psblues.c (19403B)
1 /**************************************************************************** 2 * 3 * psblues.c 4 * 5 * Adobe's code for handling Blue Zones (body). 6 * 7 * Copyright 2009-2014 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 "psft.h" 40 #include <freetype/internal/ftdebug.h> 41 42 #include "psblues.h" 43 #include "pshints.h" 44 #include "psfont.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 cf2blues 55 56 57 FT_LOCAL_DEF( void ) 58 cf2_blues_init( CF2_Blues blues, 59 CF2_Font font ) 60 { 61 /* pointer to parsed font object */ 62 PS_Decoder* decoder = font->decoder; 63 64 CF2_Fixed zoneHeight; 65 CF2_Fixed maxZoneHeight = 0; 66 CF2_Fixed csUnitsPerPixel; 67 68 size_t numBlueValues; 69 size_t numOtherBlues; 70 size_t numFamilyBlues; 71 size_t numFamilyOtherBlues; 72 73 FT_Fixed* blueValues; 74 FT_Fixed* otherBlues; 75 FT_Fixed* familyBlues; 76 FT_Fixed* familyOtherBlues; 77 78 size_t i; 79 CF2_Fixed emBoxBottom, emBoxTop; 80 81 #if 0 82 CF2_Int unitsPerEm = font->unitsPerEm; 83 84 85 if ( unitsPerEm == 0 ) 86 unitsPerEm = 1000; 87 #endif 88 89 FT_ZERO( blues ); 90 blues->scale = font->innerTransform.d; 91 92 cf2_getBlueMetrics( decoder, 93 &blues->blueScale, 94 &blues->blueShift, 95 &blues->blueFuzz ); 96 97 cf2_getBlueValues( decoder, &numBlueValues, &blueValues ); 98 cf2_getOtherBlues( decoder, &numOtherBlues, &otherBlues ); 99 cf2_getFamilyBlues( decoder, &numFamilyBlues, &familyBlues ); 100 cf2_getFamilyOtherBlues( decoder, &numFamilyOtherBlues, &familyOtherBlues ); 101 102 /* 103 * synthetic em box hint heuristic 104 * 105 * Apply this when ideographic dictionary (LanguageGroup 1) has no 106 * real alignment zones. Adobe tools generate dummy zones at -250 and 107 * 1100 for a 1000 unit em. Fonts with ICF-based alignment zones 108 * should not enable the heuristic. When the heuristic is enabled, 109 * the font's blue zones are ignored. 110 * 111 */ 112 113 /* get em box from OS/2 typoAscender/Descender */ 114 /* TODO: FreeType does not parse these metrics. Skip them for now. */ 115 #if 0 116 FCM_getHorizontalLineMetrics( &e, 117 font->font, 118 &ascender, 119 &descender, 120 &linegap ); 121 if ( ascender - descender == unitsPerEm ) 122 { 123 emBoxBottom = cf2_intToFixed( descender ); 124 emBoxTop = cf2_intToFixed( ascender ); 125 } 126 else 127 #endif 128 { 129 emBoxBottom = CF2_ICF_Bottom; 130 emBoxTop = CF2_ICF_Top; 131 } 132 133 if ( cf2_getLanguageGroup( decoder ) == 1 && 134 ( numBlueValues == 0 || 135 ( numBlueValues == 4 && 136 blueValues[0] < emBoxBottom && 137 blueValues[1] < emBoxBottom && 138 blueValues[2] > emBoxTop && 139 blueValues[3] > emBoxTop ) ) ) 140 { 141 /* 142 * Construct hint edges suitable for synthetic ghost hints at top 143 * and bottom of em box. +-CF2_MIN_COUNTER allows for unhinted 144 * features above or below the last hinted edge. This also gives a 145 * net 1 pixel boost to the height of ideographic glyphs. 