Custom percentage thresholds on y-axis with uneven spacing

Question

My problem: Using jfreechart, I need to display unevenly spaced percentage thresholds on the y-axis. For example, the only labels on my y-axis should be the thresholds as follows; all other ordinates should be blank:

-
93%
85%
78%
72%
66%
-
50%
-
-
-
-
-

I am currently using this code snippet for percentages display, but this will just create an evenly spaced percentage axis:

    CategoryPlot plot = (CategoryPlot) chart.getPlot();

    NumberAxis rangeAxis = (NumberAxis) plot.getRangeAxis();
    DecimalFormat pctFormat = new DecimalFormat("#.0%");
    rangeAxis.setNumberFormatOverride(pctFormat);

Any help would be appreciated!

Answer 1

This is a somewhat hacked-up answer, and i will upvote any answer that gets the same result in a good way. But it works - here is what i did.

First, i created a list of the double values i wanted to be used:

public static List<Double> m_lPercentageValuesForY = Arrays.asList(0.1,0.2,0.3,0.4,0.5,0.58,0.66,0.70,0.74,0.78,0.82,0.95,1.0);

Then i overwrite the refreshTicks method in NumberAxis to first set all default ticks to Ticktype.MINOR, and then add and create my custom ticks with Ticktype.MAJOR:

    NumberAxis axisLeft = new NumberAxis(plot.getRangeAxis().getLabel()) {
        @Override
        public List refreshTicks(
                Graphics2D g2, 
                AxisState state,
                Rectangle2D dataArea, 
                RectangleEdge edge) {

            List defaultTicks = super.refreshTicks(g2, state, dataArea, edge);
            List customTicks = new ArrayList();

            for (Object aTick : defaultTicks) {
                NumberTick currenttick = (NumberTick) aTick;

                customTicks.add(new NumberTick(
                        TickType.MINOR, 
                        currenttick.getValue(), 
                        "",  //empty
                        currenttick.getTextAnchor(), 
                        currenttick.getRotationAnchor(),
                        currenttick.getAngle()));
            }
            NumberTick aTick = (NumberTick) defaultTicks.get(0);
            for (double dTest : m_lPercentageValuesForY) {
                customTicks.add(new NumberTick(
                        TickType.MAJOR, 
                        dTest, 
                        String.format("%.0f%%", dTest * 100), //only wanted values are set to major
                        aTick.getTextAnchor(), 
                        aTick.getRotationAnchor(),
                        aTick.getAngle()));
            }
            return customTicks;
        }
    };
    plot.setRangeAxis(axisLeft);