1 /***************************************************************************/ 2 /* */ 3 /* afloader.c */ 4 /* */ 5 /* Auto-fitter glyph loading routines (body). */ 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 #include "afglobal.h" 20 #include "afloader.h" 21 #include "afhints.h" 22 #include "aferrors.h" 23 #include "afmodule.h" 24 #include "afpic.h" 25 26 #include FT_INTERNAL_CALC_H 27 28 29 /* Initialize glyph loader. */ 30 31 FT_LOCAL_DEF( void ) 32 af_loader_init( AF_Loader loader, 33 AF_GlyphHints hints ) 34 { 35 FT_ZERO( loader ); 36 37 loader->hints = hints; 38 } 39 40 41 /* Reset glyph loader and compute globals if necessary. */ 42 43 FT_LOCAL_DEF( FT_Error ) 44 af_loader_reset( AF_Loader loader, 45 AF_Module module, 46 FT_Face face ) 47 { 48 FT_Error error = FT_Err_Ok; 49 50 51 loader->face = face; 52 loader->globals = (AF_FaceGlobals)face->autohint.data; 53 54 if ( !loader->globals ) 55 { 56 error = af_face_globals_new( face, &loader->globals, module ); 57 if ( !error ) 58 { 59 face->autohint.data = 60 (FT_Pointer)loader->globals; 61 face->autohint.finalizer = 62 (FT_Generic_Finalizer)af_face_globals_free; 63 } 64 } 65 66 return error; 67 } 68 69 70 /* Finalize glyph loader. */ 71 72 FT_LOCAL_DEF( void ) 73 af_loader_done( AF_Loader loader ) 74 { 75 loader->face = NULL; 76 loader->globals = NULL; 77 loader->hints = NULL; 78 } 79 80 81 #define af_intToFixed( i ) \ 82 ( (FT_Fixed)( (FT_UInt32)(i) << 16 ) ) 83 #define af_fixedToInt( x ) \ 84 ( (FT_Short)( ( (FT_UInt32)(x) + 0x8000U ) >> 16 ) ) 85 #define af_floatToFixed( f ) \ 86 ( (FT_Fixed)( (f) * 65536.0 + 0.5 ) ) 87 88 89 static FT_Error 90 af_loader_embolden_glyph_in_slot( AF_Loader loader, 91 FT_Face face, 92 AF_StyleMetrics style_metrics ) 93 { 94 FT_Error error = FT_Err_Ok; 95 96 FT_GlyphSlot slot = face->glyph; 97 AF_FaceGlobals globals = loader->globals; 98 AF_WritingSystemClass writing_system_class; 99 100 FT_Size_Metrics* size_metrics = &face->size->internal->autohint_metrics; 101 102 FT_Pos stdVW = 0; 103 FT_Pos stdHW = 0; 104 105 FT_Bool size_changed = size_metrics->x_ppem != 106 globals->stem_darkening_for_ppem; 107 108 FT_Fixed em_size = af_intToFixed( face->units_per_EM ); 109 FT_Fixed em_ratio = FT_DivFix( af_intToFixed( 1000 ), em_size ); 110 111 FT_Matrix scale_down_matrix = { 0x10000L, 0, 0, 0x10000L }; 112 113 114 /* Skip stem darkening for broken fonts. */ 115 if ( !face->units_per_EM ) 116 { 117 error = FT_ERR( Corrupted_Font_Header ); 118 goto Exit; 119 } 120 121 /* 122 * We depend on the writing system (script analyzers) to supply 123 * standard widths for the script of the glyph we are looking at. If 124 * it can't deliver, stem darkening is disabled. 