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1 /****************************************************************************
2  *
3  * freetype.h
4  *
5  *   FreeType high-level API and common types (specification only).
6  *
7  * Copyright (C) 1996-2021 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 #ifndef FREETYPE_H_
20 #define FREETYPE_H_
21 
22 
23 #include <ft2build.h>
24 #include FT_CONFIG_CONFIG_H
25 #include <freetype/fttypes.h>
26 #include <freetype/fterrors.h>
27 
28 
29 FT_BEGIN_HEADER
30 
31 
32 
33   /**************************************************************************
34    *
35    * @section:
36    *   preamble
37    *
38    * @title:
39    *   Preamble
40    *
41    * @abstract:
42    *   What FreeType is and isn't
43    *
44    * @description:
45    *   FreeType is a library that provides access to glyphs in font files.  It
46    *   scales the glyph images and their metrics to a requested size, and it
47    *   rasterizes the glyph images to produce pixel or subpixel alpha coverage
48    *   bitmaps.
49    *
50    *   Note that FreeType is _not_ a text layout engine.  You have to use
51    *   higher-level libraries like HarfBuzz, Pango, or ICU for that.
52    *
53    *   Note also that FreeType does _not_ perform alpha blending or
54    *   compositing the resulting bitmaps or pixmaps by itself.  Use your
55    *   favourite graphics library (for example, Cairo or Skia) to further
56    *   process FreeType's output.
57    *
58    */
59 
60 
61   /**************************************************************************
62    *
63    * @section:
64    *   header_inclusion
65    *
66    * @title:
67    *   FreeType's header inclusion scheme
68    *
69    * @abstract:
70    *   How client applications should include FreeType header files.
71    *
72    * @description:
73    *   To be as flexible as possible (and for historical reasons), you must
74    *   load file `ft2build.h` first before other header files, for example
75    *
76    *   ```
77    *     #include <ft2build.h>
78    *
79    *     #include <freetype/freetype.h>
80    *     #include <freetype/ftoutln.h>
81    *   ```
82    */
83 
84 
85   /**************************************************************************
86    *
87    * @section:
88    *   user_allocation
89    *
90    * @title:
91    *   User allocation
92    *
93    * @abstract:
94    *   How client applications should allocate FreeType data structures.
95    *
96    * @description:
97    *   FreeType assumes that structures allocated by the user and passed as
98    *   arguments are zeroed out except for the actual data.  In other words,
99    *   it is recommended to use `calloc` (or variants of it) instead of
100    *   `malloc` for allocation.
101    *
102    */
103 
104 
105 
106   /*************************************************************************/
107   /*************************************************************************/
108   /*                                                                       */
109   /*                        B A S I C   T Y P E S                          */
110   /*                                                                       */
111   /*************************************************************************/
112   /*************************************************************************/
113 
114 
115   /**************************************************************************
116    *
117    * @section:
118    *   base_interface
119    *
120    * @title:
121    *   Base Interface
122    *
123    * @abstract:
124    *   The FreeType~2 base font interface.
125    *
126    * @description:
127    *   This section describes the most important public high-level API
128    *   functions of FreeType~2.
129    *
130    * @order:
131    *   FT_Library
132    *   FT_Face
133    *   FT_Size
134    *   FT_GlyphSlot
135    *   FT_CharMap
136    *   FT_Encoding
137    *   FT_ENC_TAG
138    *
139    *   FT_FaceRec
140    *
141    *   FT_FACE_FLAG_SCALABLE
142    *   FT_FACE_FLAG_FIXED_SIZES
143    *   FT_FACE_FLAG_FIXED_WIDTH
144    *   FT_FACE_FLAG_HORIZONTAL
145    *   FT_FACE_FLAG_VERTICAL
146    *   FT_FACE_FLAG_COLOR
147    *   FT_FACE_FLAG_SFNT
148    *   FT_FACE_FLAG_CID_KEYED
149    *   FT_FACE_FLAG_TRICKY
150    *   FT_FACE_FLAG_KERNING
151    *   FT_FACE_FLAG_MULTIPLE_MASTERS
152    *   FT_FACE_FLAG_VARIATION
153    *   FT_FACE_FLAG_GLYPH_NAMES
154    *   FT_FACE_FLAG_EXTERNAL_STREAM
155    *   FT_FACE_FLAG_HINTER
156    *
157    *   FT_HAS_HORIZONTAL
158    *   FT_HAS_VERTICAL
159    *   FT_HAS_KERNING
160    *   FT_HAS_FIXED_SIZES
161    *   FT_HAS_GLYPH_NAMES
162    *   FT_HAS_COLOR
163    *   FT_HAS_MULTIPLE_MASTERS
164    *
165    *   FT_IS_SFNT
166    *   FT_IS_SCALABLE
167    *   FT_IS_FIXED_WIDTH
168    *   FT_IS_CID_KEYED
169    *   FT_IS_TRICKY
170    *   FT_IS_NAMED_INSTANCE
171    *   FT_IS_VARIATION
172    *
173    *   FT_STYLE_FLAG_BOLD
174    *   FT_STYLE_FLAG_ITALIC
175    *
176    *   FT_SizeRec
177    *   FT_Size_Metrics
178    *
179    *   FT_GlyphSlotRec
180    *   FT_Glyph_Metrics
181    *   FT_SubGlyph
182    *
183    *   FT_Bitmap_Size
184    *
185    *   FT_Init_FreeType
186    *   FT_Done_FreeType
187    *
188    *   FT_New_Face
189    *   FT_Done_Face
190    *   FT_Reference_Face
191    *   FT_New_Memory_Face
192    *   FT_Face_Properties
193    *   FT_Open_Face
194    *   FT_Open_Args
195    *   FT_Parameter
196    *   FT_Attach_File
197    *   FT_Attach_Stream
198    *
199    *   FT_Set_Char_Size
200    *   FT_Set_Pixel_Sizes
201    *   FT_Request_Size
202    *   FT_Select_Size
203    *   FT_Size_Request_Type
204    *   FT_Size_RequestRec
205    *   FT_Size_Request
206    *   FT_Set_Transform
207    *   FT_Get_Transform
208    *   FT_Load_Glyph
209    *   FT_Get_Char_Index
210    *   FT_Get_First_Char
211    *   FT_Get_Next_Char
212    *   FT_Get_Name_Index
213    *   FT_Load_Char
214    *
215    *   FT_OPEN_MEMORY
216    *   FT_OPEN_STREAM
217    *   FT_OPEN_PATHNAME
218    *   FT_OPEN_DRIVER
219    *   FT_OPEN_PARAMS
220    *
221    *   FT_LOAD_DEFAULT
222    *   FT_LOAD_RENDER
223    *   FT_LOAD_MONOCHROME
224    *   FT_LOAD_LINEAR_DESIGN
225    *   FT_LOAD_NO_SCALE
226    *   FT_LOAD_NO_HINTING
227    *   FT_LOAD_NO_BITMAP
228    *   FT_LOAD_NO_AUTOHINT
229    *   FT_LOAD_COLOR
230    *
231    *   FT_LOAD_VERTICAL_LAYOUT
232    *   FT_LOAD_IGNORE_TRANSFORM
233    *   FT_LOAD_FORCE_AUTOHINT
234    *   FT_LOAD_NO_RECURSE
235    *   FT_LOAD_PEDANTIC
236    *
237    *   FT_LOAD_TARGET_NORMAL
238    *   FT_LOAD_TARGET_LIGHT
239    *   FT_LOAD_TARGET_MONO
240    *   FT_LOAD_TARGET_LCD
241    *   FT_LOAD_TARGET_LCD_V
242    *
243    *   FT_LOAD_TARGET_MODE
244    *
245    *   FT_Render_Glyph
246    *   FT_Render_Mode
247    *   FT_Get_Kerning
248    *   FT_Kerning_Mode
249    *   FT_Get_Track_Kerning
250    *   FT_Get_Glyph_Name
251    *   FT_Get_Postscript_Name
252    *
253    *   FT_CharMapRec
254    *   FT_Select_Charmap
255    *   FT_Set_Charmap
256    *   FT_Get_Charmap_Index
257    *
258    *   FT_Get_FSType_Flags
259    *   FT_Get_SubGlyph_Info
260    *
261    *   FT_Face_Internal
262    *   FT_Size_Internal
263    *   FT_Slot_Internal
264    *
265    *   FT_FACE_FLAG_XXX
266    *   FT_STYLE_FLAG_XXX
267    *   FT_OPEN_XXX
268    *   FT_LOAD_XXX
269    *   FT_LOAD_TARGET_XXX
270    *   FT_SUBGLYPH_FLAG_XXX
271    *   FT_FSTYPE_XXX
272    *
273    *   FT_HAS_FAST_GLYPHS
274    *
275    */
276 
277 
278   /**************************************************************************
279    *
280    * @struct:
281    *   FT_Glyph_Metrics
282    *
283    * @description:
284    *   A structure to model the metrics of a single glyph.  The values are
285    *   expressed in 26.6 fractional pixel format; if the flag
286    *   @FT_LOAD_NO_SCALE has been used while loading the glyph, values are
287    *   expressed in font units instead.
288    *
289    * @fields:
290    *   width ::
291    *     The glyph's width.
292    *
293    *   height ::
294    *     The glyph's height.
295    *
296    *   horiBearingX ::
297    *     Left side bearing for horizontal layout.
298    *
299    *   horiBearingY ::
300    *     Top side bearing for horizontal layout.
301    *
302    *   horiAdvance ::
303    *     Advance width for horizontal layout.
304    *
305    *   vertBearingX ::
306    *     Left side bearing for vertical layout.
307    *
308    *   vertBearingY ::
309    *     Top side bearing for vertical layout.  Larger positive values mean
310    *     further below the vertical glyph origin.
311    *
312    *   vertAdvance ::
313    *     Advance height for vertical layout.  Positive values mean the glyph
314    *     has a positive advance downward.
315    *
316    * @note:
317    *   If not disabled with @FT_LOAD_NO_HINTING, the values represent
318    *   dimensions of the hinted glyph (in case hinting is applicable).
319    *
320    *   Stroking a glyph with an outside border does not increase
321    *   `horiAdvance` or `vertAdvance`; you have to manually adjust these
322    *   values to account for the added width and height.
323    *
324    *   FreeType doesn't use the 'VORG' table data for CFF fonts because it
325    *   doesn't have an interface to quickly retrieve the glyph height.  The
326    *   y~coordinate of the vertical origin can be simply computed as
327    *   `vertBearingY + height` after loading a glyph.
328    */
329   typedef struct  FT_Glyph_Metrics_
330   {
331     FT_Pos  width;
332     FT_Pos  height;
333 
334     FT_Pos  horiBearingX;
335     FT_Pos  horiBearingY;
336     FT_Pos  horiAdvance;
337 
338     FT_Pos  vertBearingX;
339     FT_Pos  vertBearingY;
340     FT_Pos  vertAdvance;
341 
342   } FT_Glyph_Metrics;
343 
344 
345   /**************************************************************************
346    *
347    * @struct:
348    *   FT_Bitmap_Size
349    *
350    * @description:
351    *   This structure models the metrics of a bitmap strike (i.e., a set of
352    *   glyphs for a given point size and resolution) in a bitmap font.  It is
353    *   used for the `available_sizes` field of @FT_Face.
354    *
355    * @fields:
356    *   height ::
357    *     The vertical distance, in pixels, between two consecutive baselines.
358    *     It is always positive.
359    *
360    *   width ::
361    *     The average width, in pixels, of all glyphs in the strike.
362    *
363    *   size ::
364    *     The nominal size of the strike in 26.6 fractional points.  This
365    *     field is not very useful.
366    *
367    *   x_ppem ::
368    *     The horizontal ppem (nominal width) in 26.6 fractional pixels.
369    *
370    *   y_ppem ::
371    *     The vertical ppem (nominal height) in 26.6 fractional pixels.
372    *
373    * @note:
374    *   Windows FNT:
375    *     The nominal size given in a FNT font is not reliable.  If the driver
376    *     finds it incorrect, it sets `size` to some calculated values, and
377    *     `x_ppem` and `y_ppem` to the pixel width and height given in the
378    *     font, respectively.
379    *
380    *   TrueType embedded bitmaps:
381    *     `size`, `width`, and `height` values are not contained in the bitmap
382    *     strike itself.  They are computed from the global font parameters.
383    */
384   typedef struct  FT_Bitmap_Size_
385   {
386     FT_Short  height;
387     FT_Short  width;
388 
389     FT_Pos    size;
390 
391     FT_Pos    x_ppem;
392     FT_Pos    y_ppem;
393 
394   } FT_Bitmap_Size;
395 
396 
397   /*************************************************************************/
398   /*************************************************************************/
399   /*                                                                       */
400   /*                     O B J E C T   C L A S S E S                       */
401   /*                                                                       */
402   /*************************************************************************/
403   /*************************************************************************/
404 
405   /**************************************************************************
406    *
407    * @type:
408    *   FT_Library
409    *
410    * @description:
411    *   A handle to a FreeType library instance.  Each 'library' is completely
412    *   independent from the others; it is the 'root' of a set of objects like
413    *   fonts, faces, sizes, etc.
414    *
415    *   It also embeds a memory manager (see @FT_Memory), as well as a
416    *   scan-line converter object (see @FT_Raster).
417    *
418    *   [Since 2.5.6] In multi-threaded applications it is easiest to use one
419    *   `FT_Library` object per thread.  In case this is too cumbersome, a
420    *   single `FT_Library` object across threads is possible also, as long as
421    *   a mutex lock is used around @FT_New_Face and @FT_Done_Face.
422    *
423    * @note:
424    *   Library objects are normally created by @FT_Init_FreeType, and
425    *   destroyed with @FT_Done_FreeType.  If you need reference-counting
426    *   (cf. @FT_Reference_Library), use @FT_New_Library and @FT_Done_Library.
427    */
428   typedef struct FT_LibraryRec_  *FT_Library;
429 
430 
431   /**************************************************************************
432    *
433    * @section:
434    *   module_management
435    *
436    */
437 
438   /**************************************************************************
439    *
440    * @type:
441    *   FT_Module
442    *
443    * @description:
444    *   A handle to a given FreeType module object.  A module can be a font
445    *   driver, a renderer, or anything else that provides services to the
446    *   former.
447    */
448   typedef struct FT_ModuleRec_*  FT_Module;
449 
450 
451   /**************************************************************************
452    *
453    * @type:
454    *   FT_Driver
455    *
456    * @description:
457    *   A handle to a given FreeType font driver object.  A font driver is a
458    *   module capable of creating faces from font files.
459    */
460   typedef struct FT_DriverRec_*  FT_Driver;
461 
462 
463   /**************************************************************************
464    *
465    * @type:
466    *   FT_Renderer
467    *
468    * @description:
469    *   A handle to a given FreeType renderer.  A renderer is a module in
470    *   charge of converting a glyph's outline image to a bitmap.  It supports
471    *   a single glyph image format, and one or more target surface depths.
472    */
473   typedef struct FT_RendererRec_*  FT_Renderer;
474 
475 
476   /**************************************************************************
477    *
478    * @section:
479    *   base_interface
480    *
481    */
482 
483   /**************************************************************************
484    *
485    * @type:
486    *   FT_Face
487    *
488    * @description:
489    *   A handle to a typographic face object.  A face object models a given
490    *   typeface, in a given style.
491    *
492    * @note:
493    *   A face object also owns a single @FT_GlyphSlot object, as well as one
494    *   or more @FT_Size objects.
495    *
496    *   Use @FT_New_Face or @FT_Open_Face to create a new face object from a
497    *   given filepath or a custom input stream.
498    *
499    *   Use @FT_Done_Face to destroy it (along with its slot and sizes).
500    *
501    *   An `FT_Face` object can only be safely used from one thread at a time.
502    *   Similarly, creation and destruction of `FT_Face` with the same
503    *   @FT_Library object can only be done from one thread at a time.  On the
504    *   other hand, functions like @FT_Load_Glyph and its siblings are
505    *   thread-safe and do not need the lock to be held as long as the same
506    *   `FT_Face` object is not used from multiple threads at the same time.
507    *
508    * @also:
509    *   See @FT_FaceRec for the publicly accessible fields of a given face
510    *   object.
511    */
512   typedef struct FT_FaceRec_*  FT_Face;
513 
514 
515   /**************************************************************************
516    *
517    * @type:
518    *   FT_Size
519    *
520    * @description:
521    *   A handle to an object that models a face scaled to a given character
522    *   size.
523    *
524    * @note:
525    *   An @FT_Face has one _active_ @FT_Size object that is used by functions
526    *   like @FT_Load_Glyph to determine the scaling transformation that in
527    *   turn is used to load and hint glyphs and metrics.
528    *
529    *   You can use @FT_Set_Char_Size, @FT_Set_Pixel_Sizes, @FT_Request_Size
530    *   or even @FT_Select_Size to change the content (i.e., the scaling
531    *   values) of the active @FT_Size.
532    *
533    *   You can use @FT_New_Size to create additional size objects for a given
534    *   @FT_Face, but they won't be used by other functions until you activate
535    *   it through @FT_Activate_Size.  Only one size can be activated at any
536    *   given time per face.
537    *
538    * @also:
539    *   See @FT_SizeRec for the publicly accessible fields of a given size
540    *   object.
541    */
542   typedef struct FT_SizeRec_*  FT_Size;
543 
544 
545   /**************************************************************************
546    *
547    * @type:
548    *   FT_GlyphSlot
549    *
550    * @description:
551    *   A handle to a given 'glyph slot'.  A slot is a container that can hold
552    *   any of the glyphs contained in its parent face.
553    *
554    *   In other words, each time you call @FT_Load_Glyph or @FT_Load_Char,
555    *   the slot's content is erased by the new glyph data, i.e., the glyph's
556    *   metrics, its image (bitmap or outline), and other control information.
557    *
558    * @also:
559    *   See @FT_GlyphSlotRec for the publicly accessible glyph fields.
560    */
561   typedef struct FT_GlyphSlotRec_*  FT_GlyphSlot;
562 
563 
564   /**************************************************************************
565    *
566    * @type:
567    *   FT_CharMap
568    *
569    * @description:
570    *   A handle to a character map (usually abbreviated to 'charmap').  A
571    *   charmap is used to translate character codes in a given encoding into
572    *   glyph indexes for its parent's face.  Some font formats may provide
573    *   several charmaps per font.
574    *
575    *   Each face object owns zero or more charmaps, but only one of them can
576    *   be 'active', providing the data used by @FT_Get_Char_Index or
577    *   @FT_Load_Char.
578    *
579    *   The list of available charmaps in a face is available through the
580    *   `face->num_charmaps` and `face->charmaps` fields of @FT_FaceRec.
581    *
582    *   The currently active charmap is available as `face->charmap`.  You
583    *   should call @FT_Set_Charmap to change it.
584    *
585    * @note:
586    *   When a new face is created (either through @FT_New_Face or
587    *   @FT_Open_Face), the library looks for a Unicode charmap within the
588    *   list and automatically activates it.  If there is no Unicode charmap,
589    *   FreeType doesn't set an 'active' charmap.
590    *
591    * @also:
592    *   See @FT_CharMapRec for the publicly accessible fields of a given
593    *   character map.
594    */
595   typedef struct FT_CharMapRec_*  FT_CharMap;
596 
597 
598   /**************************************************************************
599    *
600    * @macro:
601    *   FT_ENC_TAG
602    *
603    * @description:
604    *   This macro converts four-letter tags into an unsigned long.  It is
605    *   used to define 'encoding' identifiers (see @FT_Encoding).
606    *
607    * @note:
608    *   Since many 16-bit compilers don't like 32-bit enumerations, you should
609    *   redefine this macro in case of problems to something like this:
610    *
611    *   ```
612    *     #define FT_ENC_TAG( value, a, b, c, d )  value
613    *   ```
614    *
615    *   to get a simple enumeration without assigning special numbers.
616    */
617 
618 #ifndef FT_ENC_TAG
619 
620 #define FT_ENC_TAG( value, a, b, c, d )                             \
621           value = ( ( FT_STATIC_BYTE_CAST( FT_UInt32, a ) << 24 ) | \
622                     ( FT_STATIC_BYTE_CAST( FT_UInt32, b ) << 16 ) | \
623                     ( FT_STATIC_BYTE_CAST( FT_UInt32, c ) <<  8 ) | \
624                       FT_STATIC_BYTE_CAST( FT_UInt32, d )         )
625 
626 #endif /* FT_ENC_TAG */
627 
628 
629   /**************************************************************************
630    *
631    * @enum:
632    *   FT_Encoding
633    *
634    * @description:
635    *   An enumeration to specify character sets supported by charmaps.  Used
636    *   in the @FT_Select_Charmap API function.
637    *
638    * @note:
639    *   Despite the name, this enumeration lists specific character
640    *   repertories (i.e., charsets), and not text encoding methods (e.g.,
641    *   UTF-8, UTF-16, etc.).
642    *
643    *   Other encodings might be defined in the future.
644    *
645    * @values:
646    *   FT_ENCODING_NONE ::
647    *     The encoding value~0 is reserved for all formats except BDF, PCF,
648    *     and Windows FNT; see below for more information.
649    *
650    *   FT_ENCODING_UNICODE ::
651    *     The Unicode character set.  This value covers all versions of the
652    *     Unicode repertoire, including ASCII and Latin-1.  Most fonts include
653    *     a Unicode charmap, but not all of them.
654    *
655    *     For example, if you want to access Unicode value U+1F028 (and the
656    *     font contains it), use value 0x1F028 as the input value for
657    *     @FT_Get_Char_Index.
658    *
659    *   FT_ENCODING_MS_SYMBOL ::
660    *     Microsoft Symbol encoding, used to encode mathematical symbols and
661    *     wingdings.  For more information, see
662    *     'https://www.microsoft.com/typography/otspec/recom.htm#non-standard-symbol-fonts',
663    *     'http://www.kostis.net/charsets/symbol.htm', and
664    *     'http://www.kostis.net/charsets/wingding.htm'.
665    *
666    *     This encoding uses character codes from the PUA (Private Unicode
667    *     Area) in the range U+F020-U+F0FF.
668    *
669    *   FT_ENCODING_SJIS ::
670    *     Shift JIS encoding for Japanese.  More info at
671    *     'https://en.wikipedia.org/wiki/Shift_JIS'.  See note on multi-byte
672    *     encodings below.
673    *
674    *   FT_ENCODING_PRC ::
675    *     Corresponds to encoding systems mainly for Simplified Chinese as
676    *     used in People's Republic of China (PRC).  The encoding layout is
677    *     based on GB~2312 and its supersets GBK and GB~18030.
678    *
679    *   FT_ENCODING_BIG5 ::
680    *     Corresponds to an encoding system for Traditional Chinese as used in
681    *     Taiwan and Hong Kong.
682    *
683    *   FT_ENCODING_WANSUNG ::
684    *     Corresponds to the Korean encoding system known as Extended Wansung
685    *     (MS Windows code page 949).  For more information see
686    *     'https://www.unicode.org/Public/MAPPINGS/VENDORS/MICSFT/WindowsBestFit/bestfit949.txt'.
687    *
688    *   FT_ENCODING_JOHAB ::
689    *     The Korean standard character set (KS~C 5601-1992), which
690    *     corresponds to MS Windows code page 1361.  This character set
691    *     includes all possible Hangul character combinations.
