1 /***************************************************************************/
2 /* */
3 /* ftglyph.h */
4 /* */
5 /* FreeType convenience functions to handle glyphs (specification). */
6 /* */
7 /* Copyright 1996-2018 by */
8 /* David Turner, Robert Wilhelm, and Werner Lemberg. */
9 /* */
10 /* This file is part of the FreeType project, and may only be used, */
11 /* modified, and distributed under the terms of the FreeType project */
12 /* license, LICENSE.TXT. By continuing to use, modify, or distribute */
13 /* this file you indicate that you have read the license and */
14 /* understand and accept it fully. */
15 /* */
16 /***************************************************************************/
17
18
19 /*************************************************************************/
20 /* */
21 /* This file contains the definition of several convenience functions */
22 /* that can be used by client applications to easily retrieve glyph */
23 /* bitmaps and outlines from a given face. */
24 /* */
25 /* These functions should be optional if you are writing a font server */
26 /* or text layout engine on top of FreeType. However, they are pretty */
27 /* handy for many other simple uses of the library. */
28 /* */
29 /*************************************************************************/
30
31
32 #ifndef FTGLYPH_H_
33 #define FTGLYPH_H_
34
35
36 #include <ft2build.h>
37 #include FT_FREETYPE_H
38
39 #ifdef FREETYPE_H
40 #error "freetype.h of FreeType 1 has been loaded!"
41 #error "Please fix the directory search order for header files"
42 #error "so that freetype.h of FreeType 2 is found first."
43 #endif
44
45
46 FT_BEGIN_HEADER
47
48
49 /*************************************************************************/
50 /* */
51 /* <Section> */
52 /* glyph_management */
53 /* */
54 /* <Title> */
55 /* Glyph Management */
56 /* */
57 /* <Abstract> */
58 /* Generic interface to manage individual glyph data. */
59 /* */
60 /* <Description> */
61 /* This section contains definitions used to manage glyph data */
62 /* through generic FT_Glyph objects. Each of them can contain a */
63 /* bitmap, a vector outline, or even images in other formats. */
64 /* */
65 /*************************************************************************/
66
67
68 /* forward declaration to a private type */
69 typedef struct FT_Glyph_Class_ FT_Glyph_Class;
70
71
72 /*************************************************************************/
73 /* */
74 /* <Type> */
75 /* FT_Glyph */
76 /* */
77 /* <Description> */
78 /* Handle to an object used to model generic glyph images. It is a */
79 /* pointer to the @FT_GlyphRec structure and can contain a glyph */
80 /* bitmap or pointer. */
81 /* */
82 /* <Note> */
83 /* Glyph objects are not owned by the library. You must thus release */
84 /* them manually (through @FT_Done_Glyph) _before_ calling */
85 /* @FT_Done_FreeType. */
86 /* */
87 typedef struct FT_GlyphRec_* FT_Glyph;
88
89
90 /*************************************************************************/
91 /* */
92 /* <Struct> */
93 /* FT_GlyphRec */
94 /* */
95 /* <Description> */
96 /* The root glyph structure contains a given glyph image plus its */
97 /* advance width in 16.16 fixed-point format. */
98 /* */
99 /* <Fields> */
100 /* library :: A handle to the FreeType library object. */
101 /* */
102 /* clazz :: A pointer to the glyph's class. Private. */
103 /* */
104 /* format :: The format of the glyph's image. */
105 /* */
106 /* advance :: A 16.16 vector that gives the glyph's advance width. */
107 /* */
108 typedef struct FT_GlyphRec_
109 {
110 FT_Library library;
111 const FT_Glyph_Class* clazz;
112 FT_Glyph_Format format;
113 FT_Vector advance;
114
115 } FT_GlyphRec;
116
117
118 /*************************************************************************/
119 /* */
120 /* <Type> */
121 /* FT_BitmapGlyph */
