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 the last line to check against other release numbers. AC_MSG_CHECKING([for version of FreeType]) FREETYPE_INCLUDE=`freetype-config --cflags | cut -c3-` FREETYPE_MAJOR=`grep '^#define FREETYPE_MAJOR' \ $FREETYPE_INCLUDE/freetype/freetype.h | cut -d' ' -f3` FREETYPE_MINOR=`grep '^#define FREETYPE_MINOR' \ $FREETYPE_INCLUDE/freetype/freetype.h | cut -d' ' -f3` FREETYPE_PATCH=`grep '^#define FREETYPE_PATCH' \ $FREETYPE_INCLUDE/freetype/freetype.h | cut -d' ' -f3` FREETYPE_VERSION=`echo | awk "BEGIN { printf \"%d\", \ ($FREETYPE_MAJOR * 1000 + $FREETYPE_MINOR) * 1000 \ + $FREETYPE_PATCH;}"` AC_MSG_RESULT([$FREETYPE_MAJOR.$FREETYPE_MINOR.$FREETYPE_PATCH]) if test "$FREETYPE_VERSION" -ge 2000009; then --- end of VERSION.DLL ---