double summaryPoint;
double reductionNumerator;
DataSet dataSet;
int nextIndex;
IntegerPair range;
// Find numerator for fraction of summary point set value to keep
summaryPoint = graphContext.getSummaryData().getValue(set, xPixel - xOffset);
if ( set == startPosition.getSetNumber() && set == endPosition.getSetNumber() ) {
reductionNumerator = Math.max(summaryPoint - ( endPosition.getSetOffset() - startPosition.getSetOffset() ), 0);