• Home
  • Line#
  • Scopes#
  • Navigate#
  • Raw
  • Download
1 /****************************************************************************
2  *
3  * ftmodapi.h
4  *
5  *   FreeType modules public interface (specification).
6  *
7  * Copyright 1996-2018 by
8  * David Turner, Robert Wilhelm, and Werner Lemberg.
9  *
10  * This file is part of the FreeType project, and may only be used,
11  * modified, and distributed under the terms of the FreeType project
12  * license, LICENSE.TXT.  By continuing to use, modify, or distribute
13  * this file you indicate that you have read the license and
14  * understand and accept it fully.
15  *
16  */
17 
18 
19 #ifndef FTMODAPI_H_
20 #define FTMODAPI_H_
21 
22 
23 #include <ft2build.h>
24 #include FT_FREETYPE_H
25 
26 #ifdef FREETYPE_H
27 #error "freetype.h of FreeType 1 has been loaded!"
28 #error "Please fix the directory search order for header files"
29 #error "so that freetype.h of FreeType 2 is found first."
30 #endif
31 
32 
33 FT_BEGIN_HEADER
34 
35 
36   /**************************************************************************
37    *
38    * @section:
39    *   module_management
40    *
41    * @title:
42    *   Module Management
43    *
44    * @abstract:
45    *   How to add, upgrade, remove, and control modules from FreeType.
46    *
47    * @description:
48    *   The definitions below are used to manage modules within FreeType.
49    *   Modules can be added, upgraded, and removed at runtime.
50    *   Additionally, some module properties can be controlled also.
51    *
52    *   Here is a list of possible values of the `module_name' field in
53    *   the @FT_Module_Class structure.
54    *
55    *   {
56    *     autofitter
57    *     bdf
58    *     cff
59    *     gxvalid
60    *     otvalid
61    *     pcf
62    *     pfr
63    *     psaux
64    *     pshinter
65    *     psnames
66    *     raster1
67    *     sfnt
68    *     smooth, smooth-lcd, smooth-lcdv
69    *     truetype
70    *     type1
71    *     type42
72    *     t1cid
73    *     winfonts
74    *   }
75    *
76    *   Note that the FreeType Cache sub-system is not a FreeType module.
77    *
78    * @order:
79    *   FT_Module
80    *   FT_Module_Constructor
81    *   FT_Module_Destructor
82    *   FT_Module_Requester
83    *   FT_Module_Class
84    *
85    *   FT_Add_Module
86    *   FT_Get_Module
87    *   FT_Remove_Module
88    *   FT_Add_Default_Modules
89    *
90    *   FT_Property_Set
91    *   FT_Property_Get
92    *   FT_Set_Default_Properties
93    *
94    *   FT_New_Library
95    *   FT_Done_Library
96    *   FT_Reference_Library
97    *
98    *   FT_Renderer
99    *   FT_Renderer_Class
100    *
101    *   FT_Get_Renderer
102    *   FT_Set_Renderer
103    *
104    *   FT_Set_Debug_Hook
105    *
106    */
107 
108 
109   /* module bit flags */
110 #define FT_MODULE_FONT_DRIVER         1  /* this module is a font driver  */
111 #define FT_MODULE_RENDERER            2  /* this module is a renderer     */
112 #define FT_MODULE_HINTER              4  /* this module is a glyph hinter */
113 #define FT_MODULE_STYLER              8  /* this module is a styler       */
114 
115 #define FT_MODULE_DRIVER_SCALABLE      0x100  /* the driver supports      */
116                                               /* scalable fonts           */
117 #define FT_MODULE_DRIVER_NO_OUTLINES   0x200  /* the driver does not      */
118                                               /* support vector outlines  */
119 #define FT_MODULE_DRIVER_HAS_HINTER    0x400  /* the driver provides its  */
120                                               /* own hinter               */
121 #define FT_MODULE_DRIVER_HINTS_LIGHTLY 0x800  /* the driver's hinter      */
122                                               /* produces LIGHT hints     */
123 
124 
125   /* deprecated values */
126 #define ft_module_font_driver         FT_MODULE_FONT_DRIVER
127 #define ft_module_renderer            FT_MODULE_RENDERER
128 #define ft_module_hinter              FT_MODULE_HINTER
129 #define ft_module_styler              FT_MODULE_STYLER
130 
131 #define ft_module_driver_scalable       FT_MODULE_DRIVER_SCALABLE
132 #define ft_module_driver_no_outlines    FT_MODULE_DRIVER_NO_OUTLINES
133 #define ft_module_driver_has_hinter     FT_MODULE_DRIVER_HAS_HINTER
134 #define ft_module_driver_hints_lightly  FT_MODULE_DRIVER_HINTS_LIGHTLY
135 
136 
137   typedef FT_Pointer  FT_Module_Interface;
138 
139 
140   /**************************************************************************
141    *
142    * @functype:
143    *   FT_Module_Constructor
144    *
145    * @description:
146    *   A function used to initialize (not create) a new module object.