146 * 147 * Note: Adjust synthetic hints outward by epsilon (0x.0001) to 148 * avoid interference. E.g., some fonts have real hints at 149 * 880 and -120. 150 */ 151 152 blues->emBoxBottomEdge.csCoord = emBoxBottom - CF2_FIXED_EPSILON; 153 blues->emBoxBottomEdge.dsCoord = cf2_fixedRound( 154 FT_MulFix( 155 blues->emBoxBottomEdge.csCoord, 156 blues->scale ) ) - 157 CF2_MIN_COUNTER; 158 blues->emBoxBottomEdge.scale = blues->scale; 159 blues->emBoxBottomEdge.flags = CF2_GhostBottom | 160 CF2_Locked | 161 CF2_Synthetic; 162 163 blues->emBoxTopEdge.csCoord = emBoxTop + CF2_FIXED_EPSILON + 164 2 * font->darkenY; 165 blues->emBoxTopEdge.dsCoord = cf2_fixedRound( 166 FT_MulFix( 167 blues->emBoxTopEdge.csCoord, 168 blues->scale ) ) + 169 CF2_MIN_COUNTER; 170 blues->emBoxTopEdge.scale = blues->scale; 171 blues->emBoxTopEdge.flags = CF2_GhostTop | 172 CF2_Locked | 173 CF2_Synthetic; 174 175 blues->doEmBoxHints = TRUE; /* enable the heuristic */ 176 177 return; 178 } 179 180 /* copy `BlueValues' and `OtherBlues' to a combined array of top and */ 181 /* bottom zones */ 182 for ( i = 0; i < numBlueValues; i += 2 ) 183 { 184 blues->zone[blues->count].csBottomEdge = blueValues[i]; 185 blues->zone[blues->count].csTopEdge = blueValues[i + 1]; 186 187 zoneHeight = SUB_INT32( blues->zone[blues->count].csTopEdge, 188 blues->zone[blues->count].csBottomEdge ); 189 190 if ( zoneHeight < 0 ) 191 { 192 FT_TRACE4(( "cf2_blues_init: ignoring negative zone height\n" )); 193 continue; /* reject this zone */ 194 } 195 196 if ( zoneHeight > maxZoneHeight ) 197 { 198 /* take maximum before darkening adjustment */ 199 /* so overshoot suppression point doesn't change */ 200 maxZoneHeight = zoneHeight; 201 } 202 203 /* adjust both edges of top zone upward by twice darkening amount */ 204 if ( i != 0 ) 205 { 206 blues->zone[blues->count].csTopEdge += 2 * font->darkenY; 207 blues->zone[blues->count].csBottomEdge += 2 * font->darkenY; 208 } 209 210 /* first `BlueValue' is bottom zone; others are top */ 211 if ( i == 0 ) 212 { 213 blues->zone[blues->count].bottomZone = 214 TRUE; 215 blues->zone[blues->count].csFlatEdge = 216 blues->zone[blues->count].csTopEdge; 217 } 218 else 219 { 220 blues->zone[blues->count].bottomZone = 221 FALSE; 222 blues->zone[blues->count].csFlatEdge = 223 blues->zone[blues->count].csBottomEdge; 224 } 225 226 blues->count += 1; 227 } 228 229 for ( i = 0; i < numOtherBlues; i += 2 ) 230 { 231 blues->zone[blues->count].csBottomEdge = otherBlues[i]; 232 blues->zone[blues->count].csTopEdge = otherBlues[i + 1]; 233 234 zoneHeight = SUB_INT32( blues->zone[blues->count].csTopEdge, 235 blues->zone[blues->count].csBottomEdge ); 236 237 if ( zoneHeight < 0 ) 238 { 239 FT_TRACE4(( "cf2_blues_init: ignoring negative zone height\n" )); 240 continue; /* reject this zone */ 241 } 242 243 if ( zoneHeight > maxZoneHeight ) 244 { 245 /* take maximum before darkening adjustment */ 246 /* so overshoot suppression point doesn't change */ 247 maxZoneHeight = zoneHeight; 248 } 249 250 /* Note: bottom zones are not adjusted for darkening amount */ 251 252 /* all OtherBlues are bottom zone */ 253 blues->zone[blues->count].bottomZone = 254 TRUE; 255 blues->zone[blues->count].csFlatEdge = 256 blues->zone[blues->count].csTopEdge; 257 258 blues->count += 1; 259 } 260 261 /* Adjust for FamilyBlues */ 262 263 /* Search for the nearest flat edge in `FamilyBlues' or */ 264 /* `FamilyOtherBlues'. According to the Black Book, any matching edge */ 265 /* must be within one device pixel */ 266 267 csUnitsPerPixel = FT_DivFix( cf2_intToFixed( 1 ), blues->scale ); 268 269 /* loop on all zones in this font */ 270 for ( i = 0; i < blues->count; i++ ) 271 { 272 size_t j; 273 CF2_Fixed minDiff; 274 CF2_Fixed flatFamilyEdge, diff; 275 /* value for this font */ 276 CF2_Fixed flatEdge = blues->zone[i].csFlatEdge; 277 278 279 if ( blues->zone[i].bottomZone ) 280 { 281 /* In a bottom zone, the top edge is the flat edge. */ 282 /* Search `FamilyOtherBlues' for bottom zones; look for closest */ 283 /* Family edge that is within the one pixel threshold. */ 284 285 minDiff = CF2_FIXED_MAX; 286 287 for ( j = 0; j < numFamilyOtherBlues; j += 2 ) 288 { 289 /* top edge */ 290 flatFamilyEdge = familyOtherBlues[j + 1]; 291 292 diff = cf2_fixedAbs( SUB_INT32( flatEdge, flatFamilyEdge ) ); 293 294 if ( diff < minDiff && diff < csUnitsPerPixel ) 295 { 296 blues->zone[i].csFlatEdge = flatFamilyEdge; 297 minDiff = diff; 298 299 if ( diff == 0 ) 300 break; 301 } 302 } 303 304 /* check the first member of FamilyBlues, which is a bottom zone */ 305 if ( numFamilyBlues >= 2 ) 306 { 307 /* top edge */ 308 flatFamilyEdge = familyBlues[1]; 309 310 diff = cf2_fixedAbs( SUB_INT32( flatEdge, flatFamilyEdge ) ); 311 312 if ( diff < minDiff && diff < csUnitsPerPixel ) 313 blues->zone[i].csFlatEdge = flatFamilyEdge; 314 } 315 } 316 else 317 { 318 /* In a top zone, the bottom edge is the flat edge. */ 319 /* Search `FamilyBlues' for top zones; skip first zone, which is a */ 320 /* bottom zone; look for closest Family edge that is within the */ 321 /* one pixel threshold */ 322 323 minDiff = CF2_FIXED_MAX; 324 325 for ( j = 2; j < numFamilyBlues; j += 2 ) 326 { 327 /* bottom edge */ 328 flatFamilyEdge = familyBlues[j]; 329 330 /* adjust edges of top zone upward by twice darkening amount */ 331 flatFamilyEdge += 2 * font->darkenY; /* bottom edge */ 332 333 diff = cf2_fixedAbs( SUB_INT32( flatEdge, flatFamilyEdge ) ); 334 335 if ( diff < minDiff && diff < csUnitsPerPixel ) 336 { 337 blues->zone[i].csFlatEdge = flatFamilyEdge; 338 minDiff = diff; 339 340 if ( diff == 0 ) 341 break; 342 } 343 } 344 } 345 } 346 347 /* TODO: enforce separation of zones, including BlueFuzz */ 348 349 /* Adjust BlueScale; similar to AdjustBlueScale() in coretype */ 350 /* `bcsetup.c'. */ 351 352 if ( maxZoneHeight > 0 ) 353 { 354 if ( blues->blueScale > FT_DivFix( cf2_intToFixed( 1 ), 355 maxZoneHeight ) ) 356 { 357 /* clamp at maximum scale */ 358 blues->blueScale = FT_DivFix( cf2_intToFixed( 1 ), 359 maxZoneHeight ); 360 } 361 362 /* 363 * TODO: Revisit the bug fix for 613448. The minimum scale 364 * requirement catches a number of library fonts. For 365 * example, with default BlueScale (.039625) and 0.4 minimum, 366 * the test below catches any font with maxZoneHeight < 10.1. 