$.jqplot.MekkoRenderer.prototype.setGridData = function( plot )

converts the user data values to grid coordinates and stores them in the gridData array.  Will convert user data into appropriate rectangles.  Called with scope of a series.

$.jqplot.MekkoRenderer.prototype.makeGridData = function( data, plot )

converts any arbitrary data values to grid coordinates and returns them.  This method exists so that plugins can use a series’ linerenderer to generate grid data points without overwriting the grid data associated with that series.  Called with scope of a series.