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javajasper-reportsjfreechart

Customize color for individual Domain axis tick labels

I have a JFreeChart which I'm running through a customizer (JRAbstractChartCustomizer). I have figured out how to color individual bars and item labels according to the data (eg green for >90%, yellow for 75-90%, red for <75%) by extending BarRenderer and overriding getItemLabelPaint(int row, int column) and getItemPaint(int row, int column). Each bar has a corresponding tick with a String label, since the domain is by name rather than by numeric value. I need a way to individually color the tick labels based on the value similar to how I color the bars and the item labels.

What method do I override in BarRenderer, or what other thing do I do in my JRChartCustomizer to override the color on an individual basis.

What I'm doing for the item labels: (I want to do basically the same thing, but for tick labels)

class CustomBarRenderer extends BarRenderer {

    private final Color COLOR_GREEN = new Color(0, 227, 0);
    private final Color COLOR_YELLOW = new Color(247, 210, 0);
    private final Color COLOR_RED = new Color(237, 26, 0);

    @Override
    public Paint getItemLabelPaint(int row, int col) {
        CategoryDataset cDataset = getPlot().getDataset();

        if (cDataset != null) {
            Number itemValue = cDataset.getValue(row, col);

            String rowKey = cDataset.getRowKey(row).toString();
            String colKey = cDataset.getColumnKey(col).toString();

            if (itemValue != null) {
                int intVal = itemValue.intValue();

                if (intVal > yellowHigh) {
                    return COLOR_GREEN;
                } else if (intVal >= yellowLow) {
                    return COLOR_YELLOW;
                } else {
                    return COLOR_RED;
                }
            }
        }

        // if all else fails...
        return super.getItemLabelPaint(row, col);
    }

    @Override
    public Paint getItemPaint(int row, int col) {
        ... similar to above ...
    }
}
Solution

  • Your chart's domain axis tick label is rendered by a CategoryAxis. You can use setTickLabelPaint() to color labels by category. The example below modifies BarChartDemo1 to make the "Test" category label a shade of green.

    image

    CategoryPlot plot = (CategoryPlot) chart.getPlot();
CategoryAxis domain = plot.getDomainAxis();
domain.setTickLabelPaint("Test", Color.green.darker());

    For finer control, you can override getTickLabelPaint() in a custom CategoryAxis that has access to the dataset referenced by your CustomBarRenderer. The existing implementation uses a Map<Category, Paint> as a lookup table. The Map is private, but the approach may give you an idea of how to proceed.