tipLengthUnit

default = "size" ("res", "identity", "size", "px"). Unit for the lenstart and lenend aesthetics. Possible values:

• "res": the unit equals the smallest distance between data points along the corresponding axis;

• "identity": a unit of 1 corresponds to a difference of 1 in data space;

• "size": a unit of 1 corresponds to the diameter of a point with size = 1;

• "px": the unit is measured in screen pixels.