PHART: The Python Hierarchical ASCII Representation Tool - A Pure Python graph visualization in ASCII, no external dependencies*
* except NetworkX, which should be mentioned prominently. but phart will not require you to stand up a webserver to run PHP and install Perl and some libraries just to render a Graph in 7-bit text (or UTF-8 or Unicode) from Python.
- Pure Python implementation
- Render using 7-bit ASCII or unicode characters
- No external dependencies (except NetworkX)
- Multiple node styles (square, round, diamond, custom)
- Customizable edge characters
- Support for directed and undirected graphs
- Handles cycles and complex layouts
- Bidirectional edge support
- Orthogonal (yet correct, though perhaps unexpected) Triad Layout
Example output PHARTs [click triangle/arrow to expand/collapse]
=================================
I was doing some last-minute testing and came across this, from the networkx gallery:
The code there creates a graph from some data pulled from a database of Chess masters tournaments and such at this site:
https://chessproblem.my-free-games.com/chess/games/Download-PGN.php
And plots it with matplotlib. It looked pretty complex so I thought as a lark I would see how difficult it would be to get phart to render the graph. The matplot can be seen here:
So, I added the following to the code at the networkx gallery page linked above:
from phart import ASCIIRenderer, NodeStyle
.. existing code remains here ...
... then directly below the existing lines to create the nx graph:
# make new undirected graph H without multi-edges
H = nx.Graph(G)
... I added this:
renderer=ASCIIRenderer(H)
renderer.write_to_file("wcc.txt")
and ran the code. Immediately this was written to wcc.txt:
---------------------------------[Botvinnik, Mikhail M]---------------------------------
| | | | |
v | | v | | | v
[Bronstein, David I]----[Euwe, Max]----[Keres, Paul]----[Petrosian, Tigran V]----[Reshevsky, Samuel H]----[Smyslov, Vassily V]----[Tal, Mikhail N]
^ | |
| | v
[Alekhine, Alexander A]----[Spassky, Boris V]
| | |
v | | | v
[Bogoljubow, Efim D]----[Capablanca, Jose Raul] ---[Fischer, Robert J]
|^
|
[Lasker, Emanuel]--------------
| |
v v v | v
[Janowski, Dawid M]----[Marshall, Frank J]----[Schlechter, Carl]----[Steinitz, Wilhelm]----[Tarrasch, Siegbert]
| |
v v | |
[Chigorin, Mikhail I]----[Gunsberg, Isidor A]----[Zukertort, Johannes H]
[Karpov, Anatoly]----[Kasparov, Gary]----[Korchnoi, Viktor L]
No fuss. No muss. Just phart.
[main.py]
|
v | v
[config.py]----[utils.py]
| |
v | v
[constants.py]----[helpers.py]
[CEO]
|
v v v
[CFO]----[COO]----[CTO]
| | |
v v | v | | v v
[Controller]----[Dev Lead]----[Marketing Dir]----[Research Lead]----[Sales Dir]
[Router1]
|
v | v
[Switch1]----[Switch2]
| |
v v | v
[Server1]----[Server2] [Server3]----[Server4]
[Start]
|
v
[Input]
|
|v
[Validate]
|
v|
--[Process]
| ^
| v
| [Check]
| |
| | v
[Error]----[Success]
|
v |
[Output]--
|
v|
[End]
[A]
|
v | v
[B]----[D]
| |
| v |
--[C]---
|
v
[E]
Different node styles for the same graph:
0
|
v | v
1----2
| |
v v | v
3----4 5----6
[0]
|
v | v
[1]----[2]
| |
v v | v
[3]----[4] [5]----[6]
(0)
|
v | v
(1)----(2)
| |
v v | v
(3)----(4) (5)----(6)
<0>
|
v | v
<1>----<2>
| |
v v | v
<3>----<4> <5>----<6>
Because it demanded to come out. OK, sorry... Actually it had a few other names early on, but when it came time to upload to PyPi, we discovered the early names we chose were already taken so we had to choose a new name. We wanted to mash up the relevant terms ("graph", "ascii", "art", "chart", and such) and bonus if the new name is a fitting acronym.
In the case of PHART, the acronym made from the first letters of the obvious first words to come to mind was discovered to spell PHART after the non abbreviated words were suggested. Fortuitous; so it had to be. Also, as I am beginning to update the usage instructions and the examples and their output in the README to more accurately reflect current capabilities, it occurs to me that the name may not be as fitting anymore. At first release PHART only handled DAGs and fairly strictly rendered a heirarchical layout.
As it's capabilities have increased (by user request if you can believe that!) faster than my knowledge of Graphs and the layout thereof, and my lack of deep understanding of exactly what NetworkX's focus and strengths are (to be fair, their dev lists and Roadmap would seem to align quite well with me not fully understanding their focus and direction, and I mean no disrespect; it's way beyond me.) Anyway, as such at times I struggle with having to remind myself "that information is already known - to the graph - you don't need to calculate or keep track of that, similarly with certain layout decisions that really don't need to be pondered by PHART at all I have spent too many hours working on.
So it might be more properly named something that indicates that it sometimes adheres mostly to a Hierarchical Layout strategy, but other times it might be more accurately branded an Orthogonal Layout. Either way, I'm not sure I knew either of those were terms for some known thing at the time I started implementing. Nevertheless, perhaps its name needs to expand along with its function. Something incorporating Orthogonal Layout. Hmm.. "OL-PHART" perhaps. Maybe it has become Boundary Invariant Geodesic Orthogonal Layout PHART - that is...
