1 /***************************************************************************/ 2 /* */ 3 /* cf2font.c */ 4 /* */ 5 /* Adobe's code for font instances (body). */ 6 /* */ 7 /* Copyright 2007-2013 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 41 #include "cf2glue.h" 42 #include "cf2font.h" 43 #include "cf2error.h" 44 #include "cf2intrp.h" 45 46 47 /* Compute a stem darkening amount in character space. */ 48 static void 49 cf2_computeDarkening( CF2_Fixed emRatio, 50 CF2_Fixed ppem, 51 CF2_Fixed stemWidth, 52 CF2_Fixed* darkenAmount, 53 CF2_Fixed boldenAmount, 54 FT_Bool stemDarkened ) 55 { 56 /* Internal calculations are done in units per thousand for */ 57 /* convenience. */ 58 CF2_Fixed stemWidthPer1000, scaledStem; 59 60 61 *darkenAmount = 0; 62 63 if ( boldenAmount == 0 && !stemDarkened ) 64 return; 65 66 /* protect against range problems and divide by zero */ 67 if ( emRatio < cf2_floatToFixed( .01 ) ) 68 return; 69 70 if ( stemDarkened ) 71 { 72 /* convert from true character space to 1000 unit character space; */ 73 /* add synthetic emboldening effect */ 74 75 /* we have to assure that the computation of `scaledStem' */ 76 /* and `stemWidthPer1000' don't overflow */ 77 78 stemWidthPer1000 = FT_MulFix( stemWidth + boldenAmount, emRatio ); 79 80 if ( emRatio > CF2_FIXED_ONE && 81 stemWidthPer1000 <= ( stemWidth + boldenAmount ) ) 82 { 83 stemWidthPer1000 = 0; /* to pacify compiler */ 84 scaledStem = cf2_intToFixed( 2333 ); 85 } 86 else 87 { 88 scaledStem = FT_MulFix( stemWidthPer1000, ppem ); 89 90 if ( ppem > CF2_FIXED_ONE && 91 scaledStem <= stemWidthPer1000 ) 92 scaledStem = cf2_intToFixed( 2333 ); 93 } 94 95 /* 96 * Total darkening amount is computed in 1000 unit character space 97 * using the modified 5 part curve as Avalon rasterizer. 98 * The darkening amount is smaller for thicker stems. 99 * It becomes zero when the stem is thicker than 2.333 pixels. 100 * 101 * In Avalon rasterizer, 102 * 103 * darkenAmount = 0.5 pixels if scaledStem <= 0.5 pixels, 104 * darkenAmount = 0.333 pixels if 1 <= scaledStem <= 1.667 pixels, 105 * darkenAmount = 0 pixel if scaledStem >= 2.333 pixels, 106 * 107 * and piecewise linear in-between. 108 * 109 */ 110 if ( scaledStem < cf2_intToFixed( 500 ) ) 111 *darkenAmount = FT_DivFix( cf2_intToFixed( 400 ), ppem ); 112 113 else if ( scaledStem < cf2_intToFixed( 1000 ) ) 114 *darkenAmount = FT_DivFix( cf2_intToFixed( 525 ), ppem ) - 115 FT_MulFix( stemWidthPer1000, 116 cf2_floatToFixed( .25 ) ); 117 118 else if ( scaledStem < cf2_intToFixed( 1667 ) ) 119 *darkenAmount = FT_DivFix( cf2_intToFixed( 275 ), ppem ); 120 121 else if ( scaledStem < cf2_intToFixed( 2333 ) ) 122 *darkenAmount = FT_DivFix( cf2_intToFixed( 963 ), ppem ) - 123 FT_MulFix( stemWidthPer1000, 124 cf2_floatToFixed( .413 ) ); 125 126 /* use half the amount on each side and convert back to true */ 127 /* character space */ 128 *darkenAmount = FT_DivFix( *darkenAmount, 2 * emRatio ); 129 } 130 131 /* add synthetic emboldening effect in character space */ 132 *darkenAmount += boldenAmount / 2; 133 } 134 135 136 /* set up values for the current FontDict and matrix */ 137 138 /* caller's transform is adjusted for subpixel positioning */ 139 static void 140 cf2_font_setup( CF2_Font font, 141 const CF2_Matrix* transform ) 142 { 143 /* pointer to parsed font object */ 144 CFF_Decoder* decoder = font->decoder; 145 146 FT_Bool needExtraSetup; 147 148 /* character space units */ 149 CF2_Fixed boldenX = font->syntheticEmboldeningAmountX; 150 CF2_Fixed boldenY = font->syntheticEmboldeningAmountY; 151 152 CF2_Fixed