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ftglyph.h
1/***************************************************************************/
2/* */
3/* ftglyph.h */
4/* */
5/* FreeType convenience functions to handle glyphs (specification). */
6/* */
7/* Copyright 1996-2016 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
46FT_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 FT_EXPORT( FT_Error )
235 FT_Get_Glyph( FT_GlyphSlot slot,
236 FT_Glyph *aglyph );
237
238
239 /*************************************************************************/
240 /* */
241 /* <Function> */
242 /* FT_Glyph_Copy */
243 /* */
244 /* <Description> */
245 /* A function used to copy a glyph image. Note that the created */
246 /* @FT_Glyph object must be released with @FT_Done_Glyph. */
247 /* */
248 /* <Input> */
249 /* source :: A handle to the source glyph object. */
250 /* */
251 /* <Output> */
252 /* target :: A handle to the target glyph object. 0~in case of */
253 /* error. */
254 /* */
255 /* <Return> */
256 /* FreeType error code. 0~means success. */
257 /* */
258 FT_EXPORT( FT_Error )
259 FT_Glyph_Copy( FT_Glyph source,
260 FT_Glyph *target );
261
262
263 /*************************************************************************/
264 /* */
265 /* <Function> */
266 /* FT_Glyph_Transform */
267 /* */
268 /* <Description> */
269 /* Transform a glyph image if its format is scalable. */
270 /* */
271 /* <InOut> */
272 /* glyph :: A handle to the target glyph object. */
273 /* */
274 /* <Input> */
275 /* matrix :: A pointer to a 2x2 matrix to apply. */
276 /* */
277 /* delta :: A pointer to a 2d vector to apply. Coordinates are */
278 /* expressed in 1/64th of a pixel. */
279 /* */
280 /* <Return> */
281 /* FreeType error code (if not 0, the glyph format is not scalable). */
282 /* */
283 /* <Note> */
284 /* The 2x2 transformation matrix is also applied to the glyph's */
285 /* advance vector. */
286 /* */
287 FT_EXPORT( FT_Error )
288 FT_Glyph_Transform( FT_Glyph glyph,
289 FT_Matrix* matrix,
290 FT_Vector* delta );
291
292
293 /*************************************************************************/
294 /* */
295 /* <Enum> */
296 /* FT_Glyph_BBox_Mode */
297 /* */
298 /* <Description> */
299 /* The mode how the values of @FT_Glyph_Get_CBox are returned. */
300 /* */
301 /* <Values> */
302 /* FT_GLYPH_BBOX_UNSCALED :: */
303 /* Return unscaled font units. */
304 /* */
305 /* FT_GLYPH_BBOX_SUBPIXELS :: */
306 /* Return unfitted 26.6 coordinates. */
307 /* */
308 /* FT_GLYPH_BBOX_GRIDFIT :: */
309 /* Return grid-fitted 26.6 coordinates. */
310 /* */
311 /* FT_GLYPH_BBOX_TRUNCATE :: */
312 /* Return coordinates in integer pixels. */
313 /* */
314 /* FT_GLYPH_BBOX_PIXELS :: */
315 /* Return grid-fitted pixel coordinates. */
316 /* */
317 typedef enum FT_Glyph_BBox_Mode_
318 {
319 FT_GLYPH_BBOX_UNSCALED = 0,
320 FT_GLYPH_BBOX_SUBPIXELS = 0,
321 FT_GLYPH_BBOX_GRIDFIT = 1,
322 FT_GLYPH_BBOX_TRUNCATE = 2,
323 FT_GLYPH_BBOX_PIXELS = 3
324
325 } FT_Glyph_BBox_Mode;
326
327
328 /* these constants are deprecated; use the corresponding */
329 /* `FT_Glyph_BBox_Mode' values instead */
330#define ft_glyph_bbox_unscaled FT_GLYPH_BBOX_UNSCALED
331#define ft_glyph_bbox_subpixels FT_GLYPH_BBOX_SUBPIXELS
332#define ft_glyph_bbox_gridfit FT_GLYPH_BBOX_GRIDFIT
333#define ft_glyph_bbox_truncate FT_GLYPH_BBOX_TRUNCATE
334#define ft_glyph_bbox_pixels FT_GLYPH_BBOX_PIXELS
335
336
337 /*************************************************************************/
338 /* */
339 /* <Function> */
340 /* FT_Glyph_Get_CBox */
341 /* */
342 /* <Description> */
343 /* Return a glyph's `control box'. The control box encloses all the */
344 /* outline's points, including Bézier control points. Though it */
345 /* coincides with the exact bounding box for most glyphs, it can be */
346 /* slightly larger in some situations (like when rotating an outline */
347 /* that contains Bézier outside arcs). */
348 /* */
349 /* Computing the control box is very fast, while getting the bounding */
350 /* box can take much more time as it needs to walk over all segments */
