1 /***************************************************************************/ 2 /* */ 3 /* ftadvanc.h */ 4 /* */ 5 /* Quick computation of advance widths (specification only). */ 6 /* */ 7 /* Copyright 2008 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 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 which 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, which 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. By default, the unhinted advance is returned in font */ 86 /* units. */ 87 /* */ 88 /* <Input> */ 89 /* face :: The source @FT_Face handle. */ 90 /* */ 91 /* gindex :: The glyph index. */ 92 /* */ 93 /* load_flags :: A set of bit flags similar to those used when */ 94 /* calling @FT_Load_Glyph, used to determine what kind */ 95 /* of advances you need. */ 96 /* <Output> */ 97 /* padvance :: The advance value, in either font units or 16.16 */ 98 /* format. */ 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. By default, the unhinted advances are returned in font */ 131 /* units. */ 132 /* */ 133 /* <Input> */ 134 /* face :: The source @FT_Face handle. */ 135 /* */ 136 /* start :: The first glyph index. */ 137 /* */ 138 /* count :: The number of advance values you want to retrieve. */ 139 /* */ 140 /* load_flags :: A set of bit flags similar to those used when */ 141 /* calling @FT_Load_Glyph. */ 142 /* */ 143 /* <Output> */ 144 /* padvance :: The advances, in either font units or 16.16 format. */ 145 /* This array must contain at least `count' elements. */ 146 /* */ 147 /* If @FT_LOAD_VERTICAL_LAYOUT is set, these are the */ 148 /* vertical advances corresponding to a vertical layout. */ 149 /* Otherwise, they are the horizontal advances in a */ 150 /* horizontal layout. */ 151 /* */ 152 /* <Return> */ 153 /* FreeType error code. 0 means success. */ 154 /* */ 155 /* <Note> */ 156 /* This function may fail if you use @FT_ADVANCE_FLAG_FAST_ONLY and */ 157 /* if the corresponding font backend doesn't have a quick way to */ 158 /* retrieve the advances. */ 159 /* */ 160 /* Scaled advances are returned in 16.16 format but aren't */ 161 /* transformed by the affine transformation specified by */ 162 /* @FT_Set_Transform. */ 163 /* */ 164 FT_EXPORT( FT_Error ) 165 FT_Get_Advances( FT_Face face, 166 FT_UInt start, 167 FT_UInt count, 168 FT_Int32 load_flags, 169 FT_Fixed *padvances ); 170 171 /* */ 172 173 174 FT_END_HEADER 175 176 #endif /* __FTADVANC_H__ */ 177 178 179 /* END */ 180
