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 /****************************************************************************
  *
  * ftmodapi.h
  *
  *   FreeType modules public interface (specification).
  *
  * Copyright (C) 1996-2023 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 */

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