692    *
693    *   FT_ENCODING_ADOBE_LATIN_1 ::
694    *     Corresponds to a Latin-1 encoding as defined in a Type~1 PostScript
695    *     font.  It is limited to 256 character codes.
696    *
697    *   FT_ENCODING_ADOBE_STANDARD ::
698    *     Adobe Standard encoding, as found in Type~1, CFF, and OpenType/CFF
699    *     fonts.  It is limited to 256 character codes.
700    *
701    *   FT_ENCODING_ADOBE_EXPERT ::
702    *     Adobe Expert encoding, as found in Type~1, CFF, and OpenType/CFF
703    *     fonts.  It is limited to 256 character codes.
704    *
705    *   FT_ENCODING_ADOBE_CUSTOM ::
706    *     Corresponds to a custom encoding, as found in Type~1, CFF, and
707    *     OpenType/CFF fonts.  It is limited to 256 character codes.
708    *
709    *   FT_ENCODING_APPLE_ROMAN ::
710    *     Apple roman encoding.  Many TrueType and OpenType fonts contain a
711    *     charmap for this 8-bit encoding, since older versions of Mac OS are
712    *     able to use it.
713    *
714    *   FT_ENCODING_OLD_LATIN_2 ::
715    *     This value is deprecated and was neither used nor reported by
716    *     FreeType.  Don't use or test for it.
717    *
718    *   FT_ENCODING_MS_SJIS ::
719    *     Same as FT_ENCODING_SJIS.  Deprecated.
720    *
721    *   FT_ENCODING_MS_GB2312 ::
722    *     Same as FT_ENCODING_PRC.  Deprecated.
723    *
724    *   FT_ENCODING_MS_BIG5 ::
725    *     Same as FT_ENCODING_BIG5.  Deprecated.
726    *
727    *   FT_ENCODING_MS_WANSUNG ::
728    *     Same as FT_ENCODING_WANSUNG.  Deprecated.
729    *
730    *   FT_ENCODING_MS_JOHAB ::
731    *     Same as FT_ENCODING_JOHAB.  Deprecated.
732    *
733    * @note:
734    *   When loading a font, FreeType makes a Unicode charmap active if
735    *   possible (either if the font provides such a charmap, or if FreeType
736    *   can synthesize one from PostScript glyph name dictionaries; in either
737    *   case, the charmap is tagged with `FT_ENCODING_UNICODE`).  If such a
738    *   charmap is synthesized, it is placed at the first position of the
739    *   charmap array.
740    *
741    *   All other encodings are considered legacy and tagged only if
742    *   explicitly defined in the font file.  Otherwise, `FT_ENCODING_NONE` is
743    *   used.
744    *
745    *   `FT_ENCODING_NONE` is set by the BDF and PCF drivers if the charmap is
746    *   neither Unicode nor ISO-8859-1 (otherwise it is set to
747    *   `FT_ENCODING_UNICODE`).  Use @FT_Get_BDF_Charset_ID to find out which
748    *   encoding is really present.  If, for example, the `cs_registry` field
749    *   is 'KOI8' and the `cs_encoding` field is 'R', the font is encoded in
750    *   KOI8-R.
751    *
752    *   `FT_ENCODING_NONE` is always set (with a single exception) by the
753    *   winfonts driver.  Use @FT_Get_WinFNT_Header and examine the `charset`
754    *   field of the @FT_WinFNT_HeaderRec structure to find out which encoding
755    *   is really present.  For example, @FT_WinFNT_ID_CP1251 (204) means
756    *   Windows code page 1251 (for Russian).
757    *
758    *   `FT_ENCODING_NONE` is set if `platform_id` is @TT_PLATFORM_MACINTOSH
759    *   and `encoding_id` is not `TT_MAC_ID_ROMAN` (otherwise it is set to
760    *   `FT_ENCODING_APPLE_ROMAN`).
761    *
762    *   If `platform_id` is @TT_PLATFORM_MACINTOSH, use the function
763    *   @FT_Get_CMap_Language_ID to query the Mac language ID that may be
764    *   needed to be able to distinguish Apple encoding variants.  See
765    *
766    *     https://www.unicode.org/Public/MAPPINGS/VENDORS/APPLE/Readme.txt
767    *
768    *   to get an idea how to do that.  Basically, if the language ID is~0,
769    *   don't use it, otherwise subtract 1 from the language ID.  Then examine
770    *   `encoding_id`.  If, for example, `encoding_id` is `TT_MAC_ID_ROMAN`
771    *   and the language ID (minus~1) is `TT_MAC_LANGID_GREEK`, it is the
772    *   Greek encoding, not Roman.  `TT_MAC_ID_ARABIC` with
773    *   `TT_MAC_LANGID_FARSI` means the Farsi variant the Arabic encoding.
774    */
775   typedef enum  FT_Encoding_
776   {
777     FT_ENC_TAG( FT_ENCODING_NONE, 0, 0, 0, 0 ),
778 
779     FT_ENC_TAG( FT_ENCODING_MS_SYMBOL, 's', 'y', 'm', 'b' ),
780     FT_ENC_TAG( FT_ENCODING_UNICODE,   'u', 'n', 'i', 'c' ),
781 
782     FT_ENC_TAG( FT_ENCODING_SJIS,    's', 'j', 'i', 's' ),
783     FT_ENC_TAG( FT_ENCODING_PRC,     'g', 'b', ' ', ' ' ),
784     FT_ENC_TAG( FT_ENCODING_BIG5,    'b', 'i', 'g', '5' ),
785     FT_ENC_TAG( FT_ENCODING_WANSUNG, 'w', 'a', 'n', 's' ),
786     FT_ENC_TAG( FT_ENCODING_JOHAB,   'j', 'o', 'h', 'a' ),
787 
788     /* for backward compatibility */
789     FT_ENCODING_GB2312     = FT_ENCODING_PRC,
790     FT_ENCODING_MS_SJIS    = FT_ENCODING_SJIS,
791     FT_ENCODING_MS_GB2312  = FT_ENCODING_PRC,
792     FT_ENCODING_MS_BIG5    = FT_ENCODING_BIG5,
793     FT_ENCODING_MS_WANSUNG = FT_ENCODING_WANSUNG,
794     FT_ENCODING_MS_JOHAB   = FT_ENCODING_JOHAB,
795 
796     FT_ENC_TAG( FT_ENCODING_ADOBE_STANDARD, 'A', 'D', 'O', 'B' ),
797     FT_ENC_TAG( FT_ENCODING_ADOBE_EXPERT,   'A', 'D', 'B', 'E' ),
798     FT_ENC_TAG( FT_ENCODING_ADOBE_CUSTOM,   'A', 'D', 'B', 'C' ),
799     FT_ENC_TAG( FT_ENCODING_ADOBE_LATIN_1,  'l', 'a', 't', '1' ),
800 
801     FT_ENC_TAG( FT_ENCODING_OLD_LATIN_2, 'l', 'a', 't', '2' ),
802 
803     FT_ENC_TAG( FT_ENCODING_APPLE_ROMAN, 'a', 'r', 'm', 'n' )
804 
805   } FT_Encoding;
806 
807 
808   /* these constants are deprecated; use the corresponding `FT_Encoding` */
809   /* values instead                                                      */
810 #define ft_encoding_none            FT_ENCODING_NONE
811 #define ft_encoding_unicode         FT_ENCODING_UNICODE
812 #define ft_encoding_symbol          FT_ENCODING_MS_SYMBOL
813 #define ft_encoding_latin_1         FT_ENCODING_ADOBE_LATIN_1
814 #define ft_encoding_latin_2         FT_ENCODING_OLD_LATIN_2
815 #define ft_encoding_sjis            FT_ENCODING_SJIS
816 #define ft_encoding_gb2312          FT_ENCODING_PRC
817 #define ft_encoding_big5            FT_ENCODING_BIG5
818 #define ft_encoding_wansung         FT_ENCODING_WANSUNG
819 #define ft_encoding_johab           FT_ENCODING_JOHAB
820 
821 #define ft_encoding_adobe_standard  FT_ENCODING_ADOBE_STANDARD
822 #define ft_encoding_adobe_expert    FT_ENCODING_ADOBE_EXPERT
823 #define ft_encoding_adobe_custom    FT_ENCODING_ADOBE_CUSTOM
824 #define ft_encoding_apple_roman     FT_ENCODING_APPLE_ROMAN
825 
826 
827   /**************************************************************************
828    *
829    * @struct:
830    *   FT_CharMapRec
831    *
832    * @description:
833    *   The base charmap structure.
834    *
835    * @fields:
836    *   face ::
837    *     A handle to the parent face object.
838    *
839    *   encoding ::
840    *     An @FT_Encoding tag identifying the charmap.  Use this with
841    *     @FT_Select_Charmap.
842    *
843    *   platform_id ::
844    *     An ID number describing the platform for the following encoding ID.
845    *     This comes directly from the TrueType specification and gets
846    *     emulated for other formats.
847    *
848    *   encoding_id ::
849    *     A platform-specific encoding number.  This also comes from the
850    *     TrueType specification and gets emulated similarly.
851    */
852   typedef struct  FT_CharMapRec_
853   {
854     FT_Face      face;
855     FT_Encoding  encoding;
856     FT_UShort    platform_id;
857     FT_UShort    encoding_id;
858 
859   } FT_CharMapRec;
860 
861 
862   /*************************************************************************/
863   /*************************************************************************/
864   /*                                                                       */
865   /*                 B A S E   O B J E C T   C L A S S E S                 */
866   /*                                                                       */
867   /*************************************************************************/
868   /*************************************************************************/
869 
870 
871   /**************************************************************************
872    *
873    * @type:
874    *   FT_Face_Internal
875    *
876    * @description:
877    *   An opaque handle to an `FT_Face_InternalRec` structure that models the
878    *   private data of a given @FT_Face object.
879    *
880    *   This structure might change between releases of FreeType~2 and is not
881    *   generally available to client applications.
882    */
883   typedef struct FT_Face_InternalRec_*  FT_Face_Internal;
884 
885 
886   /**************************************************************************
887    *
888    * @struct:
889    *   FT_FaceRec
890    *
891    * @description:
892    *   FreeType root face class structure.  A face object models a typeface
893    *   in a font file.
894    *
895    * @fields:
896    *   num_faces ::
897    *     The number of faces in the font file.  Some font formats can have
898    *     multiple faces in a single font file.
899    *
900    *   face_index ::
901    *     This field holds two different values.  Bits 0-15 are the index of
902    *     the face in the font file (starting with value~0).  They are set
903    *     to~0 if there is only one face in the font file.
904    *
905    *     [Since 2.6.1] Bits 16-30 are relevant to GX and OpenType variation
906    *     fonts only, holding the named instance index for the current face
907    *     index (starting with value~1; value~0 indicates font access without
908    *     a named instance).  For non-variation fonts, bits 16-30 are ignored.
909    *     If we have the third named instance of face~4, say, `face_index` is
910    *     set to 0x00030004.
911    *
912    *     Bit 31 is always zero (this is, `face_index` is always a positive
913    *     value).
914    *
915    *     [Since 2.9] Changing the design coordinates with
916    *     @FT_Set_Var_Design_Coordinates or @FT_Set_Var_Blend_Coordinates does
917    *     not influence the named instance index value (only
918    *     @FT_Set_Named_Instance does that).
919    *
920    *   face_flags ::
921    *     A set of bit flags that give important information about the face;
922    *     see @FT_FACE_FLAG_XXX for the details.
923    *
924    *   style_flags ::
925    *     The lower 16~bits contain a set of bit flags indicating the style of
926    *     the face; see @FT_STYLE_FLAG_XXX for the details.
927    *
928    *     [Since 2.6.1] Bits 16-30 hold the number of named instances
929    *     available for the current face if we have a GX or OpenType variation
930    *     (sub)font.  Bit 31 is always zero (this is, `style_flags` is always
931    *     a positive value).  Note that a variation font has always at least
932    *     one named instance, namely the default instance.
933    *
934    *   num_glyphs ::
935    *     The number of glyphs in the face.  If the face is scalable and has
936    *     sbits (see `num_fixed_sizes`), it is set to the number of outline
937    *     glyphs.
938    *
939    *     For CID-keyed fonts (not in an SFNT wrapper) this value gives the
940    *     highest CID used in the font.
941    *
942    *   family_name ::
943    *     The face's family name.  This is an ASCII string, usually in
944    *     English, that describes the typeface's family (like 'Times New
945    *     Roman', 'Bodoni', 'Garamond', etc).  This is a least common
946    *     denominator used to list fonts.  Some formats (TrueType & OpenType)
947    *     provide localized and Unicode versions of this string.  Applications
948    *     should use the format-specific interface to access them.  Can be
949    *     `NULL` (e.g., in fonts embedded in a PDF file).
950    *
951    *     In case the font doesn't provide a specific family name entry,
952    *     FreeType tries to synthesize one, deriving it from other name
953    *     entries.
954    *
955    *   style_name ::
956    *     The face's style name.  This is an ASCII string, usually in English,
957    *     that describes the typeface's style (like 'Italic', 'Bold',
958    *     'Condensed', etc).  Not all font formats provide a style name, so
959    *     this field is optional, and can be set to `NULL`.  As for
960    *     `family_name`, some formats provide localized and Unicode versions
961    *     of this string.  Applications should use the format-specific
962    *     interface to access them.
963    *
964    *   num_fixed_sizes ::
965    *     The number of bitmap strikes in the face.  Even if the face is
966    *     scalable, there might still be bitmap strikes, which are called
967    *     'sbits' in that case.
968    *
969    *   available_sizes ::
970    *     An array of @FT_Bitmap_Size for all bitmap strikes in the face.  It
971    *     is set to `NULL` if there is no bitmap strike.
972    *
973    *     Note that FreeType tries to sanitize the strike data since they are
974    *     sometimes sloppy or incorrect, but this can easily fail.
975    *
976    *   num_charmaps ::
977    *     The number of charmaps in the face.
978    *
979    *   charmaps ::
980    *     An array of the charmaps of the face.
981    *
982    *   generic ::
983    *     A field reserved for client uses.  See the @FT_Generic type
984    *     description.
985    *
986    *   bbox ::
987    *     The font bounding box.  Coordinates are expressed in font units (see
988    *     `units_per_EM`).  The box is large enough to contain any glyph from
989    *     the font.  Thus, `bbox.yMax` can be seen as the 'maximum ascender',
990    *     and `bbox.yMin` as the 'minimum descender'.  Only relevant for
991    *     scalable formats.
992    *
993    *     Note that the bounding box might be off by (at least) one pixel for
994    *     hinted fonts.  See @FT_Size_Metrics for further discussion.
995    *
996    *     Note that the bounding box does not vary in OpenType variable fonts
997    *     and should only be used in relation to the default instance.
998    *
999    *   units_per_EM ::
1000    *     The number of font units per EM square for this face.  This is
1001    *     typically 2048 for TrueType fonts, and 1000 for Type~1 fonts.  Only
1002    *     relevant for scalable formats.
1003    *
1004    *   ascender ::
1005    *     The typographic ascender of the face, expressed in font units.  For
1006    *     font formats not having this information, it is set to `bbox.yMax`.
1007    *     Only relevant for scalable formats.
1008    *
1009    *   descender ::
1010    *     The typographic descender of the face, expressed in font units.  For
1011    *     font formats not having this information, it is set to `bbox.yMin`.
1012    *     Note that this field is negative for values below the baseline.
1013    *     Only relevant for scalable formats.
1014    *
1015    *   height ::
1016    *     This value is the vertical distance between two consecutive
1017    *     baselines, expressed in font units.  It is always positive.  Only
1018    *     relevant for scalable formats.
1019    *
1020    *     If you want the global glyph height, use `ascender - descender`.
1021    *
1022    *   max_advance_width ::
1023    *     The maximum advance width, in font units, for all glyphs in this
1024    *     face.  This can be used to make word wrapping computations faster.
1025    *     Only relevant for scalable formats.
1026    *
1027    *   max_advance_height ::
1028    *     The maximum advance height, in font units, for all glyphs in this
1029    *     face.  This is only relevant for vertical layouts, and is set to
1030    *     `height` for fonts that do not provide vertical metrics.  Only
1031    *     relevant for scalable formats.
1032    *
1033    *   underline_position ::
1034    *     The position, in font units, of the underline line for this face.
1035    *     It is the center of the underlining stem.  Only relevant for
1036    *     scalable formats.
1037    *
1038    *   underline_thickness ::
1039    *     The thickness, in font units, of the underline for this face.  Only
1040    *     relevant for scalable formats.
1041    *
1042    *   glyph ::
1043    *     The face's associated glyph slot(s).
1044    *
1045    *   size ::
1046    *     The current active size for this face.
1047    *
1048    *   charmap ::
1049    *     The current active charmap for this face.
1050    *
1051    * @note:
1052    *   Fields may be changed after a call to @FT_Attach_File or
1053    *   @FT_Attach_Stream.
1054    *
1055    *   For an OpenType variation font, the values of the following fields can
1056    *   change after a call to @FT_Set_Var_Design_Coordinates (and friends) if
1057    *   the font contains an 'MVAR' table: `ascender`, `descender`, `height`,
1058    *   `underline_position`, and `underline_thickness`.
1059    *
1060    *   Especially for TrueType fonts see also the documentation for
1061    *   @FT_Size_Metrics.
1062    */
1063   typedef struct  FT_FaceRec_
1064   {
1065     FT_Long           num_faces;
1066     FT_Long           face_index;
1067 
1068     FT_Long           face_flags;
1069     FT_Long           style_flags;
1070 
1071     FT_Long           num_glyphs;
1072 
1073     FT_String*        family_name;
1074     FT_String*        style_name;
1075 
1076     FT_Int            num_fixed_sizes;
1077     FT_Bitmap_Size*   available_sizes;
1078 
1079     FT_Int            num_charmaps;
1080     FT_CharMap*       charmaps;
1081 
1082     FT_Generic        generic;
1083 
1084     /*# The following member variables (down to `underline_thickness`) */
1085     /*# are only relevant to scalable outlines; cf. @FT_Bitmap_Size    */
1086     /*# for bitmap fonts.                                              */
1087     FT_BBox           bbox;
1088 
1089     FT_UShort         units_per_EM;
1090     FT_Short          ascender;
1091     FT_Short          descender;
1092     FT_Short          height;
1093 
1094     FT_Short          max_advance_width;
1095     FT_Short          max_advance_height;
1096 
1097     FT_Short          underline_position;
1098     FT_Short          underline_thickness;
1099 
1100     FT_GlyphSlot      glyph;
1101     FT_Size           size;
1102     FT_CharMap        charmap;
1103 
1104     /*@private begin */
1105 
1106     FT_Driver         driver;
1107     FT_Memory         memory;
1108     FT_Stream         stream;
1109 
1110     FT_ListRec        sizes_list;
1111 
1112     FT_Generic        autohint;   /* face-specific auto-hinter data */
1113     void*             extensions; /* unused                         */
1114 
1115     FT_Face_Internal  internal;
1116 
1117     /*@private end */
1118 
1119   } FT_FaceRec;
1120 
1121 
1122   /**************************************************************************
1123    *
1124    * @enum:
1125    *   FT_FACE_FLAG_XXX
1126    *
1127    * @description:
1128    *   A list of bit flags used in the `face_flags` field of the @FT_FaceRec
1129    *   structure.  They inform client applications of properties of the
1130    *   corresponding face.
1131    *
1132    * @values:
1133    *   FT_FACE_FLAG_SCALABLE ::
1134    *     The face contains outline glyphs.  Note that a face can contain
1135    *     bitmap strikes also, i.e., a face can have both this flag and
1136    *     @FT_FACE_FLAG_FIXED_SIZES set.
1137    *
1138    *   FT_FACE_FLAG_FIXED_SIZES ::
1139    *     The face contains bitmap strikes.  See also the `num_fixed_sizes`
1140    *     and `available_sizes` fields of @FT_FaceRec.
1141    *
1142    *   FT_FACE_FLAG_FIXED_WIDTH ::
1143    *     The face contains fixed-width characters (like Courier, Lucida,
1144    *     MonoType, etc.).
1145    *
1146    *   FT_FACE_FLAG_SFNT ::
1147    *     The face uses the SFNT storage scheme.  For now, this means TrueType
1148    *     and OpenType.
1149    *
1150    *   FT_FACE_FLAG_HORIZONTAL ::
1151    *     The face contains horizontal glyph metrics.  This should be set for
1152    *     all common formats.
1153    *
1154    *   FT_FACE_FLAG_VERTICAL ::
1155    *     The face contains vertical glyph metrics.  This is only available in
1156    *     some formats, not all of them.
1157    *
1158    *   FT_FACE_FLAG_KERNING ::
1159    *     The face contains kerning information.  If set, the kerning distance
1160    *     can be retrieved using the function @FT_Get_Kerning.  Otherwise the
1161    *     function always return the vector (0,0).  Note that FreeType doesn't
1162    *     handle kerning data from the SFNT 'GPOS' table (as present in many
1163    *     OpenType fonts).
1164    *
1165    *   FT_FACE_FLAG_FAST_GLYPHS ::
1166    *     THIS FLAG IS DEPRECATED.  DO NOT USE OR TEST IT.
1167    *
1168    *   FT_FACE_FLAG_MULTIPLE_MASTERS ::
1169    *     The face contains multiple masters and is capable of interpolating
1170    *     between them.  Supported formats are Adobe MM, TrueType GX, and
1171    *     OpenType variation fonts.
1172    *
1173    *     See section @multiple_masters for API details.
1174    *
1175    *   FT_FACE_FLAG_GLYPH_NAMES ::
1176    *     The face contains glyph names, which can be retrieved using
1177    *     @FT_Get_Glyph_Name.  Note that some TrueType fonts contain broken
1178    *     glyph name tables.  Use the function @FT_Has_PS_Glyph_Names when
1179    *     needed.
1180    *
1181    *   FT_FACE_FLAG_EXTERNAL_STREAM ::
1182    *     Used internally by FreeType to indicate that a face's stream was
1183    *     provided by the client application and should not be destroyed when
1184    *     @FT_Done_Face is called.  Don't read or test this flag.
1185    *
1186    *   FT_FACE_FLAG_HINTER ::
1187    *     The font driver has a hinting machine of its own.  For example, with
1188    *     TrueType fonts, it makes sense to use data from the SFNT 'gasp'
1189    *     table only if the native TrueType hinting engine (with the bytecode
1190    *     interpreter) is available and active.
1191    *
1192    *   FT_FACE_FLAG_CID_KEYED ::
1193    *     The face is CID-keyed.  In that case, the face is not accessed by
1194    *     glyph indices but by CID values.  For subsetted CID-keyed fonts this
1195    *     has the consequence that not all index values are a valid argument
1196    *     to @FT_Load_Glyph.  Only the CID values for which corresponding
1197    *     glyphs in the subsetted font exist make `FT_Load_Glyph` return
1198    *     successfully; in all other cases you get an
1199    *     `FT_Err_Invalid_Argument` error.
1200    *
1201    *     Note that CID-keyed fonts that are in an SFNT wrapper (this is, all
1202    *     OpenType/CFF fonts) don't have this flag set since the glyphs are
1203    *     accessed in the normal way (using contiguous indices); the
1204    *     'CID-ness' isn't visible to the application.
