1 /***************************************************************************/ 2 /* */ 3 /* cf2font.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 "cf2ft.h" 43 44 #include "cf2glue.h" 45 #include "cf2font.h" 46 #include "cf2error.h" 47 #include "cf2intrp.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_floatToFixed( .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 CFF_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; 262 263 264 /* clear previous error */ 265 font->error = FT_Err_Ok; 266 267 /* if a CID fontDict has changed, we need to recompute some cached */ 268 /* data */ 269 subFont = cf2_getSubfont( decoder ); 270 if ( font->lastSubfont != subFont ) 271 { 272 font->lastSubfont = subFont; 273 needExtraSetup = TRUE; 274 } 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 /* check whether Private DICT in this subfont needs to be reparsed */ 284 font->error = cf2_getNormalizedVector( decoder, 285 &lenNormalizedV, 286 &normalizedV ); 287 if ( font->error ) 288 return; 289 290 if ( cff_blend_check_vector( &subFont->blend, 291 subFont->private_dict.vsindex, 292 lenNormalizedV, 293 normalizedV ) ) 294 { 295 /* blend has changed, reparse */ 296 cff_load_private_dict( decoder->cff, 297 subFont, 298 lenNormalizedV, 299 normalizedV ); 300 needExtraSetup = TRUE; 301 } 302 #endif 303 304 /* copy from subfont */ 305 font->blend.font = subFont->blend.font; 306 307 /* clear state of charstring blend */ 308 font->blend.usedBV = FALSE; 309 310 /* initialize value for charstring */ 311 font->vsindex = subFont->private_dict.vsindex; 312 313 /* store vector inputs for blends in charstring */ 314 font->lenNDV = lenNormalizedV; 315 font->NDV = normalizedV; 316 } 317 318 /* if ppem has changed, we need to recompute some cached data */ 319 /* note: because of CID font matrix concatenation, ppem and transform */ 320 /* do not necessarily track. */ 321 ppem = cf2_getPpemY( decoder ); 322 if ( font->ppem != ppem ) 323 { 324 font->ppem = ppem; 325 needExtraSetup = TRUE; 326 } 327 328 /* copy hinted flag on each call */ 329 font->hinted = (FT_Bool)( font->renderingFlags & CF2_FlagsHinted ); 330 331 /* determine if transform has changed; */ 332 /* include Fontmatrix but ignore translation */ 333 if ( ft_memcmp( transform, 334 &font->currentTransform, 335 4 * sizeof ( CF2_Fixed ) ) != 0 ) 336 { 337 /* save `key' information for `cache of one' matrix data; */ 338 /* save client transform, without the translation */ 339 font->currentTransform = *transform; 340 font->currentTransform.tx = 341 font->currentTransform.ty = cf2_intToFixed( 0 ); 342 343 /* TODO: FreeType transform is simple scalar; for now, use identity */ 344 /* for outer */ 345 font->innerTransform = *transform; 346 font->outerTransform.a = 347 font->outerTransform.d = cf2_intToFixed( 1 ); 348 font->outerTransform.b = 349 font->outerTransform.c = cf2_intToFixed( 0 ); 350 351 needExtraSetup = TRUE; 352 } 353 354 /* 355 * font->darkened is set to true if there is a stem darkening request or 356 * the font is synthetic emboldened. 357 * font->darkened controls whether to adjust blue zones, winding order, 358 * and hinting. 359 * 360 */ 361 if ( font->stemDarkened != ( font->renderingFlags & CF2_FlagsDarkened ) ) 362 { 363 font->stemDarkened = 364 (FT_Bool)( font->renderingFlags & CF2_FlagsDarkened ); 365 366 /* blue zones depend on darkened flag */ 367 needExtraSetup = TRUE; 368 } 369 370 /* recompute variables that are dependent on transform or FontDict or */ 371 /* darken flag */ 372 if ( needExtraSetup ) 373 { 374 /* StdVW is found in the private dictionary; */ 375 /* recompute darkening amounts whenever private dictionary or */ 376 /* transform change */ 377 /* Note: a rendering flag turns darkening on or off, so we want to */ 378 /* store the `on' amounts; */ 379 /* darkening amount is computed in character space */ 380 /* TODO: testing size-dependent darkening here; */ 381 /* what to do for rotations? */ 382 383 CF2_Fixed emRatio; 384 CF2_Fixed stdHW; 385 CF2_Int unitsPerEm = font->unitsPerEm; 386 387 388 if ( unitsPerEm == 0 ) 389 unitsPerEm = 1000; 390 391 ppem = FT_MAX( cf2_intToFixed( 4 ), 392 font->ppem ); /* use minimum ppem of 4 */ 393 394 #if 0 395 /* since vstem is measured in the x-direction, we use the `a' member */ 396 /* of the fontMatrix */ 397 emRatio = cf2_fixedFracMul( cf2_intToFixed( 1000 ), fontMatrix->a ); 398 #endif 399 400 /* Freetype does not preserve the fontMatrix when parsing; use */ 401 /* unitsPerEm instead. */ 402 /* TODO: check precision of this */ 403 emRatio = cf2_intToFixed( 1000 ) / unitsPerEm; 404 font->stdVW = cf2_getStdVW( decoder ); 405 406 if ( font->stdVW <= 0 ) 407 font->stdVW = FT_DivFix( cf2_intToFixed( 75 ), emRatio ); 408 409 if ( boldenX > 0 ) 410 { 411 /* Ensure that boldenX is at least 1 pixel for synthetic bold font */ 412 /* (similar to what Avalon does) */ 413 boldenX = FT_MAX( boldenX, 414 FT_DivFix( cf2_intToFixed( unitsPerEm ), ppem ) ); 415 416 /* Synthetic emboldening adds at least 1 pixel to darkenX, while */ 417 /* stem darkening adds at most half pixel. Since the purpose of */ 418 /* stem darkening (readability at small sizes) is met with */ 419 /* synthetic emboldening, no need to add stem darkening for a */ 420 /* synthetic bold font. */ 421 cf2_computeDarkening( emRatio, 422 ppem, 423 font->stdVW, 424 &font->darkenX, 425 boldenX, 426 FALSE, 427 font->darkenParams ); 428 } 429 else 430 cf2_computeDarkening( emRatio, 431 ppem, 432 font->stdVW, 433 &font->darkenX, 434 0, 435 font->stemDarkened, 436 font->darkenParams ); 437 438 #if 0 439 /* since hstem is measured in the y-direction, we use the `d' member */ 440 /* of the fontMatrix */ 441 /* TODO: use the same units per em as above; check this */ 442 emRatio = cf2_fixedFracMul( cf2_intToFixed( 1000 ), fontMatrix->d ); 443 #endif 444 445 /* set the default stem width, because it must be the same for all */ 446 /* family members; */ 447 /* choose a constant for StdHW that depends on font contrast */ 448 stdHW = cf2_getStdHW( decoder ); 449 450 if ( stdHW > 0 && font->stdVW > 2 * stdHW ) 451 font->stdHW = FT_DivFix( cf2_intToFixed( 75 ), emRatio ); 452 else 453 { 454 /* low contrast font gets less hstem darkening */ 455 font->stdHW = FT_DivFix( cf2_intToFixed( 110 ), emRatio ); 456 } 457 458 cf2_computeDarkening( emRatio, 459 ppem, 460 font->stdHW, 461 &font->darkenY, 462 boldenY, 463 font->stemDarkened, 464 font->darkenParams ); 465 466 if ( font->darkenX != 0 || font->darkenY != 0 ) 467 font->darkened = TRUE; 468 else 469 font->darkened = FALSE; 470 471 font->reverseWinding = FALSE; /* initial expectation is CCW */ 472 473 /* compute blue zones for this instance */ 474 cf2_blues_init( &font->blues, font ); 475 476 } /* needExtraSetup */ 477 } 478 479 480 /* equivalent to AdobeGetOutline */ 481 FT_LOCAL_DEF( FT_Error ) 482 cf2_getGlyphOutline( CF2_Font font, 483 CF2_Buffer charstring, 484 const CF2_Matrix* transform, 485 CF2_F16Dot16* glyphWidth ) 486 { 487 FT_Error lastError = FT_Err_Ok; 488 489 FT_Vector translation; 490 491 #if 0 492 FT_Vector advancePoint; 493 #endif 494 495 CF2_Fixed advWidth = 0; 496 FT_Bool needWinding; 497 498 499 /* Note: use both integer and fraction for outlines. This allows bbox */ 500 /* to come out directly. */ 501 502 translation.x = transform->tx; 503 translation.y = transform->ty; 504 505 /* set up values based on transform */ 506 cf2_font_setup( font, transform ); 507 if ( font->error ) 508 goto exit; /* setup encountered an error */ 509 510 /* reset darken direction */ 511 font->reverseWinding = FALSE; 512 513 /* winding order only affects darkening */ 514 needWinding = font->darkened; 515 516 while ( 1 ) 517 { 518 /* reset output buffer */ 519 cf2_outline_reset( &font->outline ); 520 521 /* build the outline, passing the full translation */ 522 cf2_interpT2CharString( font, 523 charstring, 524 (CF2_OutlineCallbacks)&font->outline, 525 &translation, 526 FALSE, 527 0, 528 0, 529 &advWidth ); 530 531 if ( font->error ) 532 goto exit; 533 534 if ( !needWinding ) 535 break; 536 537 /* check winding order */ 538 if ( font->outline.root.windingMomentum >= 0 ) /* CFF is CCW */ 539 break; 540 541 /* invert darkening and render again */ 542 /* TODO: this should be a parameter to getOutline-computeOffset */ 543 font->reverseWinding = TRUE; 544 545 needWinding = FALSE; /* exit after next iteration */ 546 } 547 548 /* finish storing client outline */ 549 cf2_outline_close( &font->outline ); 550 551 exit: 552 /* FreeType just wants the advance width; there is no translation */ 553 *glyphWidth = advWidth; 554 555 /* free resources and collect errors from objects we've used */ 556 cf2_setError( &font->error, lastError ); 557 558 return font->error; 559 } 560 561 562 /* END */ 563
