1 /***************************************************************************/ 2 /* */ 3 /* cf2blues.c */ 4 /* */ 5 /* Adobe's code for handling Blue Zones (body). */ 6 /* */ 7 /* Copyright 2009-2013 Adobe Systems Incorporated. */ 8 /* */ 9 /* This software, and all works of authorship, whether in source or */ 10 /* object code form as indicated by the copyright notice(s) included */ 11 /* herein (collectively, the "Work") is made available, and may only be */ 12 /* used, modified, and distributed under the FreeType Project License, */ 13 /* LICENSE.TXT. Additionally, subject to the terms and conditions of the */ 14 /* FreeType Project License, each contributor to the Work hereby grants */ 15 /* to any individual or legal entity exercising permissions granted by */ 16 /* the FreeType Project License and this section (hereafter, "You" or */ 17 /* "Your") a perpetual, worldwide, non-exclusive, no-charge, */ 18 /* royalty-free, irrevocable (except as stated in this section) patent */ 19 /* license to make, have made, use, offer to sell, sell, import, and */ 20 /* otherwise transfer the Work, where such license applies only to those */ 21 /* patent claims licensable by such contributor that are necessarily */ 22 /* infringed by their contribution(s) alone or by combination of their */ 23 /* contribution(s) with the Work to which such contribution(s) was */ 24 /* submitted. If You institute patent litigation against any entity */ 25 /* (including a cross-claim or counterclaim in a lawsuit) alleging that */ 26 /* the Work or a contribution incorporated within the Work constitutes */ 27 /* direct or contributory patent infringement, then any patent licenses */ 28 /* granted to You under this License for that Work shall terminate as of */ 29 /* the date such litigation is filed. */ 30 /* */ 31 /* By using, modifying, or distributing the Work you indicate that you */ 32 /* have read and understood the terms and conditions of the */ 33 /* FreeType Project License as well as those provided in this section, */ 34 /* and you accept them fully. */ 35 /* */ 36 /***************************************************************************/ 37 38 39 #include "cf2ft.h" 40 #include FT_INTERNAL_DEBUG_H 41 42 #include "cf2blues.h" 43 #include "cf2hints.h" 44 #include "cf2font.h" 45 46 47 /*************************************************************************/ 48 /* */ 49 /* The macro FT_COMPONENT is used in trace mode. It is an implicit */ 50 /* parameter of the FT_TRACE() and FT_ERROR() macros, used to print/log */ 51 /* messages during execution. */ 52 /* */ 53 #undef FT_COMPONENT 54 #define FT_COMPONENT trace_cf2blues 55 56 57 /* 58 * For blue values, the FreeType parser produces an array of integers, 59 * while the Adobe CFF engine produces an array of fixed. 60 * Define a macro to convert FreeType to fixed. 61 */ 62 #define cf2_blueToFixed( x ) cf2_intToFixed( x ) 63 64 65 FT_LOCAL_DEF( void ) 66 cf2_blues_init( CF2_Blues blues, 67 CF2_Font font ) 68 { 69 /* pointer to parsed font object */ 70 CFF_Decoder* decoder = font->decoder; 71 72 CF2_Fixed zoneHeight; 73 CF2_Fixed maxZoneHeight = 0; 74 CF2_Fixed csUnitsPerPixel; 75 76 size_t numBlueValues; 77 size_t numOtherBlues; 78 size_t numFamilyBlues; 79 size_t numFamilyOtherBlues; 80 81 FT_Pos* blueValues; 82 FT_Pos* otherBlues; 83 FT_Pos* familyBlues; 84 FT_Pos* familyOtherBlues; 85 86 size_t i; 87 CF2_Fixed emBoxBottom, emBoxTop; 88 89 