Chart with inverted y axis

Question

Using JavaFX Charts, I need to invert the y-axis of a stacked area chart so that a positive zero is at the top and the positive numbers work downward on the y-axis. Below is a mock-up of what I'm trying to achieve.

What is the best (read: shortest development time and high code-reuse) way to achieve this in JavaFX?

UPDATE

Converting the data to negative numbers is not an option. I'm looking for answers that will work with the positive numbers, "untouched."

Answer 1

You can use regular axis with negative values, but add TickLabelFormatter which will strip minus sign.

    final NumberAxis yAxis = new NumberAxis(-25, 0, 5);

    yAxis.setTickLabelFormatter(new NumberAxis.DefaultFormatter(yAxis) {
        @Override
        public String toString(Number value) {
            // note we are printing minus value
            return String.format("%7.1f", -value.doubleValue());
        }
    });

    series1.getData().add(new XYChart.Data("Jan", -1));
    series1.getData().add(new XYChart.Data("Feb", -5));
    series1.getData().add(new XYChart.Data("Mar", -20));