00001 /***************************************************************************/ 00002 /* */ 00003 /* ftadvanc.h */ 00004 /* */ 00005 /* Quick computation of advance widths (specification only). */ 00006 /* */ 00007 /* Copyright 2008 by */ 00008 /* David Turner, Robert Wilhelm, and Werner Lemberg. */ 00009 /* */ 00010 /* This file is part of the FreeType project, and may only be used, */ 00011 /* modified, and distributed under the terms of the FreeType project */ 00012 /* license, LICENSE.TXT. By continuing to use, modify, or distribute */ 00013 /* this file you indicate that you have read the license and */ 00014 /* understand and accept it fully. */ 00015 /* */ 00016 /***************************************************************************/ 00017 00018 00019 #ifndef __FTADVANC_H__ 00020 #define __FTADVANC_H__ 00021 00022 00023 #include <ft2build.h> 00024 #include FT_FREETYPE_H 00025 00026 #ifdef FREETYPE_H 00027 #error "freetype.h of FreeType 1 has been loaded!" 00028 #error "Please fix the directory search order for header files" 00029 #error "so that freetype.h of FreeType 2 is found first." 00030 #endif 00031 00032 00033 FT_BEGIN_HEADER 00034 00035 00036 /************************************************************************** 00037 * 00038 * @section: 00039 * quick_advance 00040 * 00041 * @title: 00042 * Quick retrieval of advance values 00043 * 00044 * @abstract: 00045 * Retrieve horizontal and vertical advance values without processing 00046 * glyph outlines, if possible. 00047 * 00048 * @description: 00049 * This section contains functions to quickly extract advance values 00050 * without handling glyph outlines, if possible. 00051 */ 00052 00053 00054 /*************************************************************************/ 00055 /* */ 00056 /* <Const> */ 00057 /* FT_ADVANCE_FLAG_FAST_ONLY */ 00058 /* */ 00059 /* <Description> */ 00060 /* A bit-flag to be OR-ed with the `flags' parameter of the */ 00061 /* @FT_Get_Advance and @FT_Get_Advances functions. */ 00062 /* */ 00063 /* If set, it indicates that you want these functions to fail if the */ 00064 /* corresponding hinting mode or font driver doesn't allow for very */ 00065 /* quick advance computation. */ 00066 /* */ 00067 /* Typically, glyphs which are either unscaled, unhinted, bitmapped, */ 00068 /* or light-hinted can have their advance width computed very */ 00069 /* quickly. */ 00070 /* */ 00071 /* Normal and bytecode hinted modes, which require loading, scaling, */ 00072 /* and hinting of the glyph outline, are extremely slow by */ 00073 /* comparison. */ 00074 /* */ 00075 #define FT_ADVANCE_FLAG_FAST_ONLY 0x20000000UL 00076 00077 00078 /*************************************************************************/ 00079 /* */ 00080 /* <Function> */ 00081 /* FT_Get_Advance */ 00082 /* */ 00083 /* <Description> */ 00084 /* Retrieve the advance value of a given glyph outline in an */ 00085 /* @FT_Face. By default, the unhinted advance is returned in font */ 00086 /* units. */ 00087 /* */ 00088 /* <Input> */ 00089 /* face :: The source @FT_Face handle. */ 00090 /* */ 00091 /* gindex :: The glyph index. */ 00092 /* */ 00093 /* load_flags :: A set of bit flags similar to those used when */ 00094 /* calling @FT_Load_Glyph, used to determine what kind */ 00095 /* of advances you need. */ 00096 /* <Output> */ 00097 /* padvance :: The advance value, in either font units or 16.16 */ 00098 /* format. */ 00099 /* */ 00100 /* If @FT_LOAD_VERTICAL_LAYOUT is set, this is the */ 00101 /* vertical advance corresponding to a vertical layout. */ 00102 /* Otherwise, it is the horizontal advance in a */ 00103 /* horizontal layout. */ 00104 /* */ 00105 /* <Return> */ 00106 /* FreeType error code. 0 means success. */ 00107 /* */ 00108 /* <Note> */ 00109 /* This function may fail if you use @FT_ADVANCE_FLAG_FAST_ONLY and */ 00110 /* if the corresponding font backend doesn't have a quick way to */ 00111 /* retrieve the advances. */ 00112 /* */ 00113 /* A scaled advance is returned in 16.16 format but isn't transformed */ 00114 /* by the affine transformation specified by @FT_Set_Transform. */ 00115 /* */ 00116 FT_EXPORT( FT_Error ) 00117 FT_Get_Advance( FT_Face face, 00118 FT_UInt gindex, 00119 FT_Int32 load_flags, 00120 FT_Fixed *padvance ); 00121 00122 00123 /*************************************************************************/ 00124 /* */ 00125 /* <Function> */ 00126 /* FT_Get_Advances */ 00127 /* */ 00128 /* <Description> */ 00129 /* Retrieve the advance values of several glyph outlines in an */ 00130 /* @FT_Face. By default, the unhinted advances are returned in font */ 00131 /* units. */ 00132 /* */ 00133 /* <Input> */ 00134 /* face :: The source @FT_Face handle. */ 00135 /* */ 00136 /* start :: The first glyph index. */ 00137 /* */ 00138 /* count :: The number of advance values you want to retrieve. */ 00139 /* */ 00140 /* load_flags :: A set of bit flags similar to those used when */ 00141 /* calling @FT_Load_Glyph. */ 00142 /* */ 00143 /* <Output> */ 00144 /* padvance :: The advances, in either font units or 16.16 format. */ 00145 /* This array must contain at least `count' elements. */ 00146 /* */ 00147 /* If @FT_LOAD_VERTICAL_LAYOUT is set, these are the */ 00148 /* vertical advances corresponding to a vertical layout. */ 00149 /* Otherwise, they are the horizontal advances in a */ 00150 /* horizontal layout. */ 00151 /* */ 00152 /* <Return> */ 00153 /* FreeType error code. 0 means success. */ 00154 /* */ 00155 /* <Note> */ 00156 /* This function may fail if you use @FT_ADVANCE_FLAG_FAST_ONLY and */ 00157 /* if the corresponding font backend doesn't have a quick way to */ 00158 /* retrieve the advances. */ 00159 /* */ 00160 /* Scaled advances are returned in 16.16 format but aren't */ 00161 /* transformed by the affine transformation specified by */ 00162 /* @FT_Set_Transform. */ 00163 /* */ 00164 FT_EXPORT( FT_Error ) 00165 FT_Get_Advances( FT_Face face, 00166 FT_UInt start, 00167 FT_UInt count, 00168 FT_Int32 load_flags, 00169 FT_Fixed *padvances ); 00170 00171 /* */ 00172 00173 00174 FT_END_HEADER 00175 00176 #endif /* __FTADVANC_H__ */ 00177 00178 00179 /* END */
1.5.1