ref: d6ec6eee78ef0d679e87df029638a0b153b297d5
dir: /docs/CUSTOMIZE/
How to customize the compilation of the library: ================================================ FreeType is highly customizable to fit various needs, and this document details how it is possible to select options and components at compilation time. I. Configuration macros: the file found in "include/freetype/config/ftoption.h" contains a list of commented configuration macros that can be toggled by developers to indicate which features to activate in their build of the library. these options range from debug level to availability of certain features, like native TrueType hinting through a bytecode interpreter. we invite you to read this file for more information. You can change the file's content to suit your needs, or override it with one of the techniques described below.. II. Modules list: the file found in "include/freetype/config/ftmodule.h" contains a list of names corresponding to the modules / font drivers to be statically compiled in the FreeType library during the build. you can change it to suit your own preferences. Be aware that certain modules depend on others, as described by the file "modules.txt" in this directory. you can modify the file's content to suit your needs, or override it at compile time with one of the methods described below III. System interface: FreeType's default interface to the system (i.e. the parts that deal with memory management and i/o streams) is located in "src/base/ftsystem.c". the current implementation uses standard C library calls to manage memory and read font files. It is however possible to write custom implementations to suit specific systems. to tell the GNU Make-based build system to use a custom system interface, you'll need to define the environment variable FTSYS_SRC to point to the relevant implementation, like in: on Unix: ./configure <youroptions> export FTSYS_SRC=foo/my_ftsystem.c make make install on Windows: make setup <compiler> set FTSYS_SRC=foo/my_ftsystem.c make IV. Overriding default configuration and module headers: it is possible to over-ride the default configuration and module headers without changing the original files. There are two ways to do that: 1. Using the C include path: use the C include path to ensure that your own versions of the files are used at compile time when the lines: #include FT_CONFIG_OPTIONS_H #include FT_CONFIG_MODULES_H are compiled. Their default values being <freetype/config/ftoption.h> and <freetype/config/ftmodule.h>, you can do something like: custom/ freetype/ config/ ftoption.h => custom options header ftmodule.h => custom modules list include/ => normal FreeType 2 include freetype/ ... then change the C include path to always give the path to "custom" before the FreeType 2 "include" 2. Re-defining FT_CONFIG_OPTIONS_H and FT_CONFIG_MODULES_H another way to do the same thing is to re-define the macros used to name the configuration headers. To do so, you'll need a custom "ft2build.h", whose content can be as simple as: #ifndef __FT2_BUILD_GENERIC_H__ #define __FT2_BUILD_GENERIC_H__ #define FT_CONFIG_OPTIONS_H <custom/my-ftoption.h> #define FT_CONFIG_MACROS_H <custom/my-ftmodule.h> #include <freetype/config/ftheader.h> #endif /* __FT2_BUILD_GENERIC_H__ */ place them in: custom/ ft2build.h => custom version described above my-ftoption.h => custom options header my-ftmodule.h => custom modules list header and change the C include path to ensure that "custom" is always placed before the FT2 "include" during compilation.