How to reposition mac desktop in cocoa

Is there a function that allows you to manipulate the desktop like Dashboard->Manage Widgets?

The desktop appears to reposition itself and slide up. What I want to do is not just slide th开发者_运维问答e desktop when my toolbar is temporarily active but have the entire desktop resize. I assume if you can grab a handle to manipulate the desktop like Dashboard, additional similar operations should be possible.

Desktop windows continue to redraw and operate normally so this is not a screen cap that is just repositioned.

Is Dashboard executing a desktop animation function? or executing a complex set of functions to emulate this effect? or private API? Anyone know?

My guess is emulation. It's probably a window at a very high window level that grabs a screen cap of your desktop to use as its background then animates the rest.

In any case, there's no Cocoa function to let you do this with your own UI.