Using Google Charts API and SQL Developer (or SQLPLUS)...
I added a page to my SQL Developer Tips and Tricks page about integrating the Google Graph API with SQL Developer HTML reports.
I sometimes run out of steam with the built in chart and gauge capabilities of SQL Developer. With a little work you can leverage the Google Graph API to create Line, Bar, Pie Charts, Map, Scatter, Venn Diagrams, Radar Charts, QR Codes and Meters.
Here is everything you need to know to get started: SQL Developer and Google Graph API Example