147    *
148    * @input:
149    *   module ::
150    *     The module to initialize.
151    */
152   typedef FT_Error
153   (*FT_Module_Constructor)( FT_Module  module );
154 
155 
156   /**************************************************************************
157    *
158    * @functype:
159    *   FT_Module_Destructor
160    *
161    * @description:
162    *   A function used to finalize (not destroy) a given module object.
163    *
164    * @input:
165    *   module ::
166    *     The module to finalize.
167    */
168   typedef void
169   (*FT_Module_Destructor)( FT_Module  module );
170 
171 
172   /**************************************************************************
173    *
174    * @functype:
175    *   FT_Module_Requester
176    *
177    * @description:
178    *   A function used to query a given module for a specific interface.
179    *
180    * @input:
181    *   module ::
182    *     The module to be searched.
183    *
184    *   name ::
185    *     The name of the interface in the module.
186    */
187   typedef FT_Module_Interface
188   (*FT_Module_Requester)( FT_Module    module,
189                           const char*  name );
190 
191 
192   /**************************************************************************
193    *
194    * @struct:
195    *   FT_Module_Class
196    *
197    * @description:
198    *   The module class descriptor.  While being a public structure
199    *   necessary for FreeType's module bookkeeping, most of the fields are
200    *   essentially internal, not to be used directly by an application.
201    *
202    * @fields:
203    *   module_flags ::
204    *     Bit flags describing the module.
205    *
206    *   module_size ::
207    *     The size of one module object/instance in bytes.
208    *
209    *   module_name ::
210    *     The name of the module.
211    *
212    *   module_version ::
213    *     The version, as a 16.16 fixed number (major.minor).
214    *
215    *   module_requires ::
216    *     The version of FreeType this module requires, as a 16.16 fixed
217    *     number (major.minor).  Starts at version 2.0, i.e., 0x20000.
218    *
219    *   module_interface ::
220    *     A typeless pointer to a structure (which varies between different
221    *     modules) that holds the module's interface functions.  This is
222    *     essentially what `get_interface' returns.
223    *
224    *   module_init ::
225    *     The initializing function.
226    *
227    *   module_done ::
228    *     The finalizing function.
229    *
230    *   get_interface ::
231    *     The interface requesting function.
232    */
233   typedef struct  FT_Module_Class_
234   {
235     FT_ULong               module_flags;
236     FT_Long                module_size;
237     const FT_String*       module_name;
238     FT_Fixed               module_version;
239     FT_Fixed               module_requires;
240 
241     const void*            module_interface;
242 
243     FT_Module_Constructor  module_init;
244     FT_Module_Destructor   module_done;
245     FT_Module_Requester    get_interface;
246 
247   } FT_Module_Class;
248 
249 
250   /**************************************************************************
251    *
252    * @function:
253    *   FT_Add_Module
254    *
255    * @description:
256    *   Add a new module to a given library instance.
257    *
258    * @inout:
259    *   library ::
260    *     A handle to the library object.
261    *
262    * @input:
263    *   clazz ::
264    *     A pointer to class descriptor for the module.
265    *
266    * @return:
267    *   FreeType error code.  0~means success.
268    *
269    * @note:
270    *   An error will be returned if a module already exists by that name,
271    *   or if the module requires a version of FreeType that is too great.
272    */
273   FT_EXPORT( FT_Error )
274   FT_Add_Module( FT_Library              library,
275                  const FT_Module_Class*  clazz );
276 
277 
278   /**************************************************************************
279    *
280    * @function:
281    *   FT_Get_Module
282    *
283    * @description:
284    *   Find a module by its name.
285    *
286    * @input:
287    *   library ::
288    *     A handle to the library object.
289    *
290    *   module_name ::
291    *     The module's name (as an ASCII string).