125 */ 126 writing_system_class = 127 AF_WRITING_SYSTEM_CLASSES_GET[style_metrics->style_class->writing_system]; 128 129 if ( writing_system_class->style_metrics_getstdw ) 130 writing_system_class->style_metrics_getstdw( style_metrics, 131 &stdHW, 132 &stdVW ); 133 else 134 { 135 error = FT_ERR( Unimplemented_Feature ); 136 goto Exit; 137 } 138 139 if ( size_changed || 140 ( stdVW > 0 && stdVW != globals->standard_vertical_width ) ) 141 { 142 FT_Fixed darken_by_font_units_x, darken_x; 143 144 145 darken_by_font_units_x = 146 af_intToFixed( af_loader_compute_darkening( loader, 147 face, 148 stdVW ) ); 149 darken_x = FT_DivFix( FT_MulFix( darken_by_font_units_x, 150 size_metrics->x_scale ), 151 em_ratio ); 152 153 globals->standard_vertical_width = stdVW; 154 globals->stem_darkening_for_ppem = size_metrics->x_ppem; 155 globals->darken_x = af_fixedToInt( darken_x ); 156 } 157 158 if ( size_changed || 159 ( stdHW > 0 && stdHW != globals->standard_horizontal_width ) ) 160 { 161 FT_Fixed darken_by_font_units_y, darken_y; 162 163 164 darken_by_font_units_y = 165 af_intToFixed( af_loader_compute_darkening( loader, 166 face, 167 stdHW ) ); 168 darken_y = FT_DivFix( FT_MulFix( darken_by_font_units_y, 169 size_metrics->y_scale ), 170 em_ratio ); 171 172 globals->standard_horizontal_width = stdHW; 173 globals->stem_darkening_for_ppem = size_metrics->x_ppem; 174 globals->darken_y = af_fixedToInt( darken_y ); 175 176 /* 177 * Scale outlines down on the Y-axis to keep them inside their blue 178 * zones. The stronger the emboldening, the stronger the downscaling 179 * (plus heuristical padding to prevent outlines still falling out 180 * their zones due to rounding). 181 * 182 * Reason: `FT_Outline_Embolden' works by shifting the rightmost 183 * points of stems farther to the right, and topmost points farther 184 * up. This positions points on the Y-axis outside their 185 * pre-computed blue zones and leads to distortion when applying the 186 * hints in the code further below. Code outside this emboldening 187 * block doesn't know we are presenting it with modified outlines the 188 * analyzer didn't see! 189 * 190 * An unfortunate side effect of downscaling is that the emboldening 191 * effect is slightly decreased. The loss becomes more pronounced 192 * versus the CFF driver at smaller sizes, e.g., at 9ppem and below. 193 */ 194 globals->scale_down_factor = 195 FT_DivFix( em_size - ( darken_by_font_units_y + af_intToFixed( 8 ) ), 196 em_size ); 197 } 198 199 FT_Outline_EmboldenXY( &slot->outline, 200 globals->darken_x, 201 globals->darken_y ); 202 203 scale_down_matrix.yy = globals->scale_down_factor; 204 FT_Outline_Transform( &slot->outline, &scale_down_matrix ); 205 206 Exit: 207 return error; 208 } 209 210 211 /* Load the glyph at index into the current slot of a face and hint it. */ 212 213 FT_LOCAL_DEF( FT_Error ) 214 af_loader_load_glyph( AF_Loader loader, 215 AF_Module module, 216 FT_Face face, 217 FT_UInt glyph_index, 218 FT_Int32 load_flags ) 219 { 220 FT_Error error; 221 222 FT_Size size = face->size; 223 FT_Size_Internal size_internal = size->internal; 224 FT_GlyphSlot slot = face->glyph; 225 FT_Slot_Internal slot_internal = slot->internal; 226 FT_GlyphLoader gloader = slot_internal->loader; 227 228 AF_GlyphHints hints = loader->hints; 229 AF_ScalerRec scaler; 230 AF_StyleMetrics style_metrics; 231 FT_UInt style_options = AF_STYLE_NONE_DFLT; 232 AF_StyleClass style_class; 233 