ftdriver.h

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/***************************************************************************/
/*                                                                         */
/*  ftdriver.h                                                             */
/*                                                                         */
/*    FreeType font driver interface (specification).                      */
/*                                                                         */
/*  Copyright 1996-2001, 2002, 2003, 2006, 2008 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 __FTDRIVER_H__
#define __FTDRIVER_H__


#include <ft2build.h>
#include FT_MODULE_H


FT_BEGIN_HEADER


  typedef FT_Error
  (*FT_Face_InitFunc)( FT_Stream      stream,
                       FT_Face        face,
                       FT_Int         typeface_index,
                       FT_Int         num_params,
                       FT_Parameter*  parameters );

  typedef void
  (*FT_Face_DoneFunc)( FT_Face  face );


  typedef FT_Error
  (*FT_Size_InitFunc)( FT_Size  size );

  typedef void
  (*FT_Size_DoneFunc)( FT_Size  size );


  typedef FT_Error
  (*FT_Slot_InitFunc)( FT_GlyphSlot  slot );

  typedef void
  (*FT_Slot_DoneFunc)( FT_GlyphSlot  slot );


  typedef FT_Error
  (*FT_Size_RequestFunc)( FT_Size          size,
                          FT_Size_Request  req );

  typedef FT_Error
  (*FT_Size_SelectFunc)( FT_Size   size,
                         FT_ULong  size_index );

#ifdef FT_CONFIG_OPTION_OLD_INTERNALS

  typedef FT_Error
  (*FT_Size_ResetPointsFunc)( FT_Size     size,
                              FT_F26Dot6  char_width,
                              FT_F26Dot6  char_height,
                              FT_UInt     horz_resolution,
                              FT_UInt     vert_resolution );

  typedef FT_Error
  (*FT_Size_ResetPixelsFunc)( FT_Size  size,
                              FT_UInt  pixel_width,
                              FT_UInt  pixel_height );

#endif /* FT_CONFIG_OPTION_OLD_INTERNALS */

  typedef FT_Error
  (*FT_Slot_LoadFunc)( FT_GlyphSlot  slot,
                       FT_Size       size,
                       FT_UInt       glyph_index,
                       FT_Int32      load_flags );


  typedef FT_UInt
  (*FT_CharMap_CharIndexFunc)( FT_CharMap  charmap,
                               FT_Long     charcode );

  typedef FT_Long
  (*FT_CharMap_CharNextFunc)( FT_CharMap  charmap,
                              FT_Long     charcode );


  typedef FT_Error
  (*FT_Face_GetKerningFunc)( FT_Face     face,
                             FT_UInt     left_glyph,
                             FT_UInt     right_glyph,
                             FT_Vector*  kerning );


  typedef FT_Error
  (*FT_Face_AttachFunc)( FT_Face    face,
                         FT_Stream  stream );


  typedef FT_Error
  (*FT_Face_GetAdvancesFunc)( FT_Face    face,
                              FT_UInt    first,
                              FT_UInt    count,
                              FT_Int32   flags,
                              FT_Fixed*  advances );