1205    *
1206    *   FT_FACE_FLAG_TRICKY ::
1207    *     The face is 'tricky', this is, it always needs the font format's
1208    *     native hinting engine to get a reasonable result.  A typical example
1209    *     is the old Chinese font `mingli.ttf` (but not `mingliu.ttc`) that
1210    *     uses TrueType bytecode instructions to move and scale all of its
1211    *     subglyphs.
1212    *
1213    *     It is not possible to auto-hint such fonts using
1214    *     @FT_LOAD_FORCE_AUTOHINT; it will also ignore @FT_LOAD_NO_HINTING.
1215    *     You have to set both @FT_LOAD_NO_HINTING and @FT_LOAD_NO_AUTOHINT to
1216    *     really disable hinting; however, you probably never want this except
1217    *     for demonstration purposes.
1218    *
1219    *     Currently, there are about a dozen TrueType fonts in the list of
1220    *     tricky fonts; they are hard-coded in file `ttobjs.c`.
1221    *
1222    *   FT_FACE_FLAG_COLOR ::
1223    *     [Since 2.5.1] The face has color glyph tables.  See @FT_LOAD_COLOR
1224    *     for more information.
1225    *
1226    *   FT_FACE_FLAG_VARIATION ::
1227    *     [Since 2.9] Set if the current face (or named instance) has been
1228    *     altered with @FT_Set_MM_Design_Coordinates,
1229    *     @FT_Set_Var_Design_Coordinates, or @FT_Set_Var_Blend_Coordinates.
1230    *     This flag is unset by a call to @FT_Set_Named_Instance.
1231    */
1232 #define FT_FACE_FLAG_SCALABLE          ( 1L <<  0 )
1233 #define FT_FACE_FLAG_FIXED_SIZES       ( 1L <<  1 )
1234 #define FT_FACE_FLAG_FIXED_WIDTH       ( 1L <<  2 )
1235 #define FT_FACE_FLAG_SFNT              ( 1L <<  3 )
1236 #define FT_FACE_FLAG_HORIZONTAL        ( 1L <<  4 )
1237 #define FT_FACE_FLAG_VERTICAL          ( 1L <<  5 )
1238 #define FT_FACE_FLAG_KERNING           ( 1L <<  6 )
1239 #define FT_FACE_FLAG_FAST_GLYPHS       ( 1L <<  7 )
1240 #define FT_FACE_FLAG_MULTIPLE_MASTERS  ( 1L <<  8 )
1241 #define FT_FACE_FLAG_GLYPH_NAMES       ( 1L <<  9 )
1242 #define FT_FACE_FLAG_EXTERNAL_STREAM   ( 1L << 10 )
1243 #define FT_FACE_FLAG_HINTER            ( 1L << 11 )
1244 #define FT_FACE_FLAG_CID_KEYED         ( 1L << 12 )
1245 #define FT_FACE_FLAG_TRICKY            ( 1L << 13 )
1246 #define FT_FACE_FLAG_COLOR             ( 1L << 14 )
1247 #define FT_FACE_FLAG_VARIATION         ( 1L << 15 )
1248 
1249 
1250   /**************************************************************************
1251    *
1252    * @macro:
1253    *   FT_HAS_HORIZONTAL
1254    *
1255    * @description:
1256    *   A macro that returns true whenever a face object contains horizontal
1257    *   metrics (this is true for all font formats though).
1258    *
1259    * @also:
1260    *   @FT_HAS_VERTICAL can be used to check for vertical metrics.
1261    *
1262    */
1263 #define FT_HAS_HORIZONTAL( face ) \
1264           ( !!( (face)->face_flags & FT_FACE_FLAG_HORIZONTAL ) )
1265 
1266 
1267   /**************************************************************************
1268    *
1269    * @macro:
1270    *   FT_HAS_VERTICAL
1271    *
1272    * @description:
1273    *   A macro that returns true whenever a face object contains real
1274    *   vertical metrics (and not only synthesized ones).
1275    *
1276    */
1277 #define FT_HAS_VERTICAL( face ) \
1278           ( !!( (face)->face_flags & FT_FACE_FLAG_VERTICAL ) )
1279 
1280 
1281   /**************************************************************************
1282    *
1283    * @macro:
1284    *   FT_HAS_KERNING
1285    *
1286    * @description:
1287    *   A macro that returns true whenever a face object contains kerning data
1288    *   that can be accessed with @FT_Get_Kerning.
1289    *
1290    */
1291 #define FT_HAS_KERNING( face ) \
1292           ( !!( (face)->face_flags & FT_FACE_FLAG_KERNING ) )
1293 
1294 
1295   /**************************************************************************
1296    *
1297    * @macro:
1298    *   FT_IS_SCALABLE
1299    *
1300    * @description:
1301    *   A macro that returns true whenever a face object contains a scalable
1302    *   font face (true for TrueType, Type~1, Type~42, CID, OpenType/CFF, and
1303    *   PFR font formats).
1304    *
1305    */
1306 #define FT_IS_SCALABLE( face ) \
1307           ( !!( (face)->face_flags & FT_FACE_FLAG_SCALABLE ) )
1308 
1309 
1310   /**************************************************************************
1311    *
1312    * @macro:
1313    *   FT_IS_SFNT
1314    *
1315    * @description:
1316    *   A macro that returns true whenever a face object contains a font whose
1317    *   format is based on the SFNT storage scheme.  This usually means:
1318    *   TrueType fonts, OpenType fonts, as well as SFNT-based embedded bitmap
1319    *   fonts.
1320    *
1321    *   If this macro is true, all functions defined in @FT_SFNT_NAMES_H and
1322    *   @FT_TRUETYPE_TABLES_H are available.
1323    *
1324    */
1325 #define FT_IS_SFNT( face ) \
1326           ( !!( (face)->face_flags & FT_FACE_FLAG_SFNT ) )
1327 
1328 
1329   /**************************************************************************
1330    *
1331    * @macro:
1332    *   FT_IS_FIXED_WIDTH
1333    *
1334    * @description:
1335    *   A macro that returns true whenever a face object contains a font face
1336    *   that contains fixed-width (or 'monospace', 'fixed-pitch', etc.)
1337    *   glyphs.
1338    *
1339    */
1340 #define FT_IS_FIXED_WIDTH( face ) \
1341           ( !!( (face)->face_flags & FT_FACE_FLAG_FIXED_WIDTH ) )
1342 
1343 
1344   /**************************************************************************
1345    *
1346    * @macro:
1347    *   FT_HAS_FIXED_SIZES
1348    *
1349    * @description:
1350    *   A macro that returns true whenever a face object contains some
1351    *   embedded bitmaps.  See the `available_sizes` field of the @FT_FaceRec
1352    *   structure.
1353    *
1354    */
1355 #define FT_HAS_FIXED_SIZES( face ) \
1356           ( !!( (face)->face_flags & FT_FACE_FLAG_FIXED_SIZES ) )
1357 
1358 
1359   /**************************************************************************
1360    *
1361    * @macro:
1362    *   FT_HAS_FAST_GLYPHS
1363    *
1364    * @description:
1365    *   Deprecated.
1366    *
1367    */
1368 #define FT_HAS_FAST_GLYPHS( face )  0
1369 
1370 
1371   /**************************************************************************
1372    *
1373    * @macro:
1374    *   FT_HAS_GLYPH_NAMES
1375    *
1376    * @description:
1377    *   A macro that returns true whenever a face object contains some glyph
1378    *   names that can be accessed through @FT_Get_Glyph_Name.
1379    *
1380    */
1381 #define FT_HAS_GLYPH_NAMES( face ) \
1382           ( !!( (face)->face_flags & FT_FACE_FLAG_GLYPH_NAMES ) )
1383 
1384 
1385   /**************************************************************************
1386    *
1387    * @macro:
1388    *   FT_HAS_MULTIPLE_MASTERS
1389    *
1390    * @description:
1391    *   A macro that returns true whenever a face object contains some
1392    *   multiple masters.  The functions provided by @FT_MULTIPLE_MASTERS_H
1393    *   are then available to choose the exact design you want.
1394    *
1395    */
1396 #define FT_HAS_MULTIPLE_MASTERS( face ) \
1397           ( !!( (face)->face_flags & FT_FACE_FLAG_MULTIPLE_MASTERS ) )
1398 
1399 
1400   /**************************************************************************
1401    *
1402    * @macro:
1403    *   FT_IS_NAMED_INSTANCE
1404    *
1405    * @description:
1406    *   A macro that returns true whenever a face object is a named instance
1407    *   of a GX or OpenType variation font.
1408    *
1409    *   [Since 2.9] Changing the design coordinates with
1410    *   @FT_Set_Var_Design_Coordinates or @FT_Set_Var_Blend_Coordinates does
1411    *   not influence the return value of this macro (only
1412    *   @FT_Set_Named_Instance does that).
1413    *
1414    * @since:
1415    *   2.7
1416    *
1417    */
1418 #define FT_IS_NAMED_INSTANCE( face ) \
1419           ( !!( (face)->face_index & 0x7FFF0000L ) )
1420 
1421 
1422   /**************************************************************************
1423    *
1424    * @macro:
1425    *   FT_IS_VARIATION
1426    *
1427    * @description:
1428    *   A macro that returns true whenever a face object has been altered by
1429    *   @FT_Set_MM_Design_Coordinates, @FT_Set_Var_Design_Coordinates, or
1430    *   @FT_Set_Var_Blend_Coordinates.
1431    *
1432    * @since:
1433    *   2.9
1434    *
1435    */
1436 #define FT_IS_VARIATION( face ) \
1437           ( !!( (face)->face_flags & FT_FACE_FLAG_VARIATION ) )
1438 
1439 
1440   /**************************************************************************
1441    *
1442    * @macro:
1443    *   FT_IS_CID_KEYED
1444    *
1445    * @description:
1446    *   A macro that returns true whenever a face object contains a CID-keyed
1447    *   font.  See the discussion of @FT_FACE_FLAG_CID_KEYED for more details.
1448    *
1449    *   If this macro is true, all functions defined in @FT_CID_H are
1450    *   available.
1451    *
1452    */
1453 #define FT_IS_CID_KEYED( face ) \
1454           ( !!( (face)->face_flags & FT_FACE_FLAG_CID_KEYED ) )
1455 
1456 
1457   /**************************************************************************
1458    *
1459    * @macro:
1460    *   FT_IS_TRICKY
1461    *
1462    * @description:
1463    *   A macro that returns true whenever a face represents a 'tricky' font.
1464    *   See the discussion of @FT_FACE_FLAG_TRICKY for more details.
1465    *
1466    */
1467 #define FT_IS_TRICKY( face ) \
1468           ( !!( (face)->face_flags & FT_FACE_FLAG_TRICKY ) )
1469 
1470 
1471   /**************************************************************************
1472    *
1473    * @macro:
1474    *   FT_HAS_COLOR
1475    *
1476    * @description:
1477    *   A macro that returns true whenever a face object contains tables for
1478    *   color glyphs.
1479    *
1480    * @since:
1481    *   2.5.1
1482    *
1483    */
1484 #define FT_HAS_COLOR( face ) \
1485           ( !!( (face)->face_flags & FT_FACE_FLAG_COLOR ) )
1486 
1487 
1488   /**************************************************************************
1489    *
1490    * @enum:
1491    *   FT_STYLE_FLAG_XXX
1492    *
1493    * @description:
1494    *   A list of bit flags to indicate the style of a given face.  These are
1495    *   used in the `style_flags` field of @FT_FaceRec.
1496    *
1497    * @values:
1498    *   FT_STYLE_FLAG_ITALIC ::
1499    *     The face style is italic or oblique.
1500    *
1501    *   FT_STYLE_FLAG_BOLD ::
1502    *     The face is bold.
1503    *
1504    * @note:
1505    *   The style information as provided by FreeType is very basic.  More
1506    *   details are beyond the scope and should be done on a higher level (for
1507    *   example, by analyzing various fields of the 'OS/2' table in SFNT based
1508    *   fonts).
1509    */
1510 #define FT_STYLE_FLAG_ITALIC  ( 1 << 0 )
1511 #define FT_STYLE_FLAG_BOLD    ( 1 << 1 )
1512 
1513 
1514   /**************************************************************************
1515    *
1516    * @type:
1517    *   FT_Size_Internal
1518    *
1519    * @description:
1520    *   An opaque handle to an `FT_Size_InternalRec` structure, used to model
1521    *   private data of a given @FT_Size object.
1522    */
1523   typedef struct FT_Size_InternalRec_*  FT_Size_Internal;
1524 
1525 
1526   /**************************************************************************
1527    *
1528    * @struct:
1529    *   FT_Size_Metrics
1530    *
1531    * @description:
1532    *   The size metrics structure gives the metrics of a size object.
1533    *
1534    * @fields:
1535    *   x_ppem ::
1536    *     The width of the scaled EM square in pixels, hence the term 'ppem'
1537    *     (pixels per EM).  It is also referred to as 'nominal width'.
1538    *
1539    *   y_ppem ::
1540    *     The height of the scaled EM square in pixels, hence the term 'ppem'
1541    *     (pixels per EM).  It is also referred to as 'nominal height'.
1542    *
1543    *   x_scale ::
1544    *     A 16.16 fractional scaling value to convert horizontal metrics from
1545    *     font units to 26.6 fractional pixels.  Only relevant for scalable
1546    *     font formats.
1547    *
1548    *   y_scale ::
1549    *     A 16.16 fractional scaling value to convert vertical metrics from
1550    *     font units to 26.6 fractional pixels.  Only relevant for scalable
1551    *     font formats.
1552    *
1553    *   ascender ::
1554    *     The ascender in 26.6 fractional pixels, rounded up to an integer
1555    *     value.  See @FT_FaceRec for the details.
1556    *
1557    *   descender ::
1558    *     The descender in 26.6 fractional pixels, rounded down to an integer
1559    *     value.  See @FT_FaceRec for the details.
1560    *
1561    *   height ::
1562    *     The height in 26.6 fractional pixels, rounded to an integer value.
1563    *     See @FT_FaceRec for the details.
1564    *
1565    *   max_advance ::
1566    *     The maximum advance width in 26.6 fractional pixels, rounded to an
1567    *     integer value.  See @FT_FaceRec for the details.
1568    *
1569    * @note:
1570    *   The scaling values, if relevant, are determined first during a size
1571    *   changing operation.  The remaining fields are then set by the driver.
1572    *   For scalable formats, they are usually set to scaled values of the
1573    *   corresponding fields in @FT_FaceRec.  Some values like ascender or
1574    *   descender are rounded for historical reasons; more precise values (for
1575    *   outline fonts) can be derived by scaling the corresponding @FT_FaceRec
1576    *   values manually, with code similar to the following.
1577    *
1578    *   ```
1579    *     scaled_ascender = FT_MulFix( face->ascender,
1580    *                                  size_metrics->y_scale );
1581    *   ```
1582    *
1583    *   Note that due to glyph hinting and the selected rendering mode these
1584    *   values are usually not exact; consequently, they must be treated as
1585    *   unreliable with an error margin of at least one pixel!
1586    *
1587    *   Indeed, the only way to get the exact metrics is to render _all_
1588    *   glyphs.  As this would be a definite performance hit, it is up to
1589    *   client applications to perform such computations.
1590    *
1591    *   The `FT_Size_Metrics` structure is valid for bitmap fonts also.
1592    *
1593    *
1594    *   **TrueType fonts with native bytecode hinting**
1595    *
1596    *   All applications that handle TrueType fonts with native hinting must
1597    *   be aware that TTFs expect different rounding of vertical font
1598    *   dimensions.  The application has to cater for this, especially if it
1599    *   wants to rely on a TTF's vertical data (for example, to properly align
1600    *   box characters vertically).
1601    *
1602    *   Only the application knows _in advance_ that it is going to use native
1603    *   hinting for TTFs!  FreeType, on the other hand, selects the hinting
1604    *   mode not at the time of creating an @FT_Size object but much later,
1605    *   namely while calling @FT_Load_Glyph.
1606    *
1607    *   Here is some pseudo code that illustrates a possible solution.
1608    *
1609    *   ```
1610    *     font_format = FT_Get_Font_Format( face );
1611    *
1612    *     if ( !strcmp( font_format, "TrueType" ) &&
1613    *          do_native_bytecode_hinting         )
1614    *     {
1615    *       ascender  = ROUND( FT_MulFix( face->ascender,
1616    *                                     size_metrics->y_scale ) );
1617    *       descender = ROUND( FT_MulFix( face->descender,
1618    *                                     size_metrics->y_scale ) );
1619    *     }
1620    *     else
1621    *     {
1622    *       ascender  = size_metrics->ascender;
1623    *       descender = size_metrics->descender;
1624    *     }
1625    *
1626    *     height      = size_metrics->height;
1627    *     max_advance = size_metrics->max_advance;
1628    *   ```
1629    */
1630   typedef struct  FT_Size_Metrics_
1631   {
1632     FT_UShort  x_ppem;      /* horizontal pixels per EM               */
1633     FT_UShort  y_ppem;      /* vertical pixels per EM                 */
1634 
1635     FT_Fixed   x_scale;     /* scaling values used to convert font    */
1636     FT_Fixed   y_scale;     /* units to 26.6 fractional pixels        */
1637 
1638     FT_Pos     ascender;    /* ascender in 26.6 frac. pixels          */
1639     FT_Pos     descender;   /* descender in 26.6 frac. pixels         */
1640     FT_Pos     height;      /* text height in 26.6 frac. pixels       */
1641     FT_Pos     max_advance; /* max horizontal advance, in 26.6 pixels */
1642 
1643   } FT_Size_Metrics;
1644 
1645 
1646   /**************************************************************************
1647    *
1648    * @struct:
1649    *   FT_SizeRec
1650    *
1651    * @description:
1652    *   FreeType root size class structure.  A size object models a face
1653    *   object at a given size.
1654    *
1655    * @fields:
1656    *   face ::
1657    *     Handle to the parent face object.
1658    *
1659    *   generic ::
1660    *     A typeless pointer, unused by the FreeType library or any of its
1661    *     drivers.  It can be used by client applications to link their own
1662    *     data to each size object.
1663    *
1664    *   metrics ::
1665    *     Metrics for this size object.  This field is read-only.
1666    */
1667   typedef struct  FT_SizeRec_
1668   {
1669     FT_Face           face;      /* parent face object              */
1670     FT_Generic        generic;   /* generic pointer for client uses */
1671     FT_Size_Metrics   metrics;   /* size metrics                    */
1672     FT_Size_Internal  internal;
1673 
1674   } FT_SizeRec;
1675 
1676 
1677   /**************************************************************************
1678    *
1679    * @struct:
1680    *   FT_SubGlyph
1681    *
1682    * @description:
1683    *   The subglyph structure is an internal object used to describe
1684    *   subglyphs (for example, in the case of composites).
1685    *
1686    * @note:
1687    *   The subglyph implementation is not part of the high-level API, hence
1688    *   the forward structure declaration.
1689    *
1690    *   You can however retrieve subglyph information with
1691    *   @FT_Get_SubGlyph_Info.
1692    */
1693   typedef struct FT_SubGlyphRec_*  FT_SubGlyph;
1694 
1695 
1696   /**************************************************************************
1697    *
1698    * @type:
1699    *   FT_Slot_Internal
1700    *
1701    * @description:
1702    *   An opaque handle to an `FT_Slot_InternalRec` structure, used to model
1703    *   private data of a given @FT_GlyphSlot object.
1704    */
1705   typedef struct FT_Slot_InternalRec_*  FT_Slot_Internal;
1706 
1707 
1708   /**************************************************************************
1709    *
1710    * @struct:
1711    *   FT_GlyphSlotRec
1712    *
1713    * @description:
1714    *   FreeType root glyph slot class structure.  A glyph slot is a container
1715    *   where individual glyphs can be loaded, be they in outline or bitmap
1716    *   format.
1717    *
1718    * @fields:
1719    *   library ::
1720    *     A handle to the FreeType library instance this slot belongs to.
1721    *
1722    *   face ::
1723    *     A handle to the parent face object.
1724    *
1725    *   next ::
1726    *     In some cases (like some font tools), several glyph slots per face
1727    *     object can be a good thing.  As this is rare, the glyph slots are
1728    *     listed through a direct, single-linked list using its `next` field.
1729    *
1730    *   glyph_index ::
1731    *     [Since 2.10] The glyph index passed as an argument to @FT_Load_Glyph
1732    *     while initializing the glyph slot.
1733    *
1734    *   generic ::
1735    *     A typeless pointer unused by the FreeType library or any of its
1736    *     drivers.  It can be used by client applications to link their own
1737    *     data to each glyph slot object.
1738    *
1739    *   metrics ::
1740    *     The metrics of the last loaded glyph in the slot.  The returned
1741    *     values depend on the last load flags (see the @FT_Load_Glyph API
1742    *     function) and can be expressed either in 26.6 fractional pixels or
1743    *     font units.
1744    *
1745    *     Note that even when the glyph image is transformed, the metrics are
1746    *     not.
1747    *
1748    *   linearHoriAdvance ::
1749    *     The advance width of the unhinted glyph.  Its value is expressed in
1750    *     16.16 fractional pixels, unless @FT_LOAD_LINEAR_DESIGN is set when
1751    *     loading the glyph.  This field can be important to perform correct
1752    *     WYSIWYG layout.  Only relevant for outline glyphs.
1753    *
1754    *   linearVertAdvance ::
1755    *     The advance height of the unhinted glyph.  Its value is expressed in
1756    *     16.16 fractional pixels, unless @FT_LOAD_LINEAR_DESIGN is set when
1757    *     loading the glyph.  This field can be important to perform correct
1758    *     WYSIWYG layout.  Only relevant for outline glyphs.
1759    *
1760    *   advance ::
1761    *     This shorthand is, depending on @FT_LOAD_IGNORE_TRANSFORM, the
1762    *     transformed (hinted) advance width for the glyph, in 26.6 fractional
1763    *     pixel format.  As specified with @FT_LOAD_VERTICAL_LAYOUT, it uses
1764    *     either the `horiAdvance` or the `vertAdvance` value of `metrics`
1765    *     field.
1766    *
1767    *   format ::
1768    *     This field indicates the format of the image contained in the glyph
1769    *     slot.  Typically @FT_GLYPH_FORMAT_BITMAP, @FT_GLYPH_FORMAT_OUTLINE,
1770    *     or @FT_GLYPH_FORMAT_COMPOSITE, but other values are possible.
1771    *
1772    *   bitmap ::
1773    *     This field is used as a bitmap descriptor.  Note that the address
1774    *     and content of the bitmap buffer can change between calls of
1775    *     @FT_Load_Glyph and a few other functions.
1776    *
1777    *   bitmap_left ::
1778    *     The bitmap's left bearing expressed in integer pixels.
1779    *
1780    *   bitmap_top ::
1781    *     The bitmap's top bearing expressed in integer pixels.  This is the
1782    *     distance from the baseline to the top-most glyph scanline, upwards
1783    *     y~coordinates being **positive**.
