Health Bars in 2D Game

Hi all. I want make health bars for enemies, which looks like on this screeshot

alt text

Main problem is an optimization, I focused on Android and iOS platforms. I tried use OnGUI boxes and changing scale in plane, but it creates many draw calls. Who can give some information or advices about creation of healthbars the same as on the screenshot without FPS reducing?


I would suggest you look at ngui. Its a plugin for Unity which will health bars and anything UI related a piece of cake.