How can I make an undecorated window in Cocoa?

Question

I like to create a Cocoa window without any chrome whatsoever. The only thing the user should see is what I draw.

I've discovered I can create a custom NSView but does this have to be in an NSWindow to display? If not, how can I display it without putting it in an NSWindow? If it does have to be in an NSWindow, how do I stop the window from drawing a title bar and other chrome?

Answer 1

Check out the sample:

http://developer.apple.com/samplecode/RoundTransparentWindow/index.html

Answer 2

I've discovered I can create a custom NSView but does this have to be in an NSWindow to display?

Yes.

If it does have to be in an NSWindow, how do I stop the window from drawing a title bar and other chrome?

Use NSBorderlessWindowMask when you create your window. (Assuming you aren't using a custom subclass of NSWindow, this means not creating the window instance in a nib. If you want to lay out your view hierarchy in a nib, do that in a top-level custom view, then load the nib and set that view as the window's content view.)