1784    *
1785    *   outline ::
1786    *     The outline descriptor for the current glyph image if its format is
1787    *     @FT_GLYPH_FORMAT_OUTLINE.  Once a glyph is loaded, `outline` can be
1788    *     transformed, distorted, emboldened, etc.  However, it must not be
1789    *     freed.
1790    *
1791    *     [Since 2.10.1] If @FT_LOAD_NO_SCALE is set, outline coordinates of
1792    *     OpenType variation fonts for a selected instance are internally
1793    *     handled as 26.6 fractional font units but returned as (rounded)
1794    *     integers, as expected.  To get unrounded font units, don't use
1795    *     @FT_LOAD_NO_SCALE but load the glyph with @FT_LOAD_NO_HINTING and
1796    *     scale it, using the font's `units_per_EM` value as the ppem.
1797    *
1798    *   num_subglyphs ::
1799    *     The number of subglyphs in a composite glyph.  This field is only
1800    *     valid for the composite glyph format that should normally only be
1801    *     loaded with the @FT_LOAD_NO_RECURSE flag.
1802    *
1803    *   subglyphs ::
1804    *     An array of subglyph descriptors for composite glyphs.  There are
1805    *     `num_subglyphs` elements in there.  Currently internal to FreeType.
1806    *
1807    *   control_data ::
1808    *     Certain font drivers can also return the control data for a given
1809    *     glyph image (e.g.  TrueType bytecode, Type~1 charstrings, etc.).
1810    *     This field is a pointer to such data; it is currently internal to
1811    *     FreeType.
1812    *
1813    *   control_len ::
1814    *     This is the length in bytes of the control data.  Currently internal
1815    *     to FreeType.
1816    *
1817    *   other ::
1818    *     Reserved.
1819    *
1820    *   lsb_delta ::
1821    *     The difference between hinted and unhinted left side bearing while
1822    *     auto-hinting is active.  Zero otherwise.
1823    *
1824    *   rsb_delta ::
1825    *     The difference between hinted and unhinted right side bearing while
1826    *     auto-hinting is active.  Zero otherwise.
1827    *
1828    * @note:
1829    *   If @FT_Load_Glyph is called with default flags (see @FT_LOAD_DEFAULT)
1830    *   the glyph image is loaded in the glyph slot in its native format
1831    *   (e.g., an outline glyph for TrueType and Type~1 formats).  [Since 2.9]
1832    *   The prospective bitmap metrics are calculated according to
1833    *   @FT_LOAD_TARGET_XXX and other flags even for the outline glyph, even
1834    *   if @FT_LOAD_RENDER is not set.
1835    *
1836    *   This image can later be converted into a bitmap by calling
1837    *   @FT_Render_Glyph.  This function searches the current renderer for the
1838    *   native image's format, then invokes it.
1839    *
1840    *   The renderer is in charge of transforming the native image through the
1841    *   slot's face transformation fields, then converting it into a bitmap
1842    *   that is returned in `slot->bitmap`.
1843    *
1844    *   Note that `slot->bitmap_left` and `slot->bitmap_top` are also used to
1845    *   specify the position of the bitmap relative to the current pen
1846    *   position (e.g., coordinates (0,0) on the baseline).  Of course,
1847    *   `slot->format` is also changed to @FT_GLYPH_FORMAT_BITMAP.
1848    *
1849    *   Here is a small pseudo code fragment that shows how to use `lsb_delta`
1850    *   and `rsb_delta` to do fractional positioning of glyphs:
1851    *
1852    *   ```
1853    *     FT_GlyphSlot  slot     = face->glyph;
1854    *     FT_Pos        origin_x = 0;
1855    *
1856    *
1857    *     for all glyphs do
1858    *       <load glyph with `FT_Load_Glyph'>
1859    *
1860    *       FT_Outline_Translate( slot->outline, origin_x & 63, 0 );
1861    *
1862    *       <save glyph image, or render glyph, or ...>
1863    *
1864    *       <compute kern between current and next glyph
1865    *        and add it to `origin_x'>
1866    *
1867    *       origin_x += slot->advance.x;
1868    *       origin_x += slot->lsb_delta - slot->rsb_delta;
1869    *     endfor
1870    *   ```
1871    *
1872    *   Here is another small pseudo code fragment that shows how to use
1873    *   `lsb_delta` and `rsb_delta` to improve integer positioning of glyphs:
1874    *
1875    *   ```
1876    *     FT_GlyphSlot  slot           = face->glyph;
1877    *     FT_Pos        origin_x       = 0;
1878    *     FT_Pos        prev_rsb_delta = 0;
1879    *
1880    *
1881    *     for all glyphs do
1882    *       <compute kern between current and previous glyph
1883    *        and add it to `origin_x'>
1884    *
1885    *       <load glyph with `FT_Load_Glyph'>
1886    *
1887    *       if ( prev_rsb_delta - slot->lsb_delta >  32 )
1888    *         origin_x -= 64;
1889    *       else if ( prev_rsb_delta - slot->lsb_delta < -31 )
1890    *         origin_x += 64;
1891    *
1892    *       prev_rsb_delta = slot->rsb_delta;
1893    *
1894    *       <save glyph image, or render glyph, or ...>
1895    *
1896    *       origin_x += slot->advance.x;
1897    *     endfor
1898    *   ```
1899    *
1900    *   If you use strong auto-hinting, you **must** apply these delta values!
1901    *   Otherwise you will experience far too large inter-glyph spacing at
1902    *   small rendering sizes in most cases.  Note that it doesn't harm to use
1903    *   the above code for other hinting modes also, since the delta values
1904    *   are zero then.
1905    */
1906   typedef struct  FT_GlyphSlotRec_
1907   {
1908     FT_Library        library;
1909     FT_Face           face;
1910     FT_GlyphSlot      next;
1911     FT_UInt           glyph_index; /* new in 2.10; was reserved previously */
1912     FT_Generic        generic;
1913 
1914     FT_Glyph_Metrics  metrics;
1915     FT_Fixed          linearHoriAdvance;
1916     FT_Fixed          linearVertAdvance;
1917     FT_Vector         advance;
1918 
1919     FT_Glyph_Format   format;
1920 
1921     FT_Bitmap         bitmap;
1922     FT_Int            bitmap_left;
1923     FT_Int            bitmap_top;
1924 
1925     FT_Outline        outline;
1926 
1927     FT_UInt           num_subglyphs;
1928     FT_SubGlyph       subglyphs;
1929 
1930     void*             control_data;
1931     long              control_len;
1932 
1933     FT_Pos            lsb_delta;
1934     FT_Pos            rsb_delta;
1935 
1936     void*             other;
1937 
1938     FT_Slot_Internal  internal;
1939 
1940   } FT_GlyphSlotRec;
1941 
1942 
1943   /*************************************************************************/
1944   /*************************************************************************/
1945   /*                                                                       */
1946   /*                         F U N C T I O N S                             */
1947   /*                                                                       */
1948   /*************************************************************************/
1949   /*************************************************************************/
1950 
1951 
1952   /**************************************************************************
1953    *
1954    * @function:
1955    *   FT_Init_FreeType
1956    *
1957    * @description:
1958    *   Initialize a new FreeType library object.  The set of modules that are
1959    *   registered by this function is determined at build time.
1960    *
1961    * @output:
1962    *   alibrary ::
1963    *     A handle to a new library object.
1964    *
1965    * @return:
1966    *   FreeType error code.  0~means success.
1967    *
1968    * @note:
1969    *   In case you want to provide your own memory allocating routines, use
1970    *   @FT_New_Library instead, followed by a call to @FT_Add_Default_Modules
1971    *   (or a series of calls to @FT_Add_Module) and
1972    *   @FT_Set_Default_Properties.
1973    *
1974    *   See the documentation of @FT_Library and @FT_Face for multi-threading
1975    *   issues.
1976    *
1977    *   If you need reference-counting (cf. @FT_Reference_Library), use
1978    *   @FT_New_Library and @FT_Done_Library.
1979    *
1980    *   If compilation option `FT_CONFIG_OPTION_ENVIRONMENT_PROPERTIES` is
1981    *   set, this function reads the `FREETYPE_PROPERTIES` environment
1982    *   variable to control driver properties.  See section @properties for
1983    *   more.
1984    */
1985   FT_EXPORT( FT_Error )
1986   FT_Init_FreeType( FT_Library  *alibrary );
1987 
1988 
1989   /**************************************************************************
1990    *
1991    * @function:
1992    *   FT_Done_FreeType
1993    *
1994    * @description:
1995    *   Destroy a given FreeType library object and all of its children,
1996    *   including resources, drivers, faces, sizes, etc.
1997    *
1998    * @input:
1999    *   library ::
2000    *     A handle to the target library object.
2001    *
2002    * @return:
2003    *   FreeType error code.  0~means success.
2004    */
2005   FT_EXPORT( FT_Error )
2006   FT_Done_FreeType( FT_Library  library );
2007 
2008 
2009   /**************************************************************************
2010    *
2011    * @enum:
2012    *   FT_OPEN_XXX
2013    *
2014    * @description:
2015    *   A list of bit field constants used within the `flags` field of the
2016    *   @FT_Open_Args structure.
2017    *
2018    * @values:
2019    *   FT_OPEN_MEMORY ::
2020    *     This is a memory-based stream.
2021    *
2022    *   FT_OPEN_STREAM ::
2023    *     Copy the stream from the `stream` field.
2024    *
2025    *   FT_OPEN_PATHNAME ::
2026    *     Create a new input stream from a C~path name.
2027    *
2028    *   FT_OPEN_DRIVER ::
2029    *     Use the `driver` field.
2030    *
2031    *   FT_OPEN_PARAMS ::
2032    *     Use the `num_params` and `params` fields.
2033    *
2034    * @note:
2035    *   The `FT_OPEN_MEMORY`, `FT_OPEN_STREAM`, and `FT_OPEN_PATHNAME` flags
2036    *   are mutually exclusive.
2037    */
2038 #define FT_OPEN_MEMORY    0x1
2039 #define FT_OPEN_STREAM    0x2
2040 #define FT_OPEN_PATHNAME  0x4
2041 #define FT_OPEN_DRIVER    0x8
2042 #define FT_OPEN_PARAMS    0x10
2043 
2044 
2045   /* these constants are deprecated; use the corresponding `FT_OPEN_XXX` */
2046   /* values instead                                                      */
2047 #define ft_open_memory    FT_OPEN_MEMORY
2048 #define ft_open_stream    FT_OPEN_STREAM
2049 #define ft_open_pathname  FT_OPEN_PATHNAME
2050 #define ft_open_driver    FT_OPEN_DRIVER
2051 #define ft_open_params    FT_OPEN_PARAMS
2052 
2053 
2054   /**************************************************************************
2055    *
2056    * @struct:
2057    *   FT_Parameter
2058    *
2059    * @description:
2060    *   A simple structure to pass more or less generic parameters to
2061    *   @FT_Open_Face and @FT_Face_Properties.
2062    *
2063    * @fields:
2064    *   tag ::
2065    *     A four-byte identification tag.
2066    *
2067    *   data ::
2068    *     A pointer to the parameter data.
2069    *
2070    * @note:
2071    *   The ID and function of parameters are driver-specific.  See section
2072    *   @parameter_tags for more information.
2073    */
2074   typedef struct  FT_Parameter_
2075   {
2076     FT_ULong    tag;
2077     FT_Pointer  data;
2078 
2079   } FT_Parameter;
2080 
2081 
2082   /**************************************************************************
2083    *
2084    * @struct:
2085    *   FT_Open_Args
2086    *
2087    * @description:
2088    *   A structure to indicate how to open a new font file or stream.  A
2089    *   pointer to such a structure can be used as a parameter for the
2090    *   functions @FT_Open_Face and @FT_Attach_Stream.
2091    *
2092    * @fields:
2093    *   flags ::
2094    *     A set of bit flags indicating how to use the structure.
2095    *
2096    *   memory_base ::
2097    *     The first byte of the file in memory.
2098    *
2099    *   memory_size ::
2100    *     The size in bytes of the file in memory.
2101    *
2102    *   pathname ::
2103    *     A pointer to an 8-bit file pathname, which must be a C~string (i.e.,
2104    *     no null bytes except at the very end).  The pointer is not owned by
2105    *     FreeType.
2106    *
2107    *   stream ::
2108    *     A handle to a source stream object.
2109    *
2110    *   driver ::
2111    *     This field is exclusively used by @FT_Open_Face; it simply specifies
2112    *     the font driver to use for opening the face.  If set to `NULL`,
2113    *     FreeType tries to load the face with each one of the drivers in its
2114    *     list.
2115    *
2116    *   num_params ::
2117    *     The number of extra parameters.
2118    *
2119    *   params ::
2120    *     Extra parameters passed to the font driver when opening a new face.
2121    *
2122    * @note:
2123    *   The stream type is determined by the contents of `flags`:
2124    *
2125    *   If the @FT_OPEN_MEMORY bit is set, assume that this is a memory file
2126    *   of `memory_size` bytes, located at `memory_address`.  The data are not
2127    *   copied, and the client is responsible for releasing and destroying
2128    *   them _after_ the corresponding call to @FT_Done_Face.
2129    *
2130    *   Otherwise, if the @FT_OPEN_STREAM bit is set, assume that a custom
2131    *   input stream `stream` is used.
2132    *
2133    *   Otherwise, if the @FT_OPEN_PATHNAME bit is set, assume that this is a
2134    *   normal file and use `pathname` to open it.
2135    *
2136    *   If none of the above bits are set or if multiple are set at the same
2137    *   time, the flags are invalid and @FT_Open_Face fails.
2138    *
2139    *   If the @FT_OPEN_DRIVER bit is set, @FT_Open_Face only tries to open
2140    *   the file with the driver whose handler is in `driver`.
2141    *
2142    *   If the @FT_OPEN_PARAMS bit is set, the parameters given by
2143    *   `num_params` and `params` is used.  They are ignored otherwise.
2144    *
2145    *   Ideally, both the `pathname` and `params` fields should be tagged as
2146    *   'const'; this is missing for API backward compatibility.  In other
2147    *   words, applications should treat them as read-only.
2148    */
2149   typedef struct  FT_Open_Args_
2150   {
2151     FT_UInt         flags;
2152     const FT_Byte*  memory_base;
2153     FT_Long         memory_size;
2154     FT_String*      pathname;
2155     FT_Stream       stream;
2156     FT_Module       driver;
2157     FT_Int          num_params;
2158     FT_Parameter*   params;
2159 
2160   } FT_Open_Args;
2161 
2162 
2163   /**************************************************************************
2164    *
2165    * @function:
2166    *   FT_New_Face
2167    *
2168    * @description:
2169    *   Call @FT_Open_Face to open a font by its pathname.
2170    *
2171    * @inout:
2172    *   library ::
2173    *     A handle to the library resource.
2174    *
2175    * @input:
2176    *   pathname ::
2177    *     A path to the font file.
2178    *
2179    *   face_index ::
2180    *     See @FT_Open_Face for a detailed description of this parameter.
2181    *
2182    * @output:
2183    *   aface ::
2184    *     A handle to a new face object.  If `face_index` is greater than or
2185    *     equal to zero, it must be non-`NULL`.
2186    *
2187    * @return:
2188    *   FreeType error code.  0~means success.
2189    *
2190    * @note:
2191    *   The `pathname` string should be recognizable as such by a standard
2192    *   `fopen` call on your system; in particular, this means that `pathname`
2193    *   must not contain null bytes.  If that is not sufficient to address all
2194    *   file name possibilities (for example, to handle wide character file
2195    *   names on Windows in UTF-16 encoding) you might use @FT_Open_Face to
2196    *   pass a memory array or a stream object instead.
2197    *
2198    *   Use @FT_Done_Face to destroy the created @FT_Face object (along with
2199    *   its slot and sizes).
2200    */
2201   FT_EXPORT( FT_Error )
2202   FT_New_Face( FT_Library   library,
2203                const char*  filepathname,
2204                FT_Long      face_index,
2205                FT_Face     *aface );
2206 
2207 
2208   /**************************************************************************
2209    *
2210    * @function:
2211    *   FT_New_Memory_Face
2212    *
2213    * @description:
2214    *   Call @FT_Open_Face to open a font that has been loaded into memory.
2215    *
2216    * @inout:
2217    *   library ::
2218    *     A handle to the library resource.
2219    *
2220    * @input:
2221    *   file_base ::
2222    *     A pointer to the beginning of the font data.
2223    *
2224    *   file_size ::
2225    *     The size of the memory chunk used by the font data.
2226    *
2227    *   face_index ::
2228    *     See @FT_Open_Face for a detailed description of this parameter.
2229    *
2230    * @output:
2231    *   aface ::
2232    *     A handle to a new face object.  If `face_index` is greater than or
2233    *     equal to zero, it must be non-`NULL`.
2234    *
2235    * @return:
2236    *   FreeType error code.  0~means success.
2237    *
2238    * @note:
2239    *   You must not deallocate the memory before calling @FT_Done_Face.
2240    */
2241   FT_EXPORT( FT_Error )
2242   FT_New_Memory_Face( FT_Library      library,
2243                       const FT_Byte*  file_base,
2244                       FT_Long         file_size,
2245                       FT_Long         face_index,
2246                       FT_Face        *aface );
2247 
2248 
2249   /**************************************************************************
2250    *
2251    * @function:
2252    *   FT_Open_Face
2253    *
2254    * @description:
2255    *   Create a face object from a given resource described by @FT_Open_Args.
2256    *
2257    * @inout:
2258    *   library ::
2259    *     A handle to the library resource.
2260    *
2261    * @input:
2262    *   args ::
2263    *     A pointer to an `FT_Open_Args` structure that must be filled by the
2264    *     caller.
2265    *
2266    *   face_index ::
2267    *     This field holds two different values.  Bits 0-15 are the index of
2268    *     the face in the font file (starting with value~0).  Set it to~0 if
2269    *     there is only one face in the font file.
2270    *
2271    *     [Since 2.6.1] Bits 16-30 are relevant to GX and OpenType variation
2272    *     fonts only, specifying the named instance index for the current face
2273    *     index (starting with value~1; value~0 makes FreeType ignore named
2274    *     instances).  For non-variation fonts, bits 16-30 are ignored.
2275    *     Assuming that you want to access the third named instance in face~4,
2276    *     `face_index` should be set to 0x00030004.  If you want to access
2277    *     face~4 without variation handling, simply set `face_index` to
2278    *     value~4.
2279    *
2280    *     `FT_Open_Face` and its siblings can be used to quickly check whether
2281    *     the font format of a given font resource is supported by FreeType.
2282    *     In general, if the `face_index` argument is negative, the function's
2283    *     return value is~0 if the font format is recognized, or non-zero
2284    *     otherwise.  The function allocates a more or less empty face handle
2285    *     in `*aface` (if `aface` isn't `NULL`); the only two useful fields in
2286    *     this special case are `face->num_faces` and `face->style_flags`.
2287    *     For any negative value of `face_index`, `face->num_faces` gives the
2288    *     number of faces within the font file.  For the negative value
2289    *     '-(N+1)' (with 'N' a non-negative 16-bit value), bits 16-30 in
2290    *     `face->style_flags` give the number of named instances in face 'N'
2291    *     if we have a variation font (or zero otherwise).  After examination,
2292    *     the returned @FT_Face structure should be deallocated with a call to
2293    *     @FT_Done_Face.
2294    *
2295    * @output:
2296    *   aface ::
2297    *     A handle to a new face object.  If `face_index` is greater than or
2298    *     equal to zero, it must be non-`NULL`.
2299    *
2300    * @return:
2301    *   FreeType error code.  0~means success.
2302    *
2303    * @note:
2304    *   Unlike FreeType 1.x, this function automatically creates a glyph slot
2305    *   for the face object that can be accessed directly through
2306    *   `face->glyph`.
2307    *
2308    *   Each new face object created with this function also owns a default
2309    *   @FT_Size object, accessible as `face->size`.
2310    *
2311    *   One @FT_Library instance can have multiple face objects, this is,
2312    *   @FT_Open_Face and its siblings can be called multiple times using the
2313    *   same `library` argument.
2314    *
2315    *   See the discussion of reference counters in the description of
2316    *   @FT_Reference_Face.
2317    *
2318    *   If `FT_OPEN_STREAM` is set in `args->flags`, the stream in
2319    *   `args->stream` is automatically closed before this function returns
2320    *   any error (including `FT_Err_Invalid_Argument`).
2321    *
2322    * @example:
2323    *   To loop over all faces, use code similar to the following snippet
2324    *   (omitting the error handling).
2325    *
2326    *   ```
2327    *     ...
2328    *     FT_Face  face;
2329    *     FT_Long  i, num_faces;
2330    *
2331    *
2332    *     error = FT_Open_Face( library, args, -1, &face );
2333    *     if ( error ) { ... }
2334    *
2335    *     num_faces = face->num_faces;
2336    *     FT_Done_Face( face );
2337    *
2338    *     for ( i = 0; i < num_faces; i++ )
2339    *     {
2340    *       ...
2341    *       error = FT_Open_Face( library, args, i, &face );
2342    *       ...
2343    *       FT_Done_Face( face );
2344    *       ...
2345    *     }
2346    *   ```
2347    *
2348    *   To loop over all valid values for `face_index`, use something similar
2349    *   to the following snippet, again without error handling.  The code
2350    *   accesses all faces immediately (thus only a single call of
2351    *   `FT_Open_Face` within the do-loop), with and without named instances.
2352    *
2353    *   ```
2354    *     ...
2355    *     FT_Face  face;
2356    *
2357    *     FT_Long  num_faces     = 0;
2358    *     FT_Long  num_instances = 0;
2359    *
2360    *     FT_Long  face_idx     = 0;
2361    *     FT_Long  instance_idx = 0;
2362    *
2363    *
2364    *     do
2365    *     {
2366    *       FT_Long  id = ( instance_idx << 16 ) + face_idx;
2367    *
2368    *
2369    *       error = FT_Open_Face( library, args, id, &face );
2370    *       if ( error ) { ... }
2371    *
2372    *       num_faces     = face->num_faces;
2373    *       num_instances = face->style_flags >> 16;
2374    *
2375    *       ...
2376    *
2377    *       FT_Done_Face( face );
2378    *
2379    *       if ( instance_idx < num_instances )
2380    *         instance_idx++;
2381    *       else
2382    *       {
2383    *         face_idx++;
2384    *         instance_idx = 0;
2385    *       }
2386    *
2387    *     } while ( face_idx < num_faces )
2388    *   ```
2389    */
2390   FT_EXPORT( FT_Error )
2391   FT_Open_Face( FT_Library           library,
2392                 const FT_Open_Args*  args,
2393                 FT_Long              face_index,
2394                 FT_Face             *aface );
2395 
2396 
2397   /**************************************************************************
2398    *
2399    * @function:
2400    *   FT_Attach_File
2401    *
2402    * @description:
2403    *   Call @FT_Attach_Stream to attach a file.
2404    *
2405    * @inout:
2406    *   face ::
2407    *     The target face object.
2408    *
2409    * @input:
2410    *   filepathname ::
2411    *     The pathname.
2412    *
2413    * @return:
2414    *   FreeType error code.  0~means success.