CF2_Int unitsPerEm = font->unitsPerEm; 90 91 92 if ( unitsPerEm == 0 ) 93 unitsPerEm = 1000; 94 95 FT_ZERO( blues ); 96 blues->scale = font->innerTransform.d; 97 98 cf2_getBlueMetrics( decoder, 99 &blues->blueScale, 100 &blues->blueShift, 101 &blues->blueFuzz ); 102 103 cf2_getBlueValues( decoder, &numBlueValues, &blueValues ); 104 cf2_getOtherBlues( decoder, &numOtherBlues, &otherBlues ); 105 cf2_getFamilyBlues( decoder, &numFamilyBlues, &familyBlues ); 106 cf2_getFamilyOtherBlues( decoder, &numFamilyOtherBlues, &familyOtherBlues ); 107 108 /* 109 * synthetic em box hint heuristic 110 * 111 * Apply this when ideographic dictionary (LanguageGroup 1) has no 112 * real alignment zones. Adobe tools generate dummy zones at -250 and 113 * 1100 for a 1000 unit em. Fonts with ICF-based alignment zones 114 * should not enable the heuristic. When the heuristic is enabled, 115 * the font's blue zones are ignored. 116 * 117 */ 118 119 /* get em box from OS/2 typoAscender/Descender */ 120 /* TODO: FreeType does not parse these metrics. Skip them for now. */ 121 #if 0 122 FCM_getHorizontalLineMetrics( &e, 123 font->font, 124 &ascender, 125 &descender, 126 &linegap ); 127 if ( ascender - descender == unitsPerEm ) 128 { 129 emBoxBottom = cf2_intToFixed( descender ); 130 emBoxTop = cf2_intToFixed( ascender ); 131 } 132 else 133 #endif 134 { 135 emBoxBottom = CF2_ICF_Bottom; 136 emBoxTop = CF2_ICF_Top; 137 } 138 139 if ( cf2_getLanguageGroup( decoder ) == 1 && 140 ( numBlueValues == 0 || 141 ( numBlueValues == 4 && 142 cf2_blueToFixed( blueValues[0] ) < emBoxBottom && 143 cf2_blueToFixed( blueValues[1] ) < emBoxBottom && 144 cf2_blueToFixed( blueValues[2] ) > emBoxTop && 145 cf2_blueToFixed( blueValues[3] ) > emBoxTop ) ) ) 146 { 147 /* 148 * Construct hint edges suitable for synthetic ghost hints at top 149 * and bottom of em box. +-CF2_MIN_COUNTER allows for unhinted 150 * features above or below the last hinted edge. This also gives a 151 * net 1 pixel boost to the height of ideographic glyphs. 152 * 153 * Note: Adjust synthetic hints outward by epsilon (0x.0001) to 154 * avoid interference. E.g., some fonts have real hints at 155 * 880 and -120. 156 */ 157 158 blues->emBoxBottomEdge.csCoord = emBoxBottom - CF2_FIXED_EPSILON; 159 blues->emBoxBottomEdge.dsCoord = cf2_fixedRound( 160 FT_MulFix( 161 blues->emBoxBottomEdge.csCoord, 162 blues->scale ) ) - 163 CF2_MIN_COUNTER; 164 blues->emBoxBottomEdge.scale = blues->scale; 165 blues->emBoxBottomEdge.flags = CF2_GhostBottom | 166 CF2_Locked | 167 CF2_Synthetic; 168 169 blues->emBoxTopEdge.csCoord = emBoxTop + CF2_FIXED_EPSILON + 170 2 * font->darkenY; 171 blues->emBoxTopEdge.dsCoord = cf2_fixedRound( 172 FT_MulFix( 173 blues->emBoxTopEdge.csCoord, 174 blues->scale ) ) + 175 CF2_MIN_COUNTER; 176 blues->emBoxTopEdge.scale = blues->scale; 177 blues->emBoxTopEdge.flags = CF2_GhostTop | 178 CF2_Locked | 179 CF2_Synthetic; 180 181 blues->doEmBoxHints = TRUE; /* enable the heuristic */ 182 183 return; 184 } 185 186 /* copy `BlueValues' and `OtherBlues' to a combined array of top and */ 187 /* bottom zones */ 188 for ( i = 0; i < numBlueValues; i += 2 ) 189 { 190 blues->zone[blues->count].csBottomEdge = 191 cf2_blueToFixed( blueValues[i] ); 192 blues->zone[blues->count].csTopEdge = 193 cf2_blueToFixed( blueValues[i + 1] ); 194 195 zoneHeight = blues->zone[blues->count].csTopEdge - 196 blues->zone[blues->count].csBottomEdge; 197 198 if ( zoneHeight < 0 ) 199 { 200 FT_TRACE4(( "cf2_blues_init: ignoring negative zone height\n" )); 201 continue; /* reject this zone */ 202 } 203 204 if ( zoneHeight > maxZoneHeight ) 205 { 206 /* take maximum before darkening adjustment */ 207 /* so overshoot suppression point doesn't change */ 208 maxZoneHeight = zoneHeight; 209 } 210 211 /* adjust both edges of top zone upward by twice darkening amount */ 212 if ( i != 0 ) 213 { 214 blues->zone[blues->count].csTopEdge += 2 * font->darkenY; 215 blues->zone[blues->count].csBottomEdge += 2 * font->darkenY; 216 } 217 218 /* first `BlueValue' is bottom zone; others are top */ 219 if ( i == 0 ) 220 { 221 blues->zone[blues->count].bottomZone = 222 TRUE; 223 blues->zone[blues->count].csFlatEdge = 224 blues->zone[blues->count].csTopEdge; 225 } 226 else 227 { 228 blues->zone[blues->count].bottomZone = 229 FALSE; 230 blues->zone[blues->count].csFlatEdge = 231 blues->zone[blues->count].csBottomEdge; 232 } 233 234 blues->count += 1; 235 } 236 237 for ( i = 0; i < numOtherBlues; i += 2 ) 238 { 239 blues->zone[blues->count].csBottomEdge = 240 cf2_blueToFixed( otherBlues[i] ); 241 blues->zone[blues->count].csTopEdge = 242 cf2_blueToFixed( otherBlues[i + 1] ); 243 244 zoneHeight = blues->zone[blues->count].csTopEdge - 245 blues->zone[blues->count].csBottomEdge; 246 247 if ( zoneHeight < 0 ) 248 { 249 FT_TRACE4(( "cf2_blues_init: ignoring negative zone height\n" )); 250 continue; /* reject this zone */ 251 } 252 253 if ( zoneHeight > maxZoneHeight ) 254 { 255 /* take maximum before darkening adjustment */ 256 /* so overshoot suppression point doesn't change */ 257 maxZoneHeight = zoneHeight; 258 } 259 260 /* Note: bottom zones are not adjusted for darkening amount */ 261 262 /* all OtherBlues are bottom zone */ 263 blues->zone[blues->count].bottomZone = 264 TRUE; 265 blues->zone[blues->count].csFlatEdge = 266 blues->zone[blues->count].csTopEdge; 267 268 blues->count += 1; 269 } 270 271 /* Adjust for FamilyBlues */ 272 273 /* Search for the nearest flat edge in `FamilyBlues' or */ 274 /* `FamilyOtherBlues'. According to the Black Book, any matching edge */ 275 /* must be within one device pixel */ 276 277 csUnitsPerPixel = FT_DivFix( cf2_intToFixed( 1 ), blues->scale ); 278 279 /* loop on all zones in this font */ 280 for ( i = 0; i < blues->count; i++ ) 281 { 282 size_t j; 283 CF2_Fixed minDiff; 284 CF2_Fixed flatFamilyEdge, diff; 285 /* value for this font */ 286 CF2_Fixed flatEdge = blues->zone[i].csFlatEdge; 287 288 289 if ( blues->zone[i].bottomZone ) 290 { 291 /* In a bottom zone, the top edge is the flat edge. */ 292 /* Search `FamilyOtherBlues' for bottom zones; look for closest */ 293 /* Family edge that is within the one pixel threshold. */ 294 295 minDiff = CF2_FIXED_MAX; 296 297 for ( j = 0; j < numFamilyOtherBlues; j += 2 ) 298 { 299 /* top edge */ 300 flatFamilyEdge = cf2_blueToFixed( familyOtherBlues[j + 1] ); 301 302 diff = cf2_fixedAbs( flatEdge - flatFamilyEdge ); 303 304 if ( diff < minDiff && diff < csUnitsPerPixel ) 305 { 306 blues->zone[i].csFlatEdge = flatFamilyEdge; 307 minDiff = diff; 308 309 if ( diff == 0 ) 310 break; 311 } 312 } 313 314 /* check the first member of FamilyBlues, which is a bottom zone */ 315 if ( numFamilyBlues >= 2 ) 316 { 317 /* top edge */ 318 flatFamilyEdge = cf2_blueToFixed( familyBlues[1] ); 319 320 diff = cf2_fixedAbs( flatEdge - flatFamilyEdge ); 321 322 if ( diff < minDiff && diff < csUnitsPerPixel ) 323 blues->zone[i].csFlatEdge = flatFamilyEdge; 324 } 325 } 326 else 327 { 328 /* In a top zone, the bottom edge is the flat edge. */ 329 /* Search `FamilyBlues' for top zones; skip first zone, which is a */ 330 /* bottom zone; look for closest Family edge that is within the */ 331 /* one pixel threshold */ 332 333 minDiff = CF2_FIXED_MAX; 334 335 for ( j = 2; j < numFamilyBlues; j += 2 ) 336 { 337 /* bottom edge */ 338 flatFamilyEdge = cf2_blueToFixed( familyBlues[j] ); 339 340 /* adjust edges of top zone upward by twice darkening amount */ 341 flatFamilyEdge += 2 * font->darkenY; /* bottom edge */ 342 343 diff = cf2_fixedAbs( flatEdge - flatFamilyEdge ); 344 345 if ( diff < minDiff && diff < csUnitsPerPixel ) 346 { 347 blues->zone[i].csFlatEdge = flatFamilyEdge; 348 minDiff = diff; 349 350 if ( diff == 0 ) 351 break; 352 } 353 } 354 } 355 } 356 357 /* TODO: enforce separation of zones, including BlueFuzz */ 358 359 /* Adjust BlueScale; similar to AdjustBlueScale() in coretype */ 360 /* `bcsetup.c'. */ 361 362 if ( maxZoneHeight > 0 ) 363 { 364 if ( blues->blueScale > FT_DivFix( cf2_intToFixed( 1 ), 365 maxZoneHeight ) ) 366 { 367 /* clamp at maximum scale */ 368 blues->blueScale = FT_DivFix( cf2_intToFixed( 1 ), 369 maxZoneHeight ); 370 } 371 372 /* 373 * TODO: Revisit the bug fix for 613448. The minimum scale 374 * requirement catches a number of library fonts. For 375 * example, with default BlueScale (.039625) and 0.4 minimum, 376 * the test below catches any font with maxZoneHeight < 10.1. 377 * There are library fonts ranging from 2 to 10 that get 378 * caught, including e.g., Eurostile LT Std Medium with 379 * maxZoneHeight of 6. 380 * 381 */ 382 #if 0 383 if ( blueScale < .4 / maxZoneHeight ) 384 { 385 tetraphilia_assert( 0 ); 386 /* clamp at minimum scale, per bug 0613448 fix */ 387 blueScale = .4 / maxZoneHeight; 388 } 389 #endif 390 391 } 392 393 /* 394 * Suppress overshoot and boost blue zones at small sizes. Boost 395 * amount varies linearly from 0.5 pixel near 0 to 0 pixel at 396 * blueScale cutoff. 397 * Note: This boost amount is different from the coretype heuristic. 398 * 399 */ 400 401 if ( blues->scale < blues->blueScale ) 402 { 403 blues->suppressOvershoot = TRUE; 404 405 /* Change rounding threshold for `dsFlatEdge'. */ 406 /* Note: constant changed from 0.5 to 0.6 to avoid a problem with */ 407 /* 10ppem Arial */ 408 409 blues->boost = FT_MulFix( 410 cf2_floatToFixed( .6 ), 411 ( cf2_intToFixed( 1 ) - 412 FT_DivFix( blues->scale, 413 blues->blueScale ) ) ); 414 if ( blues->boost > 0x7FFF ) 415 { 416 /* boost must remain less than 0.5, or baseline could go negative */ 417 blues->boost = 0x7FFF; 418 } 419 } 420 421 /* boost and darkening have similar effects; don't do both */ 422 if ( font->stemDarkened ) 423 blues->boost = 0; 424 425 /* set device space alignment for each zone; */ 426 /* apply boost amount before rounding flat edge */ 427 428 for ( i = 0; i < blues->count; i++ ) 429 { 430 if ( blues->zone[i].bottomZone ) 431 blues->zone[i].dsFlatEdge = cf2_fixedRound( 432 FT_MulFix( 433 blues->zone[i].csFlatEdge, 434 blues->scale ) - 435 blues->boost ); 436 else 437 blues->zone[i].dsFlatEdge = cf2_fixedRound( 438 FT_MulFix( 439 blues->zone[i].csFlatEdge, 440 blues->scale ) + 441 blues->boost ); 442 } 443 } 444 445 446 /* 447 * Check whether `stemHint' is captured by one of the blue zones. 