AF_WritingSystemClass writing_system_class; 234 235 #ifdef FT_CONFIG_OPTION_PIC 236 AF_FaceGlobals globals = loader->globals; 237 #endif 238 239 240 if ( !size ) 241 return FT_THROW( Invalid_Size_Handle ); 242 243 FT_ZERO( &scaler ); 244 245 if ( !size_internal->autohint_metrics.x_scale || 246 size_internal->autohint_mode != FT_LOAD_TARGET_MODE( load_flags ) ) 247 { 248 /* switching between hinting modes usually means different scaling */ 249 /* values; this later on enforces recomputation of everything */ 250 /* related to the current size */ 251 252 size_internal->autohint_mode = FT_LOAD_TARGET_MODE( load_flags ); 253 size_internal->autohint_metrics = size->metrics; 254 255 #ifdef AF_CONFIG_OPTION_TT_SIZE_METRICS 256 { 257 FT_Size_Metrics* size_metrics = &size_internal->autohint_metrics; 258 259 260 /* set metrics to integer values and adjust scaling accordingly; */ 261 /* this is the same setup as with TrueType fonts, cf. function */ 262 /* `tt_size_reset' in file `ttobjs.c' */ 263 size_metrics->ascender = FT_PIX_ROUND( 264 FT_MulFix( face->ascender, 265 size_metrics->y_scale ) ); 266 size_metrics->descender = FT_PIX_ROUND( 267 FT_MulFix( face->descender, 268 size_metrics->y_scale ) ); 269 size_metrics->height = FT_PIX_ROUND( 270 FT_MulFix( face->height, 271 size_metrics->y_scale ) ); 272 273 size_metrics->x_scale = FT_DivFix( size_metrics->x_ppem << 6, 274 face->units_per_EM ); 275 size_metrics->y_scale = FT_DivFix( size_metrics->y_ppem << 6, 276 face->units_per_EM ); 277 size_metrics->max_advance = FT_PIX_ROUND( 278 FT_MulFix( face->max_advance_width, 279 size_metrics->x_scale ) ); 280 } 281 #endif /* AF_CONFIG_OPTION_TT_SIZE_METRICS */ 282 } 283 284 /* 285 * TODO: This code currently doesn't support fractional advance widths, 286 * i.e., placing hinted glyphs at anything other than integer 287 * x-positions. This is only relevant for the warper code, which 288 * scales and shifts glyphs to optimize blackness of stems (hinting on 289 * the x-axis by nature places things on pixel integers, hinting on the 290 * y-axis only, i.e., LIGHT mode, doesn't touch the x-axis). The delta 291 * values of the scaler would need to be adjusted. 292 */ 293 scaler.face = face; 294 scaler.x_scale = size_internal->autohint_metrics.x_scale; 295 scaler.x_delta = 0; 296 scaler.y_scale = size_internal->autohint_metrics.y_scale; 297 scaler.y_delta = 0; 298 299 scaler.render_mode = FT_LOAD_TARGET_MODE( load_flags ); 300 scaler.flags = 0; 301 302 /* note that the fallback style can't be changed anymore */ 303 /* after the first call of `af_loader_load_glyph' */ 304 error = af_loader_reset( loader, module, face ); 305 if ( error ) 306 goto Exit; 307 308 #ifdef FT_OPTION_AUTOFIT2 309 /* XXX: undocumented hook to activate the latin2 writing system. */ 310 if ( load_flags & ( 1UL << 20 ) ) 311 style_options = AF_STYLE_LTN2_DFLT; 312 #endif 313 314 /* 315 * Glyphs (really code points) are assigned to scripts. Script 316 * analysis is done lazily: For each glyph that passes through here, 317 * the corresponding script analyzer is called, but returns immediately 318 * if it has been run already. 