351 /* and arcs in the outline. To get the latter, you can use the */
352 /* `ftbbox' component, which is dedicated to this single task. */
353 /* */
354 /* <Input> */
355 /* glyph :: A handle to the source glyph object. */
356 /* */
357 /* mode :: The mode that indicates how to interpret the returned */
358 /* bounding box values. */
359 /* */
360 /* <Output> */
361 /* acbox :: The glyph coordinate bounding box. Coordinates are */
362 /* expressed in 1/64th of pixels if it is grid-fitted. */
363 /* */
364 /* <Note> */
365 /* Coordinates are relative to the glyph origin, using the y~upwards */
366 /* convention. */
367 /* */
368 /* If the glyph has been loaded with @FT_LOAD_NO_SCALE, `bbox_mode' */
369 /* must be set to @FT_GLYPH_BBOX_UNSCALED to get unscaled font */
370 /* units in 26.6 pixel format. The value @FT_GLYPH_BBOX_SUBPIXELS */
371 /* is another name for this constant. */
372 /* */
373 /* If the font is tricky and the glyph has been loaded with */
374 /* @FT_LOAD_NO_SCALE, the resulting CBox is meaningless. To get */
375 /* reasonable values for the CBox it is necessary to load the glyph */
376 /* at a large ppem value (so that the hinting instructions can */
377 /* properly shift and scale the subglyphs), then extracting the CBox, */
378 /* which can be eventually converted back to font units. */
379 /* */
380 /* Note that the maximum coordinates are exclusive, which means that */
381 /* one can compute the width and height of the glyph image (be it in */
382 /* integer or 26.6 pixels) as: */
383 /* */
384 /* { */
385 /* width = bbox.xMax - bbox.xMin; */
386 /* height = bbox.yMax - bbox.yMin; */
387 /* } */
388 /* */
389 /* Note also that for 26.6 coordinates, if `bbox_mode' is set to */
390 /* @FT_GLYPH_BBOX_GRIDFIT, the coordinates will also be grid-fitted, */
391 /* which corresponds to: */
392 /* */
393 /* { */
394 /* bbox.xMin = FLOOR(bbox.xMin); */
395 /* bbox.yMin = FLOOR(bbox.yMin); */
396 /* bbox.xMax = CEILING(bbox.xMax); */
397 /* bbox.yMax = CEILING(bbox.yMax); */
398 /* } */
399 /* */
400 /* To get the bbox in pixel coordinates, set `bbox_mode' to */
401 /* @FT_GLYPH_BBOX_TRUNCATE. */
402 /* */
403 /* To get the bbox in grid-fitted pixel coordinates, set `bbox_mode' */
404 /* to @FT_GLYPH_BBOX_PIXELS. */
405 /* */
406 FT_EXPORT( void )
407 FT_Glyph_Get_CBox( FT_Glyph glyph,
408 FT_UInt bbox_mode,
409 FT_BBox *acbox );
410
411
412 /*************************************************************************/
413 /* */
414 /* <Function> */
415 /* FT_Glyph_To_Bitmap */
416 /* */
417 /* <Description> */
418 /* Convert a given glyph object to a bitmap glyph object. */
419 /* */
420 /* <InOut> */
421 /* the_glyph :: A pointer to a handle to the target glyph. */
422 /* */
423 /* <Input> */
424 /* render_mode :: An enumeration that describes how the data is */
425 /* rendered. */
426 /* */
427 /* origin :: A pointer to a vector used to translate the glyph */
428 /* image before rendering. Can be~0 (if no */
429 /* translation). The origin is expressed in */
430 /* 26.6 pixels. */
431 /* */
432 /* destroy :: A boolean that indicates that the original glyph */
433 /* image should be destroyed by this function. It is */
434 /* never destroyed in case of error. */
435 /* */
436 /* <Return> */
437 /* FreeType error code. 0~means success. */
438 /* */
439 /* <Note> */
440 /* This function does nothing if the glyph format isn't scalable. */
441 /* */
442 /* The glyph image is translated with the `origin' vector before */
443 /* rendering. */
444 /* */
445 /* The first parameter is a pointer to an @FT_Glyph handle, that will */
446 /* be _replaced_ by this function (with newly allocated data). */
447 /* Typically, you would use (omitting error handling): */
448 /* */
449 /* */
450 /* { */
451 /* FT_Glyph glyph; */
452 /* FT_BitmapGlyph glyph_bitmap; */
453 /* */
454 /* */
455 /* // load glyph */
456 /* error = FT_Load_Char( face, glyph_index, FT_LOAD_DEFAUT ); */
457 /* */
458 /* // extract glyph image */
459 /* error = FT_Get_Glyph( face->glyph, &glyph ); */
