Make a graph graph networkx available

Question

I am trying to create a clickable graph image in python. First I called Graphviz, then I found networkx http://networkx.lanl.gov .

I want my program to get information about which node is displayed at the coordinate (x, y), where the user clicked on the graph. I think I could work with a pyplot window that opens and displays a graph using the coordinates (x, y) with a mouse click, but I need some kind of image map to find out which node was rendered at these coordinates!

Can you tell if / how can this be done?

Answer 1

I solved this thanks to the nice people at http://groups.google.com/group/networkx-discuss ( http://groups.google.com/group/networkx-discuss/browse_thread/thread/aac227e1fb2a4719 ):

The following (partial) code works in Tkinter, allows you to create a matplotlib window (without blocking, by the way) containing the networkx graph, and executes the visitNode () procedure if you click on this node.

import networkx as nx import matplotlib.pyplot as plt import pylab class AnnoteFinder: # thanks to http://www.scipy.org/Cookbook/Matplotlib/Interactive_Plotting """ callback for matplotlib to visit a node (display an annotation) when points are clicked on. The point which is closest to the click and within xtol and ytol is identified. """ def __init__(self, xdata, ydata, annotes, axis=None, xtol=None, ytol=None): self.data = zip(xdata, ydata, annotes) if xtol is None: xtol = ((max(xdata) - min(xdata))/float(len(xdata)))/2 if ytol is None: ytol = ((max(ydata) - min(ydata))/float(len(ydata)))/2 self.xtol = xtol self.ytol = ytol if axis is None: axis = pylab.gca() self.axis= axis self.drawnAnnotations = {} self.links = [] def __call__(self, event): if event.inaxes: clickX = event.xdata clickY = event.ydata if self.axis is None or self.axis==event.inaxes: annotes = [] for x,y,a in self.data: if clickX-self.xtol < x < clickX+self.xtol and clickY-self.ytol < y < clickY+self.ytol : dx,dy=x-clickX,y-clickY annotes.append((dx*dx+dy*dy,x,y, a) ) if annotes: annotes.sort() # to select the nearest node distance, x, y, annote = annotes[0] self.visitNode(annote) def visitNode(self, annote): # Visit the selected node # do something with the annote value print "visitNode", annote fig = plt.figure() ax = fig.add_subplot(111) ax.set_title('select nodes to navigate there') G=nx.MultiDiGraph() # directed graph G = nx.wheel_graph(5) pos=nx.spring_layout(G) # the layout gives us the nodes position x,y,annotes=[],[],[] for key in pos: d=pos[key] annotes.append(key) x.append(d[0]) y.append(d[1]) nx.draw(G,pos,font_size=8) af = AnnoteFinder(x,y, annotes) fig.canvas.mpl_connect('button_press_event', af) plt.show()