servlet that generates buttons

I'd like a servlet that I can call like this:
    <img src="http://knowlist.com/know/buttonGenerator?text=click+for+happiness&height=15&bgcolor=559955&textColor=ffffff">

Actually, the easiest thing would be to have some simple java code that takes various parameters like the text and colors and size and style and returns the button. I could write the servlet wrapper and caching for it.

Basically, I'm tired of having to create a new image for every button and then create a new version of each button for every color scheme I use. It's a lot of busywork.