JMSL Chart Programmer's Guide

Charting 2D Types >> Area Plot

Area Plot

Area plots are similar to line plots, but with the area between the line and a reference line filled in. An area plot is created if the DATA_TYPE_FILL bit is on in the value of the DataType attribute. The default reference line is y=0. The location of the reference line can be changed from 0 by using setReference(double). The Fill Area Attributes determine how the area is filled.

Simple Area Plot

This example draws a simple area plot. The default value of the FillType attribute is FILL_TYPE_SOLID. The example sets the FillColor attribute to blue. So the area between the line and y=0 is solid blue.

import com.imsl.chart.*;
import java.awt.Color;

public class SampleArea extends JFrameChart {

    public SampleArea() {        
        Chart chart = getChart();
        AxisXY axis = new AxisXY(chart);
  
        double y[] = {4, -6, 2, 1, -8};
        Data data = new Data(axis, y);
        data.setDataType(Data.DATA_TYPE_FILL);
        data.setFillColor(Color.blue);
    }
    
    public static void main(String argv[]) {
        new SampleArea().setVisible(true);
    }
}

Painted Area Example

This example shows an area chart filled in with a painted texture. The texture is created by a static method FillPaint.crosshatch.

A second data set is plotted as a set of markers.

The Legend node is painted in this example and has entries for both the filled area data set and the marker data set.

import com.imsl.chart.*;
import java.awt.Color;

public class SampleAreaPaint extends JFrameChart {

    public SampleAreaPaint() {        
        Chart chart = getChart();
        AxisXY axis = new AxisXY(chart);
        chart.getLegend().setPaint(true);
  
        double y1[] = {4, -6, 2, 1, -8};
        Data data1 = new Data(axis, y1);
        data1.setTitle("Area");
        data1.setDataType(Data.DATA_TYPE_FILL);
        data1.setFillType(Data.FILL_TYPE_PAINT);
        data1.setFillPaint(FillPaint.crosshatch
        (10,5,Color.red,Color.yellow));
        
        double y2[] = {5, -3, 6, -7, 2};
        Data data2 = new Data(axis, y2);
        data2.setTitle("Marker");
        data2.setDataType(Data.DATA_TYPE_MARKER);
        data2.setMarkerColor(Color.blue);
        data2.setMarkerType(Data.MARKER_TYPE_FILLED_CIRCLE);
    }
    
    public static void main(String argv[]) {
        new SampleAreaPaint().setVisible(true);
    }
}

Attribute Reference

The attribute Reference defines the reference line. If its value is a, then the reference line is y = a. Its default value is 0.

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