319 */ 320 error = af_face_globals_get_metrics( loader->globals, glyph_index, 321 style_options, &style_metrics ); 322 if ( error ) 323 goto Exit; 324 325 style_class = style_metrics->style_class; 326 writing_system_class = 327 AF_WRITING_SYSTEM_CLASSES_GET[style_class->writing_system]; 328 329 loader->metrics = style_metrics; 330 331 if ( writing_system_class->style_metrics_scale ) 332 writing_system_class->style_metrics_scale( style_metrics, &scaler ); 333 else 334 style_metrics->scaler = scaler; 335 336 if ( writing_system_class->style_hints_init ) 337 { 338 error = writing_system_class->style_hints_init( hints, 339 style_metrics ); 340 if ( error ) 341 goto Exit; 342 } 343 344 /* 345 * Do the main work of `af_loader_load_glyph'. Note that we never have 346 * to deal with composite glyphs as those get loaded into 347 * FT_GLYPH_FORMAT_OUTLINE by the recursed `FT_Load_Glyph' function. 348 * In the rare cases where FT_LOAD_NO_RECURSE is set, it implies 349 * FT_LOAD_NO_SCALE and as such the auto-hinter is never called. 350 */ 351 load_flags |= FT_LOAD_NO_SCALE | 352 FT_LOAD_IGNORE_TRANSFORM | 353 FT_LOAD_LINEAR_DESIGN; 354 load_flags &= ~FT_LOAD_RENDER; 355 356 error = FT_Load_Glyph( face, glyph_index, load_flags ); 357 if ( error ) 358 goto Exit; 359 360 /* 361 * Apply stem darkening (emboldening) here before hints are applied to 362 * the outline. Glyphs are scaled down proportionally to the 363 * emboldening so that curve points don't fall outside their 364 * precomputed blue zones. 365 * 366 * Any emboldening done by the font driver (e.g., the CFF driver) 367 * doesn't reach here because the autohinter loads the unprocessed 368 * glyphs in font units for analysis (functions `af_*_metrics_init_*') 369 * and then above to prepare it for the rasterizers by itself, 370 * independently of the font driver. So emboldening must be done here, 371 * within the autohinter. 372 * 373 * All glyphs to be autohinted pass through here one by one. The 374 * standard widths can therefore change from one glyph to the next, 375 * depending on what script a glyph is assigned to (each script has its 376 * own set of standard widths and other metrics). The darkening amount 377 * must therefore be recomputed for each size and 378 * `standard_{vertical,horizontal}_width' change. 379 * 380 * Ignore errors and carry on without emboldening. 381 * 382 */ 383 384 /* stem darkening only works well in `light' mode */ 385 if ( scaler.render_mode == FT_RENDER_MODE_LIGHT && 386 ( !face->internal->no_stem_darkening || 387 ( face->internal->no_stem_darkening < 0 && 388 !module->no_stem_darkening ) ) ) 389 af_loader_embolden_glyph_in_slot( loader, face, style_metrics ); 390 391 loader->transformed = slot_internal->glyph_transformed; 392 if ( loader->transformed ) 393 { 394 FT_Matrix inverse; 395 396 397 loader->trans_matrix = slot_internal->glyph_matrix; 398 loader->trans_delta = slot_internal->glyph_delta; 399 400 inverse = loader->trans_matrix; 401 if ( !FT_Matrix_Invert( &inverse ) ) 402 