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1 /***************************************************************************/ |
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2 /* */ |
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3 /* ftadvanc.c */ |
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4 /* */ |
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5 /* Quick computation of advance widths (body). */ |
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6 /* */ |
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7 /* Copyright 2008, 2009 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 #include <ft2build.h> |
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20 #include FT_ADVANCES_H |
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21 #include FT_INTERNAL_OBJECTS_H |
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22 |
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23 |
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24 static FT_Error |
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25 _ft_face_scale_advances( FT_Face face, |
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26 FT_Fixed* advances, |
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27 FT_UInt count, |
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28 FT_Int32 flags ) |
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29 { |
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30 FT_Fixed scale; |
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31 FT_UInt nn; |
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32 |
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33 |
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34 if ( flags & FT_LOAD_NO_SCALE ) |
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35 return FT_Err_Ok; |
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36 |
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37 if ( face->size == NULL ) |
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38 return FT_Err_Invalid_Size_Handle; |
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39 |
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40 if ( flags & FT_LOAD_VERTICAL_LAYOUT ) |
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41 scale = face->size->metrics.y_scale; |
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42 else |
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43 scale = face->size->metrics.x_scale; |
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44 |
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45 /* this must be the same scaling as to get linear{Hori,Vert}Advance */ |
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46 /* (see `FT_Load_Glyph' implementation in src/base/ftobjs.c) */ |
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47 |
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48 for ( nn = 0; nn < count; nn++ ) |
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49 advances[nn] = FT_MulDiv( advances[nn], scale, 64 ); |
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50 |
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51 return FT_Err_Ok; |
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52 } |
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53 |
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54 |
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55 /* at the moment, we can perform fast advance retrieval only in */ |
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56 /* the following cases: */ |
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57 /* */ |
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58 /* - unscaled load */ |
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59 /* - unhinted load */ |
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60 /* - light-hinted load */ |
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61 |
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62 #define LOAD_ADVANCE_FAST_CHECK( flags ) \ |
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63 ( flags & ( FT_LOAD_NO_SCALE | FT_LOAD_NO_HINTING ) || \ |
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64 FT_LOAD_TARGET_MODE( flags ) == FT_RENDER_MODE_LIGHT ) |
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65 |
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66 |
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67 /* documentation is in ftadvanc.h */ |
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68 |
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69 FT_EXPORT_DEF( FT_Error ) |
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70 FT_Get_Advance( FT_Face face, |
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71 FT_UInt gindex, |
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72 FT_Int32 flags, |
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73 FT_Fixed *padvance ) |
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74 { |
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75 FT_Face_GetAdvancesFunc func; |
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76 |
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77 |
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78 if ( !face ) |
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79 return FT_Err_Invalid_Face_Handle; |
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80 |
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81 if ( gindex >= (FT_UInt)face->num_glyphs ) |
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82 return FT_Err_Invalid_Glyph_Index; |
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83 |
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84 func = face->driver->clazz->get_advances; |
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85 if ( func && LOAD_ADVANCE_FAST_CHECK( flags ) ) |
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86 { |
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87 FT_Error error; |
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88 |
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89 |
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90 error = func( face, gindex, 1, flags, padvance ); |
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91 if ( !error ) |
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92 return _ft_face_scale_advances( face, padvance, 1, flags ); |
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93 |
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94 if ( error != FT_ERROR_BASE( FT_Err_Unimplemented_Feature ) ) |
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95 return error; |
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96 } |
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97 |
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98 return FT_Get_Advances( face, gindex, 1, flags, padvance ); |
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99 } |
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100 |
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101 |
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102 /* documentation is in ftadvanc.h */ |
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103 |
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104 FT_EXPORT_DEF( FT_Error ) |
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105 FT_Get_Advances( FT_Face face, |
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106 FT_UInt start, |
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107 FT_UInt count, |
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108 FT_Int32 flags, |
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109 FT_Fixed *padvances ) |
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110 { |
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111 FT_Face_GetAdvancesFunc func; |
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112 FT_UInt num, end, nn; |
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113 FT_Error error = FT_Err_Ok; |
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114 |
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115 |
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116 if ( !face ) |
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117 return FT_Err_Invalid_Face_Handle; |
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118 |
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119 num = (FT_UInt)face->num_glyphs; |
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120 end = start + count; |
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121 if ( start >= num || end < start || end > num ) |
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122 return FT_Err_Invalid_Glyph_Index; |
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123 |
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124 if ( count == 0 ) |
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125 return FT_Err_Ok; |
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126 |
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127 func = face->driver->clazz->get_advances; |
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128 if ( func && LOAD_ADVANCE_FAST_CHECK( flags ) ) |
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129 { |
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130 error = func( face, start, count, flags, padvances ); |
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131 if ( !error ) |
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132 goto Exit; |
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133 |
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134 if ( error != FT_ERROR_BASE( FT_Err_Unimplemented_Feature ) ) |
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135 return error; |
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136 } |
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137 |
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138 error = FT_Err_Ok; |
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139 |
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140 if ( flags & FT_ADVANCE_FLAG_FAST_ONLY ) |
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141 return FT_Err_Unimplemented_Feature; |
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142 |
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143 flags |= (FT_UInt32)FT_LOAD_ADVANCE_ONLY; |
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144 for ( nn = 0; nn < count; nn++ ) |
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145 { |
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146 error = FT_Load_Glyph( face, start + nn, flags ); |
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147 if ( error ) |
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148 break; |
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149 |
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150 padvances[nn] = ( flags & FT_LOAD_VERTICAL_LAYOUT ) |
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151 ? face->glyph->advance.y |
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152 : face->glyph->advance.x; |
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153 } |
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154 |
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155 if ( error ) |
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156 return error; |
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157 |
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158 Exit: |
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159 return _ft_face_scale_advances( face, padvances, count, flags ); |
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160 } |
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161 |
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162 |
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163 /* END */ |