367 * There are library fonts ranging from 2 to 10 that get 368 * caught, including e.g., Eurostile LT Std Medium with 369 * maxZoneHeight of 6. 370 * 371 */ 372 #if 0 373 if ( blueScale < .4 / maxZoneHeight ) 374 { 375 tetraphilia_assert( 0 ); 376 /* clamp at minimum scale, per bug 0613448 fix */ 377 blueScale = .4 / maxZoneHeight; 378 } 379 #endif 380 381 } 382 383 /* 384 * Suppress overshoot and boost blue zones at small sizes. Boost 385 * amount varies linearly from 0.5 pixel near 0 to 0 pixel at 386 * blueScale cutoff. 387 * Note: This boost amount is different from the coretype heuristic. 388 * 389 */ 390 391 if ( blues->scale < blues->blueScale ) 392 { 393 blues->suppressOvershoot = TRUE; 394 395 /* Change rounding threshold for `dsFlatEdge'. */ 396 /* Note: constant changed from 0.5 to 0.6 to avoid a problem with */ 397 /* 10ppem Arial */ 398 399 blues->boost = cf2_doubleToFixed( .6 ) - 400 FT_MulDiv( cf2_doubleToFixed ( .6 ), 401 blues->scale, 402 blues->blueScale ); 403 if ( blues->boost > 0x7FFF ) 404 { 405 /* boost must remain less than 0.5, or baseline could go negative */ 406 blues->boost = 0x7FFF; 407 } 408 } 409 410 /* boost and darkening have similar effects; don't do both */ 411 if ( font->stemDarkened ) 412 blues->boost = 0; 413 414 /* set device space alignment for each zone; */ 415 /* apply boost amount before rounding flat edge */ 416 417 for ( i = 0; i < blues->count; i++ ) 418 { 419 if ( blues->zone[i].bottomZone ) 420 blues->zone[i].dsFlatEdge = cf2_fixedRound( 421 FT_MulFix( 422 blues->zone[i].csFlatEdge, 423 blues->scale ) - 424 blues->boost ); 425 else 426 blues->zone[i].dsFlatEdge = cf2_fixedRound( 427 FT_MulFix( 428 blues->zone[i].csFlatEdge, 429 blues->scale ) + 430 blues->boost ); 431 } 432 } 433 434 435 /* 436 * Check whether `stemHint' is captured by one of the blue zones. 437 * 438 * Zero, one or both edges may be valid; only valid edges can be 439 * captured. For compatibility with CoolType, search top and bottom 440 * zones in the same pass (see `BlueLock'). If a hint is captured, 441 * return true and position the edge(s) in one of 3 ways: 442 * 443 * 1) If `BlueScale' suppresses overshoot, position the captured edge 444 * at the flat edge of the zone. 445 * 2) If overshoot is not suppressed and `BlueShift' requires 446 * overshoot, position the captured edge a minimum of 1 device pixel 447 * from the flat edge. 448 * 3) If overshoot is not suppressed or required, position the captured 449 * edge at the nearest device pixel. 