1 /***************************************************************************/ 2 /* */ 3 /* psfont.c */ 4 /* */ 5 /* Adobe's code for font instances (body). */ 6 /* */ 7 /* Copyright 2007-2014 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 <ft2build.h> 40 #include FT_INTERNAL_CALC_H 41 42 #include "psft.h" 43 44 #include "psglue.h" 45 #include "psfont.h" 46 #include "pserror.h" 47 #include "psintrp.h" 48 49 50 /* Compute a stem darkening amount in character space. */ 51 static void 52 cf2_computeDarkening( CF2_Fixed emRatio, 53 CF2_Fixed ppem, 54 CF2_Fixed stemWidth, 55 CF2_Fixed* darkenAmount, 56 CF2_Fixed boldenAmount, 57 FT_Bool stemDarkened, 58 FT_Int* darkenParams ) 59 { 60 /* 61 * Total darkening amount is computed in 1000 unit character space 62 * using the modified 5 part curve as Adobe's Avalon rasterizer. 63 * The darkening amount is smaller for thicker stems. 64 * It becomes zero when the stem is thicker than 2.333 pixels. 65 * 66 * By default, we use 67 * 68 * darkenAmount = 0.4 pixels if scaledStem <= 0.5 pixels, 69 * darkenAmount = 0.275 pixels if 1 <= scaledStem <= 1.667 pixels, 70 * darkenAmount = 0 pixel if scaledStem >= 2.333 pixels, 71 * 72 * and piecewise linear in-between: 73 * 74 * 75 * darkening 76 * ^ 77 * | 78 * | (x1,y1) 79 * |--------+ 80 * | \ 81 * | \ 82 * | \ (x3,y3) 83 * | +----------+ 84 * | (x2,y2) \ 85 * | \ 86 * | \ 87 * | +----------------- 88 * | (x4,y4) 89 * +---------------------------------------------> stem 90 * thickness 91 * 92 * 93 * This corresponds to the following values for the 94 * `darkening-parameters' property: 95 * 96 * (x1, y1) = (500, 400) 97 * (x2, y2) = (1000, 275) 98 * (x3, y3) = (1667, 275) 99 * (x4, y4) = (2333, 0) 100 * 101 */ 102 103 /* Internal calculations are done in units per thousand for */ 104 /* convenience. The x axis is scaled stem width in */ 105 /* thousandths of a pixel. That is, 1000 is 1 pixel. */ 106 /* The y axis is darkening amount in thousandths of a pixel.*/ 107 /* In the code, below, dividing by ppem and */ 108 /* adjusting for emRatio converts darkenAmount to character */ 109 /* space (font units). */ 110 CF2_Fixed stemWidthPer1000, scaledStem; 111 FT_Int logBase2; 112 113 114 *darkenAmount = 0; 115 116 if ( boldenAmount == 0 && !stemDarkened ) 117 return; 118 119 /* protect against range problems and divide by zero */ 120 if ( emRatio < cf2_doubleToFixed( .01 ) ) 121 return; 122 123 if ( stemDarkened ) 124 { 125 FT_Int x1 = darkenParams[0]; 126 FT_Int y1 = darkenParams[1]; 127 FT_Int x2 = darkenParams[2]; 128 FT_Int y2 = darkenParams[3]; 129 FT_Int x3 = darkenParams[4]; 130 FT_Int y3 = darkenParams[5]; 131 FT_Int x4 = darkenParams[6]; 132 FT_Int y4 = darkenParams[7]; 133 134 135 /* convert from true character space to 1000 unit character space; */ 136 /* add synthetic emboldening effect */ 137 138 /* `stemWidthPer1000' will not overflow for a legitimate font */ 139 140 stemWidthPer1000 = FT_MulFix( stemWidth + boldenAmount, emRatio ); 141 142 /* `scaledStem' can easily overflow, so we must clamp its maximum */ 143 /* value; the test doesn't need to be precise, but must be */ 144 /* conservative. The clamp value (default 2333) where */ 145 /* `darkenAmount' is zero is well below the overflow value of */ 146 /* 32767. */ 147 /* */ 148 /* FT_MSB computes the integer part of the base 2 logarithm. The */ 149 /* number of bits for the product is 1 or 2 more than the sum of */ 150 /* logarithms; remembering that the 16 lowest bits of the fraction */ 151 /* are dropped this is correct to within a factor of almost 4. */ 152 /* For example, 0x80.0000 * 0x80.0000 = 0x4000.0000 is 23+23 and */ 153 /* is flagged as possible overflow because 0xFF.FFFF * 0xFF.FFFF = */ 154 /* 0xFFFF.FE00 is