There is an open source charting program written in Perl called, simply, Chart.

Unfortunately, at this time it does not seem to support any datafeeds that would be useful for intraday futures trading.

Is anyone familiar with this program? Is this approach one that should be pursued?

Here's a link to the online manual. For one thing, it has a treasure trove of calculation formulas for numerous indicators.

Chart Manual

Hmm, Perl with GTK2, I think you should not spend too much time on this. It was maybe very good 10 years ago, but it's too late now, some other "non-GNU" with proprietary code do a much better job.