tor-browser

ftmodapi.h (22544B)

---

/****************************************************************************
*
* ftmodapi.h
*
*   FreeType modules public interface (specification).
*
* Copyright (C) 1996-2025 by
* David Turner, Robert Wilhelm, and Werner Lemberg.
*
* This file is part of the FreeType project, and may only be used,
* modified, and distributed under the terms of the FreeType project
* license, LICENSE.TXT.  By continuing to use, modify, or distribute
* this file you indicate that you have read the license and
* understand and accept it fully.
*
*/


#ifndef FTMODAPI_H_
#define FTMODAPI_H_


#include <freetype/freetype.h>

#ifdef FREETYPE_H
#error "freetype.h of FreeType 1 has been loaded!"
#error "Please fix the directory search order for header files"
#error "so that freetype.h of FreeType 2 is found first."
#endif


FT_BEGIN_HEADER


 /**************************************************************************
  *
  * @section:
  *   module_management
  *
  * @title:
  *   Module Management
  *
  * @abstract:
  *   How to add, upgrade, remove, and control modules from FreeType.
  *
  * @description:
  *   The definitions below are used to manage modules within FreeType.
  *   Internal and external modules can be added, upgraded, and removed at
  *   runtime.  For example, an alternative renderer or proprietary font
  *   driver can be registered and prioritized.  Additionally, some module
  *   properties can also be controlled.
  *
  *   Here is a list of existing values of the `module_name` field in the
  *   @FT_Module_Class structure.
  *
  *   ```
  *     autofitter
  *     bdf
  *     cff
  *     gxvalid
  *     otvalid
  *     pcf
  *     pfr
  *     psaux
  *     pshinter
  *     psnames
  *     raster1
  *     sfnt
  *     smooth
  *     truetype
  *     type1
  *     type42
  *     t1cid
  *     winfonts
  *   ```
  *
  *   Note that the FreeType Cache sub-system is not a FreeType module.
  *
  * @order:
  *   FT_Module
  *   FT_Module_Constructor
  *   FT_Module_Destructor
  *   FT_Module_Requester
  *   FT_Module_Class
  *
  *   FT_Add_Module
  *   FT_Get_Module
  *   FT_Remove_Module
  *   FT_Add_Default_Modules
  *
  *   FT_FACE_DRIVER_NAME
  *   FT_Property_Set
  *   FT_Property_Get
  *   FT_Set_Default_Properties
  *
  *   FT_New_Library
  *   FT_Done_Library
  *   FT_Reference_Library
  *
  *   FT_Renderer
  *   FT_Renderer_Class
  *
  *   FT_Get_Renderer
  *   FT_Set_Renderer
  *
  *   FT_Set_Debug_Hook
  *
  */


 /* module bit flags */
#define FT_MODULE_FONT_DRIVER         1  /* this module is a font driver  */
#define FT_MODULE_RENDERER            2  /* this module is a renderer     */
#define FT_MODULE_HINTER              4  /* this module is a glyph hinter */
#define FT_MODULE_STYLER              8  /* this module is a styler       */

#define FT_MODULE_DRIVER_SCALABLE      0x100  /* the driver supports      */
                                             /* scalable fonts           */
#define FT_MODULE_DRIVER_NO_OUTLINES   0x200  /* the driver does not      */
                                             /* support vector outlines  */
#define FT_MODULE_DRIVER_HAS_HINTER    0x400  /* the driver provides its  */
                                             /* own hinter               */
#define FT_MODULE_DRIVER_HINTS_LIGHTLY 0x800  /* the driver's hinter      */
                                             /* produces LIGHT hints     */


 /* deprecated values */
#define ft_module_font_driver         FT_MODULE_FONT_DRIVER
#define ft_module_renderer            FT_MODULE_RENDERER
#define ft_module_hinter              FT_MODULE_HINTER
#define ft_module_styler              FT_MODULE_STYLER

#define ft_module_driver_scalable       FT_MODULE_DRIVER_SCALABLE
#define ft_module_driver_no_outlines    FT_MODULE_DRIVER_NO_OUTLINES
#define ft_module_driver_has_hinter     FT_MODULE_DRIVER_HAS_HINTER
#define ft_module_driver_hints_lightly  FT_MODULE_DRIVER_HINTS_LIGHTLY


 typedef FT_Pointer  FT_Module_Interface;