ppem; 153 154 155 /* clear previous error */ 156 font->error = FT_Err_Ok; 157 158 /* if a CID fontDict has changed, we need to recompute some cached */ 159 /* data */ 160 needExtraSetup = font->lastSubfont != cf2_getSubfont( decoder ); 161 162 /* if ppem has changed, we need to recompute some cached data */ 163 /* note: because of CID font matrix concatenation, ppem and transform */ 164 /* do not necessarily track. */ 165 ppem = cf2_getPpemY( decoder ); 166 if ( font->ppem != ppem ) 167 { 168 font->ppem = ppem; 169 needExtraSetup = TRUE; 170 } 171 172 /* copy hinted flag on each call */ 173 font->hinted = font->renderingFlags & CF2_FlagsHinted; 174 175 /* determine if transform has changed; */ 176 /* include Fontmatrix but ignore translation */ 177 if ( ft_memcmp( transform, 178 &font->currentTransform, 179 4 * sizeof ( CF2_Fixed ) ) != 0 ) 180 { 181 /* save `key' information for `cache of one' matrix data; */ 182 /* save client transform, without the translation */ 183 font->currentTransform = *transform; 184 font->currentTransform.tx = 185 font->currentTransform.ty = cf2_intToFixed( 0 ); 186 187 /* TODO: FreeType transform is simple scalar; for now, use identity */ 188 /* for outer */ 189 font->innerTransform = *transform; 190 font->outerTransform.a = 191 font->outerTransform.d = cf2_intToFixed( 1 ); 192 font->outerTransform.b = 193 font->outerTransform.c = cf2_intToFixed( 0 ); 194 195 needExtraSetup = TRUE; 196 } 197 198 /* 199 * font->darkened is set to true if there is a stem darkening request or 200 * the font is synthetic emboldened. 201 * font->darkened controls whether to adjust blue zones, winding order, 202 * and hinting. 203 * 204 */ 205 if ( font->stemDarkened != ( font->renderingFlags & CF2_FlagsDarkened ) ) 206 { 207 font->stemDarkened = font->renderingFlags & CF2_FlagsDarkened; 208 209 /* blue zones depend on darkened flag */ 210 needExtraSetup = TRUE; 211 } 212 213 /* recompute variables that are dependent on transform or FontDict or */ 214 /* darken flag */ 215 if ( needExtraSetup ) 216 { 217 /* StdVW is found in the private dictionary; */ 218 /* recompute darkening amounts whenever private dictionary or */ 219 /* transform change */ 220 /* Note: a rendering flag turns darkening on or off, so we want to */ 221 /* store the `on' amounts; */ 222 /* darkening amount is computed in character space */ 223 /* TODO: testing size-dependent darkening here; */ 224 /* what to do for rotations? */ 225 226 CF2_Fixed emRatio; 227 CF2_Fixed stdHW; 228 CF2_Int unitsPerEm = font->unitsPerEm; 229 230 231 if ( unitsPerEm == 0 ) 232 unitsPerEm = 1000; 233 234 ppem = FT_MAX( cf2_intToFixed( 4 ), 235 font->ppem ); /* use minimum ppem of 4 */ 236 237 #if 0 238 /* since vstem is measured in the x-direction, we use the `a' member */ 239 /* of the fontMatrix */ 240 emRatio = cf2_fixedFracMul( cf2_intToFixed( 1000 ), fontMatrix->a ); 241 #endif 242 243 /* Freetype does not preserve the fontMatrix when parsing; use */ 244 /* unitsPerEm instead. */ 245 /* TODO: check precision of this */ 246 emRatio = cf2_intToFixed( 1000 ) / unitsPerEm; 247 font->stdVW = cf2_getStdVW( decoder ); 248 249 if ( font->stdVW <= 0 ) 250 font->stdVW = FT_DivFix( cf2_intToFixed( 75 ), emRatio ); 251 252 if ( boldenX > 0 ) 253 { 254 /* Ensure that boldenX is at least 1 pixel for synthetic bold font */ 255 /* (similar to what Avalon does) */ 256 boldenX = FT_MAX( boldenX, 257 FT_DivFix( cf2_intToFixed( unitsPerEm ), ppem ) ); 258 259 /* Synthetic emboldening adds at least 1 pixel to darkenX, while */ 260 /* stem darkening adds at most half