122 /* */
123 /* <Description> */
124 /* A handle to an object used to model a bitmap glyph image. This is */
125 /* a sub-class of @FT_Glyph, and a pointer to @FT_BitmapGlyphRec. */
126 /* */
127 typedef struct FT_BitmapGlyphRec_* FT_BitmapGlyph;
128
129
130 /*************************************************************************/
131 /* */
132 /* <Struct> */
133 /* FT_BitmapGlyphRec */
134 /* */
135 /* <Description> */
136 /* A structure used for bitmap glyph images. This really is a */
137 /* `sub-class' of @FT_GlyphRec. */
138 /* */
139 /* <Fields> */
140 /* root :: The root @FT_Glyph fields. */
141 /* */
142 /* left :: The left-side bearing, i.e., the horizontal distance */
143 /* from the current pen position to the left border of the */
144 /* glyph bitmap. */
145 /* */
146 /* top :: The top-side bearing, i.e., the vertical distance from */
147 /* the current pen position to the top border of the glyph */
148 /* bitmap. This distance is positive for upwards~y! */
149 /* */
150 /* bitmap :: A descriptor for the bitmap. */
151 /* */
152 /* <Note> */
153 /* You can typecast an @FT_Glyph to @FT_BitmapGlyph if you have */
154 /* `glyph->format == FT_GLYPH_FORMAT_BITMAP'. This lets you access */
155 /* the bitmap's contents easily. */
156 /* */
157 /* The corresponding pixel buffer is always owned by @FT_BitmapGlyph */
158 /* and is thus created and destroyed with it. */
159 /* */
160 typedef struct FT_BitmapGlyphRec_
161 {
162 FT_GlyphRec root;
163 FT_Int left;
164 FT_Int top;
165 FT_Bitmap bitmap;
166
167 } FT_BitmapGlyphRec;
168
169
170 /*************************************************************************/
171 /* */
172 /* <Type> */
173 /* FT_OutlineGlyph */
174 /* */
175 /* <Description> */
176 /* A handle to an object used to model an outline glyph image. This */
177 /* is a sub-class of @FT_Glyph, and a pointer to @FT_OutlineGlyphRec. */
178 /* */
179 typedef struct FT_OutlineGlyphRec_* FT_OutlineGlyph;
180
181
182 /*************************************************************************/
183 /* */
184 /* <Struct> */
185 /* FT_OutlineGlyphRec */
186 /* */
187 /* <Description> */
188 /* A structure used for outline (vectorial) glyph images. This */
189 /* really is a `sub-class' of @FT_GlyphRec. */
190 /* */
191 /* <Fields> */
192 /* root :: The root @FT_Glyph fields. */
193 /* */
194 /* outline :: A descriptor for the outline. */
195 /* */
196 /* <Note> */
197 /* You can typecast an @FT_Glyph to @FT_OutlineGlyph if you have */
198 /* `glyph->format == FT_GLYPH_FORMAT_OUTLINE'. This lets you access */
199 /* the outline's content easily. */
200 /* */
201 /* As the outline is extracted from a glyph slot, its coordinates are */
202 /* expressed normally in 26.6 pixels, unless the flag */
203 /* @FT_LOAD_NO_SCALE was used in @FT_Load_Glyph() or @FT_Load_Char(). */
204 /* */
205 /* The outline's tables are always owned by the object and are */
206 /* destroyed with it. */
207 /* */
208 typedef struct FT_OutlineGlyphRec_
209 {
210 FT_GlyphRec root;
211 FT_Outline outline;
212
213 } FT_OutlineGlyphRec;
214
215
216 /*************************************************************************/
217 /* */
218 /* <Function> */
219 /* FT_Get_Glyph */
220 /* */
221 /* <Description> */
222 /* A function used to extract a glyph image from a slot. Note that */
223 /* the created @FT_Glyph object must be released with @FT_Done_Glyph. */
224 /* */
225 /* <Input> */
226 /* slot :: A handle to the source glyph slot. */
227 /* */
228 /* <Output> */
229 /* aglyph :: A handle to the glyph object. */
230 /* */
231 /* <Return> */
232 /* FreeType error code. 0~means success. */
233 /* */
234 /* <Note> */
235 /* Because `*aglyph->advance.x' and '*aglyph->advance.y' are 16.16 */
236 /* fixed-point numbers, `slot->advance.x' and `slot->advance.y' */
237 /* (which are in 26.6 fixed-point format) must be in the range */