 /**************************************************************************
  *
  * @functype:
  *   FT_Module_Constructor
  *
  * @description:
  *   A function used to initialize (not create) a new module object.
  *
  * @input:
  *   module ::
  *     The module to initialize.
  */
 typedef FT_Error
 (*FT_Module_Constructor)( FT_Module  module );


 /**************************************************************************
  *
  * @functype:
  *   FT_Module_Destructor
  *
  * @description:
  *   A function used to finalize (not destroy) a given module object.
  *
  * @input:
  *   module ::
  *     The module to finalize.
  */
 typedef void
 (*FT_Module_Destructor)( FT_Module  module );


 /**************************************************************************
  *
  * @functype:
  *   FT_Module_Requester
  *
  * @description:
  *   A function used to query a given module for a specific interface.
  *
  * @input:
  *   module ::
  *     The module to be searched.
  *
  *   name ::
  *     The name of the interface in the module.
  */
 typedef FT_Module_Interface
 (*FT_Module_Requester)( FT_Module    module,
                         const char*  name );


 /**************************************************************************
  *
  * @struct:
  *   FT_Module_Class
  *
  * @description:
  *   The module class descriptor.  While being a public structure necessary
  *   for FreeType's module bookkeeping, most of the fields are essentially
  *   internal, not to be used directly by an application.
  *
  * @fields:
  *   module_flags ::
  *     Bit flags describing the module.
  *
  *   module_size ::
  *     The size of one module object/instance in bytes.
  *
  *   module_name ::
  *     The name of the module.
  *
  *   module_version ::
  *     The version, as a 16.16 fixed number (major.minor).
  *
  *   module_requires ::
  *     The version of FreeType this module requires, as a 16.16 fixed
  *     number (major.minor).  Starts at version 2.0, i.e., 0x20000.
  *
  *   module_interface ::
  *     A typeless pointer to a structure (which varies between different
  *     modules) that holds the module's interface functions.  This is
  *     essentially what `get_interface` returns.
  *
  *   module_init ::
  *     The initializing function.
  *
  *   module_done ::
  *     The finalizing function.
  *
  *   get_interface ::
  *     The interface requesting function.
  */
 typedef struct  FT_Module_Class_
 {
   FT_ULong               module_flags;
   FT_Long                module_size;
   const FT_String*       module_name;
   FT_Fixed               module_version;
   FT_Fixed               module_requires;

   const void*            module_interface;

   FT_Module_Constructor  module_init;
   FT_Module_Destructor   module_done;
   FT_Module_Requester    get_interface;

 } FT_Module_Class;


 /**************************************************************************
  *
  * @function:
  *   FT_Add_Module
  *
  * @description:
  *   Add a new module to a given library instance.
  *
  * @inout:
  *   library ::
  *     A handle to the library object.
  *
  * @input:
  *   clazz ::
  *     A pointer to class descriptor for the module.
  *
  * @return:
  *   FreeType error code.  0~means success.
  *
  * @note:
  *   An error will be returned if a module already exists by that name, or
  *   if the module requires a version of FreeType that is too great.
  */
 FT_EXPORT( FT_Error )
 FT_Add_Module( FT_Library              library,
                const FT_Module_Class*  clazz );


 /**************************************************************************
  *
  * @function:
  *   FT_Get_Module
  *
  * @description:
  *   Find a module by its name.
  *
  * @input:
  *   library ::
  *     A handle to the library object.
  *
  *   module_name ::
  *     The module's name (as an ASCII string).
  *
  * @return:
  *   A module handle.  0~if none was found.
  *
  * @note:
  *   FreeType's internal modules aren't documented very well, and you
  *   should look up the source code for details.
  */
 FT_EXPORT( FT_Module )
 FT_Get_Module( FT_Library   library,
                const char*  module_name );


 /**************************************************************************
  *
  * @function:
  *   FT_Remove_Module
  *
  * @description:
  *   Remove a given module from a library instance.
  *
  * @inout:
  *   library ::
  *     A handle to a library object.
  *
  * @input:
  *   module ::
  *     A handle to a module object.
  *
  * @return:
  *   FreeType error code.  0~means success.
  *
  * @note:
  *   The module object is destroyed by the function in case of success.
  */
 FT_EXPORT( FT_Error )
 FT_Remove_Module( FT_Library  library,
                   FT_Module   module );


