ClipPathElementClipPathUnitsAttribute: clipPathUnits
In mslegrand/svgR: svgR is an R DSL to generate svg markup

Governs how to interpret the coordinates for the contents of the clipPath. That should they be interpeted as objectBoundingBox or userSpaceOnUse?

The value can be either of the one of the following:

'userSpaceOnUse': Specifies that the coordinate system for the contents of the 'clipPath' is given in terms of the specific user coordinate system that is in effect at the time of clipPath referrencing. (Default)
'objectBoundingBox': Specifies that the coordinate system for the contents of the 'clipPath' is given in terms of the bounding box of target object(s) to be clipped.