pixel. Since the purpose of */ 261 /* stem darkening (readability at small sizes) is met with */ 262 /* synthetic emboldening, no need to add stem darkening for a */ 263 /* synthetic bold font. */ 264 cf2_computeDarkening( emRatio, 265 ppem, 266 font->stdVW, 267 &font->darkenX, 268 boldenX, 269 FALSE ); 270 } 271 else 272 cf2_computeDarkening( emRatio, 273 ppem, 274 font->stdVW, 275 &font->darkenX, 276 0, 277 font->stemDarkened ); 278 279 #if 0 280 /* since hstem is measured in the y-direction, we use the `d' member */ 281 /* of the fontMatrix */ 282 /* TODO: use the same units per em as above; check this */ 283 emRatio = cf2_fixedFracMul( cf2_intToFixed( 1000 ), fontMatrix->d ); 284 #endif 285 286 /* set the default stem width, because it must be the same for all */ 287 /* family members; */ 288 /* choose a constant for StdHW that depends on font contrast */ 289 stdHW = cf2_getStdHW( decoder ); 290 291 if ( stdHW > 0 && font->stdVW > 2 * stdHW ) 292 font->stdHW = FT_DivFix( cf2_intToFixed( 75 ), emRatio ); 293 else 294 { 295 /* low contrast font gets less hstem darkening */ 296 font->stdHW = FT_DivFix( cf2_intToFixed( 110 ), emRatio ); 297 } 298 299 cf2_computeDarkening( emRatio, 300 ppem, 301 font->stdHW, 302 &font->darkenY, 303 boldenY, 304 font->stemDarkened ); 305 306 if ( font->darkenX != 0 || font->darkenY != 0 ) 307 font->darkened = TRUE; 308 else 309 font->darkened = FALSE; 310 311 font->reverseWinding = FALSE; /* initial expectation is CCW */ 312 313 /* compute blue zones for this instance */ 314 cf2_blues_init( &font->blues, font ); 315 } 316 } 317 318 319 /* equivalent to AdobeGetOutline */ 320 FT_LOCAL_DEF( FT_Error ) 321 cf2_getGlyphOutline( CF2_Font font, 322 CF2_Buffer charstring, 323 const CF2_Matrix* transform, 324 CF2_F16Dot16* glyphWidth ) 325 { 326 FT_Error lastError = FT_Err_Ok; 327 328 FT_Vector translation; 329 330 #if 0 331 FT_Vector advancePoint; 332 #endif 333 334 CF2_Fixed advWidth = 0; 335 FT_Bool needWinding; 336 337 338 /* Note: use both integer and fraction for outlines. This allows bbox */ 339 /* to come out directly. */ 340 341 translation.x = transform->tx; 342 translation.y = transform->ty; 343 344 /* set up values based on transform */ 345 cf2_font_setup( font, transform ); 346 if ( font->error ) 347 goto exit; /* setup encountered an error */ 348 349 /* reset darken direction */ 350 font->reverseWinding = FALSE; 351 352 /* winding order only affects darkening */ 353 needWinding = font->darkened; 354 355 while ( 1 ) 356 { 357 /* reset output buffer */ 358 cf2_outline_reset( &font->outline ); 359 360 /* build the outline, passing the full translation */ 361 cf2_interpT2CharString( font, 362 charstring, 363 (CF2_OutlineCallbacks)&font->outline, 364 &translation, 365 FALSE, 366 0, 367 0, 368 &advWidth ); 369 370 if ( font->error ) 371 goto exit; 372 373 if ( !needWinding ) 374 break; 375 376 /* check winding order */ 377 if ( font->outline.root.windingMomentum >= 0 ) /* CFF is CCW */ 378 break; 379 380 /* invert darkening and render again */ 381 /* TODO: this should be a parameter to getOutline-computeOffset */ 382 font->reverseWinding = TRUE; 383 384 needWinding = FALSE; /* exit after next iteration */ 385 } 386 387 /* finish storing client outline */ 388 cf2_outline_close( &font->outline ); 389 390 exit: 391 /* FreeType just wants the advance width; there is no translation */ 392 *glyphWidth = advWidth; 393 394 /* free resources and collect errors from objects we've used */ 395 cf2_setError( &font->error, lastError ); 396 397 return font->error; 398 } 399 400 401 /* END */ 402
