I am just finishing a wxperl-based app that goes through an excel file that tracks the progress of jobs and draws a bar chart (like a gantt chart with no vertical connectors) for 7 business days. Each bar is colored by department with a stipple over the color for whether it is done or not, and a line of text providing owner, client and other information is drawn above each bar.

Spreadsheet::ParseExcel to read the sheets (slightly modified to update a progress bar and abort on a button click). After looking around a bit, I settled on using plain GD for drawing and am quite happy with it. Of course you are telling it where to plot each line, but if you just want the commonest graph types GD::Graph I believe. Of course if you are just automating Excel graph creation go for it. But mine draws graphs Excel doesn't have and works cross-platform. There is a PHP based graph drawing system out there called JpGraph but I decided I really didn't want to use PHP. But it can do pies etc.

As it is the GD drawing is fast, the problem is the Spreadsheet module which takes 1 minute to go through a megabyte-sized file. (I think about 200 rows by 15 columns). Which is okay but a little slow (of course this is on an old Win 98 machine not your screaming multi-gigahertz box).