JFreeChart：如何在同一图表上绘制折线图和散点图

Question

i have two sets of data

int[] x1 = {1,2,3,4,5,6,7,8,9,10};
int[] y1 = {1,2,3,5,6,8,9,10,14,11};

int[] x2 = {1,2,3,4,5,6,7,8,9,10};
int[] y2 = {0,2,3,5,0,8,9,8,14,11};

int[] z2 = {1,2,3,1,2,3,1,2,3,1};

I want to plot the x1,y1 as an XYLineChart and then plot x2,y2 as a scatter on the same plot without a line.

I also need each scatter point of xy,y2 to be a different color depending on the value of z2 (1=Color.red, 2=Color.green, 3=Color.blue)

How can i do this?

So far i have:

JPanel panel_1 = new JPanel();
panel_1.setLayout(new BorderLayout(0, 0));
XYSeriesCollection dataset = new XYSeriesCollection();
XYSeries series1 = new XYSeries("series1");
for(int i=0; i<x1.length; i++){
    series1.add(x1[i],y1[i]);
}
dataset.add(series1);
JFreeChart chart = ChartFactory.createXYLineChart("Title", "x", "y", dataset, PlotOrientation.VERTICAL, false, false, false);
ChartPanel cp = new ChartPanel(chart);
panel_1.add(cp, BorderLayout.CENTER);

This gets the line graph sorted. I now need to code the scatter plot for x2,y2 (with colors described above) which is where im stuck.

Answer 1

The createXYLineChart() method will create a chart that uses an XYLineAndShapeRenderer . So fetch the renderer from the plot and cast it to XYLineAndShapeRenderer. Then you can call the methods setSeriesLinesVisible() and setSeriesShapesVisible() to control, for each series, whether shapes and/or lines are drawn for the data items. That way you can use a single renderer and dataset, which makes things simpler.

Your requirement to change the colors depending on another data value requires a little more work. You should subclass the XYLineAndShapeRenderer class and override the getItemPaint(int, int) method. Here you can return any color you want for a data item. The default implementation looks at the series index and returns the color for the series. You need to look at the item index as well, then do a lookup in your table of z-values and decide what color to return.