1 /***************************************************************************/ 2 /* */ 3 /* ftadvanc.h */ 4 /* */ 5 /* Quick computation of advance widths (specification only). */ 6 /* */ 7 /* Copyright 2008-2018 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 33 FT_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 * @order: 53 * FT_Get_Advance 54 * FT_Get_Advances 55 * 56 */ 57 58 59 /*************************************************************************/ 60 /* */ 61 /* <Const> */ 62 /* FT_ADVANCE_FLAG_FAST_ONLY */ 63 /* */ 64 /* <Description> */ 65 /* A bit-flag to be OR-ed with the `flags' parameter of the */ 66 /* @FT_Get_Advance and @FT_Get_Advances functions. */ 67 /* */ 68 /* If set, it indicates that you want these functions to fail if the */ 69 /* corresponding hinting mode or font driver doesn't allow for very */ 70 /* quick advance computation. */ 71 /* */ 72 /* Typically, glyphs that are either unscaled, unhinted, bitmapped, */ 73 /* or light-hinted can have their advance width computed very */ 74 /* quickly. */ 75 /* */ 76 /* Normal and bytecode hinted modes that require loading, scaling, */ 77 /* and hinting of the glyph outline, are extremely slow by */ 78 /* comparison. */ 79 /* */ 80 #define FT_ADVANCE_FLAG_FAST_ONLY 0x20000000L 81 82 83 /*************************************************************************/ 84 /* */ 85 /* <Function> */ 86 /* FT_Get_Advance */ 87 /* */ 88 /* <Description> */ 89 /* Retrieve the advance value of a given glyph outline in an */ 90 /* @FT_Face. */ 91 /* */ 92 /* <Input> */ 93 /* face :: The source @FT_Face handle. */ 94 /* */ 95 /* gindex :: The glyph index. */ 96 /* */ 97 /* load_flags :: A set of bit flags similar to those used when */ 98 /* calling @FT_Load_Glyph, used to determine what kind */ 99 /* of advances you need. */ 100 /* <Output> */ 101 /* padvance :: The advance value. If scaling is performed (based on */ 102 /* the value of `load_flags'), the advance value is in */ 103 /* 16.16 format. Otherwise, it is in font units. */ 104 /* */ 105 /* If @FT_LOAD_VERTICAL_LAYOUT is set, this is the */ 106 /* vertical advance corresponding to a vertical layout. */ 107 /* Otherwise, it is the horizontal advance in a */ 108 /* horizontal layout. */ 109 /* */ 110 /* <Return> */ 111 /* FreeType error code. 0 means success. */ 112 /* */ 113 /* <Note> */ 114 /* This function may fail if you use @FT_ADVANCE_FLAG_FAST_ONLY and */ 115 /* if the corresponding font backend doesn't have a quick way to */ 116 /* retrieve the advances. */ 117 /* */ 118 /* A scaled advance is returned in 16.16 format but isn't transformed */ 119 /* by the affine transformation specified by @FT_Set_Transform. */ 120 /* */ 121 FT_EXPORT( FT_Error ) 122 FT_Get_Advance( FT_Face face, 123 FT_UInt gindex, 124 FT_Int32 load_flags, 125 FT_Fixed *padvance ); 126 127 128 /*************************************************************************/ 129 /* */ 130 /* <Function> */ 131 /* FT_Get_Advances */ 132 /* */ 133 /* <Description> */ 134 /* Retrieve the advance values of several glyph outlines in an */ 135 /* @FT_Face. */ 136 /* */ 137 /* <Input> */ 138 /* face :: The source @FT_Face handle. */ 139 /* */ 140 /* start :: The first glyph index. */ 141 /* */ 142 /* count :: The number of advance values you want to retrieve. */ 143 /* */ 144 /* load_flags :: A set of bit flags similar to those used when */ 145 /* calling @FT_Load_Glyph. */ 146 /* */ 147 /* <Output> */ 148 /* padvance :: The advance values. This array, to be provided by the */ 149 /* caller, must contain at least `count' elements. */ 150 /* */ 151 /* If scaling is performed (based on the value of */ 152 /* `load_flags'), the advance values are in 16.16 format. */ 153 /* Otherwise, they are in font units. */ 154 /* */ 155 /* If @FT_LOAD_VERTICAL_LAYOUT is set, these are the */ 156 /* vertical advances corresponding to a vertical layout. */ 157 /* Otherwise, they are the horizontal advances in a */ 158 /* horizontal layout. */ 159 /* */ 160 /* <Return> */ 161 /* FreeType error code. 0 means success. */ 162 /* */ 163 /* <Note> */ 164 /* This function may fail if you use @FT_ADVANCE_FLAG_FAST_ONLY and */ 165 /* if the corresponding font backend doesn't have a quick way to */ 166 /* retrieve the advances. */ 167 /* */ 168 /* Scaled advances are returned in 16.16 format but aren't */ 169 /* transformed by the affine transformation specified by */ 170 /* @FT_Set_Transform. */ 171 /* */ 172 FT_EXPORT( FT_Error ) 173 FT_Get_Advances( FT_Face face, 174 FT_UInt start, 175 FT_UInt count, 176 FT_Int32 load_flags, 177 FT_Fixed *padvances ); 178 179 /* */ 180 181 182 FT_END_HEADER 183 184 #endif /* FTADVANC_H_ */ 185 186 187 /* END */ 188