238 /* ]-32768;32768[. */
239 /* */
240 FT_EXPORT( FT_Error )
241 FT_Get_Glyph( FT_GlyphSlot slot,
242 FT_Glyph *aglyph );
243
244
245 /*************************************************************************/
246 /* */
247 /* <Function> */
248 /* FT_Glyph_Copy */
249 /* */
250 /* <Description> */
251 /* A function used to copy a glyph image. Note that the created */
252 /* @FT_Glyph object must be released with @FT_Done_Glyph. */
253 /* */
254 /* <Input> */
255 /* source :: A handle to the source glyph object. */
256 /* */
257 /* <Output> */
258 /* target :: A handle to the target glyph object. 0~in case of */
259 /* error. */
260 /* */
261 /* <Return> */
262 /* FreeType error code. 0~means success. */
263 /* */
264 FT_EXPORT( FT_Error )
265 FT_Glyph_Copy( FT_Glyph source,
266 FT_Glyph *target );
267
268
269 /*************************************************************************/
270 /* */
271 /* <Function> */
272 /* FT_Glyph_Transform */
273 /* */
274 /* <Description> */
275 /* Transform a glyph image if its format is scalable. */
276 /* */
277 /* <InOut> */
278 /* glyph :: A handle to the target glyph object. */
279 /* */
280 /* <Input> */
281 /* matrix :: A pointer to a 2x2 matrix to apply. */
282 /* */
283 /* delta :: A pointer to a 2d vector to apply. Coordinates are */
284 /* expressed in 1/64th of a pixel. */
285 /* */
286 /* <Return> */
287 /* FreeType error code (if not 0, the glyph format is not scalable). */
288 /* */
289 /* <Note> */
290 /* The 2x2 transformation matrix is also applied to the glyph's */
291 /* advance vector. */
292 /* */
293 FT_EXPORT( FT_Error )
294 FT_Glyph_Transform( FT_Glyph glyph,
295 FT_Matrix* matrix,
296 FT_Vector* delta );
297
298
299 /*************************************************************************/
300 /* */
301 /* <Enum> */
302 /* FT_Glyph_BBox_Mode */
303 /* */
304 /* <Description> */
305 /* The mode how the values of @FT_Glyph_Get_CBox are returned. */
306 /* */
307 /* <Values> */
308 /* FT_GLYPH_BBOX_UNSCALED :: */
309 /* Return unscaled font units. */
310 /* */
311 /* FT_GLYPH_BBOX_SUBPIXELS :: */
312 /* Return unfitted 26.6 coordinates. */
313 /* */
314 /* FT_GLYPH_BBOX_GRIDFIT :: */
315 /* Return grid-fitted 26.6 coordinates. */
316 /* */
317 /* FT_GLYPH_BBOX_TRUNCATE :: */
318 /* Return coordinates in integer pixels. */
319 /* */
320 /* FT_GLYPH_BBOX_PIXELS :: */
321 /* Return grid-fitted pixel coordinates. */
322 /* */
323 typedef enum FT_Glyph_BBox_Mode_
324 {
325 FT_GLYPH_BBOX_UNSCALED = 0,
326 FT_GLYPH_BBOX_SUBPIXELS = 0,
327 FT_GLYPH_BBOX_GRIDFIT = 1,
328 FT_GLYPH_BBOX_TRUNCATE = 2,
329 FT_GLYPH_BBOX_PIXELS = 3
330
331 } FT_Glyph_BBox_Mode;
332
333
334 /* these constants are deprecated; use the corresponding */
335 /* `FT_Glyph_BBox_Mode' values instead */
336 #define ft_glyph_bbox_unscaled FT_GLYPH_BBOX_UNSCALED
337 #define ft_glyph_bbox_subpixels FT_GLYPH_BBOX_SUBPIXELS
338 #define ft_glyph_bbox_gridfit FT_GLYPH_BBOX_GRIDFIT
339 #define ft_glyph_bbox_truncate FT_GLYPH_BBOX_TRUNCATE
340 #define ft_glyph_bbox_pixels FT_GLYPH_BBOX_PIXELS
341
342
343 /*************************************************************************/
344 /* */
345 /* <Function> */
346 /* FT_Glyph_Get_CBox */
347 /* */
348 /* <Description> */
349 /* Return a glyph's `control box'. The control box encloses all the */
350 /* outline's points, including Bezier control points. Though it */
351 /* coincides with the exact bounding box for most glyphs, it can be */
352 /* slightly larger in some situations (like when rotating an outline */
353 /* that contains Bezier outside arcs). */
354 /* */
355 /* Computing the control box is very fast, while getting the bounding */
356 /* box can take much more time as it needs to walk over all segments */
357 /* and arcs in the outline. To get the latter, you can use the */
