psfont.c (19883B)
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 <freetype/internal/ftcalc.h> 40 41 #include "psft.h" 42 43 #include "psglue.h" 44 #include "psfont.h" 45 #include "pserror.h" 46 #include "psintrp.h" 47 48 49 /* Compute a stem darkening amount in character space. */ 50 static void 51 cf2_computeDarkening( CF2_Fixed emRatio, 52 CF2_Fixed ppem, 53 CF2_Fixed stemWidth, 54 CF2_Fixed* darkenAmount, 55 CF2_Fixed boldenAmount, 56 FT_Bool stemDarkened, 57 FT_Int* darkenParams ) 58 { 59 /* 60 * Total darkening amount is computed in 1000 unit character space 61 * using the modified 5 part curve as Adobe's Avalon rasterizer. 62 * The darkening amount is smaller for thicker stems. 63 * It becomes zero when the stem is thicker than 2.333 pixels. 64 * 65 * By default, we use 66 * 67 * darkenAmount = 0.4 pixels if scaledStem <= 0.5 pixels, 68 * darkenAmount = 0.275 pixels if 1 <= scaledStem <= 1.667 pixels, 69 * darkenAmount = 0 pixel if scaledStem >= 2.333 pixels, 70 * 71 * and piecewise linear in-between: 72 * 73 * 74 * darkening 75 * ^ 76 * | 77 * | (x1,y1) 78 * |--------+ 79 * | \ 80 * | \ 81 * | \ (x3,y3) 82 * | +----------+ 83 * | (x2,y2) \ 84 * | \ 85 * | \ 86 * | +----------------- 87 * | (x4,y4) 88 * +---------------------------------------------> stem 89 * thickness 90 * 91 * 92 * This corresponds to the following values for the 93 * `darkening-parameters' property: 94 * 95 * (x1, y1) = (500, 400) 96 * (x2, y2) = (1000, 275) 97 * (x3, y3) = (1667, 275) 98 * (x4, y4) = (2333, 0) 99 * 100 */ 101 102 /* Internal calculations are done in units per thousand for */ 103 /* convenience. The x axis is scaled stem width in */ 104 /* thousandths of a pixel. That is, 1000 is 1 pixel. */ 105 /* The y axis is darkening amount in thousandths of a pixel.*/ 106 /* In the code, below, dividing by ppem and */ 107 /* adjusting for emRatio converts darkenAmount to character */ 108 /* space (font units). */ 109 CF2_Fixed stemWidthPer1000, scaledStem; 110 FT_Int logBase2; 111 112 113 *darkenAmount = 0; 114 115 if ( boldenAmount == 0 && !stemDarkened ) 116 return; 117 118 /* protect against range problems and divide by zero */ 119 if ( emRatio < cf2_doubleToFixed( .01 ) ) 120 return; 121 122 if ( stemDarkened ) 123 { 124 FT_Int x1 = darkenParams[0]; 125 FT_Int y1 = darkenParams[1]; 126 FT_Int x2 = darkenParams[2]; 127 FT_Int y2 = darkenParams[3]; 128 FT_Int x3 = darkenParams[4]; 129 FT_Int y3 = darkenParams[5]; 130 FT_Int x4 = darkenParams[6]; 131 FT_Int y4 = darkenParams[7]; 132 133 134 /* convert from true character space to 1000 unit character space; */ 135 /* add synthetic emboldening effect */ 136 137 /* `stemWidthPer1000' will not overflow for a legitimate font */ 138 139 stemWidthPer1000 = FT_MulFix( stemWidth + boldenAmount, emRatio ); 140 141 /* `scaledStem' can easily overflow, so we must clamp its maximum */ 142 /* value; the test doesn't need to be precise, but must be */ 143 /* conservative. The clamp value (default 2333) where */ 144 /* `darkenAmount' is zero is well below the overflow value of */ 145 /* 32767. */ 146 /* */ 147 /* FT_MSB computes the integer part of the base 2 logarithm. The */ 148 /* number of bits for the product is 1 or 2 more than the sum of */ 149 /* logarithms; remembering that the 16 lowest bits of the fraction */ 150 /* are dropped this is correct to within a factor of almost 4. */ 151 /* For example, 0x80.0000 * 0x80.0000 = 0x4000.0000 is 23+23 and */ 152 /* is flagged as possible overflow because 0xFF.FFFF * 0xFF.FFFF = */ 153 /* 0xFFFF.FE00 is also 23+23. */ 154 155 logBase2 = FT_MSB( (FT_UInt32)stemWidthPer1000 ) + 156 FT_MSB( (FT_UInt32)ppem ); 157 158 if ( logBase2 >= 46 ) 159 /* possible overflow */ 160 scaledStem = cf2_intToFixed( x4 ); 161 else 162 scaledStem = FT_MulFix( stemWidthPer1000, ppem ); 163 164 /* now apply the darkening parameters */ 165 166 if ( scaledStem < cf2_intToFixed( x1 ) ) 167 *darkenAmount = FT_DivFix( cf2_intToFixed( y1 ), ppem ); 168 169 else if ( scaledStem < cf2_intToFixed( x2 ) ) 170 { 171 FT_Int xdelta = x2 - x1; 172 FT_Int ydelta = y2 - y1; 173 FT_Int x = stemWidthPer1000 - 174 FT_DivFix( cf2_intToFixed( x1 ), ppem ); 175 176 177 if ( !xdelta ) 178 goto Try_x3; 179 180 *darkenAmount = FT_MulDiv( x, ydelta, xdelta ) + 181 FT_DivFix( cf2_intToFixed( y1 ), ppem ); 182 } 183 184 else if ( scaledStem < cf2_intToFixed( x3 ) ) 185 { 186 Try_x3: 187 { 188 FT_Int xdelta = x3 - x2; 189 FT_Int ydelta = y3 - y2; 190 FT_Int x = stemWidthPer1000 - 191 FT_DivFix( cf2_intToFixed( x2 ), ppem ); 192 193 194 if ( !xdelta ) 195 goto Try_x4; 196 197 *darkenAmount = FT_MulDiv( x, ydelta, xdelta ) + 198 FT_DivFix( cf2_intToFixed( y2 ), ppem ); 199 } 200 } 201 202 else if ( scaledStem < cf2_intToFixed( x4 ) ) 203 { 204 Try_x4: 205 { 206 FT_Int xdelta = x4 - x3; 207 FT_Int ydelta = y4 - y3; 208 FT_Int x = stemWidthPer1000 - 209 FT_DivFix( cf2_intToFixed( x3 ), ppem ); 210 211 212 if ( !xdelta ) 213 goto Use_y4; 214 215 *darkenAmount = FT_MulDiv( x, ydelta, xdelta ) + 216 FT_DivFix( cf2_intToFixed( y3 ), ppem ); 217 } 218 } 219 220 else 221 { 222 Use_y4: 223 *darkenAmount = FT_DivFix( cf2_intToFixed( y4 ), ppem ); 224 } 225 226 /* use half the amount on each side and convert back to true */ 227 /* character space */ 228 *darkenAmount = FT_DivFix( *darkenAmount, 2 * emRatio ); 229 } 230 231 /* add synthetic emboldening effect in character space */ 232 *darkenAmount += boldenAmount / 2; 233 } 234 235 236 /* set up values for the current FontDict and matrix; */ 237 /* called for each glyph to be rendered */ 238 239 /* caller's transform is adjusted for subpixel positioning */ 240 static void 241 cf2_font_setup( CF2_Font font, 242 const CF2_Matrix* transform ) 243 { 244 /* pointer to parsed font object */ 245 PS_Decoder* decoder = font->decoder; 246 247 FT_Bool needExtraSetup = FALSE; 248 249 CFF_VStoreRec* vstore; 250 FT_Bool hasVariations = FALSE; 251 252 /* character space units */ 253 CF2_Fixed boldenX = font->syntheticEmboldeningAmountX; 254 CF2_Fixed boldenY = font->syntheticEmboldeningAmountY; 255 256 CFF_SubFont subFont; 257 CF2_Fixed ppem; 258 259 CF2_UInt lenNormalizedV = 0; 260 FT_Fixed* normalizedV = NULL; 261 262 /* clear previous error */ 263 font->error = FT_Err_Ok; 264 265 /* if a CID fontDict has changed, we need to recompute some cached */ 266 /* data */ 267 subFont = cf2_getSubfont( decoder ); 268 if ( font->lastSubfont != subFont ) 269 { 270 font->lastSubfont = subFont; 271 needExtraSetup = TRUE; 272 } 273 274 if ( !font->isT1 ) 275 { 276 /* check for variation vectors */ 277 vstore = cf2_getVStore( decoder ); 278 hasVariations = ( vstore->dataCount != 0 ); 279 280 if ( hasVariations ) 281 { 282 #ifdef TT_CONFIG_OPTION_GX_VAR_SUPPORT 283 FT_Service_CFFLoad cffload = (FT_Service_CFFLoad)font->cffload; 284 285 286 /* check whether Private DICT in this subfont needs to be reparsed */ 287 font->error = cf2_getNormalizedVector( decoder, 288 &lenNormalizedV, 289 &normalizedV ); 290 if ( font->error ) 291 return; 292 293 if ( cffload->blend_check_vector( &subFont->blend, 294 subFont->private_dict.vsindex, 295 lenNormalizedV, 296 normalizedV ) ) 297 { 298 /* blend has changed, reparse */ 299 cffload->load_private_dict( decoder->cff, 300 subFont, 301 lenNormalizedV, 302 normalizedV ); 303 needExtraSetup = TRUE; 304 } 305 #endif 306 307 /* copy from subfont */ 308 font->blend.font = subFont->blend.font; 309 310 /* clear state of charstring blend */ 311 font->blend.usedBV = FALSE; 312 313 /* initialize value for charstring */ 314 font->vsindex = subFont->private_dict.vsindex; 315 316 /* store vector inputs for blends in charstring */ 317 font->lenNDV = lenNormalizedV; 318 font->NDV = normalizedV; 319 } 320 } 321 322 /* if ppem has changed, we need to recompute some cached data */ 323 /* note: because of CID font matrix concatenation, ppem and transform */ 324 /* do not necessarily track. */ 325 ppem = cf2_getPpemY( decoder ); 326 if ( font->ppem != ppem ) 327 { 328 font->ppem = ppem; 329 needExtraSetup = TRUE; 330 } 331 332 /* copy hinted flag on each call */ 333 font->hinted = FT_BOOL( font->renderingFlags & CF2_FlagsHinted ); 334 335 /* determine if transform has changed; */ 336 /* include Fontmatrix but ignore translation */ 337 if ( ft_memcmp( transform, 338 &font->currentTransform, 339 4 * sizeof ( CF2_Fixed ) ) != 0 ) 340 { 341 /* save `key' information for `cache of one' matrix data; */ 342 /* save client transform, without the translation */ 343 font->currentTransform = *transform; 344 font->currentTransform.tx = 345 font->currentTransform.ty = cf2_intToFixed( 0 ); 346 347 /* TODO: FreeType transform is simple scalar; for now, use identity */ 348 /* for outer */ 349 font->innerTransform = *transform; 350 font->outerTransform.a = 351 font->outerTransform.d = cf2_intToFixed( 1 ); 352 font->outerTransform.b = 353 font->outerTransform.c = cf2_intToFixed( 0 ); 354 355 needExtraSetup = TRUE; 356 } 357 358 /* 359 * font->darkened is set to true if there is a stem darkening request or 360 * the font is synthetic emboldened. 361 * font->darkened controls whether to adjust blue zones, winding order, 362 * and hinting. 363 * 364 */ 365 if ( font->stemDarkened != ( font->renderingFlags & CF2_FlagsDarkened ) ) 366 { 367 font->stemDarkened = 368 FT_BOOL( font->renderingFlags & CF2_FlagsDarkened ); 369 370 /* blue zones depend on darkened flag */ 371 needExtraSetup = TRUE; 372 } 373 374 /* recompute variables that are dependent on transform or FontDict or */ 375 /* darken flag */ 376 if ( needExtraSetup ) 377 { 378 /* StdVW is found in the private dictionary; */ 379 /* recompute darkening amounts whenever private dictionary or */ 380 /* transform change */ 381 /* Note: a rendering flag turns darkening on or off, so we want to */ 382 /* store the `on' amounts; */ 383 /* darkening amount is computed in character space */ 384 /* TODO: testing size-dependent darkening here; */ 385 /* what to do for rotations? */ 386 387 CF2_Fixed emRatio; 388 CF2_Fixed stdHW; 389 CF2_Int unitsPerEm = font->unitsPerEm; 390 391 392 if ( unitsPerEm == 0 ) 393 unitsPerEm = 1000; 394 395 ppem = FT_MAX( cf2_intToFixed( 4 ), 396 font->ppem ); /* use minimum ppem of 4 */ 397 398 #if 0 399 /* since vstem is measured in the x-direction, we use the `a' member */ 400 /* of the fontMatrix */ 401 emRatio = cf2_fixedFracMul( cf2_intToFixed( 1000 ), fontMatrix->a ); 402 #endif 403 404 /* Freetype does not preserve the fontMatrix when parsing; use */ 405 /* unitsPerEm instead. */ 406 /* TODO: check precision of this */ 407 emRatio = cf2_intToFixed( 1000 ) / unitsPerEm; 408 font->stdVW = cf2_getStdVW( decoder ); 409 410 if ( font->stdVW <= 0 ) 411 font->stdVW = FT_DivFix( cf2_intToFixed( 75 ), emRatio ); 412 413 if ( boldenX > 0 ) 414 { 415 /* Ensure that boldenX is at least 1 pixel for synthetic bold font */ 416 /* (similar to what Avalon does) */ 417 boldenX = FT_MAX( boldenX, 418 FT_DivFix( cf2_intToFixed( unitsPerEm ), ppem ) ); 419 420 /* Synthetic emboldening adds at least 1 pixel to darkenX, while */ 421 /* stem darkening adds at most