 /**************************************************************************
  *
  * @macro:
  *   FT_FACE_DRIVER_NAME
  *
  * @description:
  *   A macro that retrieves the name of a font driver from a face object.
  *
  * @note:
  *   The font driver name is a valid `module_name` for @FT_Property_Set
  *   and @FT_Property_Get.  This is not the same as @FT_Get_Font_Format.
  *
  * @since:
  *   2.11
  *
  */
#define FT_FACE_DRIVER_NAME( face )                                     \
         ( ( *FT_REINTERPRET_CAST( FT_Module_Class**,                  \
                                   ( face )->driver ) )->module_name )


 /**************************************************************************
  *
  * @function:
  *    FT_Property_Set
  *
  * @description:
  *    Set a property for a given module.
  *
  * @input:
  *    library ::
  *      A handle to the library the module is part of.
  *
  *    module_name ::
  *      The module name.
  *
  *    property_name ::
  *      The property name.  Properties are described in section
  *      @properties.
  *
  *      Note that only a few modules have properties.
  *
  *    value ::
  *      A generic pointer to a variable or structure that gives the new
  *      value of the property.  The exact definition of `value` is
  *      dependent on the property; see section @properties.
  *
  * @return:
  *   FreeType error code.  0~means success.
  *
  * @note:
  *    If `module_name` isn't a valid module name, or `property_name`
  *    doesn't specify a valid property, or if `value` doesn't represent a
  *    valid value for the given property, an error is returned.
  *
  *    The following example sets property 'bar' (a simple integer) in
  *    module 'foo' to value~1.
  *
  *    ```
  *      FT_UInt  bar;
  *
  *
  *      bar = 1;
  *      FT_Property_Set( library, "foo", "bar", &bar );
  *    ```
  *
  *    Note that the FreeType Cache sub-system doesn't recognize module
  *    property changes.  To avoid glyph lookup confusion within the cache
  *    you should call @FTC_Manager_Reset to completely flush the cache if a
  *    module property gets changed after @FTC_Manager_New has been called.
  *
  *    It is not possible to set properties of the FreeType Cache sub-system
  *    itself with FT_Property_Set; use @FTC_Property_Set instead.
  *
  * @since:
  *   2.4.11
  *
  */
 FT_EXPORT( FT_Error )
 FT_Property_Set( FT_Library        library,
                  const FT_String*  module_name,
                  const FT_String*  property_name,
                  const void*       value );


 /**************************************************************************
  *
  * @function:
  *    FT_Property_Get
  *
  * @description:
  *    Get a module's property value.
  *
  * @input:
  *    library ::
  *      A handle to the library the module is part of.
  *
  *    module_name ::
  *      The module name.
  *
  *    property_name ::
  *      The property name.  Properties are described in section
  *      @properties.
  *
  * @inout:
  *    value ::
  *      A generic pointer to a variable or structure that gives the value
  *      of the property.  The exact definition of `value` is dependent on
  *      the property; see section @properties.
  *
  * @return:
  *   FreeType error code.  0~means success.
  *
  * @note:
  *    If `module_name` isn't a valid module name, or `property_name`
  *    doesn't specify a valid property, or if `value` doesn't represent a
  *    valid value for the given property, an error is returned.
  *
  *    The following example gets property 'baz' (a range) in module 'foo'.
  *
  *    ```
  *      typedef  range_
  *      {
  *        FT_Int32  min;
  *        FT_Int32  max;
  *
  *      } range;
  *
  *      range  baz;
  *
  *
  *      FT_Property_Get( library, "foo", "baz", &baz );
  *    ```
  *
  *    It is not possible to retrieve properties of the FreeType Cache
  *    sub-system with FT_Property_Get; use @FTC_Property_Get instead.
  *
  * @since:
  *   2.4.11
  *
  */
 FT_EXPORT( FT_Error )
 FT_Property_Get( FT_Library        library,
                  const FT_String*  module_name,
                  const FT_String*  property_name,
                  void*             value );