FT_Vector_Transform( &loader->trans_delta, &inverse ); 403 } 404 405 switch ( slot->format ) 406 { 407 case FT_GLYPH_FORMAT_OUTLINE: 408 /* translate the loaded glyph when an internal transform is needed */ 409 if ( loader->transformed ) 410 FT_Outline_Translate( &slot->outline, 411 loader->trans_delta.x, 412 loader->trans_delta.y ); 413 414 /* compute original horizontal phantom points */ 415 /* (and ignore vertical ones) */ 416 loader->pp1.x = hints->x_delta; 417 loader->pp1.y = hints->y_delta; 418 loader->pp2.x = FT_MulFix( slot->metrics.horiAdvance, 419 hints->x_scale ) + hints->x_delta; 420 loader->pp2.y = hints->y_delta; 421 422 /* be sure to check for spacing glyphs */ 423 if ( slot->outline.n_points == 0 ) 424 goto Hint_Metrics; 425 426 /* now load the slot image into the auto-outline */ 427 /* and run the automatic hinting process */ 428 if ( writing_system_class->style_hints_apply ) 429 writing_system_class->style_hints_apply( glyph_index, 430 hints, 431 &gloader->base.outline, 432 style_metrics ); 433 434 /* we now need to adjust the metrics according to the change in */ 435 /* width/positioning that occurred during the hinting process */ 436 if ( scaler.render_mode != FT_RENDER_MODE_LIGHT ) 437 { 438 FT_Pos old_rsb, old_lsb, new_lsb; 439 FT_Pos pp1x_uh, pp2x_uh; 440 441 AF_AxisHints axis = &hints->axis[AF_DIMENSION_HORZ]; 442 AF_Edge edge1 = axis->edges; /* leftmost edge */ 443 AF_Edge edge2 = edge1 + 444 axis->num_edges - 1; /* rightmost edge */ 445 446 447 if ( axis->num_edges > 1 && AF_HINTS_DO_ADVANCE( hints ) ) 448 { 449 old_rsb = loader->pp2.x - edge2->opos; 450 /* loader->pp1.x is always zero at this point of time */ 451 old_lsb = edge1->opos /* - loader->pp1.x */; 452 new_lsb = edge1->pos; 453 454 /* remember unhinted values to later account */ 455 /* for rounding errors */ 456 pp1x_uh = new_lsb - old_lsb; 457 pp2x_uh = edge2->pos + old_rsb; 458 459 /* prefer too much space over too little space */ 460 /* for very small sizes */ 461 462 if ( old_lsb < 24 ) 463 pp1x_uh -= 8; 464 465 if ( old_rsb < 24 ) 466 pp2x_uh += 8; 467 468 loader->pp1.x = FT_PIX_ROUND( pp1x_uh ); 469 loader->pp2.x = FT_PIX_ROUND( pp2x_uh ); 470 471 if ( loader->pp1.x >= new_lsb && old_lsb > 0 ) 472 loader->pp1.x -= 64; 473 474 if ( loader->pp2.x <= edge2->pos && old_rsb > 0 ) 475 loader->pp2.x += 64; 476 477 slot->lsb_delta = loader->pp1.x - pp1x_uh; 478 slot->rsb_delta = loader->pp2.x - pp2x_uh; 479 } 480 else 481 { 482 FT_Pos pp1x = loader->pp1.x; 483 FT_Pos pp2x = loader->pp2.x; 484 485 486 loader->pp1.x = FT_PIX_ROUND( pp1x + hints->xmin_delta ); 487 loader->pp2.x = FT_PIX_ROUND( pp2x + hints->xmax_delta ); 488 489 slot->lsb_delta = loader->pp1.x - pp1x; 490 slot->rsb_delta = loader->pp2.x - pp2x; 491 } 492 } 493 /* `light' mode uses integer advance widths */ 494 /* but sets `lsb_delta' and `rsb_delta' */ 495 else 496 { 497 FT_Pos pp1x = loader->pp1.x; 498 FT_Pos pp2x = loader->pp2.x; 499 500 501 loader->pp1.x = FT_PIX_ROUND( pp1x ); 502 loader->pp2.x = FT_PIX_ROUND( pp2x ); 503 504 slot->lsb_delta = loader->pp1.x - pp1x; 505 