freetype2/include/ftadvanc.h

188 lines
10 KiB
C

/***************************************************************************/
/* */
/* ftadvanc.h */
/* */
/* Quick computation of advance widths (specification only). */
/* */
/* Copyright 2008, 2013, 2014 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 __FTADVANC_H__
#define __FTADVANC_H__
#include <ft2build.h>
#include FT_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:
* quick_advance
*
* @title:
* Quick retrieval of advance values
*
* @abstract:
* Retrieve horizontal and vertical advance values without processing
* glyph outlines, if possible.
*
* @description:
* This section contains functions to quickly extract advance values
* without handling glyph outlines, if possible.
*
* @order:
* FT_Get_Advance
* FT_Get_Advances
*
*/
/*************************************************************************/
/* */
/* <Const> */
/* FT_ADVANCE_FLAG_FAST_ONLY */
/* */
/* <Description> */
/* A bit-flag to be OR-ed with the `flags' parameter of the */
/* @FT_Get_Advance and @FT_Get_Advances functions. */
/* */
/* If set, it indicates that you want these functions to fail if the */
/* corresponding hinting mode or font driver doesn't allow for very */
/* quick advance computation. */
/* */
/* Typically, glyphs that are either unscaled, unhinted, bitmapped, */
/* or light-hinted can have their advance width computed very */
/* quickly. */
/* */
/* Normal and bytecode hinted modes that require loading, scaling, */
/* and hinting of the glyph outline, are extremely slow by */
/* comparison. */
/* */
#define FT_ADVANCE_FLAG_FAST_ONLY 0x20000000UL
/*************************************************************************/
/* */
/* <Function> */
/* FT_Get_Advance */
/* */
/* <Description> */
/* Retrieve the advance value of a given glyph outline in an */
/* @FT_Face. */
/* */
/* <Input> */
/* face :: The source @FT_Face handle. */
/* */
/* gindex :: The glyph index. */
/* */
/* load_flags :: A set of bit flags similar to those used when */
/* calling @FT_Load_Glyph, used to determine what kind */
/* of advances you need. */
/* <Output> */
/* padvance :: The advance value. If scaling is performed (based on */
/* the value of `load_flags'), the advance value is in */
/* 16.16 format. Otherwise, it is in font units. */
/* */
/* If @FT_LOAD_VERTICAL_LAYOUT is set, this is the */
/* vertical advance corresponding to a vertical layout. */
/* Otherwise, it is the horizontal advance in a */
/* horizontal layout. */
/* */
/* <Return> */
/* FreeType error code. 0 means success. */
/* */
/* <Note> */
/* This function may fail if you use @FT_ADVANCE_FLAG_FAST_ONLY and */
/* if the corresponding font backend doesn't have a quick way to */
/* retrieve the advances. */
/* */
/* A scaled advance is returned in 16.16 format but isn't transformed */
/* by the affine transformation specified by @FT_Set_Transform. */
/* */
FT_EXPORT( FT_Error )
FT_Get_Advance( FT_Face face,
FT_UInt gindex,
FT_Int32 load_flags,
FT_Fixed *padvance );
/*************************************************************************/
/* */
/* <Function> */
/* FT_Get_Advances */
/* */
/* <Description> */
/* Retrieve the advance values of several glyph outlines in an */
/* @FT_Face. */
/* */
/* <Input> */
/* face :: The source @FT_Face handle. */
/* */
/* start :: The first glyph index. */
/* */
/* count :: The number of advance values you want to retrieve. */
/* */
/* load_flags :: A set of bit flags similar to those used when */
/* calling @FT_Load_Glyph. */
/* */
/* <Output> */
/* padvance :: The advance values. This array, to be provided by the */
/* caller, must contain at least `count' elements. */
/* */
/* If scaling is performed (based on the value of */
/* `load_flags'), the advance values are in 16.16 format. */
/* Otherwise, they are in font units. */
/* */
/* If @FT_LOAD_VERTICAL_LAYOUT is set, these are the */
/* vertical advances corresponding to a vertical layout. */
/* Otherwise, they are the horizontal advances in a */
/* horizontal layout. */
/* */
/* <Return> */
/* FreeType error code. 0 means success. */
/* */
/* <Note> */
/* This function may fail if you use @FT_ADVANCE_FLAG_FAST_ONLY and */
/* if the corresponding font backend doesn't have a quick way to */
/* retrieve the advances. */
/* */
/* Scaled advances are returned in 16.16 format but aren't */
/* transformed by the affine transformation specified by */
/* @FT_Set_Transform. */
/* */
FT_EXPORT( FT_Error )
FT_Get_Advances( FT_Face face,
FT_UInt start,
FT_UInt count,
FT_Int32 load_flags,
FT_Fixed *padvances );
/* */
FT_END_HEADER
#endif /* __FTADVANC_H__ */
/* END */