Question

I’m in charge of maintaining an application which can draw graphs using JFreeChart.
The application is written in Eclipse-RCP and SWT and use a ChartComposite to display the charts.

The ChartComposite has been partially overridden in order to customize contextual menus depending on the selection:

@Override
    public void createPartControl(Composite parent) {
    super.createPartControl(parent);

    chart = createChart(timeSeriesDataset);

    chartComposite = new MyChartComposite(this, parent, SWT.NONE, chart, true);
    chartComposite.setLayoutData(new GridData(GridData.FILL_BOTH));

    selectionProvider = new GenericObjectSelectionProvider();
    getSite().setSelectionProvider(selectionProvider);

    // add information to the status line:
    selectionProvider.addSelectionChangedListener(statusLineListener);

    addDropSupport();// add D'n D support for dropping TimeSeries 

}


protected JFreeChart createChart(TimeSeriesCollection ptimeSeriesDataset) {

        JFreeChart vChart = ChartFactory.createTimeSeriesChart(null, "time", "values", ptimeSeriesDataset, true,
                false, false);
        vChart.setBackgroundPaint(Color.white);

        XYPlot plot = vChart.getXYPlot();
        plot.setBackgroundPaint(Color.lightGray);
        plot.setDomainGridlinePaint(Color.white);
        plot.setRangeGridlinePaint(Color.white);
        // plot.setAxisOffset(new RectangleInsets(5.0, 5.0, 5.0, 5.0));
        plot.setDomainCrosshairVisible(true);
        plot.setRangeCrosshairVisible(true);

        plot.setRenderer(new /*OptimisedXYLineAndShapeRenderer()*/ StandardXYItemRendererFast());
        XYItemRenderer renderer = plot.getRenderer();
        renderer.setBaseToolTipGenerator(new MyXYSeriesToolTipGenerator());
        renderer.setBaseItemLabelGenerator(new MyXYSeriesItemLabelGenerator());
        renderer.setLegendItemLabelGenerator(new MyXYSeriesLegendItemLabelGenerator());
        if (renderer instanceof XYLineAndShapeRenderer) {
            XYLineAndShapeRenderer r = (XYLineAndShapeRenderer) renderer;
            r.setBaseShapesVisible(false);
            r.setBaseShapesFilled(true);
        }

        SimpleDateFormat dateFormat = getDateFormatAbscissa();
        if (dateFormat != null){
            DateAxis axis = (DateAxis) plot.getDomainAxis();
            axis.setDateFormatOverride(dateFormat);
        }   

        return vChart;
    }

My problem is that when too many variables are added to the chart (a TimeSeriesChart) the caption takes too much space and the graph disappears from the view:

ChartComposite with 2 series

ChartComposite many series

I tried to create a ScrollComposite to scroll in the ChartComposite and the result is a little better; but it only makes it possible to add more items in the caption before the graph disappears again:

ScrolledComposite scrollableChart = new ScrolledComposite(parent, SWT.BORDER|SWT.V_SCROLL);

chartComposite = new MyChartComposite(this, scrollableChart, SWT.NONE, chart, true);
//chartComposite = new MyChartComposite(this, parent, SWT.NONE, chart, true);
//chartComposite.setLayoutData(new GridData(GridData.FILL_BOTH));

scrollableChart.setContent(chartComposite);
scrollableChart.setExpandVertical(true);
scrollableChart.setExpandHorizontal(true);
scrollableChart.setMinSize(ChartComposite.DEFAULT_MINIMUM_DRAW_WIDTH, ChartComposite.DEFAULT_MINIMUM_DRAW_WIDTH);

My question is: How to provide a real scrollbar to the ChartComposite in order to keep the graph when many series are plotted on the graph?

Answer 1

I was able to sync a slider to the XYSeries in SWT using a ChartComosite and Slider objects through the use of FormData. And every time I move the slider I capture that event and update the chart myself according to my needs.

My use case may be different than yours, but it’s worth to take a look to my answer here.

If you have questions regarding my implementation, described in that answer, feel free to ask for details