 /**************************************************************************
  *
  * @function:
  *   FT_Set_Default_Properties
  *
  * @description:
  *   If compilation option `FT_CONFIG_OPTION_ENVIRONMENT_PROPERTIES` is
  *   set, this function reads the `FREETYPE_PROPERTIES` environment
  *   variable to control driver properties.  See section @properties for
  *   more.
  *
  *   If the compilation option is not set, this function does nothing.
  *
  *   `FREETYPE_PROPERTIES` has the following syntax form (broken here into
  *   multiple lines for better readability).
  *
  *   ```
  *     <optional whitespace>
  *     <module-name1> ':'
  *     <property-name1> '=' <property-value1>
  *     <whitespace>
  *     <module-name2> ':'
  *     <property-name2> '=' <property-value2>
  *     ...
  *   ```
  *
  *   Example:
  *
  *   ```
  *     FREETYPE_PROPERTIES=truetype:interpreter-version=35 \
  *                         cff:no-stem-darkening=0
  *   ```
  *
  * @inout:
  *   library ::
  *     A handle to a new library object.
  *
  * @since:
  *   2.8
  */
 FT_EXPORT( void )
 FT_Set_Default_Properties( FT_Library  library );


 /**************************************************************************
  *
  * @function:
  *   FT_Reference_Library
  *
  * @description:
  *   A counter gets initialized to~1 at the time an @FT_Library structure
  *   is created.  This function increments the counter.  @FT_Done_Library
  *   then only destroys a library if the counter is~1, otherwise it simply
  *   decrements the counter.
  *
  *   This function helps in managing life-cycles of structures that
  *   reference @FT_Library objects.
  *
  * @input:
  *   library ::
  *     A handle to a target library object.
  *
  * @return:
  *   FreeType error code.  0~means success.
  *
  * @since:
  *   2.4.2
  */
 FT_EXPORT( FT_Error )
 FT_Reference_Library( FT_Library  library );


 /**************************************************************************
  *
  * @function:
  *   FT_New_Library
  *
  * @description:
  *   This function is used to create a new FreeType library instance from a
  *   given memory object.  It is thus possible to use libraries with
  *   distinct memory allocators within the same program.  Note, however,
  *   that the used @FT_Memory structure is expected to remain valid for the
  *   life of the @FT_Library object.
  *
  *   Normally, you would call this function (followed by a call to
  *   @FT_Add_Default_Modules or a series of calls to @FT_Add_Module, and a
  *   call to @FT_Set_Default_Properties) instead of @FT_Init_FreeType to
  *   initialize the FreeType library.
  *
  *   Don't use @FT_Done_FreeType but @FT_Done_Library to destroy a library
  *   instance.
  *
  * @input:
  *   memory ::
  *     A handle to the original memory object.
  *
  * @output:
  *   alibrary ::
  *     A pointer to handle of a new library object.
  *
  * @return:
  *   FreeType error code.  0~means success.
  *
  * @note:
  *   See the discussion of reference counters in the description of
  *   @FT_Reference_Library.
  */
 FT_EXPORT( FT_Error )
 FT_New_Library( FT_Memory    memory,
                 FT_Library  *alibrary );


 /**************************************************************************
  *
  * @function:
  *   FT_Done_Library
  *
  * @description:
  *   Discard a given library object.  This closes all drivers and discards
  *   all resource objects.
  *
  * @input:
  *   library ::
  *     A handle to the target library.
  *
  * @return:
  *   FreeType error code.  0~means success.
  *
  * @note:
  *   See the discussion of reference counters in the description of
  *   @FT_Reference_Library.
  */
 FT_EXPORT( FT_Error )
 FT_Done_Library( FT_Library  library );


 /**************************************************************************
  *
  * @functype:
  *   FT_DebugHook_Func
  *
  * @description:
  *   A drop-in replacement (or rather a wrapper) for the bytecode or
  *   charstring interpreter's main loop function.
  *
  *   Its job is essentially
  *
  *   - to activate debug mode to enforce single-stepping,
  *
  *   - to call the main loop function to interpret the next opcode, and
  *
  *   - to show the changed context to the user.
  *
  *   An example for such a main loop function is `TT_RunIns` (declared in
  *   FreeType's internal header file `src/truetype/ttinterp.h`).
  *
  *   Have a look at the source code of the `ttdebug` FreeType demo program
  *   for an example of a drop-in replacement.
  *
  * @inout:
  *   arg ::
  *     A typeless pointer, to be cast to the main loop function's data
  *     structure (which depends on the font module).  For TrueType fonts
  *     it is bytecode interpreter's execution context, `TT_ExecContext`,
  *     which is declared in FreeType's internal header file `tttypes.h`.
  */
 typedef FT_Error
 (*FT_DebugHook_Func)( void*  arg );