  /*************************************************************************/
  /*                                                                       */
  /* <Struct>                                                              */
  /*    FT_Driver_ClassRec                                                 */
  /*                                                                       */
  /* <Description>                                                         */
  /*    The font driver class.  This structure mostly contains pointers to */
  /*    driver methods.                                                    */
  /*                                                                       */
  /* <Fields>                                                              */
  /*    root             :: The parent module.                             */
  /*                                                                       */
  /*    face_object_size :: The size of a face object in bytes.            */
  /*                                                                       */
  /*    size_object_size :: The size of a size object in bytes.            */
  /*                                                                       */
  /*    slot_object_size :: The size of a glyph object in bytes.           */
  /*                                                                       */
  /*    init_face        :: The format-specific face constructor.          */
  /*                                                                       */
  /*    done_face        :: The format-specific face destructor.           */
  /*                                                                       */
  /*    init_size        :: The format-specific size constructor.          */
  /*                                                                       */
  /*    done_size        :: The format-specific size destructor.           */
  /*                                                                       */
  /*    init_slot        :: The format-specific slot constructor.          */
  /*                                                                       */
  /*    done_slot        :: The format-specific slot destructor.           */
  /*                                                                       */
  /*                                                                       */
  /*    load_glyph       :: A function handle to load a glyph to a slot.   */
  /*                        This field is mandatory!                       */
  /*                                                                       */
  /*    get_kerning      :: A function handle to return the unscaled       */
  /*                        kerning for a given pair of glyphs.  Can be    */
  /*                        set to 0 if the format doesn't support         */
  /*                        kerning.                                       */
  /*                                                                       */
  /*    attach_file      :: This function handle is used to read           */
  /*                        additional data for a face from another        */
  /*                        file/stream.  For example, this can be used to */
  /*                        add data from AFM or PFM files on a Type 1     */
  /*                        face, or a CIDMap on a CID-keyed face.         */
  /*                                                                       */
  /*    get_advances     :: A function handle used to return advance       */
  /*                        widths of `count' glyphs (in font units),      */
  /*                        starting at `first'.  The `vertical' flag must */
  /*                        be set to get vertical advance heights.  The   */
  /*                        `advances' buffer is caller-allocated.         */
  /*                        Currently not implemented.  The idea of this   */
  /*                        function is to be able to perform              */
  /*                        device-independent text layout without loading */
  /*                        a single glyph image.                          */
  /*                                                                       */
  /*    request_size     :: A handle to a function used to request the new */
  /*                        character size.  Can be set to 0 if the        */
  /*                        scaling done in the base layer suffices.       */
  /*                                                                       */
  /*    select_size      :: A handle to a function used to select a new    */
  /*                        fixed size.  It is used only if                */
  /*                        @FT_FACE_FLAG_FIXED_SIZES is set.  Can be set  */
  /*                        to 0 if the scaling done in the base layer     */
  /*                        suffices.                                      */
  /* <Note>                                                                */
  /*    Most function pointers, with the exception of `load_glyph', can be */
  /*    set to 0 to indicate a default behaviour.                          */
  /*                                                                       */
  typedef struct  FT_Driver_ClassRec_
  {
    FT_Module_Class           root;

    FT_Long                   face_object_size;
    FT_Long                   size_object_size;
    FT_Long                   slot_object_size;

    FT_Face_InitFunc          init_face;
    FT_Face_DoneFunc          done_face;

    FT_Size_InitFunc          init_size;
    FT_Size_DoneFunc          done_size;

    FT_Slot_InitFunc          init_slot;
    FT_Slot_DoneFunc          done_slot;

#ifdef FT_CONFIG_OPTION_OLD_INTERNALS

    FT_Size_ResetPointsFunc   set_char_sizes;
    FT_Size_ResetPixelsFunc   set_pixel_sizes;

#endif /* FT_CONFIG_OPTION_OLD_INTERNALS */

    FT_Slot_LoadFunc          load_glyph;

    FT_Face_GetKerningFunc    get_kerning;
    FT_Face_AttachFunc        attach_file;
    FT_Face_GetAdvancesFunc   get_advances;

    /* since version 2.2 */
    FT_Size_RequestFunc       request_size;
    FT_Size_SelectFunc        select_size;

  } FT_Driver_ClassRec, *FT_Driver_Class;


  /*
   *  The following functions are used as stubs for `set_char_sizes' and
   *  `set_pixel_sizes'; the code uses `request_size' and `select_size'
   *  functions instead.
   *
   *  Implementation is in `src/base/ftobjs.c'.
   */
#ifdef FT_CONFIG_OPTION_OLD_INTERNALS

  FT_BASE( FT_Error )
  ft_stub_set_char_sizes( FT_Size     size,
                          FT_F26Dot6  width,
                          FT_F26Dot6  height,
                          FT_UInt     horz_res,
                          FT_UInt     vert_res );

