java - JFreeChart | How to add percentage to top of each bar and format domain axis (X axis) ticklabels?

Question

I'm using JFreeChart and following is a screenshot of the developed chart by me and the related code.

    private void getBarChart(List<Data> data) {
JFreeChart barChart = ChartFactory.createBarChart("", "", "", createDataset(data), PlotOrientation.VERTICAL, false, true, false);
        CategoryPlot plot = barChart.getCategoryPlot();
        plot.getRenderer().setSeriesPaint(0, new Color(7, 43, 97));

        barChart.getCategoryPlot().getRangeAxis().setLowerBound(0);
        barChart.getCategoryPlot().getRangeAxis().setUpperBound(1);
        NumberAxis xAxis2 = (NumberAxis) barChart.getCategoryPlot().getRangeAxis();
        xAxis2.setNumberFormatOverride(NumberFormat.getPercentInstance());

        plot.getRenderer().setSeriesItemLabelGenerator(0, new StandardCategoryItemLabelGenerator());
        plot.getRenderer().setSeriesItemLabelsVisible(1, true);
        plot.getRenderer().setBaseItemLabelsVisible(true);
        plot.getRenderer().setBaseSeriesVisible(true);
        barChart.getCategoryPlot().setRenderer(plot.getRenderer());


        BarRenderer.setDefaultBarPainter(new StandardBarPainter());
        ((BarRenderer) plot.getRenderer()).setBarPainter(new StandardBarPainter());

        BufferedImage image = new BufferedImage(650, 250, BufferedImage.TYPE_INT_ARGB);
        Graphics2D g2 = image.createGraphics();
        g2.setRenderingHint(JFreeChart.KEY_SUPPRESS_SHADOW_GENERATION, true);
        Rectangle r = new Rectangle(0, 0, 650, 250);
        barChart.draw(g2, r);
        BufferedImage chartImage = barChart.createBufferedImage(600, 400, null);
}

The expected chart should be something like following.

Question 1.) How to format the x axis lables as per like the expected graph ?(CategoryLables or TickLabels in barChart.getCategoryPlot().getDomainAxis())

Question 2.) The values displayed in top of each bar (SeriesItemLabels) needs to be formatted with a percentage mark(%) similar to the y axis. (Also I think, like I have done in xAxis2.setNumberFormatOverride, the values will automatically get multipled by 100%. Right now it displays the decimal value only). How to achieve this ?

Please help me out. Thanks.

Answer 1

Working from BarChartDemo1.java, updated for JFreechart 1.5, the following alternative are illustrated below.

1. As shown here and here, you can invoke setCategoryLabelPositions() on the domain axis and use CategoryLabelPositions.createUpRotationLabelPositions to fine-tune the angle. The example below rotates counter-clockwise π/4 radians or 45°.

   CategoryAxis domainAxis = plot.getDomainAxis();
   domainAxis.setCategoryLabelPositions(
       CategoryLabelPositions.createUpRotationLabelPositions(Math.PI / 4.0));
   

2. A shown here, you can construct a custom StandardCategoryItemLabelGenerator, but you may want to use ArgumentIndex {3}, which is the value as a percentage of the column total, as well as a suitable NumberFormat.

   renderer.setDefaultItemLabelGenerator(
       new StandardCategoryItemLabelGenerator(
           "{3}", NumberFormat.getPercentInstance()));
   renderer.setDefaultItemLabelsVisible(true);