2415    */
2416   FT_EXPORT( FT_Error )
2417   FT_Attach_File( FT_Face      face,
2418                   const char*  filepathname );
2419 
2420 
2421   /**************************************************************************
2422    *
2423    * @function:
2424    *   FT_Attach_Stream
2425    *
2426    * @description:
2427    *   'Attach' data to a face object.  Normally, this is used to read
2428    *   additional information for the face object.  For example, you can
2429    *   attach an AFM file that comes with a Type~1 font to get the kerning
2430    *   values and other metrics.
2431    *
2432    * @inout:
2433    *   face ::
2434    *     The target face object.
2435    *
2436    * @input:
2437    *   parameters ::
2438    *     A pointer to @FT_Open_Args that must be filled by the caller.
2439    *
2440    * @return:
2441    *   FreeType error code.  0~means success.
2442    *
2443    * @note:
2444    *   The meaning of the 'attach' (i.e., what really happens when the new
2445    *   file is read) is not fixed by FreeType itself.  It really depends on
2446    *   the font format (and thus the font driver).
2447    *
2448    *   Client applications are expected to know what they are doing when
2449    *   invoking this function.  Most drivers simply do not implement file or
2450    *   stream attachments.
2451    */
2452   FT_EXPORT( FT_Error )
2453   FT_Attach_Stream( FT_Face        face,
2454                     FT_Open_Args*  parameters );
2455 
2456 
2457   /**************************************************************************
2458    *
2459    * @function:
2460    *   FT_Reference_Face
2461    *
2462    * @description:
2463    *   A counter gets initialized to~1 at the time an @FT_Face structure is
2464    *   created.  This function increments the counter.  @FT_Done_Face then
2465    *   only destroys a face if the counter is~1, otherwise it simply
2466    *   decrements the counter.
2467    *
2468    *   This function helps in managing life-cycles of structures that
2469    *   reference @FT_Face objects.
2470    *
2471    * @input:
2472    *   face ::
2473    *     A handle to a target face object.
2474    *
2475    * @return:
2476    *   FreeType error code.  0~means success.
2477    *
2478    * @since:
2479    *   2.4.2
2480    *
2481    */
2482   FT_EXPORT( FT_Error )
2483   FT_Reference_Face( FT_Face  face );
2484 
2485 
2486   /**************************************************************************
2487    *
2488    * @function:
2489    *   FT_Done_Face
2490    *
2491    * @description:
2492    *   Discard a given face object, as well as all of its child slots and
2493    *   sizes.
2494    *
2495    * @input:
2496    *   face ::
2497    *     A handle to a target face object.
2498    *
2499    * @return:
2500    *   FreeType error code.  0~means success.
2501    *
2502    * @note:
2503    *   See the discussion of reference counters in the description of
2504    *   @FT_Reference_Face.
2505    */
2506   FT_EXPORT( FT_Error )
2507   FT_Done_Face( FT_Face  face );
2508 
2509 
2510   /**************************************************************************
2511    *
2512    * @function:
2513    *   FT_Select_Size
2514    *
2515    * @description:
2516    *   Select a bitmap strike.  To be more precise, this function sets the
2517    *   scaling factors of the active @FT_Size object in a face so that
2518    *   bitmaps from this particular strike are taken by @FT_Load_Glyph and
2519    *   friends.
2520    *
2521    * @inout:
2522    *   face ::
2523    *     A handle to a target face object.
2524    *
2525    * @input:
2526    *   strike_index ::
2527    *     The index of the bitmap strike in the `available_sizes` field of
2528    *     @FT_FaceRec structure.
2529    *
2530    * @return:
2531    *   FreeType error code.  0~means success.
2532    *
2533    * @note:
2534    *   For bitmaps embedded in outline fonts it is common that only a subset
2535    *   of the available glyphs at a given ppem value is available.  FreeType
2536    *   silently uses outlines if there is no bitmap for a given glyph index.
2537    *
2538    *   For GX and OpenType variation fonts, a bitmap strike makes sense only
2539    *   if the default instance is active (this is, no glyph variation takes
2540    *   place); otherwise, FreeType simply ignores bitmap strikes.  The same
2541    *   is true for all named instances that are different from the default
2542    *   instance.
2543    *
2544    *   Don't use this function if you are using the FreeType cache API.
2545    */
2546   FT_EXPORT( FT_Error )
2547   FT_Select_Size( FT_Face  face,
2548                   FT_Int   strike_index );
2549 
2550 
2551   /**************************************************************************
2552    *
2553    * @enum:
2554    *   FT_Size_Request_Type
2555    *
2556    * @description:
2557    *   An enumeration type that lists the supported size request types, i.e.,
2558    *   what input size (in font units) maps to the requested output size (in
2559    *   pixels, as computed from the arguments of @FT_Size_Request).
2560    *
2561    * @values:
2562    *   FT_SIZE_REQUEST_TYPE_NOMINAL ::
2563    *     The nominal size.  The `units_per_EM` field of @FT_FaceRec is used
2564    *     to determine both scaling values.
2565    *
2566    *     This is the standard scaling found in most applications.  In
2567    *     particular, use this size request type for TrueType fonts if they
2568    *     provide optical scaling or something similar.  Note, however, that
2569    *     `units_per_EM` is a rather abstract value which bears no relation to
2570    *     the actual size of the glyphs in a font.
2571    *
2572    *   FT_SIZE_REQUEST_TYPE_REAL_DIM ::
2573    *     The real dimension.  The sum of the `ascender` and (minus of) the
2574    *     `descender` fields of @FT_FaceRec is used to determine both scaling
2575    *     values.
2576    *
2577    *   FT_SIZE_REQUEST_TYPE_BBOX ::
2578    *     The font bounding box.  The width and height of the `bbox` field of
2579    *     @FT_FaceRec are used to determine the horizontal and vertical
2580    *     scaling value, respectively.
2581    *
2582    *   FT_SIZE_REQUEST_TYPE_CELL ::
2583    *     The `max_advance_width` field of @FT_FaceRec is used to determine
2584    *     the horizontal scaling value; the vertical scaling value is
2585    *     determined the same way as @FT_SIZE_REQUEST_TYPE_REAL_DIM does.
2586    *     Finally, both scaling values are set to the smaller one.  This type
2587    *     is useful if you want to specify the font size for, say, a window of
2588    *     a given dimension and 80x24 cells.
2589    *
2590    *   FT_SIZE_REQUEST_TYPE_SCALES ::
2591    *     Specify the scaling values directly.
2592    *
2593    * @note:
2594    *   The above descriptions only apply to scalable formats.  For bitmap
2595    *   formats, the behaviour is up to the driver.
2596    *
2597    *   See the note section of @FT_Size_Metrics if you wonder how size
2598    *   requesting relates to scaling values.
2599    */
2600   typedef enum  FT_Size_Request_Type_
2601   {
2602     FT_SIZE_REQUEST_TYPE_NOMINAL,
2603     FT_SIZE_REQUEST_TYPE_REAL_DIM,
2604     FT_SIZE_REQUEST_TYPE_BBOX,
2605     FT_SIZE_REQUEST_TYPE_CELL,
2606     FT_SIZE_REQUEST_TYPE_SCALES,
2607 
2608     FT_SIZE_REQUEST_TYPE_MAX
2609 
2610   } FT_Size_Request_Type;
2611 
2612 
2613   /**************************************************************************
2614    *
2615    * @struct:
2616    *   FT_Size_RequestRec
2617    *
2618    * @description:
2619    *   A structure to model a size request.
2620    *
2621    * @fields:
2622    *   type ::
2623    *     See @FT_Size_Request_Type.
2624    *
2625    *   width ::
2626    *     The desired width, given as a 26.6 fractional point value (with 72pt
2627    *     = 1in).
2628    *
2629    *   height ::
2630    *     The desired height, given as a 26.6 fractional point value (with
2631    *     72pt = 1in).
2632    *
2633    *   horiResolution ::
2634    *     The horizontal resolution (dpi, i.e., pixels per inch).  If set to
2635    *     zero, `width` is treated as a 26.6 fractional **pixel** value, which
2636    *     gets internally rounded to an integer.
2637    *
2638    *   vertResolution ::
2639    *     The vertical resolution (dpi, i.e., pixels per inch).  If set to
2640    *     zero, `height` is treated as a 26.6 fractional **pixel** value,
2641    *     which gets internally rounded to an integer.
2642    *
2643    * @note:
2644    *   If `width` is zero, the horizontal scaling value is set equal to the
2645    *   vertical scaling value, and vice versa.
2646    *
2647    *   If `type` is `FT_SIZE_REQUEST_TYPE_SCALES`, `width` and `height` are
2648    *   interpreted directly as 16.16 fractional scaling values, without any
2649    *   further modification, and both `horiResolution` and `vertResolution`
2650    *   are ignored.
2651    */
2652   typedef struct  FT_Size_RequestRec_
2653   {
2654     FT_Size_Request_Type  type;
2655     FT_Long               width;
2656     FT_Long               height;
2657     FT_UInt               horiResolution;
2658     FT_UInt               vertResolution;
2659 
2660   } FT_Size_RequestRec;
2661 
2662 
2663   /**************************************************************************
2664    *
2665    * @struct:
2666    *   FT_Size_Request
2667    *
2668    * @description:
2669    *   A handle to a size request structure.
2670    */
2671   typedef struct FT_Size_RequestRec_  *FT_Size_Request;
2672 
2673 
2674   /**************************************************************************
2675    *
2676    * @function:
2677    *   FT_Request_Size
2678    *
2679    * @description:
2680    *   Resize the scale of the active @FT_Size object in a face.
2681    *
2682    * @inout:
2683    *   face ::
2684    *     A handle to a target face object.
2685    *
2686    * @input:
2687    *   req ::
2688    *     A pointer to a @FT_Size_RequestRec.
2689    *
2690    * @return:
2691    *   FreeType error code.  0~means success.
2692    *
2693    * @note:
2694    *   Although drivers may select the bitmap strike matching the request,
2695    *   you should not rely on this if you intend to select a particular
2696    *   bitmap strike.  Use @FT_Select_Size instead in that case.
2697    *
2698    *   The relation between the requested size and the resulting glyph size
2699    *   is dependent entirely on how the size is defined in the source face.
2700    *   The font designer chooses the final size of each glyph relative to
2701    *   this size.  For more information refer to
2702    *   'https://www.freetype.org/freetype2/docs/glyphs/glyphs-2.html'.
2703    *
2704    *   Contrary to @FT_Set_Char_Size, this function doesn't have special code
2705    *   to normalize zero-valued widths, heights, or resolutions (which lead
2706    *   to errors in most cases).
2707    *
2708    *   Don't use this function if you are using the FreeType cache API.
2709    */
2710   FT_EXPORT( FT_Error )
2711   FT_Request_Size( FT_Face          face,
2712                    FT_Size_Request  req );
2713 
2714 
2715   /**************************************************************************
2716    *
2717    * @function:
2718    *   FT_Set_Char_Size
2719    *
2720    * @description:
2721    *   Call @FT_Request_Size to request the nominal size (in points).
2722    *
2723    * @inout:
2724    *   face ::
2725    *     A handle to a target face object.
2726    *
2727    * @input:
2728    *   char_width ::
2729    *     The nominal width, in 26.6 fractional points.
2730    *
2731    *   char_height ::
2732    *     The nominal height, in 26.6 fractional points.
2733    *
2734    *   horz_resolution ::
2735    *     The horizontal resolution in dpi.
2736    *
2737    *   vert_resolution ::
2738    *     The vertical resolution in dpi.
2739    *
2740    * @return:
2741    *   FreeType error code.  0~means success.
2742    *
2743    * @note:
2744    *   While this function allows fractional points as input values, the
2745    *   resulting ppem value for the given resolution is always rounded to the
2746    *   nearest integer.
2747    *
2748    *   If either the character width or height is zero, it is set equal to
2749    *   the other value.
2750    *
2751    *   If either the horizontal or vertical resolution is zero, it is set
2752    *   equal to the other value.
2753    *
2754    *   A character width or height smaller than 1pt is set to 1pt; if both
2755    *   resolution values are zero, they are set to 72dpi.
2756    *
2757    *   Don't use this function if you are using the FreeType cache API.
2758    */
2759   FT_EXPORT( FT_Error )
2760   FT_Set_Char_Size( FT_Face     face,
2761                     FT_F26Dot6  char_width,
2762                     FT_F26Dot6  char_height,
2763                     FT_UInt     horz_resolution,
2764                     FT_UInt     vert_resolution );
2765 
2766 
2767   /**************************************************************************
2768    *
2769    * @function:
2770    *   FT_Set_Pixel_Sizes
2771    *
2772    * @description:
2773    *   Call @FT_Request_Size to request the nominal size (in pixels).
2774    *
2775    * @inout:
2776    *   face ::
2777    *     A handle to the target face object.
2778    *
2779    * @input:
2780    *   pixel_width ::
2781    *     The nominal width, in pixels.
2782    *
2783    *   pixel_height ::
2784    *     The nominal height, in pixels.
2785    *
2786    * @return:
2787    *   FreeType error code.  0~means success.
2788    *
2789    * @note:
2790    *   You should not rely on the resulting glyphs matching or being
2791    *   constrained to this pixel size.  Refer to @FT_Request_Size to
2792    *   understand how requested sizes relate to actual sizes.
2793    *
2794    *   Don't use this function if you are using the FreeType cache API.
2795    */
2796   FT_EXPORT( FT_Error )
2797   FT_Set_Pixel_Sizes( FT_Face  face,
2798                       FT_UInt  pixel_width,
2799                       FT_UInt  pixel_height );
2800 
2801 
2802   /**************************************************************************
2803    *
2804    * @function:
2805    *   FT_Load_Glyph
2806    *
2807    * @description:
2808    *   Load a glyph into the glyph slot of a face object.
2809    *
2810    * @inout:
2811    *   face ::
2812    *     A handle to the target face object where the glyph is loaded.
2813    *
2814    * @input:
2815    *   glyph_index ::
2816    *     The index of the glyph in the font file.  For CID-keyed fonts
2817    *     (either in PS or in CFF format) this argument specifies the CID
2818    *     value.
2819    *
2820    *   load_flags ::
2821    *     A flag indicating what to load for this glyph.  The @FT_LOAD_XXX
2822    *     constants can be used to control the glyph loading process (e.g.,
2823    *     whether the outline should be scaled, whether to load bitmaps or
2824    *     not, whether to hint the outline, etc).
2825    *
2826    * @return:
2827    *   FreeType error code.  0~means success.
2828    *
2829    * @note:
2830    *   The loaded glyph may be transformed.  See @FT_Set_Transform for the
2831    *   details.
2832    *
2833    *   For subsetted CID-keyed fonts, `FT_Err_Invalid_Argument` is returned
2834    *   for invalid CID values (this is, for CID values that don't have a
2835    *   corresponding glyph in the font).  See the discussion of the
2836    *   @FT_FACE_FLAG_CID_KEYED flag for more details.
2837    *
2838    *   If you receive `FT_Err_Glyph_Too_Big`, try getting the glyph outline
2839    *   at EM size, then scale it manually and fill it as a graphics
2840    *   operation.
2841    */
2842   FT_EXPORT( FT_Error )
2843   FT_Load_Glyph( FT_Face   face,
2844                  FT_UInt   glyph_index,
2845                  FT_Int32  load_flags );
2846 
2847 
2848   /**************************************************************************
2849    *
2850    * @function:
2851    *   FT_Load_Char
2852    *
2853    * @description:
2854    *   Load a glyph into the glyph slot of a face object, accessed by its
2855    *   character code.
2856    *
2857    * @inout:
2858    *   face ::
2859    *     A handle to a target face object where the glyph is loaded.
2860    *
2861    * @input:
2862    *   char_code ::
2863    *     The glyph's character code, according to the current charmap used in
2864    *     the face.
2865    *
2866    *   load_flags ::
2867    *     A flag indicating what to load for this glyph.  The @FT_LOAD_XXX
2868    *     constants can be used to control the glyph loading process (e.g.,
2869    *     whether the outline should be scaled, whether to load bitmaps or
2870    *     not, whether to hint the outline, etc).
2871    *
2872    * @return:
2873    *   FreeType error code.  0~means success.
2874    *
2875    * @note:
2876    *   This function simply calls @FT_Get_Char_Index and @FT_Load_Glyph.
2877    *
2878    *   Many fonts contain glyphs that can't be loaded by this function since
2879    *   its glyph indices are not listed in any of the font's charmaps.
2880    *
2881    *   If no active cmap is set up (i.e., `face->charmap` is zero), the call
2882    *   to @FT_Get_Char_Index is omitted, and the function behaves identically
2883    *   to @FT_Load_Glyph.
2884    */
2885   FT_EXPORT( FT_Error )
2886   FT_Load_Char( FT_Face   face,
2887                 FT_ULong  char_code,
2888                 FT_Int32  load_flags );
2889 
2890 
2891   /**************************************************************************
2892    *
2893    * @enum:
2894    *   FT_LOAD_XXX
2895    *
2896    * @description:
2897    *   A list of bit field constants for @FT_Load_Glyph to indicate what kind
2898    *   of operations to perform during glyph loading.
2899    *
2900    * @values:
2901    *   FT_LOAD_DEFAULT ::
2902    *     Corresponding to~0, this value is used as the default glyph load
2903    *     operation.  In this case, the following happens:
2904    *
2905    *     1. FreeType looks for a bitmap for the glyph corresponding to the
2906    *     face's current size.  If one is found, the function returns.  The
2907    *     bitmap data can be accessed from the glyph slot (see note below).
2908    *
2909    *     2. If no embedded bitmap is searched for or found, FreeType looks
2910    *     for a scalable outline.  If one is found, it is loaded from the font
2911    *     file, scaled to device pixels, then 'hinted' to the pixel grid in
2912    *     order to optimize it.  The outline data can be accessed from the
2913    *     glyph slot (see note below).
2914    *
2915    *     Note that by default the glyph loader doesn't render outlines into
2916    *     bitmaps.  The following flags are used to modify this default
2917    *     behaviour to more specific and useful cases.
2918    *
2919    *   FT_LOAD_NO_SCALE ::
2920    *     Don't scale the loaded outline glyph but keep it in font units.
2921    *
2922    *     This flag implies @FT_LOAD_NO_HINTING and @FT_LOAD_NO_BITMAP, and
2923    *     unsets @FT_LOAD_RENDER.
2924    *
2925    *     If the font is 'tricky' (see @FT_FACE_FLAG_TRICKY for more), using
2926    *     `FT_LOAD_NO_SCALE` usually yields meaningless outlines because the
2927    *     subglyphs must be scaled and positioned with hinting instructions.
2928    *     This can be solved by loading the font without `FT_LOAD_NO_SCALE`
2929    *     and setting the character size to `font->units_per_EM`.
2930    *
2931    *   FT_LOAD_NO_HINTING ::
2932    *     Disable hinting.  This generally generates 'blurrier' bitmap glyphs
2933    *     when the glyph are rendered in any of the anti-aliased modes.  See
2934    *     also the note below.
2935    *
2936    *     This flag is implied by @FT_LOAD_NO_SCALE.
2937    *
2938    *   FT_LOAD_RENDER ::
2939    *     Call @FT_Render_Glyph after the glyph is loaded.  By default, the
2940    *     glyph is rendered in @FT_RENDER_MODE_NORMAL mode.  This can be
2941    *     overridden by @FT_LOAD_TARGET_XXX or @FT_LOAD_MONOCHROME.
2942    *
2943    *     This flag is unset by @FT_LOAD_NO_SCALE.
2944    *
2945    *   FT_LOAD_NO_BITMAP ::
2946    *     Ignore bitmap strikes when loading.  Bitmap-only fonts ignore this
2947    *     flag.
2948    *
2949    *     @FT_LOAD_NO_SCALE always sets this flag.
2950    *
2951    *   FT_LOAD_VERTICAL_LAYOUT ::
2952    *     Load the glyph for vertical text layout.  In particular, the
2953    *     `advance` value in the @FT_GlyphSlotRec structure is set to the
2954    *     `vertAdvance` value of the `metrics` field.
2955    *
2956    *     In case @FT_HAS_VERTICAL doesn't return true, you shouldn't use this
2957    *     flag currently.  Reason is that in this case vertical metrics get
2958    *     synthesized, and those values are not always consistent across
2959    *     various font formats.
2960    *
2961    *   FT_LOAD_FORCE_AUTOHINT ::
2962    *     Prefer the auto-hinter over the font's native hinter.  See also the
2963    *     note below.
2964    *
2965    *   FT_LOAD_PEDANTIC ::
2966    *     Make the font driver perform pedantic verifications during glyph
2967    *     loading and hinting.  This is mostly used to detect broken glyphs in
2968    *     fonts.  By default, FreeType tries to handle broken fonts also.
2969    *
2970    *     In particular, errors from the TrueType bytecode engine are not
2971    *     passed to the application if this flag is not set; this might result
2972    *     in partially hinted or distorted glyphs in case a glyph's bytecode
2973    *     is buggy.
2974    *
2975    *   FT_LOAD_NO_RECURSE ::
2976    *     Don't load composite glyphs recursively.  Instead, the font driver
2977    *     fills the `num_subglyph` and `subglyphs` values of the glyph slot;
2978    *     it also sets `glyph->format` to @FT_GLYPH_FORMAT_COMPOSITE.  The
2979    *     description of subglyphs can then be accessed with
2980    *     @FT_Get_SubGlyph_Info.
2981    *
2982    *     Don't use this flag for retrieving metrics information since some
2983    *     font drivers only return rudimentary data.
2984    *
2985    *     This flag implies @FT_LOAD_NO_SCALE and @FT_LOAD_IGNORE_TRANSFORM.
2986    *
2987    *   FT_LOAD_IGNORE_TRANSFORM ::
2988    *     Ignore the transform matrix set by @FT_Set_Transform.
2989    *
2990    *   FT_LOAD_MONOCHROME ::
2991    *     This flag is used with @FT_LOAD_RENDER to indicate that you want to
2992    *     render an outline glyph to a 1-bit monochrome bitmap glyph, with
2993    *     8~pixels packed into each byte of the bitmap data.
2994    *
2995    *     Note that this has no effect on the hinting algorithm used.  You
2996    *     should rather use @FT_LOAD_TARGET_MONO so that the
2997    *     monochrome-optimized hinting algorithm is used.
2998    *
2999    *   FT_LOAD_LINEAR_DESIGN ::
3000    *     Keep `linearHoriAdvance` and `linearVertAdvance` fields of
3001    *     @FT_GlyphSlotRec in font units.  See @FT_GlyphSlotRec for details.
3002    *
3003    *   FT_LOAD_NO_AUTOHINT ::
3004    *     Disable the auto-hinter.  See also the note below.
3005    *
3006    *   FT_LOAD_COLOR ::
3007    *     Load colored glyphs.  There are slight differences depending on the
3008    *     font format.
3009    *
3010    *     [Since 2.5] Load embedded color bitmap images.  The resulting color
3011    *     bitmaps, if available, will have the @FT_PIXEL_MODE_BGRA format,
3012    *     with pre-multiplied color channels.  If the flag is not set and
3013    *     color bitmaps are found, they are converted to 256-level gray
3014    *     bitmaps, using the @FT_PIXEL_MODE_GRAY format.