 /**************************************************************************
  *
  * @enum:
  *   FT_DEBUG_HOOK_XXX
  *
  * @description:
  *   A list of named debug hook indices.
  *
  * @values:
  *   FT_DEBUG_HOOK_TRUETYPE::
  *     This hook index identifies the TrueType bytecode debugger.
  */
#define FT_DEBUG_HOOK_TRUETYPE  0


 /**************************************************************************
  *
  * @function:
  *   FT_Set_Debug_Hook
  *
  * @description:
  *   Set a debug hook function for debugging the interpreter of a font
  *   format.
  *
  *   While this is a public API function, an application needs access to
  *   FreeType's internal header files to do something useful.
  *
  *   Have a look at the source code of the `ttdebug` FreeType demo program
  *   for an example of its usage.
  *
  * @inout:
  *   library ::
  *     A handle to the library object.
  *
  * @input:
  *   hook_index ::
  *     The index of the debug hook.  You should use defined enumeration
  *     macros like @FT_DEBUG_HOOK_TRUETYPE.
  *
  *   debug_hook ::
  *     The function used to debug the interpreter.
  *
  * @note:
  *   Currently, four debug hook slots are available, but only one (for the
  *   TrueType interpreter) is defined.
  */
 FT_EXPORT( void )
 FT_Set_Debug_Hook( FT_Library         library,
                    FT_UInt            hook_index,
                    FT_DebugHook_Func  debug_hook );


 /**************************************************************************
  *
  * @function:
  *   FT_Add_Default_Modules
  *
  * @description:
  *   Add the set of default drivers to a given library object.  This is
  *   only useful when you create a library object with @FT_New_Library
  *   (usually to plug a custom memory manager).
  *
  * @inout:
  *   library ::
  *     A handle to a new library object.
  */
 FT_EXPORT( void )
 FT_Add_Default_Modules( FT_Library  library );



 /**************************************************************************
  *
  * @section:
  *   truetype_engine
  *
  * @title:
  *   The TrueType Engine
  *
  * @abstract:
  *   TrueType bytecode support.
  *
  * @description:
  *   This section contains a function used to query the level of TrueType
  *   bytecode support compiled in this version of the library.
  *
  */


 /**************************************************************************
  *
  * @enum:
  *    FT_TrueTypeEngineType
  *
  * @description:
  *    A list of values describing which kind of TrueType bytecode engine is
  *    implemented in a given FT_Library instance.  It is used by the
  *    @FT_Get_TrueType_Engine_Type function.
  *
  * @values:
  *    FT_TRUETYPE_ENGINE_TYPE_NONE ::
  *      The library doesn't implement any kind of bytecode interpreter.
  *
  *    FT_TRUETYPE_ENGINE_TYPE_UNPATENTED ::
  *      Deprecated and removed.
  *
  *    FT_TRUETYPE_ENGINE_TYPE_PATENTED ::
  *      The library implements a bytecode interpreter that covers the full
  *      instruction set of the TrueType virtual machine (this was governed
  *      by patents until May 2010, hence the name).
  *
  * @since:
  *    2.2
  *
  */
 typedef enum  FT_TrueTypeEngineType_
 {
   FT_TRUETYPE_ENGINE_TYPE_NONE = 0,
   FT_TRUETYPE_ENGINE_TYPE_UNPATENTED,
   FT_TRUETYPE_ENGINE_TYPE_PATENTED

 } FT_TrueTypeEngineType;


 /**************************************************************************
  *
  * @function:
  *    FT_Get_TrueType_Engine_Type
  *
  * @description:
  *    Return an @FT_TrueTypeEngineType value to indicate which level of the
  *    TrueType virtual machine a given library instance supports.
  *
  * @input:
  *    library ::
  *      A library instance.
  *
  * @return:
  *    A value indicating which level is supported.
  *
  * @since:
  *    2.2
  *
  */
 FT_EXPORT( FT_TrueTypeEngineType )
 FT_Get_TrueType_Engine_Type( FT_Library  library );

 /* */


FT_END_HEADER

#endif /* FTMODAPI_H_ */


/* END */