1 How to customize the compilation of the library |
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2 =============================================== |
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3 |
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4 FreeType is highly customizable to fit various needs, and this |
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5 document describes how it is possible to select options and |
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6 components at compilation time. |
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7 |
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8 |
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9 I. Configuration macros |
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10 |
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11 The file found in `include/freetype/config/ftoption.h' contains a |
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12 list of commented configuration macros that can be toggled by |
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13 developers to indicate which features should be active while |
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14 building the library. |
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15 |
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16 These options range from debug level to availability of certain |
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17 features, like native TrueType hinting through a bytecode |
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18 interpreter. |
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19 |
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20 We invite you to read this file for more information. You can |
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21 change the file's content to suit your needs, or override it with |
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22 one of the techniques described below. |
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23 |
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24 |
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25 II. Modules list |
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26 |
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27 If you use GNU make please edit the top-level file `modules.cfg'. |
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28 It contains a list of available FreeType modules and extensions to |
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29 be compiled. Change it to suit your own preferences. Be aware that |
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30 certain modules depend on others, as described in the file. GNU |
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31 make uses `modules.cfg' to generate `ftmodule.h' (in the object |
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32 directory). |
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33 |
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34 If you don't use GNU make you have to manually edit the file |
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35 `include/freetype/config/ftmodule.h' (which is *not* used with if |
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36 compiled with GNU make) to add or remove the drivers and components |
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37 you want to compile into the library. See `INSTALL.ANY' for more |
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38 information. |
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39 |
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40 |
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41 III. System interface |
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42 |
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43 FreeType's default interface to the system (i.e., the parts that |
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44 deal with memory management and i/o streams) is located in |
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45 `src/base/ftsystem.c'. |
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46 |
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47 The current implementation uses standard C library calls to manage |
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48 memory and to read font files. It is however possible to write |
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49 custom implementations to suit specific systems. |
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50 |
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51 To tell the GNU Make-based build system to use a custom system |
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52 interface, you have to define the environment variable FTSYS_SRC to |
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53 point to the relevant implementation: |
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54 |
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55 on Unix: |
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56 |
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57 ./configure <your options> |
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58 export FTSYS_SRC=foo/my_ftsystem.c |
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59 make |
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60 make install |
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61 |
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62 on Windows: |
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63 |
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64 make setup <compiler> |
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65 set FTSYS_SRC=foo/my_ftsystem.c |
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66 make |
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67 |
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68 |
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69 IV. Overriding default configuration and module headers |
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70 |
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71 It is possible to override the default configuration and module |
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72 headers without changing the original files. There are three ways |
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73 to do that: |
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74 |
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75 |
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76 1. With GNU make |
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77 |
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78 [This is actually a combination of method 2 and 3.] |
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79 |
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80 Just put your custom `ftoption.h' file into the objects directory |
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81 (normally `<topdir>/objs'), which GNU make prefers over the |
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82 standard location. No action is needed for `ftmodule.h' because |
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83 it is generated automatically in the objects directory. |
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84 |
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85 |
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86 2. Using the C include path |
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87 |
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88 Use the C include path to ensure that your own versions of the |
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89 files are used at compile time when the lines |
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90 |
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91 #include FT_CONFIG_OPTIONS_H |
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92 #include FT_CONFIG_MODULES_H |
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93 |
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94 are compiled. Their default values being |
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95 <freetype/config/ftoption.h> and <freetype/config/ftmodule.h>, you |
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96 can do something like: |
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97 |
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98 custom/ |
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99 freetype/ |
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100 config/ |
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101 ftoption.h => custom options header |
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102 ftmodule.h => custom modules list |
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103 |
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104 include/ => normal FreeType 2 include |
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105 freetype/ |
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106 ... |
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107 |
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108 then change the C include path to always give the path to `custom' |
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109 before the FreeType 2 `include'. |
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110 |
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111 |
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112 3. Redefining FT_CONFIG_OPTIONS_H and FT_CONFIG_MODULES_H |
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113 |
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114 Another way to do the same thing is to redefine the macros used to |
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115 name the configuration headers. To do so, you need a custom |
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116 `ft2build.h' whose content can be as simple as: |
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117 |
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118 #ifndef __FT2_BUILD_MY_PLATFORM_H__ |
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119 #define __FT2_BUILD_MY_PLATFORM_H__ |
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120 |
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121 #define FT_CONFIG_OPTIONS_H <custom/my-ftoption.h> |
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122 #define FT_CONFIG_MODULES_H <custom/my-ftmodule.h> |
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123 |
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124 #include <freetype/config/ftheader.h> |
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125 |
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126 #endif /* __FT2_BUILD_MY_PLATFORM_H__ */ |
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127 |
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128 Place those files in a separate directory, e.g., |
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129 |
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130 custom/ |
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131 ft2build.h => custom version described above |
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132 my-ftoption.h => custom options header |
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133 my-ftmodule.h => custom modules list header |
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134 |
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135 and change the C include path to ensure that `custom' is always |
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136 placed before the FT2 `include' during compilation. |
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137 |
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138 ---------------------------------------------------------------------- |
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139 |
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140 Copyright 2003, 2005, 2006 by |
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141 David Turner, Robert Wilhelm, and Werner Lemberg. |
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142 |
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143 This file is part of the FreeType project, and may only be used, |
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144 modified, and distributed under the terms of the FreeType project |
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145 license, LICENSE.TXT. By continuing to use, modify, or distribute |
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146 this file you indicate that you have read the license and understand |
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147 and accept it fully. |
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148 |
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149 |
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150 --- end of CUSTOMIZE --- |
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