如何为iPhone/iPad应用程序创建一个浮动工具栏?

I'm working on a bitmap editor app for the iPad/iPhone and I'd like to have a floating toolbar that the user can move around the drawing canvas so it doesn't get in the way of the drawing surface. I'd use a standard UIToolbar, but I'd like the toolbar to have a zoom navigation view, which wouldn't fit elegantly in a standard UIToolbar.I'm working on a bitmap editor app for the iPad