450 * 451 */ 452 FT_LOCAL_DEF( FT_Bool ) 453 cf2_blues_capture( const CF2_Blues blues, 454 CF2_Hint bottomHintEdge, 455 CF2_Hint topHintEdge ) 456 { 457 /* TODO: validate? */ 458 CF2_Fixed csFuzz = blues->blueFuzz; 459 460 /* new position of captured edge */ 461 CF2_Fixed dsNew; 462 463 /* amount that hint is moved when positioned */ 464 CF2_Fixed dsMove = 0; 465 466 FT_Bool captured = FALSE; 467 CF2_UInt i; 468 469 470 /* assert edge flags are consistent */ 471 FT_ASSERT( !cf2_hint_isTop( bottomHintEdge ) && 472 !cf2_hint_isBottom( topHintEdge ) ); 473 474 /* TODO: search once without blue fuzz for compatibility with coretype? */ 475 for ( i = 0; i < blues->count; i++ ) 476 { 477 if ( blues->zone[i].bottomZone && 478 cf2_hint_isBottom( bottomHintEdge ) ) 479 { 480 if ( SUB_INT32( blues->zone[i].csBottomEdge, csFuzz ) <= 481 bottomHintEdge->csCoord && 482 bottomHintEdge->csCoord <= 483 ADD_INT32( blues->zone[i].csTopEdge, csFuzz ) ) 484 { 485 /* bottom edge captured by bottom zone */ 486 487 if ( blues->suppressOvershoot ) 488 dsNew = blues->zone[i].dsFlatEdge; 489 490 else if ( SUB_INT32( blues->zone[i].csTopEdge, 491 bottomHintEdge->csCoord ) >= 492 blues->blueShift ) 493 { 494 /* guarantee minimum of 1 pixel overshoot */ 495 dsNew = FT_MIN( 496 cf2_fixedRound( bottomHintEdge->dsCoord ), 497 SUB_INT32( blues->zone[i].dsFlatEdge, 498 cf2_intToFixed( 1 ) ) ); 499 } 500 501 else 502 { 503 /* simply round captured edge */ 504 dsNew = cf2_fixedRound( bottomHintEdge->dsCoord ); 505 } 506 507 dsMove = SUB_INT32( dsNew, bottomHintEdge->dsCoord ); 508 captured = TRUE; 509 510 break; 511 } 512 } 513 514 if ( !blues->zone[i].bottomZone && cf2_hint_isTop( topHintEdge ) ) 515 { 516 if ( SUB_INT32( blues->zone[i].csBottomEdge, csFuzz ) <= 517 topHintEdge->csCoord && 518 topHintEdge->csCoord <= 519 ADD_INT32( blues->zone[i].csTopEdge, csFuzz ) ) 520 { 521 /* top edge captured by top zone */ 522 523 if ( blues->suppressOvershoot ) 524 dsNew = blues->zone[i].dsFlatEdge; 525 526 else if ( SUB_INT32( topHintEdge->csCoord, 527 blues->zone[i].csBottomEdge ) >= 528 blues->blueShift ) 529 { 530 /* guarantee minimum of 1 pixel overshoot */ 531 dsNew = FT_MAX( 532 cf2_fixedRound( topHintEdge->dsCoord ), 533 blues->zone[i].dsFlatEdge + cf2_intToFixed( 1 ) ); 534 } 535 536 else 537 { 538 /* simply round captured edge */ 539 dsNew = cf2_fixedRound( topHintEdge->dsCoord ); 540 } 541 542 dsMove = SUB_INT32( dsNew, topHintEdge->dsCoord ); 543 captured = TRUE; 544 545 break; 546 } 547 } 548 } 549 550 if ( captured ) 551 { 552 /* move both edges and flag them `locked' */ 553 if ( cf2_hint_isValid( bottomHintEdge ) ) 554 { 555 bottomHintEdge->dsCoord = ADD_INT32( bottomHintEdge->dsCoord, 556 dsMove ); 557 cf2_hint_lock( bottomHintEdge ); 558 } 559 560 if ( cf2_hint_isValid( topHintEdge ) ) 561 { 562 topHintEdge->dsCoord = ADD_INT32( topHintEdge->dsCoord, dsMove ); 563 cf2_hint_lock( topHintEdge ); 564 } 565 } 566 567 return captured; 568 } 569 570 571 /* END */