overlaid

[johnd]

Can someone point me in the right direction...

I have the code to create two charts. They both have the the same
amount of data represented. One chart is a bar chart the other is a
line chart.

Basically it is prices by month for 24 months.

I just want to show both charts together. I want them superimposed.

I am reading all the code about overlaying, and and having a bit of
trouble.

Has anyone done this?

here is the code I use to make the two separate charts....



-------------------------------------------------------------------------------------------
public static byte[] makeGraph(double[] in) {
String[] names={"one","two", "three", "four"};
double[][] vals=new double[1][in.length];
double[][] vals1=new double[in.length][1];
for(int i=0; i<in.length; i++) {
System.out.println("on: "+i);
vals[0]=in;
vals1[0]=in;
}

CategoryDataset data=new DefaultCategoryDataset(vals1);
JFreeChart bar=ChartFactory.createVerticalBarChart(
"Price Trends",// (Indices Re-Based at 100)",
"this is a test this is a test axis label",
"I N D E X",
data,
true
);

data=new DefaultCategoryDataset(vals);
JFreeChart line=ChartFactory.createLineChart(
"Price Trends",// (Indices Re-Based at 100)",
"this is a test this is a test axis label",
"I N D E X",
data,
true
);



System.out.println("made chart");
BufferedImage img=line.createBufferedImage(400, 400);
System.out.println("made image");
PngEncoder enc=new PngEncoder(img);
return enc.pngEncode();
}

[Edward Pottasch]

maybe have a look at \com\jrefinery\chart\demo\OverlaidPlotDemo.java. Note: it is only possible to overlay charts that have the same y-axis. Multiple y-axis are not possible (unfortunately).

basicly what you do is (see the demo also):

1)
// make an overlaid plot...
OverlaidXYPlot plot = new OverlaidXYPlot("Date", "Value");

2)
// add subplot 1...
IntervalXYDataset data1 = this.createDataset1();
XYItemRenderer renderer1 = new VerticalXYBarRenderer(0.20);
renderer1.setToolTipGenerator(new TimeSeriesToolTipGenerator("d-MMM-yyyy", "0.00"));
XYPlot subplot1 = new XYPlot(data1, null, null, renderer1);
plot.add(subplot1);

3)
// add subplot 2...
XYDataset data2 = this.createDataset2();
XYItemRenderer renderer2 = new StandardXYItemRenderer();
renderer2.setToolTipGenerator(new TimeSeriesToolTipGenerator("d-MMM-yyyy", "0.00"));
XYPlot subplot2 = new XYPlot(data2, null, null, renderer2);
plot.add(subplot2);

in your case you need to define the renderers properly so that subplot1 renders bars and subplot2 renders lines.

[David Gilbert]

There is a demo that relates to category charts:

com.jrefinery.chart.demo.OverlaidCategoryChartDemo

Follow that as an example, and if you have any problems ask some more questions.

Regards,

DG.