JFreeChart - How to remove gaps between XYBarRenderer in a TimeSeriesChart

Question

I am trying to remove the gaps between the bars on a XYBarRenderer in a TimeSeriesChart. In other words, I would like to expand the bar when there is no data before and after the bar's time. Is it possible? I will really appreciate your help.

here is my code:

protected JFreeChart criarChart(XYDataset dataset){
    JFreeChart chart;

    chart = ChartFactory.createTimeSeriesChart(
            this.getTitulo(), //titulo
            this.getEixoX(), //nome do eixo-x
            this.getEixoY(), //nome do eixo-y
            dataset, //dados
            true, //criar legenda?
            true, //criar tooltips?
            false); //criar URLs?

    chart.setBackgroundPaint(Color.white);

    XYPlot plot = (XYPlot) chart.getPlot();
    plot.setOrientation(PlotOrientation.VERTICAL);
    plot.setBackgroundPaint(Color.lightGray);
    plot.setDomainGridlinePaint(Color.white);
    plot.setRangeGridlinePaint(Color.white);
    plot.setDomainCrosshairVisible(true);
    plot.setRangeCrosshairVisible(true);
    plot.getRenderer().setSeriesPaint(0, Color.red);

    plot.setRenderer(new ClusteredXYBarRenderer() {
                @Override
                public Paint getItemPaint(int series, int item) {
                    XYDataset dataset = getPlot().getDataset();
                    if (dataset.getYValue(series, item) >= 0.0) {
                        return Color.green;
                    }
                    else {
                        return Color.red;
                    }
                }
            }
    );
    XYItemRenderer renderer = plot.getRenderer();
    if(renderer instanceof XYBarRenderer){
        XYBarRenderer r = (XYBarRenderer)renderer;
        r.setBarPainter(new StandardXYBarPainter());
        r.setMargin(-20.0);
        r.setShadowVisible(false);
    }
    //mostra o tooltip das barras do grafico
    plot.getRenderer().setBaseToolTipGenerator(new StandardXYToolTipGenerator(
    StandardXYToolTipGenerator.DEFAULT_TOOL_TIP_FORMAT,
    new SimpleDateFormat("HH:mm"), new DecimalFormat("#0")));

    DateAxis axis = (DateAxis) plot.getDomainAxis();
    axis.setDateFormatOverride(new SimpleDateFormat("HH:mm"));

    return chart;
}

I saw somewhere to change the Margin, so I tried to use:

r.setMargin(-20.0);

but didn't work.

Answer 1

The XYBarRenderer relies on the dataset to supply values that determine the width of the bars (see the getStartXValue() and getEndXValue() methods). It also trims the width by a percentage referred to as the 'margin'. The margin is only used if it is greater than zero, and you would specify a number like 0.20 (twenty percent). The default margin is 0.0.