BIGOL-PHART
Regardless, you may pronounce it the obvious monosyllabic way, or as "eff art", or perhaps "pee heart", or any way that you like, so long as the audience you are speaking it to knows it is PHART you are referring to.
The mention of not being Perl or a PHP webapp may appear to be throwing shade at the existing solutions, but it is meant in a good-hearted way. Wrapping the OG Graph::Easy is a straightforeard way to go about it, and a web interface to the same is a project I might create as well, but Perl being installed is not the sure ubiquitous thing it once was, and spinning up a Docker container in order to add ascii art graph output to a python tool seemed a bit excessive.
Additionally, I'm not sure how I didn't find pydot2ascii - which is native python - when I first looked for a solution, but even if I had seen it I may not have realized that I could have exported my NX DAG to DOT, and then used pydot2ascii to go from DOT to ascii art.
So now we have PHART, and the ability to render a NX digraph in ASCII/Unicode, read a DOT file, read GraphML, and a few other things in a well-tested Python module published to PyPi. I hope you find it useful.
requires Python >= 3.10 and NetworkX >= 3.3
pip install phartThese docs are pretty out of date now, which I will try to remedy soon.
In the mean time, I should mention that the primary focus lately has been
use from the CLI command phart which is installed when you install via pip.
This repor is well ahead of the release in PyPi as I work on some specific
graphlet features for a user. I will update the docs to match when the package is released.
But to fill in some of the info garp here is the CLI usage info, which should be
self-explanatory to many of you.
└─$ phart --help
usage: phart [-h] [--output OUTPUT] [--style {minimal,square,round,diamond,custom}]
[--node-spacing NODE_SPACING] [--layer-spacing LAYER_SPACING] [--charset {ascii,unicode}]
[--ascii] [--function FUNCTION]
input
PHART: Python Hierarchical ASCII Rendering Tool
positional arguments:
input Input file (.dot, .graphml, or .py format)
options:
-h, --help show this help message and exit
--output OUTPUT, -o OUTPUT
Output file (if not specified, prints to stdout)
--style {minimal,square,round,diamond,custom}
Node style (default: square)
--node-spacing NODE_SPACING
Horizontal space between nodes (default: 4)
--layer-spacing LAYER_SPACING
Vertical space between layers (default: 2)
--charset {ascii,unicode}
Character set to use for rendering (default: unicode)
--ascii Force ASCII output (deprecated, use --charset ascii instead)
--function FUNCTION, -f FUNCTION
Function to call in Python file (default: main)import networkx as nx
from phart import ASCIIRenderer
# Create a simple graph
G = nx.DiGraph()
G.add_edges_from([("A", "B"), ("A", "C"), ("B", "D")])
# Render it in ASCII
renderer = ASCIIRenderer(G)
print(renderer.render())
[A]
│
v │ v
[B]────[C]
│
│ v
──[D]The renderer shows edge direction using arrows:
- v : downward flow
- ^ : upward flow
- > or < : horizontal flow
These directional indicators are particularly useful for:
- Dependency graphs
- Workflow diagrams
- Process flows
- Any directed relationships
PHART supports multiple character sets for rendering:
--charset unicode(default): Uses Unicode box drawing characters and arrows for cleaner visualization--charset ascii: Uses only 7-bit ASCII characters, ensuring maximum compatibility with all terminals
Example:
# Using Unicode (default)
phart graph.dot
# ┌─A─┐
# │ │
# └─B─┘
# Using ASCII only
phart --charset ascii graph.dot
# +-A-+
# | |
# +-B-+- DOT file support
- requires pydot
pip install phart[extras]or using requirements file
pip install -r requirements\extra.txt>>> dot = '''
... digraph {
... A -> B
... B -> C
... }
... '''
>>> renderer = ASCIIRenderer.from_dot(dot)
>>> print(renderer.render())
A
|
B
|
C
>>>
PHART uses pydot for DOT format support. When processing DOT strings containing multiple graph definitions, only the first graph will be rendered. For more complex DOT processing needs, you can convert your graphs using NetworkX's various graph reading utilities before passing them to PHART.
PHART supports reading GraphML files:
renderer = ASCIIRenderer.from_graphml("graph.graphml")
print(renderer.render())or, of course just
phart graph.graphml PHART can directly execute Python files that create and render graphs. When given a Python file, PHART will:
- First try to execute the specified function (if
--functionis provided) - Otherwise, try to execute a
main()function if one exists - Finally, execute code in the
if __name__ == "__main__":block
Example Python file:
import networkx as nx
from phart import ASCIIRenderer
def demonstrate_graph():
# Create a simple directed graph
G = nx.DiGraph()
G.add_edges_from([("A", "B"), ("B", "C")])
# Create renderer and display the graph
renderer = ASCIIRenderer(G)
print(renderer.render())
if __name__ == "__main__":
demonstrate_graph()You can execute this file in several ways:
# Execute main() or __main__ block (default behavior)
phart graph.py
# Execute a specific function
phart graph.py --function demonstrate_graph
# Use specific rendering options
phart graph.py --charset ascii --style roundWhen executing Python files, PHART intelligently merges command-line options with any options specified in your code:
- Options set in your Python code (like custom_decorators or specific node styles) are preserved
- Command-line options will override general settings (like --charset or --style)
- Custom settings (like custom_decorators) are never overridden by command-line defaults
This means you can set specific options in your code while still using command-line options to adjust general rendering settings.
MIT License