/****************************************************************************
*
* ftdrv.h
*
* FreeType internal font driver interface (specification).
*
* Copyright (C) 1996-2019 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 FTDRV_H_
#define FTDRV_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 );
typedef FT_Error
(*FT_Slot_LoadFunc)( FT_GlyphSlot slot,
FT_Size size,
FT_UInt glyph_index,
FT_Int32 load_flags );
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. 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;
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;
/**************************************************************************
*
* @macro:
* FT_DECLARE_DRIVER
*
* @description:
* Used to create a forward declaration of an FT_Driver_ClassRec struct
* instance.
*
* @macro:
* FT_DEFINE_DRIVER
*
* @description:
* Used to initialize an instance of FT_Driver_ClassRec struct.
*
* `ftinit.c` (ft_create_default_module_classes) already contains a
* mechanism to call these functions for the default modules described in
* `ftmodule.h`.
*
* The struct will be allocated in the global scope (or the scope where
* the macro is used).
*/
#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_, \
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_, \
\
load_glyph_, \
\
get_kerning_, \
attach_file_, \
get_advances_, \
\
request_size_, \
select_size_ \
};
FT_END_HEADER
#endif /* FTDRV_H_ */
/* END */