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Side by Side Diff: core/src/fxge/fx_freetype/fxft2.5.01/src/cff/cf2font.c

Issue 815103002: Update freetype to 2.5.4. (Closed) Base URL: https://pdfium.googlesource.com/pdfium.git@master
Patch Set: Adjust GYP and GN Created 6 years ago
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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 =
161 (FT_Bool)( font->lastSubfont != cf2_getSubfont( decoder ) );
162
163 /* if ppem has changed, we need to recompute some cached data */
164 /* note: because of CID font matrix concatenation, ppem and transform */
165 /* do not necessarily track. */
166 ppem = cf2_getPpemY( decoder );
167 if ( font->ppem != ppem )
168 {
169 font->ppem = ppem;
170 needExtraSetup = TRUE;
171 }
172
173 /* copy hinted flag on each call */
174 font->hinted = (FT_Bool)( font->renderingFlags & CF2_FlagsHinted );
175
176 /* determine if transform has changed; */
177 /* include Fontmatrix but ignore translation */
178 if ( ft_memcmp( transform,
179 &font->currentTransform,
180 4 * sizeof ( CF2_Fixed ) ) != 0 )
181 {
182 /* save `key' information for `cache of one' matrix data; */
183 /* save client transform, without the translation */
184 font->currentTransform = *transform;
185 font->currentTransform.tx =
186 font->currentTransform.ty = cf2_intToFixed( 0 );
187
188 /* TODO: FreeType transform is simple scalar; for now, use identity */
189 /* for outer */
190 font->innerTransform = *transform;
191 font->outerTransform.a =
192 font->outerTransform.d = cf2_intToFixed( 1 );
193 font->outerTransform.b =
194 font->outerTransform.c = cf2_intToFixed( 0 );
195
196 needExtraSetup = TRUE;
197 }
198
199 /*
200 * font->darkened is set to true if there is a stem darkening request or
201 * the font is synthetic emboldened.
202 * font->darkened controls whether to adjust blue zones, winding order,
203 * and hinting.
204 *
205 */
206 if ( font->stemDarkened != ( font->renderingFlags & CF2_FlagsDarkened ) )
207 {
208 font->stemDarkened =
209 (FT_Bool)( font->renderingFlags & CF2_FlagsDarkened );
210
211 /* blue zones depend on darkened flag */
212 needExtraSetup = TRUE;
213 }
214
215 /* recompute variables that are dependent on transform or FontDict or */
216 /* darken flag */
217 if ( needExtraSetup )
218 {
219 /* StdVW is found in the private dictionary; */
220 /* recompute darkening amounts whenever private dictionary or */
221 /* transform change */
222 /* Note: a rendering flag turns darkening on or off, so we want to */
223 /* store the `on' amounts; */
224 /* darkening amount is computed in character space */
225 /* TODO: testing size-dependent darkening here; */
226 /* what to do for rotations? */
227
228 CF2_Fixed emRatio;
229 CF2_Fixed stdHW;
230 CF2_Int unitsPerEm = font->unitsPerEm;
231
232
233 if ( unitsPerEm == 0 )
234 unitsPerEm = 1000;
235
236 ppem = FT_MAX( cf2_intToFixed( 4 ),
237 font->ppem ); /* use minimum ppem of 4 */
238
239 #if 0
240 /* since vstem is measured in the x-direction, we use the `a' member */
241 /* of the fontMatrix */
242 emRatio = cf2_fixedFracMul( cf2_intToFixed( 1000 ), fontMatrix->a );
243 #endif
244
245 /* Freetype does not preserve the fontMatrix when parsing; use */
246 /* unitsPerEm instead. */
247 /* TODO: check precision of this */
248 emRatio = cf2_intToFixed( 1000 ) / unitsPerEm;
249 font->stdVW = cf2_getStdVW( decoder );
250
251 if ( font->stdVW <= 0 )
252 font->stdVW = FT_DivFix( cf2_intToFixed( 75 ), emRatio );
253
254 if ( boldenX > 0 )
255 {
256 /* Ensure that boldenX is at least 1 pixel for synthetic bold font */
257 /* (similar to what Avalon does) */
258 boldenX = FT_MAX( boldenX,
259 FT_DivFix( cf2_intToFixed( unitsPerEm ), ppem ) );
260