  FT_BASE( FT_Error )
  ft_stub_set_pixel_sizes( FT_Size  size,
                           FT_UInt  width,
                           FT_UInt  height );

#endif /* FT_CONFIG_OPTION_OLD_INTERNALS */

  /*************************************************************************/
  /*                                                                       */
  /* <Macro>                                                               */
  /*    FT_DECLARE_DRIVER                                                  */
  /*                                                                       */
  /* <Description>                                                         */
  /*    Used to create a forward declaration of a                          */
  /*    FT_Driver_ClassRec stract instance.                                */
  /*                                                                       */
  /* <Macro>                                                               */
  /*    FT_DEFINE_DRIVER                                                   */
  /*                                                                       */
  /* <Description>                                                         */
  /*    Used to initialize an instance of FT_Driver_ClassRec struct.       */
  /*                                                                       */
  /*    When FT_CONFIG_OPTION_PIC is defined a Create funtion will need    */
  /*    to called with a pointer where the allocated stracture is returned.*/
  /*    And when it is no longer needed a Destroy function needs           */
  /*    to be called to release that allocation.                           */
  /*    fcinit.c (ft_create_default_module_classes) already contains       */
  /*    a mechanism to call these functions for the default modules        */
  /*    described in ftmodule.h                                            */
  /*                                                                       */
  /*    Notice that the created Create and Destroy functions call          */
  /*    pic_init and pic_free function to allow you to manually allocate   */
  /*    and initialize any additional global data, like module specific    */
  /*    interface, and put them in the global pic container defined in     */
  /*    ftpic.h. if you don't need them just implement the functions as    */
  /*    empty to resolve the link error.                                   */
  /*                                                                       */
  /*    When FT_CONFIG_OPTION_PIC is not defined the struct will be        */
  /*    allocated in the global scope (or the scope where the macro        */
  /*    is used).                                                          */
  /*                                                                       */
#ifndef FT_CONFIG_OPTION_PIC

#ifdef FT_CONFIG_OPTION_OLD_INTERNALS
#define FT_DEFINE_DRIVERS_OLD_INTERNALS(a_,b_) \
  a_, b_,
#else
  #define FT_DEFINE_DRIVERS_OLD_INTERNALS(a_,b_)
#endif

#define FT_DECLARE_DRIVER(class_)    \
  FT_CALLBACK_TABLE                  \
  const FT_Driver_ClassRec  class_;  

#define FT_DEFINE_DRIVER(class_,                                             \
                         flags_, size_, name_, version_, requires_,          \
                         interface_, init_, done_, get_interface_,           \
                         face_object_size_, size_object_size_,               \
                         slot_object_size_, init_face_, done_face_,          \
                         init_size_, done_size_, init_slot_, done_slot_,     \
                         old_set_char_sizes_, old_set_pixel_sizes_,          \
                         load_glyph_, get_kerning_, attach_file_,            \
                         get_advances_, request_size_, select_size_ )        \
  FT_CALLBACK_TABLE_DEF                                                      \
  const FT_Driver_ClassRec class_ =                                          \
  {                                                                          \
    FT_DEFINE_ROOT_MODULE(flags_,size_,name_,version_,requires_,interface_,  \
                          init_,done_,get_interface_)                        \
                                                                             \
    face_object_size_,                                                       \
    size_object_size_,                                                       \
    slot_object_size_,                                                       \
                                                                             \
    init_face_,                                                              \
    done_face_,                                                              \
                                                                             \
    init_size_,                                                              \
    done_size_,                                                              \
                                                                             \
    init_slot_,                                                              \
    done_slot_,                                                              \
                                                                             \
    FT_DEFINE_DRIVERS_OLD_INTERNALS(old_set_char_sizes_, old_set_pixel_sizes_) \
                                                                             \
    load_glyph_,                                                             \
                                                                             \
    get_kerning_,                                                            \
    attach_file_,                                                            \
    get_advances_,                                                           \
                                                                             \
    request_size_,                                                           \
    select_size_                                                             \
  };

