Develop Reference

JFreeChart Candlestick zoom into last n candles on creation

I have an app and I somehow successfully managed to get a candlestick chart visible. However, once the chart is displayed, it shows all the candles (can be several hundred) which causes the chart to be very tiny and zoomed out. What I actually want is, the chart to be zoomed into the range of the last N candles so it looks more visible to the eye.
Here is how my charts look once they get created
I tried working with setRange, the Range on the Date Axis returns values in the format of [09.02.2023, 23:21:02 --> 10.02.2023, 08:29:56]
I dont seem to get how to make the chart like zoom in to a range of for example range.length-100 -> range.length. Whatever I tried, I always end up somewhere randomly without any data really shown.
Is there a way to define the last n entries on the range and set the dateAxis to start showing this range?
What I actually want to see after creation is something like this
private void displayChart(String title, String quoteMarket, BarSeries series) {
OHLCDataset dataSet = createOHLCDataset(title,series);
JFreeChart chart = ChartFactory.createCandlestickChart(
title,
"Time",
quoteMarket,
dataSet,
false);
chart.setBackgroundPaint(new Color(28, 39, 57));
chart.setBorderVisible(false);
chart.getTitle().setPaint(Color.WHITE);
// Candlestick rendering
CandlestickRenderer renderer = new CandlestickRenderer();
renderer.setAutoWidthMethod(CandlestickRenderer.WIDTHMETHOD_INTERVALDATA);
renderer.setUpPaint(new Color(0, 214, 110));
renderer.setDownPaint(new Color(196, 19, 30));
renderer.setSeriesPaint(0,new Color(211, 211, 211));
renderer.setCandleWidth(3.0);
XYPlot plot = chart.getXYPlot();
plot.setRenderer(renderer);
plot.setRangeGridlinePaint(Color.lightGray);
plot.setBackgroundPaint(new Color(28, 39, 57));
plot.setDomainGridlinesVisible( false );
plot.setRangeGridlinesVisible( false );
NumberAxis numberAxis = (NumberAxis) plot.getRangeAxis();
numberAxis.setAutoRangeIncludesZero(false);
numberAxis.setLabelPaint(Color.WHITE);
numberAxis.setTickLabelPaint(Color.WHITE);
numberAxis.setAutoRangeIncludesZero(false);
DateAxis dateAxis = (DateAxis) plot.getDomainAxis();
dateAxis.setAutoRange(true);
dateAxis.setLabelPaint(Color.WHITE);
dateAxis.setTickLabelPaint(Color.WHITE);
dateAxis.setTickMarkPosition(DateTickMarkPosition.MIDDLE);
plot.setDatasetRenderingOrder(DatasetRenderingOrder.FORWARD);
ChartPanel panel = new ChartPanel(chart);
panel.setMouseWheelEnabled(true);
panel.setMouseZoomable(true);
panel.setRangeZoomable(true);
panel.setDomainZoomable(true);
this.add(panel);
System.out.println(dateAxis.getRange());
}

Change Plot label position in a Combined Plot JFreeChart

Is there a way to change the position of the Category Plot Labels (title) (censored with black bars in the image) to be on top of the chart and / or aligned vertically to each other?
Here's the classes I use to construct it.
var renderer = new LineAndShapeRenderer();
...
var yAxis = new NumberAxis();
...
var xAxis = new CategoryAxis(title);
...
CategoryPlot plot = new CategoryPlot(dataset, xAxis, yAxis, renderer);
...
var combinedPlot = new CombinedRangeCategoryPlot();
combinedPlot.add(plot, weight);
...
I'm using version 1.0.19 of JFreeChart since newer versions produce some visual artifacts.

There has been a misunderstanding: I meant the labels, "Plot 0" and "Plot1", in your example; and I'm asking for the ability to move them on top of the chart…
Invoke setDomainAxisLocation() on each subplot domain axis to move the axis and its label. Alternatively, obtain the required axis references from the List<CategoryPlot> shown below.
plot0.setDomainAxisLocation(AxisLocation.TOP_OR_LEFT);
plot1.setDomainAxisLocation(AxisLocation.TOP_OR_LEFT);
I only need those "Plot 0" and "Plot1" labels on top, not the tick labels…
You can hide the tick labels as desired using setTickLabelsVisible(false), and you can have multiple axes, as shown here.
To adjust the tick label orientation, invoke setCategoryLabelPositions() on each sublot comprising the combined plot. Do this either
When the plot is created.
CategoryAxis axis0 = new CategoryAxis("Plot 0");
axis0.setCategoryLabelPositions(CategoryLabelPositions.UP_90);
CategoryPlot plot0 = new CategoryPlot(…, axis0, …);
…
CategoryAxis axis1 = new CategoryAxis("Plot 1");
axis1.setCategoryLabelPositions(CategoryLabelPositions.UP_90);
CategoryPlot plot1 = new CategoryPlot(…, axis1, …);
After creating the combined plot.
CombinedRangeCategoryPlot combinedplot = new CombinedRangeCategoryPlot(…);
…
List<CategoryPlot> list = combinedplot.getSubplots();
list.get(0).getDomainAxis().setCategoryLabelPositions(CategoryLabelPositions.UP_90);
list.get(1).getDomainAxis().setCategoryLabelPositions(CategoryLabelPositions.UP_90);
Vertical labels are illustrated below.

Dynamic Pie chart in Jfreechart - how to set colours

I am trying to plot a dynamic pie chart using JFreeChart. I do not know how many sections will be present in advance. I receive data every second which updates the graph.
How can I set colour for each section of the chart ? I do not wish to have the default colours.
I have tried setting the DrawingSupplier. Doesn't work. Can anybody help ?