slot->rsb_delta = loader->pp2.x - pp2x; 506 } 507 508 break; 509 510 default: 511 /* we don't support other formats (yet?) */ 512 error = FT_THROW( Unimplemented_Feature ); 513 } 514 515 Hint_Metrics: 516 { 517 FT_BBox bbox; 518 FT_Vector vvector; 519 520 521 vvector.x = slot->metrics.vertBearingX - slot->metrics.horiBearingX; 522 vvector.y = slot->metrics.vertBearingY - slot->metrics.horiBearingY; 523 vvector.x = FT_MulFix( vvector.x, style_metrics->scaler.x_scale ); 524 vvector.y = FT_MulFix( vvector.y, style_metrics->scaler.y_scale ); 525 526 /* transform the hinted outline if needed */ 527 if ( loader->transformed ) 528 { 529 FT_Outline_Transform( &gloader->base.outline, &loader->trans_matrix ); 530 FT_Vector_Transform( &vvector, &loader->trans_matrix ); 531 } 532 533 /* we must translate our final outline by -pp1.x and compute */ 534 /* the new metrics */ 535 if ( loader->pp1.x ) 536 FT_Outline_Translate( &gloader->base.outline, -loader->pp1.x, 0 ); 537 538 FT_Outline_Get_CBox( &gloader->base.outline, &bbox ); 539 540 bbox.xMin = FT_PIX_FLOOR( bbox.xMin ); 541 bbox.yMin = FT_PIX_FLOOR( bbox.yMin ); 542 bbox.xMax = FT_PIX_CEIL( bbox.xMax ); 543 bbox.yMax = FT_PIX_CEIL( bbox.yMax ); 544 545 slot->metrics.width = bbox.xMax - bbox.xMin; 546 slot->metrics.height = bbox.yMax - bbox.yMin; 547 slot->metrics.horiBearingX = bbox.xMin; 548 slot->metrics.horiBearingY = bbox.yMax; 549 550 slot->metrics.vertBearingX = FT_PIX_FLOOR( bbox.xMin + vvector.x ); 551 slot->metrics.vertBearingY = FT_PIX_FLOOR( bbox.yMax + vvector.y ); 552 553 /* for mono-width fonts (like Andale, Courier, etc.) we need */ 554 /* to keep the original rounded advance width; ditto for */ 555 /* digits if all have the same advance width */ 556 if ( scaler.render_mode != FT_RENDER_MODE_LIGHT && 557 ( FT_IS_FIXED_WIDTH( slot->face ) || 558 ( af_face_globals_is_digit( loader->globals, glyph_index ) && 559 style_metrics->digits_have_same_width ) ) ) 560 { 561 slot->metrics.horiAdvance = 562 FT_MulFix( slot->metrics.horiAdvance, 563 style_metrics->scaler.x_scale ); 564 565 /* Set delta values to 0. Otherwise code that uses them is */ 566 /* going to ruin the fixed advance width. */ 567 slot->lsb_delta = 0; 568 slot->rsb_delta = 0; 569 } 570 else 571 { 572 /* non-spacing glyphs must stay as-is */ 573 if ( slot->metrics.horiAdvance ) 574 slot->metrics.horiAdvance = loader->pp2.x - loader->pp1.x; 575 } 576 577 slot->metrics.vertAdvance = FT_MulFix( slot->metrics.vertAdvance, 578 style_metrics->scaler.y_scale ); 579 580 slot->metrics.horiAdvance = FT_PIX_ROUND( slot->metrics.horiAdvance ); 581 slot->metrics.vertAdvance = FT_PIX_ROUND( slot->metrics.vertAdvance ); 582 583 slot->format = FT_GLYPH_FORMAT_OUTLINE; 584 } 585 586 Exit: 587 return error; 588 } 589 590 591 /* 592 * Compute amount of font units the face should be emboldened by, in 593 * analogy to the CFF driver's `cf2_computeDarkening' function. See there 594 * for details of the algorithm. 595 * 596 * XXX: Currently a crude adaption of the original algorithm. Do better? 