460 /* */
461 /* // convert to a bitmap (default render mode + destroying old) */
462 /* if ( glyph->format != FT_GLYPH_FORMAT_BITMAP ) */
463 /* { */
464 /* error = FT_Glyph_To_Bitmap( &glyph, FT_RENDER_MODE_NORMAL, */
465 /* 0, 1 ); */
466 /* if ( error ) // `glyph' unchanged */
467 /* ... */
468 /* } */
469 /* */
470 /* // access bitmap content by typecasting */
471 /* glyph_bitmap = (FT_BitmapGlyph)glyph; */
472 /* */
473 /* // do funny stuff with it, like blitting/drawing */
474 /* ... */
475 /* */
476 /* // discard glyph image (bitmap or not) */
477 /* FT_Done_Glyph( glyph ); */
478 /* } */
479 /* */
480 /* */
481 /* Here another example, again without error handling: */
482 /* */
483 /* */
484 /* { */
485 /* FT_Glyph glyphs[MAX_GLYPHS] */
486 /* */
487 /* */
488 /* ... */
489 /* */
490 /* for ( idx = 0; i < MAX_GLYPHS; i++ ) */
491 /* error = FT_Load_Glyph( face, idx, FT_LOAD_DEFAULT ) || */
492 /* FT_Get_Glyph ( face->glyph, &glyph[idx] ); */
493 /* */
494 /* ... */
495 /* */
496 /* for ( idx = 0; i < MAX_GLYPHS; i++ ) */
497 /* { */
498 /* FT_Glyph bitmap = glyphs[idx]; */
499 /* */
500 /* */
501 /* ... */
502 /* */
503 /* // after this call, `bitmap' no longer points into */
504 /* // the `glyphs' array (and the old value isn't destroyed) */
505 /* FT_Glyph_To_Bitmap( &bitmap, FT_RENDER_MODE_MONO, 0, 0 ); */
506 /* */
507 /* ... */
508 /* */
509 /* FT_Done_Glyph( bitmap ); */
510 /* } */
511 /* */
512 /* ... */
513 /* */
514 /* for ( idx = 0; i < MAX_GLYPHS; i++ ) */
515 /* FT_Done_Glyph( glyphs[idx] ); */
516 /* } */
517 /* */
518 FT_EXPORT( FT_Error )
519 FT_Glyph_To_Bitmap( FT_Glyph* the_glyph,
520 FT_Render_Mode render_mode,
521 FT_Vector* origin,
522 FT_Bool destroy );
523
524
525 /*************************************************************************/
526 /* */
527 /* <Function> */
528 /* FT_Done_Glyph */
529 /* */
530 /* <Description> */
531 /* Destroy a given glyph. */
532 /* */
533 /* <Input> */
534 /* glyph :: A handle to the target glyph object. */
535 /* */
536 FT_EXPORT( void )
537 FT_Done_Glyph( FT_Glyph glyph );
538
539 /* */
540
541
542 /* other helpful functions */
543
544 /*************************************************************************/
545 /* */
546 /* <Section> */
547 /* computations */
548 /* */
549 /*************************************************************************/
550
551
552 /*************************************************************************/
553 /* */
554 /* <Function> */
555 /* FT_Matrix_Multiply */
556 /* */
557 /* <Description> */
558 /* Perform the matrix operation `b = a*b'. */
559 /* */
560 /* <Input> */
561 /* a :: A pointer to matrix `a'. */
562 /* */
563 /* <InOut> */
564 /* b :: A pointer to matrix `b'. */
565 /* */
566 /* <Note> */
567 /* The result is undefined if either `a' or `b' is zero. */
568 /* */
569 FT_EXPORT( void )
570 FT_Matrix_Multiply( const FT_Matrix* a,
571 FT_Matrix* b );
572
573
574 /*************************************************************************/
575 /* */
576 /* <Function> */
577 /* FT_Matrix_Invert */
578 /* */
579 /* <Description> */
580 /* Invert a 2x2 matrix. Return an error if it can't be inverted. */
581 /* */
582 /* <InOut> */
583 /* matrix :: A pointer to the target matrix. Remains untouched in */
584 /* case of error. */
585 /* */
586 /* <Return> */
587 /* FreeType error code. 0~means success. */
588 /* */
589 FT_EXPORT( FT_Error )
590 FT_Matrix_Invert( FT_Matrix* matrix );
591
592 /* */
593
594
595FT_END_HEADER
596
597#endif /* FTGLYPH_H_ */
598
599
600/* END */
601
602
603/* Local Variables: */
604/* coding: utf-8 */
605/* End: */
FT_BBox_
Definition ftimage.h:116
FT_Bitmap_
Definition ftimage.h:262
FT_BitmapGlyphRec_
Definition ftglyph.h:161
FT_Glyph_Class_
Definition ftrender.h:75
FT_GlyphRec_
Definition ftglyph.h:109
FT_GlyphSlotRec_
Definition freetype.h:1745
FT_Matrix_
Definition fttypes.h:386
FT_Outline_
Definition ftimage.h:335
FT_OutlineGlyphRec_
Definition ftglyph.h:209
FT_Vector_
Definition ftimage.h:75
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