Create a Tikz latex drawing feature for networkx (#6238)

* Implemented conversion from networkx graph to latex graph.

* Removed latex cache files uploaded by error.

* Resolved placeholders file import issue.

* Removed dependency to numpy

* Updated test

* Wrapped test for numpy dependency

* Updated test name

* format changes to nx_latex.py and friends.

vertex -> node,  vertices -> nodes
PEP8 spacing and tabs
pytest function instead of class (class not needed here -- no imports)
Moved author info to CONTRIBUTORS.rst as our new standard
converted list comprehension done for side-effects to for-loop.
switch to f-strings from string-format calls
update setup.py to remove conflicts

* Remove numpy requirement for testing latex

Also pep8 formatting

* reorder imports in __init__

* Attempt to debug windows/appveyor adigraph error

* try again

* Remove types, run pre-commit

* blackify

* pyupgradify

* inline latex placeholders and expected_tex.

Check not multigraph.
Add example
Change variable name `file` to `latex_code`
inline if/else for __init__ setup

* Change tabs to spaces

* pull apart Adigraph to simplify interface

* remove class Adigraph completely in favor of functions

* replace default layout to be circular.

(matches adigraph and avoids using random seeds in tests

* fix old version of isort result

* update documentation and include with rst file. Update some tests

* make docs more complete, checked and add tests

* Cleanup extra file changes that aren't needed

* Add TikZ version of to_latex as default

* improve docs

* Make the networkx latex interface via TikZ and not adigraph

* fix rebase

* Apply suggestions from code review

Co-authored-by: Mridul Seth <mail@mriduls.com>

* comment out print statements in tests

* Turn off multigraph for latex

* Remove tests of `line width` and edge label placement

* add back line width style, fix placement of style on edges.

* Set default layout to have radius 10

Co-authored-by: Mridul Seth <mail@mriduls.com>

* fix docstring test

* Minor docstring formatting nits.

Co-authored-by: Luca Cappelletti <cappelletti.luca94@gmail.com>
Co-authored-by: Mridul Seth <seth.mridul@gmail.com>
Co-authored-by: Mridul Seth <git@mriduls.com>
Co-authored-by: Mridul Seth <mail@mriduls.com>
Co-authored-by: Ross Barnowski <rossbar@berkeley.edu>

doc/developer/about_us.rst

@@ -145,6 +145,7 @@ to add your name to the bottom of the list.
 - Philip Boalch
 - Matt Schwennesen, Github: `mjschwenne <https://github.com/mjschwenne>`_
 - Andrew Knyazev, Github: `lobpcg <https://github.com/lobpcg>`_, LinkedIn: `andrew-knyazev <https://www.linkedin.com/in/andrew-knyazev>`_
+- Luca Cappelletti, GitHub: `LucaCappelletti94 <https://github.com/LucaCappelletti94>`_
 - Sultan Orazbayev, GitHub: `SultanOrazbayev <https://github.com/SultanOrazbayev>`_, LinkedIn: `Sultan Orazbayev <https://www.linkedin.com/in/sultan-orazbayev/>`_
 
 A supplementary (but still incomplete) list of contributors is given by the

doc/reference/drawing.rst

@@ -95,4 +95,14 @@ Graph Layout
    spectral_layout
    spiral_layout
    multipartite_layout
-
+
+
+LaTeX Code
+==========
+.. automodule:: networkx.drawing.nx_latex
+.. autosummary::
+   :toctree: generated/
+
+   to_latex_raw
+   to_latex
+   write_latex

networkx/drawing/__init__.py

@@ -1,6 +1,7 @@
 # graph drawing and interface to graphviz
 
 from .layout import *
+from .nx_latex import *
 from .nx_pylab import *
 from . import nx_agraph
 from . import nx_pydot