/**************************************************************************** * * ftdrv.h * * FreeType internal font driver interface (specification). * * Copyright (C) 1996-2024 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 #include "compiler-macros.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 */