Any chance of having labels in Unicode?

graph-tool
1

dear all,

I would like to use math symbols (such as ∈, ⊆ and ∡) and Greek letters into labels (vertex properties and edge properties), so that they can appear in graph-tool-made or graphviz-made graphs.

How can I use graph-tool in a Unicode-compliant way?

thanks in advance

Yannis H.

2

It should work out of the box. You just need to use a font family that
has the necessary glyphs. For instance, for me the following works:

    graph_draw(g, vertex_text="∈", vertex_font_family="Bitstream Vera Sans")

Best,
Tiago

3

When I attempt to use a ∈ in a label, I get the following error message:

  File "apply-rules.py", line 25
SyntaxError: Non-ASCII character '\xe2' in file apply-rules.py on line 25, but no encoding declared; see for details

When I include

# coding=utf-8

at the beginning, and when I use u"∈" in the code
then I get the following message:

Traceback (most recent call last):
  File "apply-rules.py", line 474, in <module>
    execfile("rules.py")
  File "rules.py", line 13, in <module>
    signature=['204:6', '20456:4', '2045654:4', '45654:2', '456:2', '654:2', '2:3', '4:3', '6:1']
  File "apply-rules.py", line 293, in apply_edge_rule
    r=att_edge(q,KNOWN[ms[0][0]],KNOWN[ms[0][5]],globals()[ms[0][3]])
  File "apply-rules.py", line 352, in att_edge
    g.ep['labele'][res]=str(g.vp['labelv'][a])+"_"+EDGE_LABEL[val]+"_"+str(g.vp['labelv'][b])
  File "/usr/local/lib/python2.7/site-packages/graph_tool/__init__.py", line 490, in __setitem__
    self.__map[key] = self.__convert(v)
  File "/usr/local/lib/python2.7/site-packages/graph_tool/__init__.py", line 254, in convert
    return vtype(val)
UnicodeEncodeError: 'ascii' codec can't encode character u'\u2208' in position 3: ordinal not in range(128)

So the problem is not yet how to make the symbol appear in graphviz output, but how to make the Python code run…

4

Well, you should really read Python's documentation:

   https://docs.python.org/2/howto/unicode.html

in short you should start your script with:

   #!/usr/bin/env python
   # -*- coding: utf-8 -*-

   example = u'abcdé'

(I'm assuming you are using python 2. With python 3 it is simpler,
since it accepts utf-8 by default.)

Best,
Tiago

Ps. Note that graph_draw() *does not* use graphviz!

5

That is exactly what I did:

# -*- coding: utf-8 -*-

and then

EDGE_LABEL=[u'∈']

and the script file stored in UTF-8 without BOM.

And here is the error I got:

Traceback (most recent call last):
  File "apply-rules.py", line 473, in <module>
    execfile("rules.py")
  File "rules.py", line 13, in <module>
    signature=['204:6', '20456:4', '2045654:4', '45654:2', '456:2', '654:2', '2:3', '4:3', '6:1']
  File "apply-rules.py", line 292, in apply_edge_rule
    r=att_edge(q,KNOWN[ms[0][0]],KNOWN[ms[0][5]],globals()[ms[0][3]])
  File "apply-rules.py", line 351, in att_edge
    g.ep['labele'][res]=str(g.vp['labelv'][a])+"_"+EDGE_LABEL[val]+"_"+str(g.vp['labelv'][b])
  File "/usr/local/lib/python2.7/site-packages/graph_tool/__init__.py", line 490, in __setitem__
    self.__map[key] = self.__convert(v)
  File "/usr/local/lib/python2.7/site-packages/graph_tool/__init__.py", line 254, in convert
    return vtype(val)
UnicodeEncodeError: 'ascii' codec can't encode character u'\u2208' in position 3: ordinal not in range(128)

6

The function does not expect unicode objects, but rather simply
strings. You should do simply:

         EDGE_LABEL=[u'∈'.encode("utf-8")]

Best,
Tiago