597 */ 598 FT_LOCAL_DEF( FT_Int32 ) 599 af_loader_compute_darkening( AF_Loader loader, 600 FT_Face face, 601 FT_Pos standard_width ) 602 { 603 AF_Module module = loader->globals->module; 604 605 FT_UShort units_per_EM; 606 FT_Fixed ppem, em_ratio; 607 FT_Fixed stem_width, stem_width_per_1000, scaled_stem, darken_amount; 608 FT_Int log_base_2; 609 FT_Int x1, y1, x2, y2, x3, y3, x4, y4; 610 611 612 ppem = FT_MAX( af_intToFixed( 4 ), 613 af_intToFixed( face->size->metrics.x_ppem ) ); 614 units_per_EM = face->units_per_EM; 615 616 em_ratio = FT_DivFix( af_intToFixed( 1000 ), 617 af_intToFixed ( units_per_EM ) ); 618 if ( em_ratio < af_floatToFixed( .01 ) ) 619 { 620 /* If something goes wrong, don't embolden. */ 621 return 0; 622 } 623 624 x1 = module->darken_params[0]; 625 y1 = module->darken_params[1]; 626 x2 = module->darken_params[2]; 627 y2 = module->darken_params[3]; 628 x3 = module->darken_params[4]; 629 y3 = module->darken_params[5]; 630 x4 = module->darken_params[6]; 631 y4 = module->darken_params[7]; 632 633 if ( standard_width <= 0 ) 634 { 635 stem_width = af_intToFixed( 75 ); /* taken from cf2font.c */ 636 stem_width_per_1000 = stem_width; 637 } 638 else 639 { 640 stem_width = af_intToFixed( standard_width ); 641 stem_width_per_1000 = FT_MulFix( stem_width, em_ratio ); 642 } 643 644 log_base_2 = FT_MSB( (FT_UInt32)stem_width_per_1000 ) + 645 FT_MSB( (FT_UInt32)ppem ); 646 647 if ( log_base_2 >= 46 ) 648 { 649 /* possible overflow */ 650 scaled_stem = af_intToFixed( x4 ); 651 } 652 else 653 scaled_stem = FT_MulFix( stem_width_per_1000, ppem ); 654 655 /* now apply the darkening parameters */ 656 if ( scaled_stem < af_intToFixed( x1 ) ) 657 darken_amount = FT_DivFix( af_intToFixed( y1 ), ppem ); 658 659 else if ( scaled_stem < af_intToFixed( x2 ) ) 660 { 661 FT_Int xdelta = x2 - x1; 662 FT_Int ydelta = y2 - y1; 663 FT_Int x = stem_width_per_1000 - 664 FT_DivFix( af_intToFixed( x1 ), ppem ); 665 666 667 if ( !xdelta ) 668 goto Try_x3; 669 670 darken_amount = FT_MulDiv( x, ydelta, xdelta ) + 671 FT_DivFix( af_intToFixed( y1 ), ppem ); 672 } 673 674 else if ( scaled_stem < af_intToFixed( x3 ) ) 675 { 676 Try_x3: 677 { 678 FT_Int xdelta = x3 - x2; 679 FT_Int ydelta = y3 - y2; 680 FT_Int x = stem_width_per_1000 - 681 FT_DivFix( af_intToFixed( x2 ), ppem ); 682 683 684 if ( !xdelta ) 685 goto Try_x4; 686 687 darken_amount = FT_MulDiv( x, ydelta, xdelta ) + 688 FT_DivFix( af_intToFixed( y2 ), ppem ); 689 } 690 } 691 692 else if ( scaled_stem < af_intToFixed( x4 ) ) 693 { 694 Try_x4: 695 { 696 FT_Int xdelta = x4 - x3; 697 FT_Int ydelta = y4 - y3; 698 FT_Int x = stem_width_per_1000 - 699 FT_DivFix( af_intToFixed( x3 ), ppem ); 700 701 702 if ( !xdelta ) 703 goto Use_y4; 704 705 darken_amount = FT_MulDiv( x, ydelta, xdelta ) + 706 FT_DivFix( af_intToFixed( y3 ), ppem ); 707 } 708 } 709 710 else 711 { 712 Use_y4: 713 darken_amount = FT_DivFix( af_intToFixed( y4 ), ppem ); 714 } 715 716 /* Convert darken_amount from per 1000 em to true character space. */ 717 return af_fixedToInt( FT_DivFix( darken_amount, em_ratio ) ); 718 } 719 720 721 /* END */ 722