358 /* `ftbbox' component, which is dedicated to this single task. */
359 /* */
360 /* <Input> */
361 /* glyph :: A handle to the source glyph object. */
362 /* */
363 /* mode :: The mode that indicates how to interpret the returned */
364 /* bounding box values. */
365 /* */
366 /* <Output> */
367 /* acbox :: The glyph coordinate bounding box. Coordinates are */
368 /* expressed in 1/64th of pixels if it is grid-fitted. */
369 /* */
370 /* <Note> */
371 /* Coordinates are relative to the glyph origin, using the y~upwards */
372 /* convention. */
373 /* */
374 /* If the glyph has been loaded with @FT_LOAD_NO_SCALE, `bbox_mode' */
375 /* must be set to @FT_GLYPH_BBOX_UNSCALED to get unscaled font */
376 /* units in 26.6 pixel format. The value @FT_GLYPH_BBOX_SUBPIXELS */
377 /* is another name for this constant. */
378 /* */
379 /* If the font is tricky and the glyph has been loaded with */
380 /* @FT_LOAD_NO_SCALE, the resulting CBox is meaningless. To get */
381 /* reasonable values for the CBox it is necessary to load the glyph */
382 /* at a large ppem value (so that the hinting instructions can */
383 /* properly shift and scale the subglyphs), then extracting the CBox, */
384 /* which can be eventually converted back to font units. */
385 /* */
386 /* Note that the maximum coordinates are exclusive, which means that */
387 /* one can compute the width and height of the glyph image (be it in */
388 /* integer or 26.6 pixels) as: */
389 /* */
390 /* { */
391 /* width = bbox.xMax - bbox.xMin; */
392 /* height = bbox.yMax - bbox.yMin; */
393 /* } */
394 /* */
395 /* Note also that for 26.6 coordinates, if `bbox_mode' is set to */
396 /* @FT_GLYPH_BBOX_GRIDFIT, the coordinates will also be grid-fitted, */
397 /* which corresponds to: */
398 /* */
399 /* { */
400 /* bbox.xMin = FLOOR(bbox.xMin); */
401 /* bbox.yMin = FLOOR(bbox.yMin); */
402 /* bbox.xMax = CEILING(bbox.xMax); */
403 /* bbox.yMax = CEILING(bbox.yMax); */
404 /* } */
405 /* */
406 /* To get the bbox in pixel coordinates, set `bbox_mode' to */
407 /* @FT_GLYPH_BBOX_TRUNCATE. */
408 /* */
409 /* To get the bbox in grid-fitted pixel coordinates, set `bbox_mode' */
410 /* to @FT_GLYPH_BBOX_PIXELS. */
411 /* */
412 FT_EXPORT( void )
413 FT_Glyph_Get_CBox( FT_Glyph glyph,
414 FT_UInt bbox_mode,
415 FT_BBox *acbox );
416
417
418 /*************************************************************************/
419 /* */
420 /* <Function> */
421 /* FT_Glyph_To_Bitmap */
422 /* */
423 /* <Description> */
424 /* Convert a given glyph object to a bitmap glyph object. */
425 /* */
426 /* <InOut> */
427 /* the_glyph :: A pointer to a handle to the target glyph. */
428 /* */
429 /* <Input> */
430 /* render_mode :: An enumeration that describes how the data is */
431 /* rendered. */
432 /* */
433 /* origin :: A pointer to a vector used to translate the glyph */
434 /* image before rendering. Can be~0 (if no */
435 /* translation). The origin is expressed in */
436 /* 26.6 pixels. */
437 /* */
438 /* destroy :: A boolean that indicates that the original glyph */
439 /* image should be destroyed by this function. It is */
440 /* never destroyed in case of error. */
441 /* */
442 /* <Return> */
443 /* FreeType error code. 0~means success. */
444 /* */
445 /* <Note> */
446 /* This function does nothing if the glyph format isn't scalable. */
447 /* */
448 /* The glyph image is translated with the `origin' vector before */
449 /* rendering. */
450 /* */
451 /* The first parameter is a pointer to an @FT_Glyph handle, that will */
452 /* be _replaced_ by this function (with newly allocated data). */
453 /* Typically, you would use (omitting error handling): */
454 /* */
455 /* */
456 /* { */
457 /* FT_Glyph glyph; */
458 /* FT_BitmapGlyph glyph_bitmap; */
459 /* */
460 /* */
461 /* // load glyph */
462 /* error = FT_Load_Char( face, glyph_index, FT_LOAD_DEFAULT ); */
