PlotOrientation orientation, int datasetIndex,
Comparable rowKey, Comparable columnKey, Stroke stroke,
Paint paint) {
CategoryDataset dataset = getDataset(datasetIndex);
CategoryAxis axis = getDomainAxisForDataset(datasetIndex);
CategoryItemRenderer renderer = getRenderer(datasetIndex);
Line2D line = null;
if (orientation == PlotOrientation.VERTICAL) {
double xx = renderer.getItemMiddle(rowKey, columnKey, dataset, axis,
dataArea, RectangleEdge.BOTTOM);