292    *
293    * @return:
294    *   A module handle.  0~if none was found.
295    *
296    * @note:
297    *   FreeType's internal modules aren't documented very well, and you
298    *   should look up the source code for details.
299    */
300   FT_EXPORT( FT_Module )
301   FT_Get_Module( FT_Library   library,
302                  const char*  module_name );
303 
304 
305   /**************************************************************************
306    *
307    * @function:
308    *   FT_Remove_Module
309    *
310    * @description:
311    *   Remove a given module from a library instance.
312    *
313    * @inout:
314    *   library ::
315    *     A handle to a library object.
316    *
317    * @input:
318    *   module ::
319    *     A handle to a module object.
320    *
321    * @return:
322    *   FreeType error code.  0~means success.
323    *
324    * @note:
325    *   The module object is destroyed by the function in case of success.
326    */
327   FT_EXPORT( FT_Error )
328   FT_Remove_Module( FT_Library  library,
329                     FT_Module   module );
330 
331 
332   /**********************************************************************
333    *
334    * @function:
335    *    FT_Property_Set
336    *
337    * @description:
338    *    Set a property for a given module.
339    *
340    * @input:
341    *    library ::
342    *      A handle to the library the module is part of.
343    *
344    *    module_name ::
345    *      The module name.
346    *
347    *    property_name ::
348    *      The property name.  Properties are described in section
349    *      @properties.
350    *
351    *      Note that only a few modules have properties.
352    *
353    *    value ::
354    *      A generic pointer to a variable or structure that gives the new
355    *      value of the property.  The exact definition of `value' is
356    *      dependent on the property; see section @properties.
357    *
358    * @return:
359    *   FreeType error code.  0~means success.
360    *
361    * @note:
362    *    If `module_name' isn't a valid module name, or `property_name'
363    *    doesn't specify a valid property, or if `value' doesn't represent a
364    *    valid value for the given property, an error is returned.
365    *
366    *    The following example sets property `bar' (a simple integer) in
367    *    module `foo' to value~1.
368    *
369    *    {
370    *      FT_UInt  bar;
371    *
372    *
373    *      bar = 1;
374    *      FT_Property_Set( library, "foo", "bar", &bar );
375    *    }
376    *
377    *    Note that the FreeType Cache sub-system doesn't recognize module
378    *    property changes.  To avoid glyph lookup confusion within the cache
379    *    you should call @FTC_Manager_Reset to completely flush the cache if
380    *    a module property gets changed after @FTC_Manager_New has been
381    *    called.
382    *
383    *    It is not possible to set properties of the FreeType Cache
384    *    sub-system itself with FT_Property_Set; use @FTC_Property_Set
385    *    instead.
386    *
387    * @since:
388    *   2.4.11
389    *
390    */
391   FT_EXPORT( FT_Error )
392   FT_Property_Set( FT_Library        library,
393                    const FT_String*  module_name,
394                    const FT_String*  property_name,
395                    const void*       value );
396 
397 
398   /**********************************************************************
399    *
400    * @function:
401    *    FT_Property_Get
402    *
403    * @description:
404    *    Get a module's property value.
405    *
406    * @input:
407    *    library ::
408    *      A handle to the library the module is part of.
409    *
410    *    module_name ::
411    *      The module name.
412    *
413    *    property_name ::
414    *      The property name.  Properties are described in section
415    *      @properties.
416    *
417    * @inout:
418    *    value ::
419    *      A generic pointer to a variable or structure that gives the
420    *      value of the property.  The exact definition of `value' is
421    *      dependent on the property; see section @properties.
422    *
423    * @return:
424    *   FreeType error code.  0~means success.
425    *
426    * @note:
427    *    If `module_name' isn't a valid module name, or `property_name'
428    *    doesn't specify a valid property, or if `value' doesn't represent a
429    *    valid value for the given property, an error is returned.
430    *
431    *    The following example gets property `baz' (a range) in module `foo'.
432    *
433    *    {
434    *      typedef  range_
435    *      {
436    *        FT_Int32  min;
437    *        FT_Int32  max;
438    *
439    *      } range;
440    *
441    *      range  baz;
442    *
443    *
444    *      FT_Property_Get( library, "foo", "baz", &baz );
445    *    }
446    *
447    *    It is not possible to retrieve properties of the FreeType Cache
448    *    sub-system with FT_Property_Get; use @FTC_Property_Get instead.