3015    *
3016    *     [Since 2.10, experimental] If the glyph index contains an entry in
3017    *     the face's 'COLR' table with a 'CPAL' palette table (as defined in
3018    *     the OpenType specification), make @FT_Render_Glyph provide a default
3019    *     blending of the color glyph layers associated with the glyph index,
3020    *     using the same bitmap format as embedded color bitmap images.  This
3021    *     is mainly for convenience; for full control of color layers use
3022    *     @FT_Get_Color_Glyph_Layer and FreeType's color functions like
3023    *     @FT_Palette_Select instead of setting @FT_LOAD_COLOR for rendering
3024    *     so that the client application can handle blending by itself.
3025    *
3026    *   FT_LOAD_COMPUTE_METRICS ::
3027    *     [Since 2.6.1] Compute glyph metrics from the glyph data, without the
3028    *     use of bundled metrics tables (for example, the 'hdmx' table in
3029    *     TrueType fonts).  This flag is mainly used by font validating or
3030    *     font editing applications, which need to ignore, verify, or edit
3031    *     those tables.
3032    *
3033    *     Currently, this flag is only implemented for TrueType fonts.
3034    *
3035    *   FT_LOAD_BITMAP_METRICS_ONLY ::
3036    *     [Since 2.7.1] Request loading of the metrics and bitmap image
3037    *     information of a (possibly embedded) bitmap glyph without allocating
3038    *     or copying the bitmap image data itself.  No effect if the target
3039    *     glyph is not a bitmap image.
3040    *
3041    *     This flag unsets @FT_LOAD_RENDER.
3042    *
3043    *   FT_LOAD_CROP_BITMAP ::
3044    *     Ignored.  Deprecated.
3045    *
3046    *   FT_LOAD_IGNORE_GLOBAL_ADVANCE_WIDTH ::
3047    *     Ignored.  Deprecated.
3048    *
3049    * @note:
3050    *   By default, hinting is enabled and the font's native hinter (see
3051    *   @FT_FACE_FLAG_HINTER) is preferred over the auto-hinter.  You can
3052    *   disable hinting by setting @FT_LOAD_NO_HINTING or change the
3053    *   precedence by setting @FT_LOAD_FORCE_AUTOHINT.  You can also set
3054    *   @FT_LOAD_NO_AUTOHINT in case you don't want the auto-hinter to be used
3055    *   at all.
3056    *
3057    *   See the description of @FT_FACE_FLAG_TRICKY for a special exception
3058    *   (affecting only a handful of Asian fonts).
3059    *
3060    *   Besides deciding which hinter to use, you can also decide which
3061    *   hinting algorithm to use.  See @FT_LOAD_TARGET_XXX for details.
3062    *
3063    *   Note that the auto-hinter needs a valid Unicode cmap (either a native
3064    *   one or synthesized by FreeType) for producing correct results.  If a
3065    *   font provides an incorrect mapping (for example, assigning the
3066    *   character code U+005A, LATIN CAPITAL LETTER~Z, to a glyph depicting a
3067    *   mathematical integral sign), the auto-hinter might produce useless
3068    *   results.
3069    *
3070    */
3071 #define FT_LOAD_DEFAULT                      0x0
3072 #define FT_LOAD_NO_SCALE                     ( 1L << 0 )
3073 #define FT_LOAD_NO_HINTING                   ( 1L << 1 )
3074 #define FT_LOAD_RENDER                       ( 1L << 2 )
3075 #define FT_LOAD_NO_BITMAP                    ( 1L << 3 )
3076 #define FT_LOAD_VERTICAL_LAYOUT              ( 1L << 4 )
3077 #define FT_LOAD_FORCE_AUTOHINT               ( 1L << 5 )
3078 #define FT_LOAD_CROP_BITMAP                  ( 1L << 6 )
3079 #define FT_LOAD_PEDANTIC                     ( 1L << 7 )
3080 #define FT_LOAD_IGNORE_GLOBAL_ADVANCE_WIDTH  ( 1L << 9 )
3081 #define FT_LOAD_NO_RECURSE                   ( 1L << 10 )
3082 #define FT_LOAD_IGNORE_TRANSFORM             ( 1L << 11 )
3083 #define FT_LOAD_MONOCHROME                   ( 1L << 12 )
3084 #define FT_LOAD_LINEAR_DESIGN                ( 1L << 13 )
3085 #define FT_LOAD_NO_AUTOHINT                  ( 1L << 15 )
3086   /* Bits 16-19 are used by `FT_LOAD_TARGET_` */
3087 #define FT_LOAD_COLOR                        ( 1L << 20 )
3088 #define FT_LOAD_COMPUTE_METRICS              ( 1L << 21 )
3089 #define FT_LOAD_BITMAP_METRICS_ONLY          ( 1L << 22 )
3090 
3091   /* */
3092 
3093   /* used internally only by certain font drivers */
3094 #define FT_LOAD_ADVANCE_ONLY                 ( 1L << 8 )
3095 #define FT_LOAD_SBITS_ONLY                   ( 1L << 14 )
3096 
3097 
3098   /**************************************************************************
3099    *
3100    * @enum:
3101    *   FT_LOAD_TARGET_XXX
3102    *
3103    * @description:
3104    *   A list of values to select a specific hinting algorithm for the
3105    *   hinter.  You should OR one of these values to your `load_flags` when
3106    *   calling @FT_Load_Glyph.
3107    *
3108    *   Note that a font's native hinters may ignore the hinting algorithm you
3109    *   have specified (e.g., the TrueType bytecode interpreter).  You can set
3110    *   @FT_LOAD_FORCE_AUTOHINT to ensure that the auto-hinter is used.
3111    *
3112    * @values:
3113    *   FT_LOAD_TARGET_NORMAL ::
3114    *     The default hinting algorithm, optimized for standard gray-level
3115    *     rendering.  For monochrome output, use @FT_LOAD_TARGET_MONO instead.
3116    *
3117    *   FT_LOAD_TARGET_LIGHT ::
3118    *     A lighter hinting algorithm for gray-level modes.  Many generated
3119    *     glyphs are fuzzier but better resemble their original shape.  This
3120    *     is achieved by snapping glyphs to the pixel grid only vertically
3121    *     (Y-axis), as is done by FreeType's new CFF engine or Microsoft's
3122    *     ClearType font renderer.  This preserves inter-glyph spacing in
3123    *     horizontal text.  The snapping is done either by the native font
3124    *     driver, if the driver itself and the font support it, or by the
3125    *     auto-hinter.
3126    *
3127    *     Advance widths are rounded to integer values; however, using the
3128    *     `lsb_delta` and `rsb_delta` fields of @FT_GlyphSlotRec, it is
3129    *     possible to get fractional advance widths for subpixel positioning
3130    *     (which is recommended to use).
3131    *
3132    *     If configuration option `AF_CONFIG_OPTION_TT_SIZE_METRICS` is
3133    *     active, TrueType-like metrics are used to make this mode behave
3134    *     similarly as in unpatched FreeType versions between 2.4.6 and 2.7.1
3135    *     (inclusive).
3136    *
3137    *   FT_LOAD_TARGET_MONO ::
3138    *     Strong hinting algorithm that should only be used for monochrome
3139    *     output.  The result is probably unpleasant if the glyph is rendered
3140    *     in non-monochrome modes.
3141    *
3142    *     Note that for outline fonts only the TrueType font driver has proper
3143    *     monochrome hinting support, provided the TTFs contain hints for B/W
3144    *     rendering (which most fonts no longer provide).  If these conditions
3145    *     are not met it is very likely that you get ugly results at smaller
3146    *     sizes.
3147    *
3148    *   FT_LOAD_TARGET_LCD ::
3149    *     A variant of @FT_LOAD_TARGET_LIGHT optimized for horizontally
3150    *     decimated LCD displays.
3151    *
3152    *   FT_LOAD_TARGET_LCD_V ::
3153    *     A variant of @FT_LOAD_TARGET_NORMAL optimized for vertically
3154    *     decimated LCD displays.
3155    *
3156    * @note:
3157    *   You should use only _one_ of the `FT_LOAD_TARGET_XXX` values in your
3158    *   `load_flags`.  They can't be ORed.
3159    *
3160    *   If @FT_LOAD_RENDER is also set, the glyph is rendered in the
3161    *   corresponding mode (i.e., the mode that matches the used algorithm
3162    *   best).  An exception is `FT_LOAD_TARGET_MONO` since it implies
3163    *   @FT_LOAD_MONOCHROME.
3164    *
3165    *   You can use a hinting algorithm that doesn't correspond to the same
3166    *   rendering mode.  As an example, it is possible to use the 'light'
3167    *   hinting algorithm and have the results rendered in horizontal LCD
3168    *   pixel mode, with code like
3169    *
3170    *   ```
3171    *     FT_Load_Glyph( face, glyph_index,
3172    *                    load_flags | FT_LOAD_TARGET_LIGHT );
3173    *
3174    *     FT_Render_Glyph( face->glyph, FT_RENDER_MODE_LCD );
3175    *   ```
3176    *
3177    *   In general, you should stick with one rendering mode.  For example,
3178    *   switching between @FT_LOAD_TARGET_NORMAL and @FT_LOAD_TARGET_MONO
3179    *   enforces a lot of recomputation for TrueType fonts, which is slow.
3180    *   Another reason is caching: Selecting a different mode usually causes
3181    *   changes in both the outlines and the rasterized bitmaps; it is thus
3182    *   necessary to empty the cache after a mode switch to avoid false hits.
3183    *
3184    */
3185 #define FT_LOAD_TARGET_( x )   ( FT_STATIC_CAST( FT_Int32, (x) & 15 ) << 16 )
3186 
3187 #define FT_LOAD_TARGET_NORMAL  FT_LOAD_TARGET_( FT_RENDER_MODE_NORMAL )
3188 #define FT_LOAD_TARGET_LIGHT   FT_LOAD_TARGET_( FT_RENDER_MODE_LIGHT  )
3189 #define FT_LOAD_TARGET_MONO    FT_LOAD_TARGET_( FT_RENDER_MODE_MONO   )
3190 #define FT_LOAD_TARGET_LCD     FT_LOAD_TARGET_( FT_RENDER_MODE_LCD    )
3191 #define FT_LOAD_TARGET_LCD_V   FT_LOAD_TARGET_( FT_RENDER_MODE_LCD_V  )
3192 
3193 
3194   /**************************************************************************
3195    *
3196    * @macro:
3197    *   FT_LOAD_TARGET_MODE
3198    *
3199    * @description:
3200    *   Return the @FT_Render_Mode corresponding to a given
3201    *   @FT_LOAD_TARGET_XXX value.
3202    *
3203    */
3204 #define FT_LOAD_TARGET_MODE( x )                               \
3205           FT_STATIC_CAST( FT_Render_Mode, ( (x) >> 16 ) & 15 )
3206 
3207 
3208   /**************************************************************************
3209    *
3210    * @function:
3211    *   FT_Set_Transform
3212    *
3213    * @description:
3214    *   Set the transformation that is applied to glyph images when they are
3215    *   loaded into a glyph slot through @FT_Load_Glyph.
3216    *
3217    * @inout:
3218    *   face ::
3219    *     A handle to the source face object.
3220    *
3221    * @input:
3222    *   matrix ::
3223    *     A pointer to the transformation's 2x2 matrix.  Use `NULL` for the
3224    *     identity matrix.
3225    *   delta ::
3226    *     A pointer to the translation vector.  Use `NULL` for the null
3227    *     vector.
3228    *
3229    * @note:
3230    *   This function is provided as a convenience, but keep in mind that
3231    *   @FT_Matrix coefficients are only 16.16 fixed-point values, which can
3232    *   limit the accuracy of the results.  Using floating-point computations
3233    *   to perform the transform directly in client code instead will always
3234    *   yield better numbers.
3235    *
3236    *   The transformation is only applied to scalable image formats after the
3237    *   glyph has been loaded.  It means that hinting is unaltered by the
3238    *   transformation and is performed on the character size given in the
3239    *   last call to @FT_Set_Char_Size or @FT_Set_Pixel_Sizes.
3240    *
3241    *   Note that this also transforms the `face.glyph.advance` field, but
3242    *   **not** the values in `face.glyph.metrics`.
3243    */
3244   FT_EXPORT( void )
3245   FT_Set_Transform( FT_Face     face,
3246                     FT_Matrix*  matrix,
3247                     FT_Vector*  delta );
3248 
3249 
3250   /**************************************************************************
3251    *
3252    * @function:
3253    *   FT_Get_Transform
3254    *
3255    * @description:
3256    *   Return the transformation that is applied to glyph images when they
3257    *   are loaded into a glyph slot through @FT_Load_Glyph.  See
3258    *   @FT_Set_Transform for more details.
3259    *
3260    * @input:
3261    *   face ::
3262    *     A handle to the source face object.
3263    *
3264    * @output:
3265    *   matrix ::
3266    *     A pointer to a transformation's 2x2 matrix.  Set this to NULL if you
3267    *     are not interested in the value.
3268    *
3269    *   delta ::
3270    *     A pointer a translation vector.  Set this to NULL if you are not
3271    *     interested in the value.
3272    *
3273    * @since:
3274    *   2.11
3275    *
3276    */
3277   FT_EXPORT( void )
3278   FT_Get_Transform( FT_Face     face,
3279                     FT_Matrix*  matrix,
3280                     FT_Vector*  delta );
3281 
3282 
3283   /**************************************************************************
3284    *
3285    * @enum:
3286    *   FT_Render_Mode
3287    *
3288    * @description:
3289    *   Render modes supported by FreeType~2.  Each mode corresponds to a
3290    *   specific type of scanline conversion performed on the outline.
3291    *
3292    *   For bitmap fonts and embedded bitmaps the `bitmap->pixel_mode` field
3293    *   in the @FT_GlyphSlotRec structure gives the format of the returned
3294    *   bitmap.
3295    *
3296    *   All modes except @FT_RENDER_MODE_MONO use 256 levels of opacity,
3297    *   indicating pixel coverage.  Use linear alpha blending and gamma
3298    *   correction to correctly render non-monochrome glyph bitmaps onto a
3299    *   surface; see @FT_Render_Glyph.
3300    *
3301    *   The @FT_RENDER_MODE_SDF is a special render mode that uses up to 256
3302    *   distance values, indicating the signed distance from the grid position
3303    *   to the nearest outline.
3304    *
3305    * @values:
3306    *   FT_RENDER_MODE_NORMAL ::
3307    *     Default render mode; it corresponds to 8-bit anti-aliased bitmaps.
3308    *
3309    *   FT_RENDER_MODE_LIGHT ::
3310    *     This is equivalent to @FT_RENDER_MODE_NORMAL.  It is only defined as
3311    *     a separate value because render modes are also used indirectly to
3312    *     define hinting algorithm selectors.  See @FT_LOAD_TARGET_XXX for
3313    *     details.
3314    *
3315    *   FT_RENDER_MODE_MONO ::
3316    *     This mode corresponds to 1-bit bitmaps (with 2~levels of opacity).
3317    *
3318    *   FT_RENDER_MODE_LCD ::
3319    *     This mode corresponds to horizontal RGB and BGR subpixel displays
3320    *     like LCD screens.  It produces 8-bit bitmaps that are 3~times the
3321    *     width of the original glyph outline in pixels, and which use the
3322    *     @FT_PIXEL_MODE_LCD mode.
3323    *
3324    *   FT_RENDER_MODE_LCD_V ::
3325    *     This mode corresponds to vertical RGB and BGR subpixel displays
3326    *     (like PDA screens, rotated LCD displays, etc.).  It produces 8-bit
3327    *     bitmaps that are 3~times the height of the original glyph outline in
3328    *     pixels and use the @FT_PIXEL_MODE_LCD_V mode.
3329    *
3330    *   FT_RENDER_MODE_SDF ::
3331    *     This mode corresponds to 8-bit, single-channel signed distance field
3332    *     (SDF) bitmaps.  Each pixel in the SDF grid is the value from the
3333    *     pixel's position to the nearest glyph's outline.  The distances are
3334    *     calculated from the center of the pixel and are positive if they are
3335    *     filled by the outline (i.e., inside the outline) and negative
3336    *     otherwise.  Check the note below on how to convert the output values
3337    *     to usable data.
3338    *
3339    * @note:
3340    *   The selected render mode only affects vector glyphs of a font.
3341    *   Embedded bitmaps often have a different pixel mode like
3342    *   @FT_PIXEL_MODE_MONO.  You can use @FT_Bitmap_Convert to transform them
3343    *   into 8-bit pixmaps.
3344    *
3345    *   For @FT_RENDER_MODE_SDF the output bitmap buffer contains normalized
3346    *   distances that are packed into unsigned 8-bit values.  To get pixel
3347    *   values in floating point representation use the following pseudo-C
3348    *   code for the conversion.
3349    *
3350    *   ```
3351    *   // Load glyph and render using FT_RENDER_MODE_SDF,
3352    *   // then use the output buffer as follows.
3353    *
3354    *   ...
3355    *   FT_Byte  buffer = glyph->bitmap->buffer;
3356    *
3357    *
3358    *   for pixel in buffer
3359    *   {
3360    *     // `sd` is the signed distance and `spread` is the current spread;
3361    *     // the default spread is 2 and can be changed.
3362    *
3363    *     float  sd = (float)pixel - 128.0f;
3364    *
3365    *
3366    *     // Convert to pixel values.
3367    *     sd = ( sd / 128.0f ) * spread;
3368    *
3369    *     // Store `sd` in a buffer or use as required.
3370    *   }
3371    *
3372    *   ```
3373    */
3374   typedef enum  FT_Render_Mode_
3375   {
3376     FT_RENDER_MODE_NORMAL = 0,
3377     FT_RENDER_MODE_LIGHT,
3378     FT_RENDER_MODE_MONO,
3379     FT_RENDER_MODE_LCD,
3380     FT_RENDER_MODE_LCD_V,
3381     FT_RENDER_MODE_SDF,
3382 
3383     FT_RENDER_MODE_MAX
3384 
3385   } FT_Render_Mode;
3386 
3387 
3388   /* these constants are deprecated; use the corresponding */
3389   /* `FT_Render_Mode` values instead                       */
3390 #define ft_render_mode_normal  FT_RENDER_MODE_NORMAL
3391 #define ft_render_mode_mono    FT_RENDER_MODE_MONO
3392 
3393 
3394   /**************************************************************************
3395    *
3396    * @function:
3397    *   FT_Render_Glyph
3398    *
3399    * @description:
3400    *   Convert a given glyph image to a bitmap.  It does so by inspecting the
3401    *   glyph image format, finding the relevant renderer, and invoking it.
3402    *
3403    * @inout:
3404    *   slot ::
3405    *     A handle to the glyph slot containing the image to convert.
3406    *
3407    * @input:
3408    *   render_mode ::
3409    *     The render mode used to render the glyph image into a bitmap.  See
3410    *     @FT_Render_Mode for a list of possible values.
3411    *
3412    *     If @FT_RENDER_MODE_NORMAL is used, a previous call of @FT_Load_Glyph
3413    *     with flag @FT_LOAD_COLOR makes FT_Render_Glyph provide a default
3414    *     blending of colored glyph layers associated with the current glyph
3415    *     slot (provided the font contains such layers) instead of rendering
3416    *     the glyph slot's outline.  This is an experimental feature; see
3417    *     @FT_LOAD_COLOR for more information.
3418    *
3419    * @return:
3420    *   FreeType error code.  0~means success.
3421    *
3422    * @note:
3423    *   To get meaningful results, font scaling values must be set with
3424    *   functions like @FT_Set_Char_Size before calling `FT_Render_Glyph`.
3425    *
3426    *   When FreeType outputs a bitmap of a glyph, it really outputs an alpha
3427    *   coverage map.  If a pixel is completely covered by a filled-in
3428    *   outline, the bitmap contains 0xFF at that pixel, meaning that
3429    *   0xFF/0xFF fraction of that pixel is covered, meaning the pixel is 100%
3430    *   black (or 0% bright).  If a pixel is only 50% covered (value 0x80),
3431    *   the pixel is made 50% black (50% bright or a middle shade of grey).
3432    *   0% covered means 0% black (100% bright or white).
3433    *
3434    *   On high-DPI screens like on smartphones and tablets, the pixels are so
3435    *   small that their chance of being completely covered and therefore
3436    *   completely black are fairly good.  On the low-DPI screens, however,
3437    *   the situation is different.  The pixels are too large for most of the
3438    *   details of a glyph and shades of gray are the norm rather than the
3439    *   exception.
3440    *
3441    *   This is relevant because all our screens have a second problem: they
3442    *   are not linear.  1~+~1 is not~2.  Twice the value does not result in
3443    *   twice the brightness.  When a pixel is only 50% covered, the coverage
3444    *   map says 50% black, and this translates to a pixel value of 128 when
3445    *   you use 8~bits per channel (0-255).  However, this does not translate
3446    *   to 50% brightness for that pixel on our sRGB and gamma~2.2 screens.
3447    *   Due to their non-linearity, they dwell longer in the darks and only a
3448    *   pixel value of about 186 results in 50% brightness -- 128 ends up too
3449    *   dark on both bright and dark backgrounds.  The net result is that dark
3450    *   text looks burnt-out, pixely and blotchy on bright background, bright
3451    *   text too frail on dark backgrounds, and colored text on colored
3452    *   background (for example, red on green) seems to have dark halos or
3453    *   'dirt' around it.  The situation is especially ugly for diagonal stems
3454    *   like in 'w' glyph shapes where the quality of FreeType's anti-aliasing
3455    *   depends on the correct display of grays.  On high-DPI screens where
3456    *   smaller, fully black pixels reign supreme, this doesn't matter, but on
3457    *   our low-DPI screens with all the gray shades, it does.  0% and 100%
3458    *   brightness are the same things in linear and non-linear space, just
3459    *   all the shades in-between aren't.
3460    *
3461    *   The blending function for placing text over a background is
3462    *
3463    *   ```
3464    *     dst = alpha * src + (1 - alpha) * dst    ,
3465    *   ```
3466    *
3467    *   which is known as the OVER operator.
3468    *
3469    *   To correctly composite an anti-aliased pixel of a glyph onto a
3470    *   surface,
3471    *
3472    *   1. take the foreground and background colors (e.g., in sRGB space)
3473    *      and apply gamma to get them in a linear space,
3474    *
3475    *   2. use OVER to blend the two linear colors using the glyph pixel
3476    *      as the alpha value (remember, the glyph bitmap is an alpha coverage
3477    *      bitmap), and
3478    *
3479    *   3. apply inverse gamma to the blended pixel and write it back to
3480    *      the image.
3481    *
3482    *   Internal testing at Adobe found that a target inverse gamma of~1.8 for
3483    *   step~3 gives good results across a wide range of displays with an sRGB
3484    *   gamma curve or a similar one.
3485    *
3486    *   This process can cost performance.  There is an approximation that
3487    *   does not need to know about the background color; see
3488    *   https://bel.fi/alankila/lcd/ and
3489    *   https://bel.fi/alankila/lcd/alpcor.html for details.
3490    *
3491    *   **ATTENTION**: Linear blending is even more important when dealing
3492    *   with subpixel-rendered glyphs to prevent color-fringing!  A
3493    *   subpixel-rendered glyph must first be filtered with a filter that
3494    *   gives equal weight to the three color primaries and does not exceed a
3495    *   sum of 0x100, see section @lcd_rendering.  Then the only difference to
3496    *   gray linear blending is that subpixel-rendered linear blending is done
3497    *   3~times per pixel: red foreground subpixel to red background subpixel
3498    *   and so on for green and blue.
