🚀 go-pugleaf

David Thiele <thieled@health.qld.gov.au> writes:

> Please excuse a question from a WWW newbie.  We are writing a web page
> which includes a graph based on input data supplied by the user.  At
> this stage we are experimenting with gnuplot to generate the graph.  Our
> CGI scripts are written in C.
> 
> What is unclear is how to incorporate this graphing function into our
> CGI scripts so that the graph appears "on the fly" with user supplied
> data.  Can gnuplot be called from the CGI script to generate say a
> postscript format of the graph which we then send to convert to generate
> a .gif file which can then be displayed on the web page.  If so how?  If
> not any suggestions on how to perform this function?

You could call gnuplot, but that's probably an expensive way to do it,
since you would have to go through several stages to get to GIF.  I
would suggest looking around for a GIF library for C.

Try http://www.freecode.com/graphics.html for a good start.  The tgd
package might appeal to you due to its simplicity (though I would
advise cgi-draw, fly or gd if performance is an issue).  Unfortunately
the charting packages are all Perl or Java.


Cheers,
Marcelo