Extract a 2D slice from an image volume
Usage
slice(x, zlevel, along, orientation, ...)
# S4 method for class 'NeuroVol,numeric,numeric,missing'
slice(x, zlevel, along, orientation)
# S4 method for class 'NeuroVol,numeric,NeuroSpace,AxisSet3D'
slice(x, zlevel, along, orientation)