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ftglyph.h
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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 
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 */
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  {
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  /* */
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  {
166 
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  /* */
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  {
212 
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  /* */
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  /* */
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  /* */
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  {
330 
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 )
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  /* */
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 )
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  /* */
600 
601  /* */
602 
603 
605 
606 #endif /* FTGLYPH_H_ */
607 
608 
609 /* END */
610 
611 
612 /* Local Variables: */
613 /* coding: utf-8 */
614 /* End: */
FT_Bitmap bitmap
Definition: ftglyph.h:165
int FT_Error
Definition: fttypes.h:300
struct FT_OutlineGlyphRec_ * FT_OutlineGlyph
Definition: ftglyph.h:179
const FT_Glyph_Class * clazz
Definition: ftglyph.h:111
typedefFT_BEGIN_HEADER struct FT_Glyph_Class_ FT_Glyph_Class
Definition: ftglyph.h:69
#define FT_END_HEADER
Definition: ftheader.h:54
signed int FT_Int
Definition: fttypes.h:220
GLuint GLenum matrix
Definition: glext.h:9407
FT_Library library
Definition: ftglyph.h:110
enum FT_Render_Mode_ FT_Render_Mode
voidpf uLong int origin
Definition: ioapi.h:142
FT_Glyph_Copy(FT_Glyph source, FT_Glyph *target)
Definition: ftglyph.c:316
FT_Glyph_Format format
Definition: ftglyph.h:112
FT_Matrix_Multiply(const FT_Matrix *a, FT_Matrix *b)
Definition: ftcalc.c:661
struct FT_BitmapGlyphRec_ * FT_BitmapGlyph
Definition: ftglyph.h:127
FT_BEGIN_HEADER typedef unsigned char FT_Bool
Definition: fttypes.h:108
FT_Glyph_BBox_Mode_
Definition: ftglyph.h:323
FT_Glyph_Transform(FT_Glyph glyph, FT_Matrix *matrix, FT_Vector *delta)
Definition: ftglyph.c:447
struct FT_BitmapGlyphRec_ FT_BitmapGlyphRec
#define FT_BEGIN_HEADER
Definition: ftheader.h:36
struct FT_GlyphRec_ * FT_Glyph
Definition: ftglyph.h:87
struct FT_GlyphRec_ FT_GlyphRec
FT_GlyphRec root
Definition: ftglyph.h:162
GLboolean GLboolean GLboolean b
Definition: glext.h:6204
FT_GlyphRec root
Definition: ftglyph.h:210
FT_Glyph_To_Bitmap(FT_Glyph *the_glyph, FT_Render_Mode render_mode, FT_Vector *origin, FT_Bool destroy)
Definition: ftglyph.c:527
void destroy(_Tp *__pointer)
Definition: _construct.h:278
FT_Get_Glyph(FT_GlyphSlot slot, FT_Glyph *aglyph)
Definition: ftglyph.c:363
Definition: vfat.h:184
struct FT_OutlineGlyphRec_ FT_OutlineGlyphRec
unsigned int FT_UInt
Definition: fttypes.h:231
#define FT_EXPORT(x)
Definition: ftconfig.h:461
enum FT_Glyph_Format_ FT_Glyph_Format
FT_Glyph_Get_CBox(FT_Glyph glyph, FT_UInt bbox_mode, FT_BBox *acbox)
Definition: ftglyph.c:480
FT_Vector advance
Definition: ftglyph.h:113
FT_Matrix_Invert(FT_Matrix *matrix)
Definition: ftcalc.c:689
GLenum target
Definition: glext.h:7315
GLboolean GLboolean GLboolean GLboolean a
Definition: glext.h:6204
FT_Outline outline
Definition: ftglyph.h:211
FT_Done_Glyph(FT_Glyph glyph)
Definition: ftglyph.c:633
enum FT_Glyph_BBox_Mode_ FT_Glyph_BBox_Mode