A number of sample KavaChart programs are included with this release in the javachart/demos directory. The programs in this directory serve as a useful set of templates for adding KavaChart graphics to any Java program.
KavaChart programs, whether applets or applications, always draw to a java.awt.Graphics class. They generally draw to a subclass of Java's java.awt.Component class, and require a Component to draw rotated labels, such as those found on axes and bars.
Here is a simple KavaChart program, with comments that describe each step.
import javachart.chart.*; import java.awt.*; import java.util.Vector; public class SimpleChart extends java.awt.Frame { public Chart chart; public static void main (String[] args) { SimpleChart f = new SimpleChart(); double x[] = new double[5]; double y[] = new double[5]; //fill an array with random numbers for (int i = 0; i < 5; i++) { x[i] = (double) i; y[i] = Math.random(); } //create a new BarChart instance f.chart = new BarChart("Test Chart"); //add the random numbers as a dataset with the name "Test" f.chart.addDataSet("Test", x, y); //Define some axis titles f.chart.getXAxis().setTitleString("X axis"); f.chart.getYAxis().setTitleString("Y axis"); f.resize(500, 300); //resize the chart to be the same size as this Frame f.chart.resize(500, 300); f.show(); } public void paint(Graphics g){ //draw the graph as part of the paint process chart.drawGraph(g); } }To compile this program with Javasoft's JDK, you would execute the following command:
To change this chart from a LineChart to a BarChart or PieChart, you could simply change the following line:
//f.chart = new BarChart("Test Chart"); f.chart = new LineChart("Test Chart");Note: if you're using the SimpleChart example in KavaChart's "standalone" directory, you'll have to run "javachart.standalone.SimpleChart", because these files have been placed into a Java package.
import java.applet.*; import java.awt.Graphics; import javachart.chart.*; public class simpleApp extends Applet { ChartInterface chart; public void init () { double yvals[] = new double[5]; for(int i=0;i < 5;i++) yvals[i] = Math.random(); chart = new BarChart("My Chart"); chart.resize(this.size().width, this.size().height); chart.addDataSet("my data", yvals); } public void paint(Graphics g) { chart.drawGraph(g); } }Compile this applet as you would any other Java class, and reference it within your HTML code like this:
<applet code=simpleApp width=400 height=400> </applet>You can also use the "CODEBASE" parameter to point to the directory that contains your applet and "javachart" directory. This can also point to a zip file containing KavaChart classes.