ftadvanc.h revision ec0bab5697bb31ba980810145f62e3799946ec60
1/***************************************************************************/ 2/* */ 3/* ftadvanc.h */ 4/* */ 5/* Quick computation of advance widths (specification only). */ 6/* */ 7/* Copyright 2008, 2013 by */ 8/* David Turner, Robert Wilhelm, and Werner Lemberg. */ 9/* */ 10/* This file is part of the FreeType project, and may only be used, */ 11/* modified, and distributed under the terms of the FreeType project */ 12/* license, LICENSE.TXT. By continuing to use, modify, or distribute */ 13/* this file you indicate that you have read the license and */ 14/* understand and accept it fully. */ 15/* */ 16/***************************************************************************/ 17 18 19#ifndef __FTADVANC_H__ 20#define __FTADVANC_H__ 21 22 23#include <ft2build.h> 24#include FT_FREETYPE_H 25 26#ifdef FREETYPE_H 27#error "freetype.h of FreeType 1 has been loaded!" 28#error "Please fix the directory search order for header files" 29#error "so that freetype.h of FreeType 2 is found first." 30#endif 31 32 33FT_BEGIN_HEADER 34 35 36 /************************************************************************** 37 * 38 * @section: 39 * quick_advance 40 * 41 * @title: 42 * Quick retrieval of advance values 43 * 44 * @abstract: 45 * Retrieve horizontal and vertical advance values without processing 46 * glyph outlines, if possible. 47 * 48 * @description: 49 * This section contains functions to quickly extract advance values 50 * without handling glyph outlines, if possible. 51 */ 52 53 54 /*************************************************************************/ 55 /* */ 56 /* <Const> */ 57 /* FT_ADVANCE_FLAG_FAST_ONLY */ 58 /* */ 59 /* <Description> */ 60 /* A bit-flag to be OR-ed with the `flags' parameter of the */ 61 /* @FT_Get_Advance and @FT_Get_Advances functions. */ 62 /* */ 63 /* If set, it indicates that you want these functions to fail if the */ 64 /* corresponding hinting mode or font driver doesn't allow for very */ 65 /* quick advance computation. */ 66 /* */ 67 /* Typically, glyphs that are either unscaled, unhinted, bitmapped, */ 68 /* or light-hinted can have their advance width computed very */ 69 /* quickly. */ 70 /* */ 71 /* Normal and bytecode hinted modes that require loading, scaling, */ 72 /* and hinting of the glyph outline, are extremely slow by */ 73 /* comparison. */ 74 /* */ 75#define FT_ADVANCE_FLAG_FAST_ONLY 0x20000000UL 76 77 78 /*************************************************************************/ 79 /* */ 80 /* <Function> */ 81 /* FT_Get_Advance */ 82 /* */ 83 /* <Description> */ 84 /* Retrieve the advance value of a given glyph outline in an */ 85 /* @FT_Face. */ 86 /* */ 87 /* <Input> */ 88 /* face :: The source @FT_Face handle. */ 89 /* */ 90 /* gindex :: The glyph index. */ 91 /* */ 92 /* load_flags :: A set of bit flags similar to those used when */ 93 /* calling @FT_Load_Glyph, used to determine what kind */ 94 /* of advances you need. */ 95 /* <Output> */ 96 /* padvance :: The advance value. If scaling is performed (based on */ 97 /* the value of `load_flags'), the advance value is in */ 98 /* 16.16 format. Otherwise, it is in font units. */ 99 /* */ 100 /* If @FT_LOAD_VERTICAL_LAYOUT is set, this is the */ 101 /* vertical advance corresponding to a vertical layout. */ 102 /* Otherwise, it is the horizontal advance in a */ 103 /* horizontal layout. */ 104 /* */ 105 /* <Return> */ 106 /* FreeType error code. 0 means success. */ 107 /* */ 108 /* <Note> */ 109 /* This function may fail if you use @FT_ADVANCE_FLAG_FAST_ONLY and */ 110 /* if the corresponding font backend doesn't have a quick way to */ 111 /* retrieve the advances. */ 112 /* */ 113 /* A scaled advance is returned in 16.16 format but isn't transformed */ 114 /* by the affine transformation specified by @FT_Set_Transform. */ 115 /* */ 116 FT_EXPORT( FT_Error ) 117 FT_Get_Advance( FT_Face face, 118 FT_UInt gindex, 119 FT_Int32 load_flags, 120 FT_Fixed *padvance ); 121 122 123 /*************************************************************************/ 124 /* */ 125 /* <Function> */ 126 /* FT_Get_Advances */ 127 /* */ 128 /* <Description> */ 129 /* Retrieve the advance values of several glyph outlines in an */ 130 /* @FT_Face. */ 131 /* */ 132 /* <Input> */ 133 /* face :: The source @FT_Face handle. */ 134 /* */ 135 /* start :: The first glyph index. */ 136 /* */ 137 /* count :: The number of advance values you want to retrieve. */ 138 /* */ 139 /* load_flags :: A set of bit flags similar to those used when */ 140 /* calling @FT_Load_Glyph. */ 141 /* */ 142 /* <Output> */ 143 /* padvance :: The advance values. This array, to be provided by the */ 144 /* caller, must contain at least `count' elements. */ 145 /* */ 146 /* If scaling is performed (based on the value of */ 147 /* `load_flags'), the advance values are in 16.16 format. */ 148 /* Otherwise, they are in font units. */ 149 /* */ 150 /* If @FT_LOAD_VERTICAL_LAYOUT is set, these are the */ 151 /* vertical advances corresponding to a vertical layout. */ 152 /* Otherwise, they are the horizontal advances in a */ 153 /* horizontal layout. */ 154 /* */ 155 /* <Return> */ 156 /* FreeType error code. 0 means success. */ 157 /* */ 158 /* <Note> */ 159 /* This function may fail if you use @FT_ADVANCE_FLAG_FAST_ONLY and */ 160 /* if the corresponding font backend doesn't have a quick way to */ 161 /* retrieve the advances. */ 162 /* */ 163 /* Scaled advances are returned in 16.16 format but aren't */ 164 /* transformed by the affine transformation specified by */ 165 /* @FT_Set_Transform. */ 166 /* */ 167 FT_EXPORT( FT_Error ) 168 FT_Get_Advances( FT_Face face, 169 FT_UInt start, 170 FT_UInt count, 171 FT_Int32 load_flags, 172 FT_Fixed *padvances ); 173 174/* */ 175 176 177FT_END_HEADER 178 179#endif /* __FTADVANC_H__ */ 180 181 182/* END */ 183