ref: 858f310b80da8655ba0d30a9551e8fbcc3de4818
dir: /docs/VERSION.DLL/
Due to our use of "libtool" to generate and install the FreeType 2
libraries on Unix systems, as well as other historical events, it is
generally very difficult to know precisely which release of the font
engine is installed on a given system.
This file tries to explain why and to document ways to properly detect
FreeType on Unix.
1. Version & Release numbers
----------------------------
For each new public release of FreeType 2, there are generally *three*
distinct "version" numbers to consider:
* The official FT2 release number, like 2.0.9, or 2.1.3.
* The libtool (and Unix) specific version number, like "9.2.3". This
is what "freetype-config --version" will return.
* The platform-specific shared object number, used for example when
the library is installed as "/usr/lib/libfreetype.so.6.3.2".
The platform-specific number is, unsurprisingly, platform-specific and
varies with the operating system you are using (several variants of
Linux, FreeBSD, Solaris, etc.). You should thus _never_ use it, even
for simple tests.
The libtool-specific number does not equal the release number but is
tied to it.
The release number is available at *compile* time through the following
macros defined in FT_FREETYPE_H:
- FREETYPE_MAJOR : major release number
- FREETYPE_MINOR : minor release number
- FREETYPE_PATCH : patch release number
See below for a small autoconf fragment.
The release number is also available at *runtime* through the
"FT_Library_Version" API. Unfortunately, this one wasn't available or
working correctly before the 2.1.3 official release.
2. History
----------
The following table gives, for each official release, the corresponding
libtool number, as well as the shared object number found on _most_
systems, but not all of them:
release libtool so
-------------------------------------
2.1.4 9.3.3 6.3.3
2.1.3 9.2.3 6.3.2
2.1.2 9.1.3 6.3.1
2.1.1 9.0.3 ?
2.1.0 8.0.2 ?
2.0.9 9.0.3 ?
2.0.8 8.0.2 ?
The libtool numbers are a bit inconsistent due to the library's history:
- 2.1.0 was created as a development branch from 2.0.8 (hence the same
libtool numbers).
- 2.0.9 was a bug-fix release of the "stable" branch, and we
incorrectly increased its libtool number.
- 2.1.4 is still in the "development" branch, however it is stable
enough to be the basis of an upcoming 2.2.0 release.
3. Autoconf Code Fragment
-------------------------
Lars Clausen contributed the following autoconf fragment to detect which
version of FreeType is installed on a system. This one tests for a
version that is at least 2.0.9; you should change it to check against
other release numbers.
AC_MSG_CHECKING([whether FreeType version is 2.0.9 or higher])
old_CPPFLAGS="$CPPFLAGS"
CPPFLAGS=`freetype-config --cflags`
AC_TRY_CPP([
#include <freetype/freetype.h>
#if (FREETYPE_MAJOR*1000 + FREETYPE_MINOR)*1000 + FREETYPE_PATCH < 2000009
#error Freetype version too low.
#endif
],[
AC_MSG_RESULT(yes)
FREETYPE_LIBS=`freetype-config --libs`
AC_SUBST(FREETYPE_LIBS)
AC_DEFINE(HAVE_FREETYPE,1,[Define if you have the FreeType2 library])
CPPFLAGS="$old_CPPFLAGS"
],[
AC_MSG_ERROR([Need FreeType library version 2.0.9 or higher])
])
--- end of VERSION.DLL ---