[XeTeX] XeTeX and libpng

[Jonathan Kew]

On 18 Aug 2008, at 12:17 PM, Johannes Engel wrote:

> Hi Jonathan et al. ;)
>
> building XeTeX from svn I have got a question: Why does XeTeX carry  
> its
> own libpng instead on relying on the installed version of the  
> respective
> build system? Are there special adaptions necessary?

No, it's just standard libpng. However, not all systems have libpng  
available (it's not present by default on OS X, for example), so to  
minimize extra build dependencies, it is included.

(Actually, the main reason is simply that this is how the texlive  
build system is set up, and the xetex tree is essentially a cut-down  
TL tree but the build system is left as near untouched as possible.  
And texlive strives to minimize dependencies on installed libs, in  
order to maximize binary portability.)

For your own use, or for use within a known distribution where you can  
guarantee the availability of libraries, it's fine to rely on system  
libs. (I think the Debian texlive packages, for example, adapt the TL  
build to use shared system libraries wherever possible.) If you want  
to build binaries to be distributed across a wide range of systems,  
though, it's more problematic.

JK