3499    */
3500   FT_EXPORT( FT_Error )
3501   FT_Render_Glyph( FT_GlyphSlot    slot,
3502                    FT_Render_Mode  render_mode );
3503 
3504 
3505   /**************************************************************************
3506    *
3507    * @enum:
3508    *   FT_Kerning_Mode
3509    *
3510    * @description:
3511    *   An enumeration to specify the format of kerning values returned by
3512    *   @FT_Get_Kerning.
3513    *
3514    * @values:
3515    *   FT_KERNING_DEFAULT ::
3516    *     Return grid-fitted kerning distances in 26.6 fractional pixels.
3517    *
3518    *   FT_KERNING_UNFITTED ::
3519    *     Return un-grid-fitted kerning distances in 26.6 fractional pixels.
3520    *
3521    *   FT_KERNING_UNSCALED ::
3522    *     Return the kerning vector in original font units.
3523    *
3524    * @note:
3525    *   `FT_KERNING_DEFAULT` returns full pixel values; it also makes FreeType
3526    *   heuristically scale down kerning distances at small ppem values so
3527    *   that they don't become too big.
3528    *
3529    *   Both `FT_KERNING_DEFAULT` and `FT_KERNING_UNFITTED` use the current
3530    *   horizontal scaling factor (as set e.g. with @FT_Set_Char_Size) to
3531    *   convert font units to pixels.
3532    */
3533   typedef enum  FT_Kerning_Mode_
3534   {
3535     FT_KERNING_DEFAULT = 0,
3536     FT_KERNING_UNFITTED,
3537     FT_KERNING_UNSCALED
3538 
3539   } FT_Kerning_Mode;
3540 
3541 
3542   /* these constants are deprecated; use the corresponding */
3543   /* `FT_Kerning_Mode` values instead                      */
3544 #define ft_kerning_default   FT_KERNING_DEFAULT
3545 #define ft_kerning_unfitted  FT_KERNING_UNFITTED
3546 #define ft_kerning_unscaled  FT_KERNING_UNSCALED
3547 
3548 
3549   /**************************************************************************
3550    *
3551    * @function:
3552    *   FT_Get_Kerning
3553    *
3554    * @description:
3555    *   Return the kerning vector between two glyphs of the same face.
3556    *
3557    * @input:
3558    *   face ::
3559    *     A handle to a source face object.
3560    *
3561    *   left_glyph ::
3562    *     The index of the left glyph in the kern pair.
3563    *
3564    *   right_glyph ::
3565    *     The index of the right glyph in the kern pair.
3566    *
3567    *   kern_mode ::
3568    *     See @FT_Kerning_Mode for more information.  Determines the scale and
3569    *     dimension of the returned kerning vector.
3570    *
3571    * @output:
3572    *   akerning ::
3573    *     The kerning vector.  This is either in font units, fractional pixels
3574    *     (26.6 format), or pixels for scalable formats, and in pixels for
3575    *     fixed-sizes formats.
3576    *
3577    * @return:
3578    *   FreeType error code.  0~means success.
3579    *
3580    * @note:
3581    *   Only horizontal layouts (left-to-right & right-to-left) are supported
3582    *   by this method.  Other layouts, or more sophisticated kernings, are
3583    *   out of the scope of this API function -- they can be implemented
3584    *   through format-specific interfaces.
3585    *
3586    *   Kerning for OpenType fonts implemented in a 'GPOS' table is not
3587    *   supported; use @FT_HAS_KERNING to find out whether a font has data
3588    *   that can be extracted with `FT_Get_Kerning`.
3589    */
3590   FT_EXPORT( FT_Error )
3591   FT_Get_Kerning( FT_Face     face,
3592                   FT_UInt     left_glyph,
3593                   FT_UInt     right_glyph,
3594                   FT_UInt     kern_mode,
3595                   FT_Vector  *akerning );
3596 
3597 
3598   /**************************************************************************
3599    *
3600    * @function:
3601    *   FT_Get_Track_Kerning
3602    *
3603    * @description:
3604    *   Return the track kerning for a given face object at a given size.
3605    *
3606    * @input:
3607    *   face ::
3608    *     A handle to a source face object.
3609    *
3610    *   point_size ::
3611    *     The point size in 16.16 fractional points.
3612    *
3613    *   degree ::
3614    *     The degree of tightness.  Increasingly negative values represent
3615    *     tighter track kerning, while increasingly positive values represent
3616    *     looser track kerning.  Value zero means no track kerning.
3617    *
3618    * @output:
3619    *   akerning ::
3620    *     The kerning in 16.16 fractional points, to be uniformly applied
3621    *     between all glyphs.
3622    *
3623    * @return:
3624    *   FreeType error code.  0~means success.
3625    *
3626    * @note:
3627    *   Currently, only the Type~1 font driver supports track kerning, using
3628    *   data from AFM files (if attached with @FT_Attach_File or
3629    *   @FT_Attach_Stream).
3630    *
3631    *   Only very few AFM files come with track kerning data; please refer to
3632    *   Adobe's AFM specification for more details.
3633    */
3634   FT_EXPORT( FT_Error )
3635   FT_Get_Track_Kerning( FT_Face    face,
3636                         FT_Fixed   point_size,
3637                         FT_Int     degree,
3638                         FT_Fixed*  akerning );
3639 
3640 
3641   /**************************************************************************
3642    *
3643    * @function:
3644    *   FT_Get_Glyph_Name
3645    *
3646    * @description:
3647    *   Retrieve the ASCII name of a given glyph in a face.  This only works
3648    *   for those faces where @FT_HAS_GLYPH_NAMES(face) returns~1.
3649    *
3650    * @input:
3651    *   face ::
3652    *     A handle to a source face object.
3653    *
3654    *   glyph_index ::
3655    *     The glyph index.
3656    *
3657    *   buffer_max ::
3658    *     The maximum number of bytes available in the buffer.
3659    *
3660    * @output:
3661    *   buffer ::
3662    *     A pointer to a target buffer where the name is copied to.
3663    *
3664    * @return:
3665    *   FreeType error code.  0~means success.
3666    *
3667    * @note:
3668    *   An error is returned if the face doesn't provide glyph names or if the
3669    *   glyph index is invalid.  In all cases of failure, the first byte of
3670    *   `buffer` is set to~0 to indicate an empty name.
3671    *
3672    *   The glyph name is truncated to fit within the buffer if it is too
3673    *   long.  The returned string is always zero-terminated.
3674    *
3675    *   Be aware that FreeType reorders glyph indices internally so that glyph
3676    *   index~0 always corresponds to the 'missing glyph' (called '.notdef').
3677    *
3678    *   This function always returns an error if the config macro
3679    *   `FT_CONFIG_OPTION_NO_GLYPH_NAMES` is not defined in `ftoption.h`.
3680    */
3681   FT_EXPORT( FT_Error )
3682   FT_Get_Glyph_Name( FT_Face     face,
3683                      FT_UInt     glyph_index,
3684                      FT_Pointer  buffer,
3685                      FT_UInt     buffer_max );
3686 
3687 
3688   /**************************************************************************
3689    *
3690    * @function:
3691    *   FT_Get_Postscript_Name
3692    *
3693    * @description:
3694    *   Retrieve the ASCII PostScript name of a given face, if available.
3695    *   This only works with PostScript, TrueType, and OpenType fonts.
3696    *
3697    * @input:
3698    *   face ::
3699    *     A handle to the source face object.
3700    *
3701    * @return:
3702    *   A pointer to the face's PostScript name.  `NULL` if unavailable.
3703    *
3704    * @note:
3705    *   The returned pointer is owned by the face and is destroyed with it.
3706    *
3707    *   For variation fonts, this string changes if you select a different
3708    *   instance, and you have to call `FT_Get_PostScript_Name` again to
3709    *   retrieve it.  FreeType follows Adobe TechNote #5902, 'Generating
3710    *   PostScript Names for Fonts Using OpenType Font Variations'.
3711    *
3712    *     https://download.macromedia.com/pub/developer/opentype/tech-notes/5902.AdobePSNameGeneration.html
3713    *
3714    *   [Since 2.9] Special PostScript names for named instances are only
3715    *   returned if the named instance is set with @FT_Set_Named_Instance (and
3716    *   the font has corresponding entries in its 'fvar' table).  If
3717    *   @FT_IS_VARIATION returns true, the algorithmically derived PostScript
3718    *   name is provided, not looking up special entries for named instances.
3719    */
3720   FT_EXPORT( const char* )
3721   FT_Get_Postscript_Name( FT_Face  face );
3722 
3723 
3724   /**************************************************************************
3725    *
3726    * @function:
3727    *   FT_Select_Charmap
3728    *
3729    * @description:
3730    *   Select a given charmap by its encoding tag (as listed in
3731    *   `freetype.h`).
3732    *
3733    * @inout:
3734    *   face ::
3735    *     A handle to the source face object.
3736    *
3737    * @input:
3738    *   encoding ::
3739    *     A handle to the selected encoding.
3740    *
3741    * @return:
3742    *   FreeType error code.  0~means success.
3743    *
3744    * @note:
3745    *   This function returns an error if no charmap in the face corresponds
3746    *   to the encoding queried here.
3747    *
3748    *   Because many fonts contain more than a single cmap for Unicode
3749    *   encoding, this function has some special code to select the one that
3750    *   covers Unicode best ('best' in the sense that a UCS-4 cmap is
3751    *   preferred to a UCS-2 cmap).  It is thus preferable to @FT_Set_Charmap
3752    *   in this case.
3753    */
3754   FT_EXPORT( FT_Error )
3755   FT_Select_Charmap( FT_Face      face,
3756                      FT_Encoding  encoding );
3757 
3758 
3759   /**************************************************************************
3760    *
3761    * @function:
3762    *   FT_Set_Charmap
3763    *
3764    * @description:
3765    *   Select a given charmap for character code to glyph index mapping.
3766    *
3767    * @inout:
3768    *   face ::
3769    *     A handle to the source face object.
3770    *
3771    * @input:
3772    *   charmap ::
3773    *     A handle to the selected charmap.
3774    *
3775    * @return:
3776    *   FreeType error code.  0~means success.
3777    *
3778    * @note:
3779    *   This function returns an error if the charmap is not part of the face
3780    *   (i.e., if it is not listed in the `face->charmaps` table).
3781    *
3782    *   It also fails if an OpenType type~14 charmap is selected (which
3783    *   doesn't map character codes to glyph indices at all).
3784    */
3785   FT_EXPORT( FT_Error )
3786   FT_Set_Charmap( FT_Face     face,
3787                   FT_CharMap  charmap );
3788 
3789 
3790   /**************************************************************************
3791    *
3792    * @function:
3793    *   FT_Get_Charmap_Index
3794    *
3795    * @description:
3796    *   Retrieve index of a given charmap.
3797    *
3798    * @input:
3799    *   charmap ::
3800    *     A handle to a charmap.
3801    *
3802    * @return:
3803    *   The index into the array of character maps within the face to which
3804    *   `charmap` belongs.  If an error occurs, -1 is returned.
3805    *
3806    */
3807   FT_EXPORT( FT_Int )
3808   FT_Get_Charmap_Index( FT_CharMap  charmap );
3809 
3810 
3811   /**************************************************************************
3812    *
3813    * @function:
3814    *   FT_Get_Char_Index
3815    *
3816    * @description:
3817    *   Return the glyph index of a given character code.  This function uses
3818    *   the currently selected charmap to do the mapping.
3819    *
3820    * @input:
3821    *   face ::
3822    *     A handle to the source face object.
3823    *
3824    *   charcode ::
3825    *     The character code.
3826    *
3827    * @return:
3828    *   The glyph index.  0~means 'undefined character code'.
3829    *
3830    * @note:
3831    *   If you use FreeType to manipulate the contents of font files directly,
3832    *   be aware that the glyph index returned by this function doesn't always
3833    *   correspond to the internal indices used within the file.  This is done
3834    *   to ensure that value~0 always corresponds to the 'missing glyph'.  If
3835    *   the first glyph is not named '.notdef', then for Type~1 and Type~42
3836    *   fonts, '.notdef' will be moved into the glyph ID~0 position, and
3837    *   whatever was there will be moved to the position '.notdef' had.  For
3838    *   Type~1 fonts, if there is no '.notdef' glyph at all, then one will be
3839    *   created at index~0 and whatever was there will be moved to the last
3840    *   index -- Type~42 fonts are considered invalid under this condition.
3841    */
3842   FT_EXPORT( FT_UInt )
3843   FT_Get_Char_Index( FT_Face   face,
3844                      FT_ULong  charcode );
3845 
3846 
3847   /**************************************************************************
3848    *
3849    * @function:
3850    *   FT_Get_First_Char
3851    *
3852    * @description:
3853    *   Return the first character code in the current charmap of a given
3854    *   face, together with its corresponding glyph index.
3855    *
3856    * @input:
3857    *   face ::
3858    *     A handle to the source face object.
3859    *
3860    * @output:
3861    *   agindex ::
3862    *     Glyph index of first character code.  0~if charmap is empty.
3863    *
3864    * @return:
3865    *   The charmap's first character code.
3866    *
3867    * @note:
3868    *   You should use this function together with @FT_Get_Next_Char to parse
3869    *   all character codes available in a given charmap.  The code should
3870    *   look like this:
3871    *
3872    *   ```
3873    *     FT_ULong  charcode;
3874    *     FT_UInt   gindex;
3875    *
3876    *
3877    *     charcode = FT_Get_First_Char( face, &gindex );
3878    *     while ( gindex != 0 )
3879    *     {
3880    *       ... do something with (charcode,gindex) pair ...
3881    *
3882    *       charcode = FT_Get_Next_Char( face, charcode, &gindex );
3883    *     }
3884    *   ```
3885    *
3886    *   Be aware that character codes can have values up to 0xFFFFFFFF; this
3887    *   might happen for non-Unicode or malformed cmaps.  However, even with
3888    *   regular Unicode encoding, so-called 'last resort fonts' (using SFNT
3889    *   cmap format 13, see function @FT_Get_CMap_Format) normally have
3890    *   entries for all Unicode characters up to 0x1FFFFF, which can cause *a
3891    *   lot* of iterations.
3892    *
3893    *   Note that `*agindex` is set to~0 if the charmap is empty.  The result
3894    *   itself can be~0 in two cases: if the charmap is empty or if the
3895    *   value~0 is the first valid character code.
3896    */
3897   FT_EXPORT( FT_ULong )
3898   FT_Get_First_Char( FT_Face   face,
3899                      FT_UInt  *agindex );
3900 
3901 
3902   /**************************************************************************
3903    *
3904    * @function:
3905    *   FT_Get_Next_Char
3906    *
3907    * @description:
3908    *   Return the next character code in the current charmap of a given face
3909    *   following the value `char_code`, as well as the corresponding glyph
3910    *   index.
3911    *
3912    * @input:
3913    *   face ::
3914    *     A handle to the source face object.
3915    *
3916    *   char_code ::
3917    *     The starting character code.
3918    *
3919    * @output:
3920    *   agindex ::
3921    *     Glyph index of next character code.  0~if charmap is empty.
3922    *
3923    * @return:
3924    *   The charmap's next character code.
3925    *
3926    * @note:
3927    *   You should use this function with @FT_Get_First_Char to walk over all
3928    *   character codes available in a given charmap.  See the note for that
3929    *   function for a simple code example.
3930    *
3931    *   Note that `*agindex` is set to~0 when there are no more codes in the
3932    *   charmap.
3933    */
3934   FT_EXPORT( FT_ULong )
3935   FT_Get_Next_Char( FT_Face    face,
3936                     FT_ULong   char_code,
3937                     FT_UInt   *agindex );
3938 
3939 
3940   /**************************************************************************
3941    *
3942    * @function:
3943    *   FT_Face_Properties
3944    *
3945    * @description:
3946    *   Set or override certain (library or module-wide) properties on a
3947    *   face-by-face basis.  Useful for finer-grained control and avoiding
3948    *   locks on shared structures (threads can modify their own faces as they
3949    *   see fit).
3950    *
3951    *   Contrary to @FT_Property_Set, this function uses @FT_Parameter so that
3952    *   you can pass multiple properties to the target face in one call.  Note
3953    *   that only a subset of the available properties can be controlled.
3954    *
3955    *   * @FT_PARAM_TAG_STEM_DARKENING (stem darkening, corresponding to the
3956    *     property `no-stem-darkening` provided by the 'autofit', 'cff',
3957    *     'type1', and 't1cid' modules; see @no-stem-darkening).
3958    *
3959    *   * @FT_PARAM_TAG_LCD_FILTER_WEIGHTS (LCD filter weights, corresponding
3960    *     to function @FT_Library_SetLcdFilterWeights).
3961    *
3962    *   * @FT_PARAM_TAG_RANDOM_SEED (seed value for the CFF, Type~1, and CID
3963    *     'random' operator, corresponding to the `random-seed` property
3964    *     provided by the 'cff', 'type1', and 't1cid' modules; see
3965    *     @random-seed).
3966    *
3967    *   Pass `NULL` as `data` in @FT_Parameter for a given tag to reset the
3968    *   option and use the library or module default again.
3969    *
3970    * @input:
3971    *   face ::
3972    *     A handle to the source face object.
3973    *
3974    *   num_properties ::
3975    *     The number of properties that follow.
3976    *
3977    *   properties ::
3978    *     A handle to an @FT_Parameter array with `num_properties` elements.
3979    *
3980    * @return:
3981    *   FreeType error code.  0~means success.
3982    *
3983    * @example:
3984    *   Here is an example that sets three properties.  You must define
3985    *   `FT_CONFIG_OPTION_SUBPIXEL_RENDERING` to make the LCD filter examples
3986    *   work.
3987    *
3988    *   ```
3989    *     FT_Parameter         property1;
3990    *     FT_Bool              darken_stems = 1;
3991    *
3992    *     FT_Parameter         property2;
3993    *     FT_LcdFiveTapFilter  custom_weight =
3994    *                            { 0x11, 0x44, 0x56, 0x44, 0x11 };
3995    *
3996    *     FT_Parameter         property3;
3997    *     FT_Int32             random_seed = 314159265;
3998    *
3999    *     FT_Parameter         properties[3] = { property1,
4000    *                                            property2,
4001    *                                            property3 };
4002    *
4003    *
4004    *     property1.tag  = FT_PARAM_TAG_STEM_DARKENING;
4005    *     property1.data = &darken_stems;
4006    *
4007    *     property2.tag  = FT_PARAM_TAG_LCD_FILTER_WEIGHTS;
4008    *     property2.data = custom_weight;
4009    *
4010    *     property3.tag  = FT_PARAM_TAG_RANDOM_SEED;
4011    *     property3.data = &random_seed;
4012    *
4013    *     FT_Face_Properties( face, 3, properties );
4014    *   ```
4015    *
4016    *   The next example resets a single property to its default value.
4017    *
4018    *   ```
4019    *     FT_Parameter  property;
4020    *
4021    *
4022    *     property.tag  = FT_PARAM_TAG_LCD_FILTER_WEIGHTS;
4023    *     property.data = NULL;
4024    *
4025    *     FT_Face_Properties( face, 1, &property );
4026    *   ```
4027    *
4028    * @since:
4029    *   2.8
4030    *
4031    */
4032   FT_EXPORT( FT_Error )
4033   FT_Face_Properties( FT_Face        face,
4034                       FT_UInt        num_properties,
4035                       FT_Parameter*  properties );
4036 
4037 
4038   /**************************************************************************
4039    *
4040    * @function:
4041    *   FT_Get_Name_Index
4042    *
4043    * @description:
4044    *   Return the glyph index of a given glyph name.
4045    *
4046    * @input:
4047    *   face ::
4048    *     A handle to the source face object.
4049    *
4050    *   glyph_name ::
4051    *     The glyph name.
4052    *
4053    * @return:
4054    *   The glyph index.  0~means 'undefined character code'.
4055    */
4056   FT_EXPORT( FT_UInt )
4057   FT_Get_Name_Index( FT_Face           face,
4058                      const FT_String*  glyph_name );
4059 
4060 
4061   /**************************************************************************
4062    *
4063    * @enum:
4064    *   FT_SUBGLYPH_FLAG_XXX
4065    *
4066    * @description:
4067    *   A list of constants describing subglyphs.  Please refer to the 'glyf'
4068    *   table description in the OpenType specification for the meaning of the
4069    *   various flags (which get synthesized for non-OpenType subglyphs).
4070    *
4071    *     https://docs.microsoft.com/en-us/typography/opentype/spec/glyf#composite-glyph-description
4072    *
4073    * @values:
4074    *   FT_SUBGLYPH_FLAG_ARGS_ARE_WORDS ::
4075    *   FT_SUBGLYPH_FLAG_ARGS_ARE_XY_VALUES ::
4076    *   FT_SUBGLYPH_FLAG_ROUND_XY_TO_GRID ::
4077    *   FT_SUBGLYPH_FLAG_SCALE ::
4078    *   FT_SUBGLYPH_FLAG_XY_SCALE ::
4079    *   FT_SUBGLYPH_FLAG_2X2 ::
4080    *   FT_SUBGLYPH_FLAG_USE_MY_METRICS ::
4081    *
4082    */
4083 #define FT_SUBGLYPH_FLAG_ARGS_ARE_WORDS          1
4084 #define FT_SUBGLYPH_FLAG_ARGS_ARE_XY_VALUES      2
4085 #define FT_SUBGLYPH_FLAG_ROUND_XY_TO_GRID        4
4086 #define FT_SUBGLYPH_FLAG_SCALE                   8
4087 #define FT_SUBGLYPH_FLAG_XY_SCALE             0x40
4088 #define FT_SUBGLYPH_FLAG_2X2                  0x80
4089 #define FT_SUBGLYPH_FLAG_USE_MY_METRICS      0x200
4090 
4091 
4092   /**************************************************************************
4093    *
4094    * @function:
4095    *   FT_Get_SubGlyph_Info
4096    *
4097    * @description:
4098    *   Retrieve a description of a given subglyph.  Only use it if
4099    *   `glyph->format` is @FT_GLYPH_FORMAT_COMPOSITE; an error is returned
4100    *   otherwise.
4101    *
4102    * @input:
4103    *   glyph ::
4104    *     The source glyph slot.
4105    *
4106    *   sub_index ::
4107    *     The index of the subglyph.  Must be less than
4108    *     `glyph->num_subglyphs`.
4109    *
4110    * @output:
4111    *   p_index ::
4112    *     The glyph index of the subglyph.
4113    *
4114    *   p_flags ::
4115    *     The subglyph flags, see @FT_SUBGLYPH_FLAG_XXX.
4116    *
4117    *   p_arg1 ::
4118    *     The subglyph's first argument (if any).
4119    *
4120    *   p_arg2 ::
4121    *     The subglyph's second argument (if any).
4122    *
4123    *   p_transform ::
4124    *     The subglyph transformation (if any).
4125    *
4126    * @return:
4127    *   FreeType error code.  0~means success.
4128    *
4129    * @note:
4130    *   The values of `*p_arg1`, `*p_arg2`, and `*p_transform` must be
4131    *   interpreted depending on the flags returned in `*p_flags`.  See the
4132    *   OpenType specification for details.
