palantir/plottable — pull request #1293 by jtlan (2014-11-05 20:31:03+00:00)
Title: Add in Interaction.Crosshair, Hover ability to Line and Area.

Enable Interaction.Hover on Plot.Line and Plot.Area, using a "closest-by-x-then-y" algorithm.

Add Interaction.Crosshair, which extends Interaction.Hover and draws a circle and two lines interesecting on the hovered point.