Using JavaGD in Java applications

Kornelius Rohmeyer — Fri, 09 Jul 2010 21:54:25 +0000

Goal: Create a Java application with a JFrame that contains a JGDPanel from JavaGD and plot something via JRI.

Solution: The following code is a derivate of JGR code snipplets under GPL-2:

import java.awt.Component;
import java.awt.event.WindowEvent;
import java.awt.event.WindowListener;

import javax.swing.JFrame;

import org.rosuda.JRI.Rengine;
import org.rosuda.javaGD.GDInterface;
import org.rosuda.javaGD.JGDBufferedPanel;

public class JavaGDExample extends GDInterface implements WindowListener {

JFrame f;

public void gdOpen(double w, double h) {
if (f!=null) gdClose();
f = new JFrame("JavaGD Example");
f.addWindowListener(this);
c = new JGDBufferedPanel(w, h);
f.getContentPane().add((Component) c);
f.pack();
f.setVisible(true);
}

public void gdClose() {
super.gdClose();
if (f!=null) {
c=null;
f.removeAll();
f.dispose();
f=null;
}
}

public static void main(String[] args) {
Rengine engine = new Rengine(new String[] {"--vanilla"}, true, null);
engine.eval(".setenv <- if (exists(\"Sys.setenv\")) Sys.setenv else Sys.putenv");
engine.eval(".setenv(\"JAVAGD_CLASS_NAME\"=\"JavaGDExample\")");
engine.eval("library(JavaGD)");
engine.eval("JavaGD()");
engine.eval("plot(rnorm(100))");
}

/** listener response to "Close" - effectively invokes dev.off() on the device */
public void windowClosing(WindowEvent e) {
if (c!=null) executeDevOff();
}
public void windowClosed(WindowEvent e) {}
public void windowOpened(WindowEvent e) {}
public void windowIconified(WindowEvent e) {}
public void windowDeiconified(WindowEvent e) {}
public void windowActivated(WindowEvent e) {}
public void windowDeactivated(WindowEvent e) {}
}

Et voilà:

Of course you have to make sure that the JRI native library is in a directory listed in java.library.path, for example on my machine via:

java -Djava.library.path=/usr/local/lib/R/site-library/rJava/jri/ JavaGDExample

Also you have to provide the correct path for the environment variable R_HOME such as:

R_HOME=/usr/lib64/R/

And of course you need the two jars javaGD.jar and JRIEngine.jar in your CLASSPATH.

Algorithm-Forge » Java

Using JavaGD in Java applications