half pixel. Since the purpose of */ 422 /* stem darkening (readability at small sizes) is met with */ 423 /* synthetic emboldening, no need to add stem darkening for a */ 424 /* synthetic bold font. */ 425 cf2_computeDarkening( emRatio, 426 ppem, 427 font->stdVW, 428 &font->darkenX, 429 boldenX, 430 FALSE, 431 font->darkenParams ); 432 } 433 else 434 cf2_computeDarkening( emRatio, 435 ppem, 436 font->stdVW, 437 &font->darkenX, 438 0, 439 font->stemDarkened, 440 font->darkenParams ); 441 442 #if 0 443 /* since hstem is measured in the y-direction, we use the `d' member */ 444 /* of the fontMatrix */ 445 /* TODO: use the same units per em as above; check this */ 446 emRatio = cf2_fixedFracMul( cf2_intToFixed( 1000 ), fontMatrix->d ); 447 #endif 448 449 /* set the default stem width, because it must be the same for all */ 450 /* family members; */ 451 /* choose a constant for StdHW that depends on font contrast */ 452 stdHW = cf2_getStdHW( decoder ); 453 454 if ( stdHW > 0 && font->stdVW > MUL_INT32( 2, stdHW ) ) 455 font->stdHW = FT_DivFix( cf2_intToFixed( 75 ), emRatio ); 456 else 457 { 458 /* low contrast font gets less hstem darkening */ 459 font->stdHW = FT_DivFix( cf2_intToFixed( 110 ), emRatio ); 460 } 461 462 cf2_computeDarkening( emRatio, 463 ppem, 464 font->stdHW, 465 &font->darkenY, 466 boldenY, 467 font->stemDarkened, 468 font->darkenParams ); 469 470 if ( font->darkenX != 0 || font->darkenY != 0 ) 471 font->darkened = TRUE; 472 else 473 font->darkened = FALSE; 474 475 font->reverseWinding = FALSE; /* initial expectation is CCW */ 476 477 /* compute blue zones for this instance */ 478 cf2_blues_init( &font->blues, font ); 479 480 } /* needExtraSetup */ 481 } 482 483 484 /* equivalent to AdobeGetOutline */ 485 FT_LOCAL_DEF( FT_Error ) 486 cf2_getGlyphOutline( CF2_Font font, 487 CF2_Buffer charstring, 488 const CF2_Matrix* transform, 489 CF2_F16Dot16* glyphWidth ) 490 { 491 FT_Error lastError = FT_Err_Ok; 492 493 FT_Vector translation; 494 495 #if 0 496 FT_Vector advancePoint; 497 #endif 498 499 CF2_Fixed advWidth = 0; 500 FT_Bool needWinding; 501 502 503 /* Note: use both integer and fraction for outlines. This allows bbox */ 504 /* to come out directly. */ 505 506 translation.x = transform->tx; 507 translation.y = transform->ty; 508 509 /* set up values based on transform */ 510 cf2_font_setup( font, transform ); 511 if ( font->error ) 512 goto exit; /* setup encountered an error */ 513 514 /* reset darken direction */ 515 font->reverseWinding = FALSE; 516 517 /* winding order only affects darkening */ 518 needWinding = font->darkened; 519 520 while ( 1 ) 521 { 522 /* reset output buffer */ 523 cf2_outline_reset( &font->outline ); 524 525 /* build the outline, passing the full translation */ 526 cf2_interpT2CharString( font, 527 charstring, 528 (CF2_OutlineCallbacks)&font->outline, 529 &translation, 530 FALSE, 531 0, 532 0, 533 &advWidth ); 534 535 if ( font->error ) 536 goto exit; 537 538 if ( !needWinding ) 539 break; 540 541 /* check winding order */ 542 if ( font->outline.root.windingMomentum >= 0 ) /* CFF is CCW */ 543 break; 544 545 /* invert darkening and render again */ 546 /* TODO: this should be a parameter to getOutline-computeOffset */ 547 font->reverseWinding = TRUE; 548 549 needWinding = FALSE; /* exit after next iteration */ 550 } 551 552 /* finish storing client outline */ 553 cf2_outline_close( &font->outline ); 554 555 exit: 556 /* FreeType just wants the advance width; there is no translation */ 557 *glyphWidth = advWidth; 558 559 /* free resources and collect errors from objects we've used */ 560 cf2_setError( &font->error, lastError ); 561 562 return font->error; 563 } 564 565 566 /* END */