grid.clip. The only difference is that a non-rectangular
clipping region can be applied.
pushClipPath(clippath = NULL, label = NULL, name = NULL, draw = TRUE)
popClipPath()pushClipPath grob. The value is returned invisibly.
label is specified, uses a clipping path that has been
supplied to registerClipPath. If clippath is specified
it will be used as the new clipping context for the current
viewport. If both are specified, it will attempt to define the
clipping path with the given label, as well as adding the clipping
path as a clipping context for the current viewport. popClipPath is an alias for popContext
registerClipPath, grid.clipPath,
popContext.