Installing PyGraphviz on Windows

Django Extensions provides a bunch of management commands for the Django Framework. One of the most handy is the graph_models command. This command creates a visual representation of the Django models existing in the database.

In order to use this command you need to have Graphviz and PyGraphviz installed on your machine. Graphviz is a package of open-source tools for representing structural information as diagrams of abstract graphs and networks. PyGraphviz is a Python interface for Graphviz and allows you can create, edit, read, write, and draw Graphviz graphs.

Download and install Graphviz from this link: http://www.graphviz.org/Download_windows.php.

I couldn’t install PyGraphviz using easy_install, because it depends on Graphviz, and easy_install doesn’t know where to find Graphviz.

Download PyGraphviz(1.1) from this link: http://networkx.lanl.gov/download/pygraphviz/, and extract it.

Adjust “setup.py” file to reflect your Graphviz instalation.

library_path='C:/Program Files (x86)/Graphviz 2.28/lib/release/lib' include_path='C:/Program Files (x86)/Graphviz 2.28/include/graphviz'

Normally, you would run python setup.py install to build and install a python application, but in this case we need to do some extra work. Running this command will output an error:

"Unable to find vcvarsall.bat"

To solve this issue, PyGraphviz needs to be compiled with a MSVC or mingw32 compiler. I haven’t found a Windows build for PyGraphviz so the only option was to built this myself.

I have used an older release of mingw because the current one doesn’t support the mno-cygwin argument anymore.

Download and install mingw-get-inst-20100831.exe from this link:
http://sourceforge.net/projects/mingw/files/Installer/mingw-get-inst/

Add mingw/bin directory to the system path.

Change line 285 from “c:\python27\lib\distutils\unixcompiler.py” from

1	compiler = os.path.basename(sysconfig.get_config_var("CC"))

1	compiler = "gcc".

or there will be an error “TypeError: ‘NoneType’ object is unsubscriptable”. Change it back after finishing installing PyGraphviz.

Now it’s time to build PyGraphviz:
C:\pygraphviz-1.1>python setup.py build -c mingw32 library_path=C:/Graphviz/lib/release/lib include_path=C:/Graphviz/include/graphviz running build running build_py creating build creating build\lib.win32-2.7 creating build\lib.win32-2.7\pygraphviz copying pygraphviz\agraph.py -> build\lib.win32-2.7\pygraphviz copying pygraphviz\graphviz.py -> build\lib.win32-2.7\pygraphviz copying pygraphviz\release.py -> build\lib.win32-2.7\pygraphviz copying pygraphviz\version.py -> build\lib.win32-2.7\pygraphviz copying pygraphviz\__init__.py -> build\lib.win32-2.7\pygraphviz creating build\lib.win32-2.7\pygraphviz\tests copying pygraphviz\tests\test.py -> build\lib.win32-2.7\pygraphviz\tests copying pygraphviz\tests\__init__.py -> build\lib.win32-2.7\pygraphviz\tests copying pygraphviz\tests\attributes.txt -> build\lib.win32-2.7\pygraphviz\tests copying pygraphviz\tests\graph.txt -> build\lib.win32-2.7\pygraphviz\tests copying pygraphviz\tests\layout_draw.txt -> build\lib.win32-2.7\pygraphviz\tests copying pygraphviz\tests\unicode.txt -> build\lib.win32-2.7\pygraphviz\tests running build_ext building 'pygraphviz._graphviz' extension creating build\temp.win32-2.7 creating build\temp.win32-2.7\Release creating build\temp.win32-2.7\Release\pygraphviz C:\MinGW\bin\gcc.exe -mno-cygwin -mdll -O -Wall -IC:/Graphviz/include/graphviz - IC:\Python27\include -IC:\Python27\PC -c pygraphviz/graphviz_wrap.c -o build\tem p.win32-2.7\Release\pygraphviz\graphviz_wrap.o pygraphviz/graphviz_wrap.c: In function 'agattr_label': pygraphviz/graphviz_wrap.c:2855:5: warning: return makes integer from pointer wi thout a cast writing build\temp.win32-2.7\Release\pygraphviz\_graphviz.def C:\MinGW\bin\gcc.exe -mno-cygwin -shared -s build\temp.win32-2.7\Release\pygraph viz\graphviz_wrap.o build\temp.win32-2.7\Release\pygraphviz\_graphviz.def -LC:/G raphviz/lib/release/lib -LC:\Python27\libs -LC:\Python27\PCbuild -Wl,-RC:/Graphv iz/lib/release/lib -lcgraph -lcdt -lpython27 -lmsvcr90 -o build\lib.win32-2.7\py graphviz\_graphviz.pyd

Copy the contents of the build/lib.win32-2.7 directory(single sub-folder called pygraphviz) into your Python’s site-packages folder.

You can create a PNG image file called my_project_visualized.png with application grouping running the following command:
manage.py graph_models -a -g -o my_project_visualized.png

Django Extensions
Graphviz website
PyGraphviz website
Minimalist GNU for Windows