forked from minhngoc25a/freetype2
126 lines
4.0 KiB
Plaintext
126 lines
4.0 KiB
Plaintext
How to customize the compilation of the library:
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================================================
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FreeType is highly customizable to fit various needs, and this
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document describes how it is possible to select options and components
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at compilation time.
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I. Configuration macros
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The file found in "include/freetype/config/ftoption.h" contains a list
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of commented configuration macros that can be toggled by developers to
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indicate which features should be active while building the library.
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These options range from debug level to availability of certain
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features, like native TrueType hinting through a bytecode interpreter.
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We invite you to read this file for more information. You can change
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the file's content to suit your needs, or override it with one of the
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techniques described below.
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II. Modules list
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The file found in "include/freetype/config/ftmodule.h" contains a list
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of names corresponding to the modules and font drivers to be
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statically compiled in the FreeType library during the build.
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You can change it to suit your own preferences. Be aware that certain
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modules depend on others, as described by the file "modules.txt" in
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this directory.
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You can modify the file's content to suit your needs, or override it
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at compile time with one of the methods described below.
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III. System interface
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FreeType's default interface to the system (i.e., the parts that deal
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with memory management and i/o streams) is located in
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"src/base/ftsystem.c".
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The current implementation uses standard C library calls to manage
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memory and to read font files. It is however possible to write custom
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implementations to suit specific systems.
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To tell the GNU Make-based build system to use a custom system
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interface, you have to define the environment variable FTSYS_SRC to
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point to the relevant implementation:
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on Unix:
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./configure <your options>
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export FTSYS_SRC=foo/my_ftsystem.c
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make
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make install
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on Windows:
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make setup <compiler>
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set FTSYS_SRC=foo/my_ftsystem.c
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make
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IV. Overriding default configuration and module headers
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It is possible to override the default configuration and module
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headers without changing the original files. There are two ways to do
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that:
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1. Using the C include path
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Use the C include path to ensure that your own versions of the files
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are used at compile time when the lines
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#include FT_CONFIG_OPTIONS_H
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#include FT_CONFIG_MODULES_H
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are compiled. Their default values being
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<freetype/config/ftoption.h> and <freetype/config/ftmodule.h>, you
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can do something like:
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custom/
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freetype/
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config/
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ftoption.h => custom options header
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ftmodule.h => custom modules list
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include/ => normal FreeType 2 include
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freetype/
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...
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then change the C include path to always give the path to "custom"
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before the FreeType 2 "include".
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2. Re-defining FT_CONFIG_OPTIONS_H and FT_CONFIG_MODULES_H
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Another way to do the same thing is to redefine the macros used to
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name the configuration headers. To do so, you need a custom
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"ft2build.h" whose content can be as simple as:
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#ifndef __FT2_BUILD_MY_PLATFORM_H__
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#define __FT2_BUILD_MY_PLATFORM_H__
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#define FT_CONFIG_OPTIONS_H <custom/my-ftoption.h>
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#define FT_CONFIG_MODULES_H <custom/my-ftmodule.h>
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#include <freetype/config/ftheader.h>
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#endif /* __FT2_BUILD_MY_PLATFORM_H__ */
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Place those files in a separate directory, e.g.:
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custom/
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ft2build.h => custom version described above
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my-ftoption.h => custom options header
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my-ftmodule.h => custom modules list header
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and change the C include path to ensure that "custom" is always
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placed before the FT2 "include" during compilation.
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--- end of CUSTOMIZE ---
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