special: It should cover everything that isn't 396 * listed separately (including the glyphs addressable by the character 397 * map). In case HarfBuzz isn't available, it exactly covers the glyphs 398 * addressable by the character map. 399 * 400 */ 401 402 #undef COVERAGE 403 #define COVERAGE( name, NAME, description, \ 404 tag1, tag2, tag3, tag4 ) \ 405 AF_COVERAGE_ ## NAME, 406 407 408 typedef enum AF_Coverage_ 409 { 410 #include "afcover.h" 411 412 AF_COVERAGE_DEFAULT 413 414 } AF_Coverage; 415 416 417 /*************************************************************************/ 418 /*************************************************************************/ 419 /***** *****/ 420 /***** S T Y L E S *****/ 421 /***** *****/ 422 /*************************************************************************/ 423 /*************************************************************************/ 424 425 /* 426 * The topmost structure for modelling the auto-hinter glyph input data 427 * is a `style class', grouping everything together. 428 */ 429 430 #undef STYLE 431 #define STYLE( s, S, d, ws, sc, ss, c ) \ 432 AF_STYLE_ ## S, 433 434 /* The list of known styles. */ 435 typedef enum AF_Style_ 436 { 437 438 #include "afstyles.h" 439 440 AF_STYLE_MAX /* do not remove */ 441 442 } AF_Style; 443 444 445 typedef struct AF_StyleClassRec_ 446 { 447 AF_Style style; 448 449 AF_WritingSystem writing_system; 450 AF_Script script; 451 AF_Blue_Stringset blue_stringset; 452 AF_Coverage coverage; 453 454 } AF_StyleClassRec; 455 456 typedef const AF_StyleClassRec* AF_StyleClass; 457 458 459 /*************************************************************************/ 460 /*************************************************************************/ 461 /***** *****/ 462 /***** S T Y L E M E T R I C S *****/ 463 /***** *****/ 464 /*************************************************************************/ 465 /*************************************************************************/ 466 467 typedef struct AF_FaceGlobalsRec_* AF_FaceGlobals; 468 469 /* This is the main structure that combines everything. Autofit modules */ 470 /* specific to writing systems derive their structures from it, for */ 471 /* example `AF_LatinMetrics'. */ 472 473 typedef struct AF_StyleMetricsRec_ 474 { 475 AF_StyleClass style_class; 476 AF_ScalerRec scaler; 477 FT_Bool digits_have_same_width; 478 479 AF_FaceGlobals globals; /* to access properties */ 480 481 } AF_StyleMetricsRec; 482 483 484 #define AF_HINTING_BOTTOM_TO_TOP 0 485 #define AF_HINTING_TOP_TO_BOTTOM 1 486 487 488 /* Declare and define vtables for classes */ 489 #ifndef FT_CONFIG_OPTION_PIC 490 491 #define AF_DECLARE_WRITING_SYSTEM_CLASS( writing_system_class ) \ 492 FT_CALLBACK_TABLE const AF_WritingSystemClassRec \ 493 writing_system_class; 494 495 #define AF_DEFINE_WRITING_SYSTEM_CLASS( \ 496 writing_system_class, \ 497 system, \ 498 m_size, \ 499 m_init, \ 500 m_scale, \ 501 m_done, \ 502 m_stdw, \ 503 h_init, \ 504 h_apply ) \ 505 FT_CALLBACK_TABLE_DEF \ 506 const AF_WritingSystemClassRec writing_system_class = \ 507 { \ 508 system, \ 509 \ 510 m_size, \ 511 \ 512 m_init, \ 513 m_scale, \ 514 