The Plot of the chart for pie charts can be cast to a PiePlot which lets you set the paint color, outline color, shadow color ect.. of each piece of the pie. Heres a little sample of setting the colors for each piece of the pie. If the number of pieces is greater than the amount of colors defined in our array then it will reuse the colors.
The setSectionPaint method takes any type of java.awt.Paint so you can also pass in gradient paints among other things.
PieDataset dataset = ...
JFreeChart chart = ChartFactory.createPieChart("My Chart", dataset, false, true, false);
// all possible colors for each piece of the pie
Color[] colors = new Color[] { new Color(232, 124, 35),
new Color(51, 109, 178), new Color(182, 52, 49),
new Color(103, 131, 45), new Color(108, 77, 146),
new Color(46, 154, 183), new Color(151, 64, 64) };
PiePlot plot = (PiePlot) chart.getPlot();
// set each sections inside paint
int i = 0;
for (Object key : dataset.getKeys()) {
plot.setSectionPaint((Comparable) key, colors[i % colors.length]);
i++;
}

JFreeChart align BarChart width across subplots

I'm building multiple stacked bar charts (subplots) that are combined through a CombinedRangeCategoryPlot.
As the subplots datasets do not have the same number of items and since JFreeChart decides to allocate the same space for each subplot, I have different widths of bars.
Is there any way I can align their width (even if it means that the subplots have different widths)?
Please see below for the result and the code I have so far.
Many thanks,
Thomas
//Builds commong range axis
NumberAxis rangeAxis = new NumberAxis("%");
rangeAxis.setRange(0, 1.0);
rangeAxis.setNumberFormatOverride(NumberFormat.getPercentInstance());
//Builds common data set
CombinedRangeCategoryPlot combinedPlots = new CombinedRangeCategoryPlot(rangeAxis);
for (int groupIndex=0; groupIndex<LeakGroups.values().length; ++groupIndex){
//Builds category axis
CategoryAxis categoryAxis = new CategoryAxis(GuiConstants.LEAK_GROUPS_LABELS[groupIndex]);
//Sets margins between bars
categoryAxis.setCategoryMargin(0.5f);
//Builds bar renderer
StackedBarRenderer barRenderer = new StackedBarRenderer();
barRenderer.setRenderAsPercentages(true);
//Builds dot/level renderer
LineAndShapeRenderer dotRenderer = new LineAndShapeRenderer();
//dotRenderer.setSeriesLinesVisible(0, false);
//dotRenderer.setSeriesShapesVisible(0, false);
//dotRenderer.setSeriesLinesVisible(1, false);
//Defines level shape height (depends on chart size): nominal values are for a height of 1000px
int shapeHeightPx = (int) Math.round(20 * (this.getHeight() / 1000.0));
dotRenderer.setSeriesShape(1, new Rectangle(-1, -shapeHeightPx/2, 2, shapeHeightPx));
//Builds plot
CategoryPlot plot = new CategoryPlot();
plot.setDomainAxis(categoryAxis);
plot.setDataset(0, data[groupIndex].bars);
plot.setRenderer(0, barRenderer);
plot.setDataset(1, data[groupIndex].dots);
plot.setRenderer(1, dotRenderer);
//Adds to combined
combinedPlots.add(plot);
}
combinedPlots.setOrientation(PlotOrientation.HORIZONTAL);
//Puts range axis at the bottom
combinedPlots.setRangeAxisLocation(AxisLocation.BOTTOM_OR_RIGHT);
//Changes plot render sequence so that bars are in the background and shapes in front
combinedPlots.setDatasetRenderingOrder(DatasetRenderingOrder.FORWARD);
//Shows gridlines for categories and not for values
combinedPlots.setDomainGridlinesVisible(true);
combinedPlots.setRangeGridlinesVisible(false);
//Creates chart
JFreeChart chart = new JFreeChart("Leaks", combinedPlots);
//Sets a margin right to allow space for last catergory label ("100%")
chart.setPadding(new RectangleInsets(0, 0, 0, 20));
return chart;

For some reason, the weight gets reset to value 1 when adding the plot.
By way of explanation,
The add(CategoryPlot subplot) method specifies a default weight of 1,
The add(CategoryPlot subplot, int weight) method lets you specify a weight value.

After a few hours of search, found the solution: use plot.setWeight().
For some reason, the weight gets reset to value 1 when adding the plot to the CombinedRangeCategoryPlot, hence it has to be set after.
Hope this helps.

How to draw line over a JFreeChart chart?

I have updatable OHLCChart.
I need to draw a line over chart.
How to implement it?

If you want to draw a vertical or horizontal line at a given position on an axis, you can use a ValueMarker :
ValueMarker marker = new ValueMarker(position); // position is the value on the axis
marker.setPaint(Color.black);
//marker.setLabel("here"); // see JavaDoc for labels, colors, strokes
XYPlot plot = (XYPlot) chart.getPlot();
plot.addDomainMarker(marker);
Use plot.addRangeMarker() if you want to draw an horizontal line.

Something like this should work if you want to plot a line indicator (like a moving average for example):
XYDataset dataSet = // your line dataset
CombinedDomainXYPlot plot = (CombinedDomainXYPlot) chart.getPlot();
XYPlot plot = (XYPlot) plot.getSubplots().get(0);
int dataSetIndx = plot.getDatasetCount();
plot.setDataset(dataSetIndx, dataSet);
XYLineAndShapeRenderer lineRenderer = new XYLineAndShapeRenderer(true, false);
plot.setRenderer(dataSetIndx, lineRenderer);