swift - Rendering a CALayer's contents that Appear outside of Window -

so i've got big calayer in nsview larger window (using cocoa on mac os x).

every time use renderincontext: thing renders what's viewable in window, , nothing outside it.

how can create bitmap of outside visible rect , export png?

i've looked @ bunch of core graphics methods can't find answer anywhere:(

this turned out easy

mylayer.maskstobounds = false 

this removes mask main window puts on calayer , allows exported, though can't see it.