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| author | John Tsiombikas <nuclear@member.fsf.org> |
|---|---|
| date | Sun, 02 Feb 2014 00:35:22 +0200 |
| parents | |
| children |
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1 /***************************************************************************/
2 /* */
3 /* ftglyph.h */
4 /* */
5 /* FreeType convenience functions to handle glyphs (specification). */
6 /* */
7 /* Copyright 1996-2001, 2002, 2003, 2006, 2008, 2009 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 /***************************************************************************/
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 /*************************************************************************/
32 #ifndef __FTGLYPH_H__
33 #define __FTGLYPH_H__
36 #include <ft2build.h>
37 #include FT_FREETYPE_H
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
46 FT_BEGIN_HEADER
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 /*************************************************************************/
68 /* forward declaration to a private type */
69 typedef struct FT_Glyph_Class_ FT_Glyph_Class;
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;
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 float 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;
115 } FT_GlyphRec;
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;
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;
167 } FT_BitmapGlyphRec;
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;
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;
213 } FT_OutlineGlyphRec;
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 );
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 );
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 );
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
325 } FT_Glyph_BBox_Mode;
328 /*************************************************************************/
329 /* */
330 /* <Enum> */
331 /* ft_glyph_bbox_xxx */
332 /* */
333 /* <Description> */
334 /* These constants are deprecated. Use the corresponding */
335 /* @FT_Glyph_BBox_Mode values instead. */
336 /* */
337 /* <Values> */
338 /* ft_glyph_bbox_unscaled :: See @FT_GLYPH_BBOX_UNSCALED. */
339 /* ft_glyph_bbox_subpixels :: See @FT_GLYPH_BBOX_SUBPIXELS. */
340 /* ft_glyph_bbox_gridfit :: See @FT_GLYPH_BBOX_GRIDFIT. */
341 /* ft_glyph_bbox_truncate :: See @FT_GLYPH_BBOX_TRUNCATE. */
342 /* ft_glyph_bbox_pixels :: See @FT_GLYPH_BBOX_PIXELS. */
343 /* */
344 #define ft_glyph_bbox_unscaled FT_GLYPH_BBOX_UNSCALED
345 #define ft_glyph_bbox_subpixels FT_GLYPH_BBOX_SUBPIXELS
346 #define ft_glyph_bbox_gridfit FT_GLYPH_BBOX_GRIDFIT
347 #define ft_glyph_bbox_truncate FT_GLYPH_BBOX_TRUNCATE
348 #define ft_glyph_bbox_pixels FT_GLYPH_BBOX_PIXELS
351 /*************************************************************************/
352 /* */
353 /* <Function> */
354 /* FT_Glyph_Get_CBox */
355 /* */
356 /* <Description> */
357 /* Return a glyph's `control box'. The control box encloses all the */
358 /* outline's points, including Bézier control points. Though it */
359 /* coincides with the exact bounding box for most glyphs, it can be */
360 /* slightly larger in some situations (like when rotating an outline */
361 /* which contains Bézier outside arcs). */
362 /* */
363 /* Computing the control box is very fast, while getting the bounding */
364 /* box can take much more time as it needs to walk over all segments */
365 /* and arcs in the outline. To get the latter, you can use the */