m_done, \ 515 m_stdw, \ 516 \ 517 h_init, \ 518 h_apply \ 519 }; 520 521 522 #define AF_DECLARE_SCRIPT_CLASS( script_class ) \ 523 FT_CALLBACK_TABLE const AF_ScriptClassRec \ 524 script_class; 525 526 #define AF_DEFINE_SCRIPT_CLASS( \ 527 script_class, \ 528 script, \ 529 ranges, \ 530 nonbase_ranges, \ 531 top_to_bottom, \ 532 std_charstring ) \ 533 FT_CALLBACK_TABLE_DEF \ 534 const AF_ScriptClassRec script_class = \ 535 { \ 536 script, \ 537 ranges, \ 538 nonbase_ranges, \ 539 top_to_bottom, \ 540 std_charstring, \ 541 }; 542 543 544 #define AF_DECLARE_STYLE_CLASS( style_class ) \ 545 FT_CALLBACK_TABLE const AF_StyleClassRec \ 546 style_class; 547 548 #define AF_DEFINE_STYLE_CLASS( \ 549 style_class, \ 550 style, \ 551 writing_system, \ 552 script, \ 553 blue_stringset, \ 554 coverage ) \ 555 FT_CALLBACK_TABLE_DEF \ 556 const AF_StyleClassRec style_class = \ 557 { \ 558 style, \ 559 writing_system, \ 560 script, \ 561 blue_stringset, \ 562 coverage \ 563 }; 564 565 #else /* FT_CONFIG_OPTION_PIC */ 566 567 #define AF_DECLARE_WRITING_SYSTEM_CLASS( writing_system_class ) \ 568 FT_LOCAL( void ) \ 569 FT_Init_Class_ ## writing_system_class( AF_WritingSystemClassRec* ac ); 570 571 #define AF_DEFINE_WRITING_SYSTEM_CLASS( \ 572 writing_system_class, \ 573 system, \ 574 m_size, \ 575 m_init, \ 576 m_scale, \ 577 m_done, \ 578 m_stdw, \ 579 h_init, \ 580 h_apply ) \ 581 FT_LOCAL_DEF( void ) \ 582 FT_Init_Class_ ## writing_system_class( AF_WritingSystemClassRec* ac ) \ 583 { \ 584 ac->writing_system = system; \ 585 \ 586 ac->style_metrics_size = m_size; \ 587 \ 588 ac->style_metrics_init = m_init; \ 589 ac->style_metrics_scale = m_scale; \ 590 ac->style_metrics_done = m_done; \ 591 ac->style_metrics_getstdw = m_stdw; \ 592 \ 593 ac->style_hints_init = h_init; \ 594 ac->style_hints_apply = h_apply; \ 595 } 596 597 598 #define AF_DECLARE_SCRIPT_CLASS( script_class ) \ 599 FT_LOCAL( void ) \ 600 FT_Init_Class_ ## script_class( AF_ScriptClassRec* ac ); 601 602 #define AF_DEFINE_SCRIPT_CLASS( \ 603 script_class, \ 604 script_, \ 605 ranges, \ 606 nonbase_ranges, \ 607 top_to_bottom, \ 608 std_charstring ) \ 609 FT_LOCAL_DEF( void ) \ 610 FT_Init_Class_ ## script_class( AF_ScriptClassRec* ac ) \ 611 { \ 612 ac->script = script_; \ 613 ac->script_uni_ranges = ranges; \ 614 ac->script_uni_nonbase_ranges = nonbase_ranges; \ 615 ac->top_to_bottom_hinting = top_to_bottom; \ 616 ac->standard_charstring = std_charstring; \ 617 } 618 619 620 #define AF_DECLARE_STYLE_CLASS( style_class ) \ 621 FT_LOCAL( void ) \ 622 FT_Init_Class_ ## style_class( AF_StyleClassRec* ac ); 623 624 #define AF_DEFINE_STYLE_CLASS( \ 625 style_class, \ 626 style_, \ 627 writing_system_, \ 628 script_, \ 629 blue_stringset_, \ 630 coverage_ ) \ 631 FT_LOCAL_DEF( void ) \ 632 FT_Init_Class_ ## style_class( AF_StyleClassRec* ac ) \ 633 { \ 634 ac->style = style_; \ 635 ac->writing_system = writing_system_; \ 636 ac->script = script_; \ 637 ac->blue_stringset = blue_stringset_; \ 638 ac->coverage = coverage_; \ 639 } 640 641 #endif /* FT_CONFIG_OPTION_PIC */ 642 643 644 /* */ 645 646 FT_END_HEADER 647 648 #endif /* AFTYPES_H_ */ 649 650 651 /* END */ 652
