Question

I’m looking for an interactive graphing library for Python.

By “graph“, I meant a set of nodes connected by a set of vertices (not a plot of values over x-y axis, nor a grid of pixels).

By “interactive”, I meant I can drag-and-drop the nodes around and I need to be able to click on the nodes/vertices and have the library pass the nodes/vertices to my callbacks, which may add/remove nodes/vertices or display information (I cannot load the full graph at startup as the dataset is too large/complex; instead I’ll be loading only the necessary slices of data depending on user inputs).

By Python, I meant the programming language Python, the graphing library should have CPython binding. I have Python 2.7 and Python 3.1, but can downgrade to 2.6 if necessary. This language requirement is because the dataset I’m working with only have Python binding.

The graphing library must support directed graph and be able to layout the nodes automatically. I need to put labels on the nodes.

Preferably, the layouting algorithm should place adjacent nodes near each other. It should be able to handle from 100-1000 nodes and about 300-4000 vertices reasonably in my 4 year old laptop (I typically start with around 100 nodes, but the number might expand depending on user input). Preferably it should be a library with not too many dependencies (except perhaps for Gnome). Open source is preferred.

I have already written a simple prototype of my program using Tkinter Canvas, but I need a more serious graphing library to expand the program. I’ve looked at graphviz and matplotlib, but apparently they’re only for working with static graphs and apparently would need significant amount of work to do interactive manipulations (correct me if I’m wrong, I’ve only looked at them briefly). I’ve also tried generating the graph to an SVG file and using Inkscape to view it, but it’s too slow and takes too much memory and because of the sheer number of vertices it becomes a tangled mess.

Answer 1

Looks like Nodebox might be what you want:

http://nodebox.net/code/index.php/Graph Mac OSX

http://www.cityinabottle.org/nodebox/ Windows (using OpenGL)

The graph object has functionality for mouse interaction as well, bundled
in the graph.events object. It has the
following properties:

• graph.events.hovered: None or the node over which the mouse hovers.
• graph.events.pressed: None or the node on which the mouse is
  pressing down.
• graph.events.dragged: None or the node being dragged.
• graph.events.clicked: None or the last node clicked.
• graph.events.popup: when True, will display a popup window over the
  hovered node.

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Also came accross Gephi, looks like that might have the functionality you want as well.

http://gephi.org/ Windows, Linux and Mac OSX

Gephi is an interactive visualization
and exploration platform for all kinds
of networks and complex systems,
dynamic and hierarchical graphs.