PHP Application Flow Graph (or function call graph)

I have never used any tool that can do that statically (i.e. from source files), but here's a way to get a callgraph when executing a script/application.

First, you need to install the Xdebug extension -- on a development/testing server (don't install it on a production server : it's quite bad for performances ^^ )

Then, you can use its profiling features to generate a .cachegrindout file corresponding to the execution of a page-load.

After that, you can load that .cachegrindout file with KCacheGrind (On linux -- I don't think there's a windows version) ; KCacheGrind can generate call-graphs from .cachegrindout files.

And here's an example of callgraph you can get :

_{(source: pascal-martin.fr)}

(Here's, it's been generated from a .cachegrindout file obtained while loading a page of Dotclear, a blogging software)

Doxygen can do it statically. Just doxygen -d to create a config file, then edit it to create callgraphs.