449    *
450    * @since:
451    *   2.4.11
452    *
453    */
454   FT_EXPORT( FT_Error )
455   FT_Property_Get( FT_Library        library,
456                    const FT_String*  module_name,
457                    const FT_String*  property_name,
458                    void*             value );
459 
460 
461   /**************************************************************************
462    *
463    * @function:
464    *   FT_Set_Default_Properties
465    *
466    * @description:
467    *   If compilation option FT_CONFIG_OPTION_ENVIRONMENT_PROPERTIES is
468    *   set, this function reads the `FREETYPE_PROPERTIES' environment
469    *   variable to control driver properties.  See section @properties
470    *   for more.
471    *
472    *   If the compilation option is not set, this function does nothing.
473    *
474    *   `FREETYPE_PROPERTIES' has the following syntax form (broken here
475    *   into multiple lines for better readability).
476    *
477    *   {
478    *     <optional whitespace>
479    *     <module-name1> ':'
480    *     <property-name1> '=' <property-value1>
481    *     <whitespace>
482    *     <module-name2> ':'
483    *     <property-name2> '=' <property-value2>
484    *     ...
485    *   }
486    *
487    *   Example:
488    *
489    *   {
490    *     FREETYPE_PROPERTIES=truetype:interpreter-version=35 \
491    *                         cff:no-stem-darkening=1 \
492    *                         autofitter:warping=1
493    *   }
494    *
495    * @inout:
496    *   library ::
497    *     A handle to a new library object.
498    *
499    * @since:
500    *   2.8
501    */
502   FT_EXPORT( void )
503   FT_Set_Default_Properties( FT_Library  library );
504 
505 
506   /**************************************************************************
507    *
508    * @function:
509    *   FT_Reference_Library
510    *
511    * @description:
512    *   A counter gets initialized to~1 at the time an @FT_Library
513    *   structure is created.  This function increments the counter.
514    *   @FT_Done_Library then only destroys a library if the counter is~1,
515    *   otherwise it simply decrements the counter.
516    *
517    *   This function helps in managing life-cycles of structures that
518    *   reference @FT_Library objects.
519    *
520    * @input:
521    *   library ::
522    *     A handle to a target library object.
523    *
524    * @return:
525    *   FreeType error code.  0~means success.
526    *
527    * @since:
528    *   2.4.2
529    */
530   FT_EXPORT( FT_Error )
531   FT_Reference_Library( FT_Library  library );
532 
533 
534   /**************************************************************************
535    *
536    * @function:
537    *   FT_New_Library
538    *
539    * @description:
540    *   This function is used to create a new FreeType library instance
541    *   from a given memory object.  It is thus possible to use libraries
542    *   with distinct memory allocators within the same program.  Note,
543    *   however, that the used @FT_Memory structure is expected to remain
544    *   valid for the life of the @FT_Library object.
545    *
546    *   Normally, you would call this function (followed by a call to
547    *   @FT_Add_Default_Modules or a series of calls to @FT_Add_Module,
548    *   and a call to @FT_Set_Default_Properties) instead of
549    *   @FT_Init_FreeType to initialize the FreeType library.
550    *
551    *   Don't use @FT_Done_FreeType but @FT_Done_Library to destroy a
552    *   library instance.
553    *
554    * @input:
555    *   memory ::
556    *     A handle to the original memory object.
557    *
558    * @output:
559    *   alibrary ::
560    *     A pointer to handle of a new library object.
561    *
562    * @return:
563    *   FreeType error code.  0~means success.
564    *
565    * @note:
566    *   See the discussion of reference counters in the description of
567    *   @FT_Reference_Library.
568    */
569   FT_EXPORT( FT_Error )
570   FT_New_Library( FT_Memory    memory,
571                   FT_Library  *alibrary );
572 
573 
574   /**************************************************************************
575    *
576    * @function:
577    *   FT_Done_Library
578    *
579    * @description:
580    *   Discard a given library object.  This closes all drivers and
581    *   discards all resource objects.
582    *
583    * @input:
584    *   library ::
585    *     A handle to the target library.
586    *
587    * @return:
588    *   FreeType error code.  0~means success.
589    *
590    * @note:
591    *   See the discussion of reference counters in the description of
592    *   @FT_Reference_Library.