also 23+23. */ 155 156 logBase2 = FT_MSB( (FT_UInt32)stemWidthPer1000 ) + 157 FT_MSB( (FT_UInt32)ppem ); 158 159 if ( logBase2 >= 46 ) 160 /* possible overflow */ 161 scaledStem = cf2_intToFixed( x4 ); 162 else 163 scaledStem = FT_MulFix( stemWidthPer1000, ppem ); 164 165 /* now apply the darkening parameters */ 166 167 if ( scaledStem < cf2_intToFixed( x1 ) ) 168 *darkenAmount = FT_DivFix( cf2_intToFixed( y1 ), ppem ); 169 170 else if ( scaledStem < cf2_intToFixed( x2 ) ) 171 { 172 FT_Int xdelta = x2 - x1; 173 FT_Int ydelta = y2 - y1; 174 FT_Int x = stemWidthPer1000 - 175 FT_DivFix( cf2_intToFixed( x1 ), ppem ); 176 177 178 if ( !xdelta ) 179 goto Try_x3; 180 181 *darkenAmount = FT_MulDiv( x, ydelta, xdelta ) + 182 FT_DivFix( cf2_intToFixed( y1 ), ppem ); 183 } 184 185 else if ( scaledStem < cf2_intToFixed( x3 ) ) 186 { 187 Try_x3: 188 { 189 FT_Int xdelta = x3 - x2; 190 FT_Int ydelta = y3 - y2; 191 FT_Int x = stemWidthPer1000 - 192 FT_DivFix( cf2_intToFixed( x2 ), ppem ); 193 194 195 if ( !xdelta ) 196 goto Try_x4; 197 198 *darkenAmount = FT_MulDiv( x, ydelta, xdelta ) + 199 FT_DivFix( cf2_intToFixed( y2 ), ppem ); 200 } 201 } 202 203 else if ( scaledStem < cf2_intToFixed( x4 ) ) 204 { 205 Try_x4: 206 { 207 FT_Int xdelta = x4 - x3; 208 FT_Int ydelta = y4 - y3; 209 FT_Int x = stemWidthPer1000 - 210 FT_DivFix( cf2_intToFixed( x3 ), ppem ); 211 212 213 if ( !xdelta ) 214 goto Use_y4; 215 216 *darkenAmount = FT_MulDiv( x, ydelta, xdelta ) + 217 FT_DivFix( cf2_intToFixed( y3 ), ppem ); 218 } 219 } 220 221 else 222 { 223 Use_y4: 224 *darkenAmount = FT_DivFix( cf2_intToFixed( y4 ), ppem ); 225 } 226 227 /* use half the amount on each side and convert back to true */ 228 /* character space */ 229 *darkenAmount = FT_DivFix( *darkenAmount, 2 * emRatio ); 230 } 231 232 /* add synthetic emboldening effect in character space */ 233 *darkenAmount += boldenAmount / 2; 234 } 235 236 237 /* set up values for the current FontDict and matrix; */ 238 /* called for each glyph to be rendered */ 239 240 /* caller's transform is adjusted for subpixel positioning */ 241 static void 242 cf2_font_setup( CF2_Font font, 243 const CF2_Matrix* transform ) 244 { 245 /* pointer to parsed font object */ 246 PS_Decoder* decoder = font->decoder; 247 248 FT_Bool needExtraSetup = FALSE; 249 250 CFF_VStoreRec* vstore; 251 FT_Bool hasVariations = FALSE; 252 253 /* character space units */ 254 CF2_Fixed boldenX = font->syntheticEmboldeningAmountX; 255 CF2_Fixed boldenY = font->syntheticEmboldeningAmountY; 256 257 CFF_SubFont subFont; 258 CF2_Fixed ppem; 259 260 CF2_UInt lenNormalizedV = 0; 261 FT_Fixed* normalizedV = NULL; 262 263 /* clear previous error */ 264 font->error = FT_Err_Ok; 265 266 /* if a CID fontDict has changed, we need to recompute some cached */ 267 /* data */ 268 subFont = cf2_getSubfont( decoder ); 269 if ( font->lastSubfont != subFont ) 270 { 271 font->lastSubfont = subFont; 272 needExtraSetup = TRUE; 273 } 274 275 if ( !font->isT1 ) 276 { 277 FT_Service_CFFLoad cffload = (FT_Service_CFFLoad)font->cffload; 278 279 280 /* check for variation vectors */ 281 vstore = cf2_getVStore( decoder ); 282 hasVariations = ( vstore->dataCount != 0 ); 283 284 if ( hasVariations ) 285 { 286 #ifdef TT_CONFIG_OPTION_GX_VAR_SUPPORT 287 /* check whether Private DICT in this subfont needs to be reparsed */ 288 font->error = cf2_getNormalizedVector( decoder, 289 &lenNormalizedV, 290 &normalizedV ); 291 if ( font->error ) 292 return; 293 294 if ( cffload->blend_check_vector( &subFont->blend, 295 subFont->private_dict.vsindex, 296 lenNormalizedV, 297 normalizedV ) ) 298 { 299 /* blend has changed, reparse */ 300 cffload->load_private_dict( decoder->cff, 301 subFont, 302 lenNormalizedV, 303 normalizedV ); 304 