Is there a way to set the colors differently for above/below the shifted y axis? Above is green (no issues); below is red (issues). Or, depending on what is being discussed, the exact opposite?
Sure!
Try this:
b := RTGrapher new. ds := RTStackedDataSet new. ds barShape width: 15; if: [:v | v < 0 ] fillColor: Color red; if: [:v | v > 0 ] fillColor: Color green. ds points: #(5 -6 10 20 -9). b add: ds. b axisX noLabel; noTick. b axisY noDecimal. b build.