593    */
594   FT_EXPORT( FT_Error )
595   FT_Done_Library( FT_Library  library );
596 
597   /* */
598 
599   typedef void
600   (*FT_DebugHook_Func)( void*  arg );
601 
602 
603   /**************************************************************************
604    *
605    * @function:
606    *   FT_Set_Debug_Hook
607    *
608    * @description:
609    *   Set a debug hook function for debugging the interpreter of a font
610    *   format.
611    *
612    * @inout:
613    *   library ::
614    *     A handle to the library object.
615    *
616    * @input:
617    *   hook_index ::
618    *     The index of the debug hook.  You should use the
619    *     values defined in `ftobjs.h', e.g.,
620    *     `FT_DEBUG_HOOK_TRUETYPE'.
621    *
622    *   debug_hook ::
623    *     The function used to debug the interpreter.
624    *
625    * @note:
626    *   Currently, four debug hook slots are available, but only two (for
627    *   the TrueType and the Type~1 interpreter) are defined.
628    *
629    *   Since the internal headers of FreeType are no longer installed,
630    *   the symbol `FT_DEBUG_HOOK_TRUETYPE' isn't available publicly.
631    *   This is a bug and will be fixed in a forthcoming release.
632    */
633   FT_EXPORT( void )
634   FT_Set_Debug_Hook( FT_Library         library,
635                      FT_UInt            hook_index,
636                      FT_DebugHook_Func  debug_hook );
637 
638 
639   /**************************************************************************
640    *
641    * @function:
642    *   FT_Add_Default_Modules
643    *
644    * @description:
645    *   Add the set of default drivers to a given library object.
646    *   This is only useful when you create a library object with
647    *   @FT_New_Library (usually to plug a custom memory manager).
648    *
649    * @inout:
650    *   library ::
651    *     A handle to a new library object.
652    */
653   FT_EXPORT( void )
654   FT_Add_Default_Modules( FT_Library  library );
655 
656 
657 
658   /**************************************************************************
659    *
660    * @section:
661    *   truetype_engine
662    *
663    * @title:
664    *   The TrueType Engine
665    *
666    * @abstract:
667    *   TrueType bytecode support.
668    *
669    * @description:
670    *   This section contains a function used to query the level of TrueType
671    *   bytecode support compiled in this version of the library.
672    *
673    */
674 
675 
676   /**************************************************************************
677    *
678    * @enum:
679    *    FT_TrueTypeEngineType
680    *
681    * @description:
682    *    A list of values describing which kind of TrueType bytecode
683    *    engine is implemented in a given FT_Library instance.  It is used
684    *    by the @FT_Get_TrueType_Engine_Type function.
685    *
686    * @values:
687    *    FT_TRUETYPE_ENGINE_TYPE_NONE ::
688    *      The library doesn't implement any kind of bytecode interpreter.
689    *
690    *    FT_TRUETYPE_ENGINE_TYPE_UNPATENTED ::
691    *      Deprecated and removed.
692    *
693    *    FT_TRUETYPE_ENGINE_TYPE_PATENTED ::
694    *      The library implements a bytecode interpreter that covers
695    *      the full instruction set of the TrueType virtual machine (this
696    *      was governed by patents until May 2010, hence the name).
697    *
698    * @since:
699    *    2.2
700    *
701    */
702   typedef enum  FT_TrueTypeEngineType_
703   {
704     FT_TRUETYPE_ENGINE_TYPE_NONE = 0,
705     FT_TRUETYPE_ENGINE_TYPE_UNPATENTED,
706     FT_TRUETYPE_ENGINE_TYPE_PATENTED
707 
708   } FT_TrueTypeEngineType;
709 
710 
711   /**************************************************************************
712    *
713    * @function:
714    *    FT_Get_TrueType_Engine_Type
715    *
716    * @description:
717    *    Return an @FT_TrueTypeEngineType value to indicate which level of
718    *    the TrueType virtual machine a given library instance supports.
719    *
720    * @input:
721    *    library ::
722    *      A library instance.
723    *
724    * @return:
725    *    A value indicating which level is supported.
726    *
727    * @since:
728    *    2.2
729    *
730    */
731   FT_EXPORT( FT_TrueTypeEngineType )
732   FT_Get_TrueType_Engine_Type( FT_Library  library );
733 
734   /* */
735 
736 
737 FT_END_HEADER
738 
739 #endif /* FTMODAPI_H_ */
740 
741 
742 /* END */
743