#else /* FT_CONFIG_OPTION_PIC */ 

#ifdef FT_CONFIG_OPTION_OLD_INTERNALS
#define FT_DEFINE_DRIVERS_OLD_INTERNALS(a_,b_) \
  clazz->set_char_sizes = a_; \
  clazz->set_pixel_sizes = b_;
#else
  #define FT_DEFINE_DRIVERS_OLD_INTERNALS(a_,b_)
#endif

#define FT_DECLARE_DRIVER(class_)    FT_DECLARE_MODULE(class_)

#define FT_DEFINE_DRIVER(class_,                                             \
                         flags_, size_, name_, version_, requires_,          \
                         interface_, init_, done_, get_interface_,           \
                         face_object_size_, size_object_size_,               \
                         slot_object_size_, init_face_, done_face_,          \
                         init_size_, done_size_, init_slot_, done_slot_,     \
                         old_set_char_sizes_, old_set_pixel_sizes_,          \
                         load_glyph_, get_kerning_, attach_file_,            \
                         get_advances_, request_size_, select_size_ )        \
  void class_##_pic_free( FT_Library library );                              \
  FT_Error class_##_pic_init( FT_Library library );                          \
                                                                             \
  void                                                                       \
  FT_Destroy_Class_##class_( FT_Library        library,                      \
                             FT_Module_Class*  clazz )                       \
  {                                                                          \
    FT_Memory       memory = library->memory;                                \
    FT_Driver_Class dclazz = (FT_Driver_Class)clazz;                         \
    class_##_pic_free( library );                                            \
    if ( dclazz )                                                            \
      FT_FREE( dclazz );                                                     \
  }                                                                          \
                                                                             \
  FT_Error                                                                   \
  FT_Create_Class_##class_( FT_Library        library,                       \
                            FT_Module_Class**  output_class )                \
  {                                                                          \
    FT_Driver_Class  clazz;                                                  \
    FT_Error         error;                                                  \
    FT_Memory        memory = library->memory;                               \
                                                                             \
    if ( FT_ALLOC( clazz, sizeof(*clazz) ) )                                 \
      return error;                                                          \
                                                                             \
    error = class_##_pic_init( library );                                    \
    if(error)                                                                \
    {                                                                        \
      FT_FREE( clazz );                                                      \
      return error;                                                          \
    }                                                                        \
                                                                             \
    FT_DEFINE_ROOT_MODULE(flags_,size_,name_,version_,requires_,interface_,  \
                          init_,done_,get_interface_)                        \
                                                                             \
    clazz->face_object_size    = face_object_size_;                          \
    clazz->size_object_size    = size_object_size_;                          \
    clazz->slot_object_size    = slot_object_size_;                          \
                                                                             \
    clazz->init_face           = init_face_;                                 \
    clazz->done_face           = done_face_;                                 \
                                                                             \
    clazz->init_size           = init_size_;                                 \
    clazz->done_size           = done_size_;                                 \
                                                                             \
    clazz->init_slot           = init_slot_;                                 \
    clazz->done_slot           = done_slot_;                                 \
                                                                             \
    FT_DEFINE_DRIVERS_OLD_INTERNALS(old_set_char_sizes_, old_set_pixel_sizes_) \
                                                                             \
    clazz->load_glyph          = load_glyph_;                                \
                                                                             \
    clazz->get_kerning         = get_kerning_;                               \
    clazz->attach_file         = attach_file_;                               \
    clazz->get_advances        = get_advances_;                              \
                                                                             \
    clazz->request_size        = request_size_;                              \
    clazz->select_size         = select_size_;                               \
                                                                             \
    *output_class = (FT_Module_Class*)clazz;                                 \
    return FT_Err_Ok;                                                        \
  }                


#endif /* FT_CONFIG_OPTION_PIC */

FT_END_HEADER

#endif /* __FTDRIVER_H__ */


/* END */

---