463 /* */
464 /* // extract glyph image */
465 /* error = FT_Get_Glyph( face->glyph, &glyph ); */
466 /* */
467 /* // convert to a bitmap (default render mode + destroying old) */
468 /* if ( glyph->format != FT_GLYPH_FORMAT_BITMAP ) */
469 /* { */
470 /* error = FT_Glyph_To_Bitmap( &glyph, FT_RENDER_MODE_NORMAL, */
471 /* 0, 1 ); */
472 /* if ( error ) // `glyph' unchanged */
473 /* ... */
474 /* } */
475 /* */
476 /* // access bitmap content by typecasting */
477 /* glyph_bitmap = (FT_BitmapGlyph)glyph; */
478 /* */
479 /* // do funny stuff with it, like blitting/drawing */
480 /* ... */
481 /* */
482 /* // discard glyph image (bitmap or not) */
483 /* FT_Done_Glyph( glyph ); */
484 /* } */
485 /* */
486 /* */
487 /* Here another example, again without error handling: */
488 /* */
489 /* */
490 /* { */
491 /* FT_Glyph glyphs[MAX_GLYPHS] */
492 /* */
493 /* */
494 /* ... */
495 /* */
496 /* for ( idx = 0; i < MAX_GLYPHS; i++ ) */
497 /* error = FT_Load_Glyph( face, idx, FT_LOAD_DEFAULT ) || */
498 /* FT_Get_Glyph ( face->glyph, &glyph[idx] ); */
499 /* */
500 /* ... */
501 /* */
502 /* for ( idx = 0; i < MAX_GLYPHS; i++ ) */
503 /* { */
504 /* FT_Glyph bitmap = glyphs[idx]; */
505 /* */
506 /* */
507 /* ... */
508 /* */
509 /* // after this call, `bitmap' no longer points into */
510 /* // the `glyphs' array (and the old value isn't destroyed) */
511 /* FT_Glyph_To_Bitmap( &bitmap, FT_RENDER_MODE_MONO, 0, 0 ); */
512 /* */
513 /* ... */
514 /* */
515 /* FT_Done_Glyph( bitmap ); */
516 /* } */
517 /* */
518 /* ... */
519 /* */
520 /* for ( idx = 0; i < MAX_GLYPHS; i++ ) */
521 /* FT_Done_Glyph( glyphs[idx] ); */
522 /* } */
523 /* */
524 FT_EXPORT( FT_Error )
525 FT_Glyph_To_Bitmap( FT_Glyph* the_glyph,
526 FT_Render_Mode render_mode,
527 FT_Vector* origin,
528 FT_Bool destroy );
529
530
531 /*************************************************************************/
532 /* */
533 /* <Function> */
534 /* FT_Done_Glyph */
535 /* */
536 /* <Description> */
537 /* Destroy a given glyph. */
538 /* */
539 /* <Input> */
540 /* glyph :: A handle to the target glyph object. */
541 /* */
542 FT_EXPORT( void )
543 FT_Done_Glyph( FT_Glyph glyph );
544
545 /* */
546
547
548 /* other helpful functions */
549
550 /*************************************************************************/
551 /* */
552 /* <Section> */
553 /* computations */
554 /* */
555 /*************************************************************************/
556
557
558 /*************************************************************************/
559 /* */
560 /* <Function> */
561 /* FT_Matrix_Multiply */
562 /* */
563 /* <Description> */
564 /* Perform the matrix operation `b = a*b'. */
565 /* */
566 /* <Input> */
567 /* a :: A pointer to matrix `a'. */
568 /* */
569 /* <InOut> */
570 /* b :: A pointer to matrix `b'. */
571 /* */
572 /* <Note> */
573 /* The result is undefined if either `a' or `b' is zero. */
574 /* */
575 /* Since the function uses wrap-around arithmetic, results become */
576 /* meaningless if the arguments are very large. */
577 /* */
578 FT_EXPORT( void )
579 FT_Matrix_Multiply( const FT_Matrix* a,
580 FT_Matrix* b );
581
582
583 /*************************************************************************/
584 /* */
585 /* <Function> */
586 /* FT_Matrix_Invert */
587 /* */
588 /* <Description> */
589 /* Invert a 2x2 matrix. Return an error if it can't be inverted. */
590 /* */
591 /* <InOut> */
592 /* matrix :: A pointer to the target matrix. Remains untouched in */
593 /* case of error. */
594 /* */
595 /* <Return> */
596 /* FreeType error code. 0~means success. */
597 /* */
598 FT_EXPORT( FT_Error )
599 FT_Matrix_Invert( FT_Matrix* matrix );
600
601 /* */
602
603
604 FT_END_HEADER
605
606 #endif /* FTGLYPH_H_ */
607
608
609 /* END */
610
611
612 /* Local Variables: */
613 /* coding: utf-8 */
614 /* End: */