  In joint work with J. Rasmussen, we gave an interpretation of Heegaard Floer
homology for manifolds with torus boundary in terms of immersed curves in a
punctured torus. In particular, knot Floer homology is captured by this
invariant. Appealing to earlier work of the authors on bordered Floer homology,
we give a formula for the behaviour of these immersed curves under cabling.
