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