366 /* `ftbbox' component which is dedicated to this single task. */
367 /* */
368 /* <Input> */
369 /* glyph :: A handle to the source glyph object. */
370 /* */
371 /* mode :: The mode which indicates how to interpret the returned */
372 /* bounding box values. */
373 /* */
374 /* <Output> */
375 /* acbox :: The glyph coordinate bounding box. Coordinates are */
376 /* expressed in 1/64th of pixels if it is grid-fitted. */
377 /* */
378 /* <Note> */
379 /* Coordinates are relative to the glyph origin, using the y~upwards */
380 /* convention. */
381 /* */
382 /* If the glyph has been loaded with @FT_LOAD_NO_SCALE, `bbox_mode' */
383 /* must be set to @FT_GLYPH_BBOX_UNSCALED to get unscaled font */
384 /* units in 26.6 pixel format. The value @FT_GLYPH_BBOX_SUBPIXELS */
385 /* is another name for this constant. */
386 /* */
387 /* Note that the maximum coordinates are exclusive, which means that */
388 /* one can compute the width and height of the glyph image (be it in */
389 /* integer or 26.6 pixels) as: */
390 /* */
391 /* { */
392 /* width = bbox.xMax - bbox.xMin; */
393 /* height = bbox.yMax - bbox.yMin; */
394 /* } */
395 /* */
396 /* Note also that for 26.6 coordinates, if `bbox_mode' is set to */
397 /* @FT_GLYPH_BBOX_GRIDFIT, the coordinates will also be grid-fitted, */
398 /* which corresponds to: */
399 /* */
400 /* { */
401 /* bbox.xMin = FLOOR(bbox.xMin); */
402 /* bbox.yMin = FLOOR(bbox.yMin); */
403 /* bbox.xMax = CEILING(bbox.xMax); */
404 /* bbox.yMax = CEILING(bbox.yMax); */
405 /* } */
406 /* */
407 /* To get the bbox in pixel coordinates, set `bbox_mode' to */
408 /* @FT_GLYPH_BBOX_TRUNCATE. */
409 /* */
410 /* To get the bbox in grid-fitted pixel coordinates, set `bbox_mode' */
411 /* to @FT_GLYPH_BBOX_PIXELS. */
412 /* */
413 FT_EXPORT( void )
414 FT_Glyph_Get_CBox( FT_Glyph glyph,
415 FT_UInt bbox_mode,
416 FT_BBox *acbox );
419 /*************************************************************************/
420 /* */
421 /* <Function> */
422 /* FT_Glyph_To_Bitmap */
423 /* */
424 /* <Description> */
425 /* Convert a given glyph object to a bitmap glyph object. */
426 /* */
427 /* <InOut> */
428 /* the_glyph :: A pointer to a handle to the target glyph. */
429 /* */
430 /* <Input> */
431 /* render_mode :: An enumeration that describes how the data is */
432 /* rendered. */
433 /* */
434 /* origin :: A pointer to a vector used to translate the glyph */
435 /* image before rendering. Can be~0 (if no */
436 /* translation). The origin is expressed in */
437 /* 26.6 pixels. */
438 /* */
439 /* destroy :: A boolean that indicates that the original glyph */
440 /* image should be destroyed by this function. It is */
441 /* never destroyed in case of error. */
442 /* */
443 /* <Return> */
444 /* FreeType error code. 0~means success. */
445 /* */
446 /* <Note> */
447 /* This function does nothing if the glyph format isn't scalable. */
448 /* */
449 /* The glyph image is translated with the `origin' vector before */
450 /* rendering. */
451 /* */
452 /* The first parameter is a pointer to an @FT_Glyph handle, that will */
453 /* be _replaced_ by this function (with newly allocated data). */
454 /* Typically, you would use (omitting error handling): */
455 /* */
456 /* */
457 /* { */
458 /* FT_Glyph glyph; */
459 /* FT_BitmapGlyph glyph_bitmap; */
460 /* */
461 /* */
462 /* // load glyph */
463 /* error = FT_Load_Char( face, glyph_index, FT_LOAD_DEFAUT ); */
464 /* */
465 /* // extract glyph image */
466 /* error = FT_Get_Glyph( face->glyph, &glyph ); */
467 /* */
