text: /****************************************************************************
   *
   * ftmodapi.h
   *
   *   FreeType modules public interface (specification).
   *
   * Copyright (C) 1996-2022 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 */
  