448 * 449 * Zero, one or both edges may be valid; only valid edges can be 450 * captured. For compatibility with CoolType, search top and bottom 451 * zones in the same pass (see `BlueLock'). If a hint is captured, 452 * return true and position the edge(s) in one of 3 ways: 453 * 454 * 1) If `BlueScale' suppresses overshoot, position the captured edge 455 * at the flat edge of the zone. 456 * 2) If overshoot is not suppressed and `BlueShift' requires 457 * overshoot, position the captured edge a minimum of 1 device pixel 458 * from the flat edge. 459 * 3) If overshoot is not suppressed or required, position the captured 460 * edge at the nearest device pixel. 461 * 462 */ 463 FT_LOCAL_DEF( FT_Bool ) 464 cf2_blues_capture( const CF2_Blues blues, 465 CF2_Hint bottomHintEdge, 466 CF2_Hint topHintEdge ) 467 { 468 /* TODO: validate? */ 469 CF2_Fixed csFuzz = blues->blueFuzz; 470 471 /* new position of captured edge */ 472 CF2_Fixed dsNew; 473 474 /* amount that hint is moved when positioned */ 475 CF2_Fixed dsMove = 0; 476 477 FT_Bool captured = FALSE; 478 CF2_UInt i; 479 480 481 /* assert edge flags are consistent */ 482 FT_ASSERT( !cf2_hint_isTop( bottomHintEdge ) && 483 !cf2_hint_isBottom( topHintEdge ) ); 484 485 /* TODO: search once without blue fuzz for compatibility with coretype? */ 486 for ( i = 0; i < blues->count; i++ ) 487 { 488 if ( blues->zone[i].bottomZone && 489 cf2_hint_isBottom( bottomHintEdge ) ) 490 { 491 if ( ( blues->zone[i].csBottomEdge - csFuzz ) <= 492 bottomHintEdge->csCoord && 493 bottomHintEdge->csCoord <= 494 ( blues->zone[i].csTopEdge + csFuzz ) ) 495 { 496 /* bottom edge captured by bottom zone */ 497 498 if ( blues->suppressOvershoot ) 499 dsNew = blues->zone[i].dsFlatEdge; 500 501 else if ( ( blues->zone[i].csTopEdge - bottomHintEdge->csCoord ) >= 502 blues->blueShift ) 503 { 504 /* guarantee minimum of 1 pixel overshoot */ 505 dsNew = FT_MIN( 506 cf2_fixedRound( bottomHintEdge->dsCoord ), 507 blues->zone[i].dsFlatEdge - cf2_intToFixed( 1 ) ); 508 } 509 510 else 511 { 512 /* simply round captured edge */ 513 dsNew = cf2_fixedRound( bottomHintEdge->dsCoord ); 514 } 515 516 dsMove = dsNew - bottomHintEdge->dsCoord; 517 captured = TRUE; 518 519 break; 520 } 521 } 522 523 if ( !blues->zone[i].bottomZone && cf2_hint_isTop( topHintEdge ) ) 524 { 525 if ( ( blues->zone[i].csBottomEdge - csFuzz ) <= 526 topHintEdge->csCoord && 527 topHintEdge->csCoord <= 528 ( blues->zone[i].csTopEdge + csFuzz ) ) 529 { 530 /* top edge captured by top zone */ 531 532 if ( blues->suppressOvershoot ) 533 dsNew = blues->zone[i].dsFlatEdge; 534 535 else if ( ( topHintEdge->csCoord - blues->zone[i].csBottomEdge ) >= 536 blues->blueShift ) 537 { 538 /* guarantee minimum of 1 pixel overshoot */ 539 dsNew = FT_MAX( 540 cf2_fixedRound( topHintEdge->dsCoord ), 541 blues->zone[i].dsFlatEdge + cf2_intToFixed( 1 ) ); 542 } 543 544 else 545 { 546 /* simply round captured edge */ 547 dsNew = cf2_fixedRound( topHintEdge->dsCoord ); 548 } 549 550 dsMove = dsNew - topHintEdge->dsCoord; 551 captured = TRUE; 552 553 break; 554 } 555 } 556 } 557 558 if ( captured ) 559 { 560 /* move both edges and flag them `locked' */ 561 if ( cf2_hint_isValid( bottomHintEdge ) ) 562 { 563 bottomHintEdge->dsCoord += dsMove; 564 cf2_hint_lock( bottomHintEdge ); 565 } 566 567 if ( cf2_hint_isValid( topHintEdge ) ) 568 { 569 topHintEdge->dsCoord += dsMove; 570 cf2_hint_lock( topHintEdge ); 571 } 572 } 573 574 return captured; 575 } 576 577 578 /* END */ 579