needExtraSetup = TRUE; 305 } 306 #endif 307 308 /* copy from subfont */ 309 font->blend.font = subFont->blend.font; 310 311 /* clear state of charstring blend */ 312 font->blend.usedBV = FALSE; 313 314 /* initialize value for charstring */ 315 font->vsindex = subFont->private_dict.vsindex; 316 317 /* store vector inputs for blends in charstring */ 318 font->lenNDV = lenNormalizedV; 319 font->NDV = normalizedV; 320 } 321 } 322 323 /* if ppem has changed, we need to recompute some cached data */ 324 /* note: because of CID font matrix concatenation, ppem and transform */ 325 /* do not necessarily track. */ 326 ppem = cf2_getPpemY( decoder ); 327 if ( font->ppem != ppem ) 328 { 329 font->ppem = ppem; 330 needExtraSetup = TRUE; 331 } 332 333 /* copy hinted flag on each call */ 334 font->hinted = (FT_Bool)( font->renderingFlags & CF2_FlagsHinted ); 335 336 /* determine if transform has changed; */ 337 /* include Fontmatrix but ignore translation */ 338 if ( ft_memcmp( transform, 339 &font->currentTransform, 340 4 * sizeof ( CF2_Fixed ) ) != 0 ) 341 { 342 /* save `key' information for `cache of one' matrix data; */ 343 /* save client transform, without the translation */ 344 font->currentTransform = *transform; 345 font->currentTransform.tx = 346 font->currentTransform.ty = cf2_intToFixed( 0 ); 347 348 /* TODO: FreeType transform is simple scalar; for now, use identity */ 349 /* for outer */ 350 font->innerTransform = *transform; 351 font->outerTransform.a = 352 font->outerTransform.d = cf2_intToFixed( 1 ); 353 font->outerTransform.b = 354 font->outerTransform.c = cf2_intToFixed( 0 ); 355 356 needExtraSetup = TRUE; 357 } 358 359 /* 360 * font->darkened is set to true if there is a stem darkening request or 361 * the font is synthetic emboldened. 362 * font->darkened controls whether to adjust blue zones, winding order, 363 * and hinting. 364 * 365 */ 366 if ( font->stemDarkened != ( font->renderingFlags & CF2_FlagsDarkened ) ) 367 { 368 font->stemDarkened = 369 (FT_Bool)( font->renderingFlags & CF2_FlagsDarkened ); 370 371 /* blue zones depend on darkened flag */ 372 needExtraSetup = TRUE; 373 } 374 375 /* recompute variables that are dependent on transform or FontDict or */ 376 /* darken flag */ 377 if ( needExtraSetup ) 378 { 379 /* StdVW is found in the private dictionary; */ 380 /* recompute darkening amounts whenever private dictionary or */ 381 /* transform change */ 382 /* Note: a rendering flag turns darkening on or off, so we want to */ 383 /* store the `on' amounts; */ 384 /* darkening amount is computed in character space */ 385 /* TODO: testing size-dependent darkening here; */ 386 /* what to do for rotations? */ 387 388 CF2_Fixed emRatio; 389 CF2_Fixed stdHW; 390 CF2_Int unitsPerEm = font->unitsPerEm; 391 392 393 if ( unitsPerEm == 0 ) 394 unitsPerEm = 1000; 395 396 ppem = FT_MAX( cf2_intToFixed( 4 ), 397 font->ppem ); /* use minimum ppem of 4 */ 398 399 #if 0 400 /* since vstem is measured in the x-direction, we use the `a' member */ 401 /* of the fontMatrix */ 402 emRatio = cf2_fixedFracMul( cf2_intToFixed( 1000 ), fontMatrix->a ); 403 #endif 404 405 /* Freetype does not preserve the fontMatrix when parsing; use */ 406 /* unitsPerEm instead. */ 407 /* TODO: check precision of this */ 408 emRatio = cf2_intToFixed( 1000 ) / unitsPerEm; 409 font->stdVW = cf2_getStdVW( decoder ); 410 411 if ( font->stdVW <= 0 ) 412 font->stdVW = FT_DivFix( cf2_intToFixed( 75 ), emRatio ); 413 414 if ( boldenX > 0 ) 415 { 416 /* Ensure that boldenX is at least 1 pixel for synthetic bold font */ 417 /* (similar to what Avalon does) */ 418 boldenX = FT_MAX( boldenX, 419 FT_DivFix( cf2_intToFixed( unitsPerEm ), ppem ) ); 420 421 /* Synthetic emboldening adds at least 1 pixel to darkenX, while */ 422 /* stem darkening adds at most half pixel. Since the purpose of */ 423 /* stem darkening (readability at small sizes) is met with */ 424 /* synthetic emboldening, no need to add stem darkening for a */ 425 /* synthetic bold font. */ 426 cf2_computeDarkening( emRatio, 427 ppem, 428 font->stdVW, 429 &font->darkenX, 430 boldenX, 431 FALSE, 432 font->darkenParams ); 433 } 434 else 435 cf2_computeDarkening( emRatio, 436 ppem, 437 font->stdVW, 438 &font->darkenX, 439 0, 440 font->stemDarkened, 441 font->darkenParams ); 442 443 #if 0 444 /* since hstem is measured in the y-direction, we use the `d' member */ 445 /* of the fontMatrix */ 446 /* TODO: use the same units per em as above; check this */ 447 emRatio = cf2_fixedFracMul( cf2_intToFixed( 1000 ), fontMatrix->d ); 448 #endif 449 450 /* set the default stem width, because it must be the same for all */ 451 /* family members; */ 452 /* choose a constant for StdHW that depends on font contrast */ 453 stdHW = cf2_getStdHW( decoder ); 454 455 if ( stdHW > 0 && font->stdVW > MUL_INT32( 2, stdHW ) ) 456 font->stdHW = FT_DivFix( cf2_intToFixed( 75 ), emRatio ); 457 else 458 { 459 /* low contrast font gets less hstem darkening */ 460 font->stdHW = FT_DivFix( cf2_intToFixed( 110 ), emRatio ); 461 } 462 463 cf2_computeDarkening( emRatio, 464 ppem, 465 font->stdHW, 466 &font->darkenY, 467 boldenY, 468 font->stemDarkened, 469 font->darkenParams ); 470 471 if ( font->darkenX != 0 || font->darkenY != 0 ) 472 font->darkened = TRUE; 473 else 474 font->darkened = FALSE; 475 476 font->reverseWinding = FALSE; /* initial expectation is CCW */ 477 478 /* compute blue zones for this instance */ 479 cf2_blues_init( &font->blues, font ); 480 481 } /* needExtraSetup */ 482 } 483 484 485 /* equivalent to AdobeGetOutline */ 486 FT_LOCAL_DEF( FT_Error ) 487 cf2_getGlyphOutline( CF2_Font font, 488 CF2_Buffer charstring, 489 const CF2_Matrix* transform, 490 CF2_F16Dot16* glyphWidth ) 491 { 492 FT_Error lastError = FT_Err_Ok; 493 494 FT_Vector translation; 495 496 #if 0 497 FT_Vector advancePoint; 498 #endif 499 500 CF2_Fixed advWidth = 0; 501 FT_Bool needWinding; 502 503 504 /* Note: use both integer and fraction for outlines. This allows bbox */ 505 /* to come out directly. */ 506 507 translation.x = transform->tx; 508 translation.y = transform->ty; 509 510 /* set up values based on transform */ 511 cf2_font_setup( font, transform ); 512 if ( font->error ) 513 goto exit; /* setup encountered an error */ 514 515 /* reset darken direction */ 516 font->reverseWinding = FALSE; 517 518 /* winding order only affects darkening */ 519 needWinding = font->darkened; 520 521 while ( 1 ) 522 { 523 /* reset output buffer */ 524 cf2_outline_reset( &font->outline ); 525 526 /* build the outline, passing the full translation */ 527 cf2_interpT2CharString( font, 528 charstring, 529 (CF2_OutlineCallbacks)&font->outline, 530 &translation, 531 FALSE, 532 0, 533 0, 534 &advWidth ); 535 536 if ( font->error ) 537 goto exit; 538 539 if ( !needWinding ) 540 break; 541 542 /* check winding order */ 543 if ( font->outline.root.windingMomentum >= 0 ) /* CFF is CCW */ 544 break; 545 546 /* invert darkening and render again */ 547 /* TODO: this should be a parameter to getOutline-computeOffset */ 548 font->reverseWinding = TRUE; 549 550 needWinding = FALSE; /* exit after next iteration */ 551 } 552 553 /* finish storing client outline */ 554 cf2_outline_close( &font->outline ); 555 556 exit: 557 /* FreeType just wants the advance width; there is no translation */ 558 *glyphWidth = advWidth; 559 560 /* free resources and collect errors from objects we've used */ 561 cf2_setError( &font->error, lastError ); 562 563 return font->error; 564 } 565 566 567 /* END */ 568