4133    *
4134    *     https://docs.microsoft.com/en-us/typography/opentype/spec/glyf#composite-glyph-description
4135    *
4136    */
4137   FT_EXPORT( FT_Error )
4138   FT_Get_SubGlyph_Info( FT_GlyphSlot  glyph,
4139                         FT_UInt       sub_index,
4140                         FT_Int       *p_index,
4141                         FT_UInt      *p_flags,
4142                         FT_Int       *p_arg1,
4143                         FT_Int       *p_arg2,
4144                         FT_Matrix    *p_transform );
4145 
4146 
4147   /**************************************************************************
4148    *
4149    * @section:
4150    *   base_interface
4151    *
4152    */
4153 
4154   /**************************************************************************
4155    *
4156    * @enum:
4157    *   FT_FSTYPE_XXX
4158    *
4159    * @description:
4160    *   A list of bit flags used in the `fsType` field of the OS/2 table in a
4161    *   TrueType or OpenType font and the `FSType` entry in a PostScript font.
4162    *   These bit flags are returned by @FT_Get_FSType_Flags; they inform
4163    *   client applications of embedding and subsetting restrictions
4164    *   associated with a font.
4165    *
4166    *   See
4167    *   https://www.adobe.com/content/dam/Adobe/en/devnet/acrobat/pdfs/FontPolicies.pdf
4168    *   for more details.
4169    *
4170    * @values:
4171    *   FT_FSTYPE_INSTALLABLE_EMBEDDING ::
4172    *     Fonts with no fsType bit set may be embedded and permanently
4173    *     installed on the remote system by an application.
4174    *
4175    *   FT_FSTYPE_RESTRICTED_LICENSE_EMBEDDING ::
4176    *     Fonts that have only this bit set must not be modified, embedded or
4177    *     exchanged in any manner without first obtaining permission of the
4178    *     font software copyright owner.
4179    *
4180    *   FT_FSTYPE_PREVIEW_AND_PRINT_EMBEDDING ::
4181    *     The font may be embedded and temporarily loaded on the remote
4182    *     system.  Documents containing Preview & Print fonts must be opened
4183    *     'read-only'; no edits can be applied to the document.
4184    *
4185    *   FT_FSTYPE_EDITABLE_EMBEDDING ::
4186    *     The font may be embedded but must only be installed temporarily on
4187    *     other systems.  In contrast to Preview & Print fonts, documents
4188    *     containing editable fonts may be opened for reading, editing is
4189    *     permitted, and changes may be saved.
4190    *
4191    *   FT_FSTYPE_NO_SUBSETTING ::
4192    *     The font may not be subsetted prior to embedding.
4193    *
4194    *   FT_FSTYPE_BITMAP_EMBEDDING_ONLY ::
4195    *     Only bitmaps contained in the font may be embedded; no outline data
4196    *     may be embedded.  If there are no bitmaps available in the font,
4197    *     then the font is unembeddable.
4198    *
4199    * @note:
4200    *   The flags are ORed together, thus more than a single value can be
4201    *   returned.
4202    *
4203    *   While the `fsType` flags can indicate that a font may be embedded, a
4204    *   license with the font vendor may be separately required to use the
4205    *   font in this way.
4206    */
4207 #define FT_FSTYPE_INSTALLABLE_EMBEDDING         0x0000
4208 #define FT_FSTYPE_RESTRICTED_LICENSE_EMBEDDING  0x0002
4209 #define FT_FSTYPE_PREVIEW_AND_PRINT_EMBEDDING   0x0004
4210 #define FT_FSTYPE_EDITABLE_EMBEDDING            0x0008
4211 #define FT_FSTYPE_NO_SUBSETTING                 0x0100
4212 #define FT_FSTYPE_BITMAP_EMBEDDING_ONLY         0x0200
4213 
4214 
4215   /**************************************************************************
4216    *
4217    * @function:
4218    *   FT_Get_FSType_Flags
4219    *
4220    * @description:
4221    *   Return the `fsType` flags for a font.
4222    *
4223    * @input:
4224    *   face ::
4225    *     A handle to the source face object.
4226    *
4227    * @return:
4228    *   The `fsType` flags, see @FT_FSTYPE_XXX.
4229    *
4230    * @note:
4231    *   Use this function rather than directly reading the `fs_type` field in
4232    *   the @PS_FontInfoRec structure, which is only guaranteed to return the
4233    *   correct results for Type~1 fonts.
4234    *
4235    * @since:
4236    *   2.3.8
4237    *
4238    */
4239   FT_EXPORT( FT_UShort )
4240   FT_Get_FSType_Flags( FT_Face  face );
4241 
4242 
4243   /**************************************************************************
4244    *
4245    * @section:
4246    *   glyph_variants
4247    *
4248    * @title:
4249    *   Unicode Variation Sequences
4250    *
4251    * @abstract:
4252    *   The FreeType~2 interface to Unicode Variation Sequences (UVS), using
4253    *   the SFNT cmap format~14.
4254    *
4255    * @description:
4256    *   Many characters, especially for CJK scripts, have variant forms.  They
4257    *   are a sort of grey area somewhere between being totally irrelevant and
4258    *   semantically distinct; for this reason, the Unicode consortium decided
4259    *   to introduce Variation Sequences (VS), consisting of a Unicode base
4260    *   character and a variation selector instead of further extending the
4261    *   already huge number of characters.
4262    *
4263    *   Unicode maintains two different sets, namely 'Standardized Variation
4264    *   Sequences' and registered 'Ideographic Variation Sequences' (IVS),
4265    *   collected in the 'Ideographic Variation Database' (IVD).
4266    *
4267    *     https://unicode.org/Public/UCD/latest/ucd/StandardizedVariants.txt
4268    *     https://unicode.org/reports/tr37/ https://unicode.org/ivd/
4269    *
4270    *   To date (January 2017), the character with the most ideographic
4271    *   variations is U+9089, having 32 such IVS.
4272    *
4273    *   Three Mongolian Variation Selectors have the values U+180B-U+180D; 256
4274    *   generic Variation Selectors are encoded in the ranges U+FE00-U+FE0F
4275    *   and U+E0100-U+E01EF.  IVS currently use Variation Selectors from the
4276    *   range U+E0100-U+E01EF only.
4277    *
4278    *   A VS consists of the base character value followed by a single
4279    *   Variation Selector.  For example, to get the first variation of
4280    *   U+9089, you have to write the character sequence `U+9089 U+E0100`.
4281    *
4282    *   Adobe and MS decided to support both standardized and ideographic VS
4283    *   with a new cmap subtable (format~14).  It is an odd subtable because
4284    *   it is not a mapping of input code points to glyphs, but contains lists
4285    *   of all variations supported by the font.
4286    *
4287    *   A variation may be either 'default' or 'non-default' for a given font.
4288    *   A default variation is the one you will get for that code point if you
4289    *   look it up in the standard Unicode cmap.  A non-default variation is a
4290    *   different glyph.
4291    *
4292    */
4293 
4294 
4295   /**************************************************************************
4296    *
4297    * @function:
4298    *   FT_Face_GetCharVariantIndex
4299    *
4300    * @description:
4301    *   Return the glyph index of a given character code as modified by the
4302    *   variation selector.
4303    *
4304    * @input:
4305    *   face ::
4306    *     A handle to the source face object.
4307    *
4308    *   charcode ::
4309    *     The character code point in Unicode.
4310    *
4311    *   variantSelector ::
4312    *     The Unicode code point of the variation selector.
4313    *
4314    * @return:
4315    *   The glyph index.  0~means either 'undefined character code', or
4316    *   'undefined selector code', or 'no variation selector cmap subtable',
4317    *   or 'current CharMap is not Unicode'.
4318    *
4319    * @note:
4320    *   If you use FreeType to manipulate the contents of font files directly,
4321    *   be aware that the glyph index returned by this function doesn't always
4322    *   correspond to the internal indices used within the file.  This is done
4323    *   to ensure that value~0 always corresponds to the 'missing glyph'.
4324    *
4325    *   This function is only meaningful if
4326    *     a) the font has a variation selector cmap sub table, and
4327    *     b) the current charmap has a Unicode encoding.
4328    *
4329    * @since:
4330    *   2.3.6
4331    *
4332    */
4333   FT_EXPORT( FT_UInt )
4334   FT_Face_GetCharVariantIndex( FT_Face   face,
4335                                FT_ULong  charcode,
4336                                FT_ULong  variantSelector );
4337 
4338 
4339   /**************************************************************************
4340    *
4341    * @function:
4342    *   FT_Face_GetCharVariantIsDefault
4343    *
4344    * @description:
4345    *   Check whether this variation of this Unicode character is the one to
4346    *   be found in the charmap.
4347    *
4348    * @input:
4349    *   face ::
4350    *     A handle to the source face object.
4351    *
4352    *   charcode ::
4353    *     The character codepoint in Unicode.
4354    *
4355    *   variantSelector ::
4356    *     The Unicode codepoint of the variation selector.
4357    *
4358    * @return:
4359    *   1~if found in the standard (Unicode) cmap, 0~if found in the variation
4360    *   selector cmap, or -1 if it is not a variation.
4361    *
4362    * @note:
4363    *   This function is only meaningful if the font has a variation selector
4364    *   cmap subtable.
4365    *
4366    * @since:
4367    *   2.3.6
4368    *
4369    */
4370   FT_EXPORT( FT_Int )
4371   FT_Face_GetCharVariantIsDefault( FT_Face   face,
4372                                    FT_ULong  charcode,
4373                                    FT_ULong  variantSelector );
4374 
4375 
4376   /**************************************************************************
4377    *
4378    * @function:
4379    *   FT_Face_GetVariantSelectors
4380    *
4381    * @description:
4382    *   Return a zero-terminated list of Unicode variation selectors found in
4383    *   the font.
4384    *
4385    * @input:
4386    *   face ::
4387    *     A handle to the source face object.
4388    *
4389    * @return:
4390    *   A pointer to an array of selector code points, or `NULL` if there is
4391    *   no valid variation selector cmap subtable.
4392    *
4393    * @note:
4394    *   The last item in the array is~0; the array is owned by the @FT_Face
4395    *   object but can be overwritten or released on the next call to a
4396    *   FreeType function.
4397    *
4398    * @since:
4399    *   2.3.6
4400    *
4401    */
4402   FT_EXPORT( FT_UInt32* )
4403   FT_Face_GetVariantSelectors( FT_Face  face );
4404 
4405 
4406   /**************************************************************************
4407    *
4408    * @function:
4409    *   FT_Face_GetVariantsOfChar
4410    *
4411    * @description:
4412    *   Return a zero-terminated list of Unicode variation selectors found for
4413    *   the specified character code.
4414    *
4415    * @input:
4416    *   face ::
4417    *     A handle to the source face object.
4418    *
4419    *   charcode ::
4420    *     The character codepoint in Unicode.
4421    *
4422    * @return:
4423    *   A pointer to an array of variation selector code points that are
4424    *   active for the given character, or `NULL` if the corresponding list is
4425    *   empty.
4426    *
4427    * @note:
4428    *   The last item in the array is~0; the array is owned by the @FT_Face
4429    *   object but can be overwritten or released on the next call to a
4430    *   FreeType function.
4431    *
4432    * @since:
4433    *   2.3.6
4434    *
4435    */
4436   FT_EXPORT( FT_UInt32* )
4437   FT_Face_GetVariantsOfChar( FT_Face   face,
4438                              FT_ULong  charcode );
4439 
4440 
4441   /**************************************************************************
4442    *
4443    * @function:
4444    *   FT_Face_GetCharsOfVariant
4445    *
4446    * @description:
4447    *   Return a zero-terminated list of Unicode character codes found for the
4448    *   specified variation selector.
4449    *
4450    * @input:
4451    *   face ::
4452    *     A handle to the source face object.
4453    *
4454    *   variantSelector ::
4455    *     The variation selector code point in Unicode.
4456    *
4457    * @return:
4458    *   A list of all the code points that are specified by this selector
4459    *   (both default and non-default codes are returned) or `NULL` if there
4460    *   is no valid cmap or the variation selector is invalid.
4461    *
4462    * @note:
4463    *   The last item in the array is~0; the array is owned by the @FT_Face
4464    *   object but can be overwritten or released on the next call to a
4465    *   FreeType function.
4466    *
4467    * @since:
4468    *   2.3.6
4469    *
4470    */
4471   FT_EXPORT( FT_UInt32* )
4472   FT_Face_GetCharsOfVariant( FT_Face   face,
4473                              FT_ULong  variantSelector );
4474 
4475 
4476   /**************************************************************************
4477    *
4478    * @section:
4479    *   computations
4480    *
4481    * @title:
4482    *   Computations
4483    *
4484    * @abstract:
4485    *   Crunching fixed numbers and vectors.
4486    *
4487    * @description:
4488    *   This section contains various functions used to perform computations
4489    *   on 16.16 fixed-float numbers or 2d vectors.
4490    *
4491    *   **Attention**: Most arithmetic functions take `FT_Long` as arguments.
4492    *   For historical reasons, FreeType was designed under the assumption
4493    *   that `FT_Long` is a 32-bit integer; results can thus be undefined if
4494    *   the arguments don't fit into 32 bits.
4495    *
4496    * @order:
4497    *   FT_MulDiv
4498    *   FT_MulFix
4499    *   FT_DivFix
4500    *   FT_RoundFix
4501    *   FT_CeilFix
4502    *   FT_FloorFix
4503    *   FT_Vector_Transform
4504    *   FT_Matrix_Multiply
4505    *   FT_Matrix_Invert
4506    *
4507    */
4508 
4509 
4510   /**************************************************************************
4511    *
4512    * @function:
4513    *   FT_MulDiv
4514    *
4515    * @description:
4516    *   Compute `(a*b)/c` with maximum accuracy, using a 64-bit intermediate
4517    *   integer whenever necessary.
4518    *
4519    *   This function isn't necessarily as fast as some processor-specific
4520    *   operations, but is at least completely portable.
4521    *
4522    * @input:
4523    *   a ::
4524    *     The first multiplier.
4525    *
4526    *   b ::
4527    *     The second multiplier.
4528    *
4529    *   c ::
4530    *     The divisor.
4531    *
4532    * @return:
4533    *   The result of `(a*b)/c`.  This function never traps when trying to
4534    *   divide by zero; it simply returns 'MaxInt' or 'MinInt' depending on
4535    *   the signs of `a` and `b`.
4536    */
4537   FT_EXPORT( FT_Long )
4538   FT_MulDiv( FT_Long  a,
4539              FT_Long  b,
4540              FT_Long  c );
4541 
4542 
4543   /**************************************************************************
4544    *
4545    * @function:
4546    *   FT_MulFix
4547    *
4548    * @description:
4549    *   Compute `(a*b)/0x10000` with maximum accuracy.  Its main use is to
4550    *   multiply a given value by a 16.16 fixed-point factor.
4551    *
4552    * @input:
4553    *   a ::
4554    *     The first multiplier.
4555    *
4556    *   b ::
4557    *     The second multiplier.  Use a 16.16 factor here whenever possible
4558    *     (see note below).
4559    *
4560    * @return:
4561    *   The result of `(a*b)/0x10000`.
4562    *
4563    * @note:
4564    *   This function has been optimized for the case where the absolute value
4565    *   of `a` is less than 2048, and `b` is a 16.16 scaling factor.  As this
4566    *   happens mainly when scaling from notional units to fractional pixels
4567    *   in FreeType, it resulted in noticeable speed improvements between
4568    *   versions 2.x and 1.x.
4569    *
4570    *   As a conclusion, always try to place a 16.16 factor as the _second_
4571    *   argument of this function; this can make a great difference.
4572    */
4573   FT_EXPORT( FT_Long )
4574   FT_MulFix( FT_Long  a,
4575              FT_Long  b );
4576 
4577 
4578   /**************************************************************************
4579    *
4580    * @function:
4581    *   FT_DivFix
4582    *
4583    * @description:
4584    *   Compute `(a*0x10000)/b` with maximum accuracy.  Its main use is to
4585    *   divide a given value by a 16.16 fixed-point factor.
4586    *
4587    * @input:
4588    *   a ::
4589    *     The numerator.
4590    *
4591    *   b ::
4592    *     The denominator.  Use a 16.16 factor here.
4593    *
4594    * @return:
4595    *   The result of `(a*0x10000)/b`.
4596    */
4597   FT_EXPORT( FT_Long )
4598   FT_DivFix( FT_Long  a,
4599              FT_Long  b );
4600 
4601 
4602   /**************************************************************************
4603    *
4604    * @function:
4605    *   FT_RoundFix
4606    *
4607    * @description:
4608    *   Round a 16.16 fixed number.
4609    *
4610    * @input:
4611    *   a ::
4612    *     The number to be rounded.
4613    *
4614    * @return:
4615    *   `a` rounded to the nearest 16.16 fixed integer, halfway cases away
4616    *   from zero.
4617    *
4618    * @note:
4619    *   The function uses wrap-around arithmetic.
4620    */
4621   FT_EXPORT( FT_Fixed )
4622   FT_RoundFix( FT_Fixed  a );
4623 
4624 
4625   /**************************************************************************
4626    *
4627    * @function:
4628    *   FT_CeilFix
4629    *
4630    * @description:
4631    *   Compute the smallest following integer of a 16.16 fixed number.
4632    *
4633    * @input:
4634    *   a ::
4635    *     The number for which the ceiling function is to be computed.
4636    *
4637    * @return:
4638    *   `a` rounded towards plus infinity.
4639    *
4640    * @note:
4641    *   The function uses wrap-around arithmetic.
4642    */
4643   FT_EXPORT( FT_Fixed )
4644   FT_CeilFix( FT_Fixed  a );
4645 
4646 
4647   /**************************************************************************
4648    *
4649    * @function:
4650    *   FT_FloorFix
4651    *
4652    * @description:
4653    *   Compute the largest previous integer of a 16.16 fixed number.
4654    *
4655    * @input:
4656    *   a ::
4657    *     The number for which the floor function is to be computed.
4658    *
4659    * @return:
4660    *   `a` rounded towards minus infinity.
4661    */
4662   FT_EXPORT( FT_Fixed )
4663   FT_FloorFix( FT_Fixed  a );
4664 
4665 
4666   /**************************************************************************
4667    *
4668    * @function:
4669    *   FT_Vector_Transform
4670    *
4671    * @description:
4672    *   Transform a single vector through a 2x2 matrix.
4673    *
4674    * @inout:
4675    *   vector ::
4676    *     The target vector to transform.
4677    *
4678    * @input:
4679    *   matrix ::
4680    *     A pointer to the source 2x2 matrix.
4681    *
4682    * @note:
4683    *   The result is undefined if either `vector` or `matrix` is invalid.
4684    */
4685   FT_EXPORT( void )
4686   FT_Vector_Transform( FT_Vector*        vector,
4687                        const FT_Matrix*  matrix );
4688 
4689 
4690   /**************************************************************************
4691    *
4692    * @section:
4693    *   version
4694    *
4695    * @title:
4696    *   FreeType Version
4697    *
4698    * @abstract:
4699    *   Functions and macros related to FreeType versions.
4700    *
4701    * @description:
4702    *   Note that those functions and macros are of limited use because even a
4703    *   new release of FreeType with only documentation changes increases the
4704    *   version number.
4705    *
4706    * @order:
4707    *   FT_Library_Version
4708    *
4709    *   FREETYPE_MAJOR
4710    *   FREETYPE_MINOR
4711    *   FREETYPE_PATCH
4712    *
4713    *   FT_Face_CheckTrueTypePatents
4714    *   FT_Face_SetUnpatentedHinting
4715    *
4716    */
4717 
4718 
4719   /**************************************************************************
4720    *
4721    * @enum:
4722    *   FREETYPE_XXX
4723    *
4724    * @description:
4725    *   These three macros identify the FreeType source code version.  Use
4726    *   @FT_Library_Version to access them at runtime.
4727    *
4728    * @values:
4729    *   FREETYPE_MAJOR ::
4730    *     The major version number.
4731    *   FREETYPE_MINOR ::
4732    *     The minor version number.
4733    *   FREETYPE_PATCH ::
4734    *     The patch level.
4735    *
4736    * @note:
4737    *   The version number of FreeType if built as a dynamic link library with
4738    *   the 'libtool' package is _not_ controlled by these three macros.
4739    *
4740    */
4741 #define FREETYPE_MAJOR  2
4742 #define FREETYPE_MINOR  11
4743 #define FREETYPE_PATCH  0
4744 
4745 
4746   /**************************************************************************
4747    *
4748    * @function:
4749    *   FT_Library_Version
4750    *
4751    * @description:
4752    *   Return the version of the FreeType library being used.  This is useful
4753    *   when dynamically linking to the library, since one cannot use the
4754    *   macros @FREETYPE_MAJOR, @FREETYPE_MINOR, and @FREETYPE_PATCH.
4755    *
4756    * @input:
4757    *   library ::
4758    *     A source library handle.
4759    *
4760    * @output:
4761    *   amajor ::
4762    *     The major version number.
4763    *
4764    *   aminor ::
4765    *     The minor version number.
4766    *
4767    *   apatch ::
4768    *     The patch version number.
4769    *
4770    * @note:
4771    *   The reason why this function takes a `library` argument is because
4772    *   certain programs implement library initialization in a custom way that
4773    *   doesn't use @FT_Init_FreeType.
4774    *
4775    *   In such cases, the library version might not be available before the
4776    *   library object has been created.
4777    */
4778   FT_EXPORT( void )
4779   FT_Library_Version( FT_Library   library,
4780                       FT_Int      *amajor,
4781                       FT_Int      *aminor,
4782                       FT_Int      *apatch );
4783 
4784 
4785   /**************************************************************************
4786    *
4787    * @function:
4788    *   FT_Face_CheckTrueTypePatents
4789    *
4790    * @description:
4791    *   Deprecated, does nothing.
4792    *
4793    * @input:
4794    *   face ::
4795    *     A face handle.
4796    *
4797    * @return:
4798    *   Always returns false.
4799    *
4800    * @note:
4801    *   Since May 2010, TrueType hinting is no longer patented.
4802    *
4803    * @since:
4804    *   2.3.5
4805    *
4806    */
4807   FT_EXPORT( FT_Bool )
4808   FT_Face_CheckTrueTypePatents( FT_Face  face );
4809 
4810 
4811   /**************************************************************************
4812    *
4813    * @function:
4814    *   FT_Face_SetUnpatentedHinting
4815    *
4816    * @description:
4817    *   Deprecated, does nothing.
4818    *
4819    * @input:
4820    *   face ::
4821    *     A face handle.
4822    *
4823    *   value ::
4824    *     New boolean setting.
4825    *
4826    * @return:
4827    *   Always returns false.
4828    *
4829    * @note:
4830    *   Since May 2010, TrueType hinting is no longer patented.
4831    *
4832    * @since:
4833    *   2.3.5
4834    *
4835    */
4836   FT_EXPORT( FT_Bool )
4837   FT_Face_SetUnpatentedHinting( FT_Face  face,
4838                                 FT_Bool  value );
4839 
4840   /* */
4841 
4842 
4843 FT_END_HEADER
4844 
4845 #endif /* FREETYPE_H_ */
4846 
4847 
4848 /* END */
4849