468 /* // convert to a bitmap (default render mode + destroying old) */
469 /* if ( glyph->format != FT_GLYPH_FORMAT_BITMAP ) */
470 /* { */
471 /* error = FT_Glyph_To_Bitmap( &glyph, FT_RENDER_MODE_NORMAL, */
472 /* 0, 1 ); */
473 /* if ( error ) // `glyph' unchanged */
474 /* ... */
475 /* } */
476 /* */
477 /* // access bitmap content by typecasting */
478 /* glyph_bitmap = (FT_BitmapGlyph)glyph; */
479 /* */
480 /* // do funny stuff with it, like blitting/drawing */
481 /* ... */
482 /* */
483 /* // discard glyph image (bitmap or not) */
484 /* FT_Done_Glyph( glyph ); */
485 /* } */
486 /* */
487 /* */
488 /* Here another example, again without error handling: */
489 /* */
490 /* */
491 /* { */
492 /* FT_Glyph glyphs[MAX_GLYPHS] */
493 /* */
494 /* */
495 /* ... */
496 /* */
497 /* for ( idx = 0; i < MAX_GLYPHS; i++ ) */
498 /* error = FT_Load_Glyph( face, idx, FT_LOAD_DEFAULT ) || */
499 /* FT_Get_Glyph ( face->glyph, &glyph[idx] ); */
500 /* */
501 /* ... */
502 /* */
503 /* for ( idx = 0; i < MAX_GLYPHS; i++ ) */
504 /* { */
505 /* FT_Glyph bitmap = glyphs[idx]; */
506 /* */
507 /* */
508 /* ... */
509 /* */
510 /* // after this call, `bitmap' no longer points into */
511 /* // the `glyphs' array (and the old value isn't destroyed) */
512 /* FT_Glyph_To_Bitmap( &bitmap, FT_RENDER_MODE_MONO, 0, 0 ); */
513 /* */
514 /* ... */
515 /* */
516 /* FT_Done_Glyph( bitmap ); */
517 /* } */
518 /* */
519 /* ... */
520 /* */
521 /* for ( idx = 0; i < MAX_GLYPHS; i++ ) */
522 /* FT_Done_Glyph( glyphs[idx] ); */
523 /* } */
524 /* */
525 FT_EXPORT( FT_Error )
526 FT_Glyph_To_Bitmap( FT_Glyph* the_glyph,
527 FT_Render_Mode render_mode,
528 FT_Vector* origin,
529 FT_Bool destroy );
532 /*************************************************************************/
533 /* */
534 /* <Function> */
535 /* FT_Done_Glyph */
536 /* */
537 /* <Description> */
538 /* Destroy a given glyph. */
539 /* */
540 /* <Input> */
541 /* glyph :: A handle to the target glyph object. */
542 /* */
543 FT_EXPORT( void )
544 FT_Done_Glyph( FT_Glyph glyph );
546 /* */
549 /* other helpful functions */
551 /*************************************************************************/
552 /* */
553 /* <Section> */
554 /* computations */
555 /* */
556 /*************************************************************************/
559 /*************************************************************************/
560 /* */
561 /* <Function> */
562 /* FT_Matrix_Multiply */
563 /* */
564 /* <Description> */
565 /* Perform the matrix operation `b = a*b'. */
566 /* */
567 /* <Input> */
568 /* a :: A pointer to matrix `a'. */
569 /* */
570 /* <InOut> */
571 /* b :: A pointer to matrix `b'. */
572 /* */
573 /* <Note> */
574 /* The result is undefined if either `a' or `b' is zero. */
575 /* */
576 FT_EXPORT( void )
577 FT_Matrix_Multiply( const FT_Matrix* a,
578 FT_Matrix* b );
581 /*************************************************************************/
582 /* */
583 /* <Function> */
584 /* FT_Matrix_Invert */
585 /* */
586 /* <Description> */
587 /* Invert a 2x2 matrix. Return an error if it can't be inverted. */
588 /* */
589 /* <InOut> */
590 /* matrix :: A pointer to the target matrix. Remains untouched in */
591 /* case of error. */
592 /* */
593 /* <Return> */
594 /* FreeType error code. 0~means success. */
595 /* */
596 FT_EXPORT( FT_Error )
597 FT_Matrix_Invert( FT_Matrix* matrix );
600 /* */
603 FT_END_HEADER
605 #endif /* __FTGLYPH_H__ */
608 /* END */
611 /* Local Variables: */
612 /* coding: utf-8 */
613 /* End: */