#! /usr/bin/env python

"""gnupyplot.py -- Develop a Gnuplot python module that takes data files
written by MathAction/Axiom statements in the "images" directory and forms
displayable graphics files for inclusion in MathAction pages.

This working version generates a png plot of data found in the file
testfile2.dat located in directory the var/LatexWiki subdirectory of the zope
instance which is the LocalFS called images in a MathAction installation (on
the original development machine: /var/lib/zope2.9/instance/dczope/var/LatexWiki)
and returns a file with name "filename".png in the same directory.  It is linked
to an ExternalMethod with the id gnupyplot.

"""

from Numeric import *

# If the package has been installed correctly, this should work:
import Gnuplot, Gnuplot.funcutils

def gnupyplot(self,plotfile="testfile2.dat",plottitle="Empty Title"):
    """Demonstrate the Gnuplot-py basis for MathAction Graphics.
       
       This will have to  be called via a URL. The Test function in the Zope management
       window will fail and spill a long error message since if we do not pass a file
       name argument, unless we provide a default value. Our test value is testfile2.dat.
       To call this function use the GET form input format, for example:
       http://guardian:9673/Math/gnupyplotfile?plotfile=testfile2.dat
       Add a title with the plottitle parameter and remember to escape spaces as %20
       http://guardian:9673/Math/gnupyplotfile?plotfile=testfile2.dat&plottitle=sin(x)%20plot

       Since the cwd given to an External Method is the root of the calling instance,
       for example: /var/lib/zope2.9/instance/dczope, in my case, we can refer to files
       relative to this root, for example in var/Latexwiki which is the "images" LocalFS
       for MathAction.
    """
    
    # Generate a plot from a list of points.
    g = Gnuplot.Gnuplot()
    g('set terminal png medium size 640,480')
    #If we pass a full path/filename, it must be in "" inside the '' quotes!
    #g('set output "/var/lib/zope2.9/instance/dczope/var/LatexWiki/testfile2.dat.png"')
    #So the outputfile name passed to g must similarly constructed with "" bracketing
    outputfile = '"var/LatexWiki/'+plotfile+'.png"'
    #Removing the following line would cause XWindow display instead
    g('set output '+outputfile)

    g.title(plottitle) # (optional)
    #g.title('Plotting from a file') # (optional)
    #g('set data style linespoints') # give gnuplot an arbitrary command
    # Plot a list of (x, y) pairs stored in a file):
    g.plot(Gnuplot.File('var/LatexWiki/testfile2.dat', using='1:2', with='lines'))
    #restore the non-file output status of gnuplot for non-zope testing
    g('set output')
    #Line below used for troubleshooting, passes text back to calling web browser
    #return "plotfile= %s." % outputfile

# when executed, just run demo():
if __name__ == '__main__':
    demo()