[Tutor] a question on the BLT plotting library

[Marco Scodeggio]

Hallo everybody.

I'm still completely new to Python, and I'm trying to figure out a =
relatively
simple method to produce some "decent looking" (scientific) plots.

Looking around on the web I have found Python megawidgets, that provide =
an=20
interface to the BLT plotting library.

I have installed the current verison of BLT (version 2.4u), to go along =
with the=20
tcl/tk installation that is standard on my workstation (version 8.2), =
and I did=20
put in the lib/python1.5/site-packages/ directory the Pmw installation.
I'm working on a Sun worstation using Solaris 2.5.1, and I have =
installed both=20
Python and the BLT library in my private directories.

Now, I can use the BLT library (which means I can run succesfully the =
self-test=20
program provided with it), and the Pmw widgets (again, the self-test =
works), but=20
when I try to run any simple demo using the Pmw.Blt class I get error =
messages=20
like this one:

>>> from Tkinter import *=20
>>> import Pmw
>>> root =3D Tk()
>>> g =3D Pmw.Blt.Graph(root)
Traceback (innermost last):
  File "<pyshell#3>", line 1, in ?
    g =3D Pmw.Blt.Graph(root)
  File=20
"/hestia/marcos/software/Python-1.5.2/lib/python1.5/site-packages/Pmw/Pmw=
_0_8_4/
lib/PmwBlt.py", line 260, in __init__
    Tkinter.Widget.__init__(self, master, _graphCommand, cnf, kw)
  File =
"/hestia/marcos/software/Python-1.5.2/lib/python1.5/lib-tk/Tkinter.py",=20
line 1084, in __init__
    self.tk.call(
TclError: invalid command name "::blt::graph"
>>>=20

Also the initialisation suggested by the Pmw folks
(  >>> import Pmw
   >>> root =3D Pmw.initialise()   )
produces the same identical error message.

Along the same lines, when I run the Pmw demos program, if I try the BLT =
related=20
tests, I get the message=20

"Sorry, the BLT package has not been installed on this system. Please =
install it=20
and try again"

Does anyone have any idea on what is happening ??? I presume Python =
cannot find=20
the BLT installation, but how do I let it know about it ??

Your help on this would be much appreciated. Thanks a lot.

		Marco Scodeggio