GC plot - GC content of a gene in a plot? (Dec/02/2007 )

So far CG content calculators can be found in various aplications, what I was searching but to no avail is some aplication that would plot the GC content of input sequence in a graph. (Primer Express can do this in a primer pair window)

Something like this, but it only works with whole genomes. I just want to add a sequence to a text field and set a window size and get a GC plot. E.g to see if a region of my gene is high in GC or not and will trouble my PCR.

Last time I needed this I did calculations of every 20 bases using Excell and made the graph there but that was awfull

Does anyone know where to get what I need? Or should I think about making a script myself?

there are several online tools allowing you to do a GC plot as well as CpG plot:

http://www.ebi.ac.uk/emboss/cpgplot/
http://www.urogene.org/methprimer/index1.html

Thanks, EMBOSS Isochore program is what I was looking for. The others find just CpG islands, I didn't realize thay can be together.