261 /* Synthetic emboldening adds at least 1 pixel to darkenX, while */
262 /* stem darkening adds at most half pixel. Since the purpose of */
263 /* stem darkening (readability at small sizes) is met with */
264 /* synthetic emboldening, no need to add stem darkening for a */
265 /* synthetic bold font. */
266 cf2_computeDarkening( emRatio,
267 ppem,
268 font->stdVW,
269 &font->darkenX,
270 boldenX,
271 FALSE );
272 }
273 else
274 cf2_computeDarkening( emRatio,
275 ppem,
276 font->stdVW,
277 &font->darkenX,
278 0,
279 font->stemDarkened );
280
281 #if 0
282 /* since hstem is measured in the y-direction, we use the `d' member */
283 /* of the fontMatrix */
284 /* TODO: use the same units per em as above; check this */
285 emRatio = cf2_fixedFracMul( cf2_intToFixed( 1000 ), fontMatrix->d );
286 #endif
287
288 /* set the default stem width, because it must be the same for all */
289 /* family members; */
290 /* choose a constant for StdHW that depends on font contrast */
291 stdHW = cf2_getStdHW( decoder );
292
293 if ( stdHW > 0 && font->stdVW > 2 * stdHW )
294 font->stdHW = FT_DivFix( cf2_intToFixed( 75 ), emRatio );
295 else
296 {
297 /* low contrast font gets less hstem darkening */
298 font->stdHW = FT_DivFix( cf2_intToFixed( 110 ), emRatio );
299 }
300
301 cf2_computeDarkening( emRatio,
302 ppem,
303 font->stdHW,
304 &font->darkenY,
305 boldenY,
306 font->stemDarkened );
307
308 if ( font->darkenX != 0 || font->darkenY != 0 )
309 font->darkened = TRUE;
310 else
311 font->darkened = FALSE;
312
313 font->reverseWinding = FALSE; /* initial expectation is CCW */
314
315 /* compute blue zones for this instance */
316 cf2_blues_init( &font->blues, font );
317 }
318 }
319
320
321 /* equivalent to AdobeGetOutline */
322 FT_LOCAL_DEF( FT_Error )
323 cf2_getGlyphOutline( CF2_Font font,
324 CF2_Buffer charstring,
325 const CF2_Matrix* transform,
326 CF2_F16Dot16* glyphWidth )
327 {
328 FT_Error lastError = FT_Err_Ok;
329
330 FT_Vector translation;
331
332 #if 0
333 FT_Vector advancePoint;
334 #endif
335
336 CF2_Fixed advWidth = 0;
337 FT_Bool needWinding;
338
339
340 /* Note: use both integer and fraction for outlines. This allows bbox */
341 /* to come out directly. */
342
343 translation.x = transform->tx;
344 translation.y = transform->ty;
345
346 /* set up values based on transform */
347 cf2_font_setup( font, transform );
348 if ( font->error )
349 goto exit; /* setup encountered an error */
350
351 /* reset darken direction */
352 font->reverseWinding = FALSE;
353
354 /* winding order only affects darkening */
355 needWinding = font->darkened;
356
357 while ( 1 )
358 {
359 /* reset output buffer */
360 cf2_outline_reset( &font->outline );
361
362 /* build the outline, passing the full translation */
363 cf2_interpT2CharString( font,
364 charstring,
365 (CF2_OutlineCallbacks)&font->outline,
366 &translation,
367 FALSE,
368 0,
369 0,
370 &advWidth );
371
372 if ( font->error )
373 goto exit;
374
375 if ( !needWinding )
376 break;
377
378 /* check winding order */
379 if ( font->outline.root.windingMomentum >= 0 ) /* CFF is CCW */
380 break;
381
382 /* invert darkening and render again */
383 /* TODO: this should be a parameter to getOutline-computeOffset */
384 font->reverseWinding = TRUE;
385
386 needWinding = FALSE; /* exit after next iteration */
387 }
388
389 /* finish storing client outline */
390 cf2_outline_close( &font->outline );
391
392 exit:
393 /* FreeType just wants the advance width; there is no translation */
394 *glyphWidth = advWidth;
395
396 /* free resources and collect errors from objects we've used */
397 cf2_setError( &font->error, lastError );
398
399 return font->error;
400 }
401
402
403 /* END */
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