CDK-JChemPaint #1: rendering molecules
I reported earlier that the CDK-JChemPaint patch is now a clean add-on from the CDK releases. This means that you download cdk-1.3.4.jar and cdk-jchempaint-8.jar separately, put them in your class path, and get started with, for example, Groovy:
$ export CLASSPATH=cdk-1.3.4.jar:cdk-jchempaint-8.jar
$ groovy renderMol.groovy

I have tuned to code in this tutorial by Gilleain a bit, resulting in this code:
import java.util.List;
import java.awt.*;
import java.awt.image.*;
import javax.imageio.*;
import org.openscience.cdk.*;
import org.openscience.cdk.interfaces.*;
import org.openscience.cdk.layout.*;
import org.openscience.cdk.renderer.*;
import org.openscience.cdk.renderer.font.*;
import org.openscience.cdk.renderer.generators.*;
import org.openscience.cdk.renderer.visitor.*;
import org.openscience.cdk.templates.*;
int WIDTH = 600;
int HEIGHT = 600;
// the draw area and the image should be the same size
Rectangle drawArea = new Rectangle(WIDTH, HEIGHT);
Image image = new BufferedImage(
WIDTH, HEIGHT, BufferedImage.TYPE_INT_RGB
);
IMolecule triazole = MoleculeFactory.make123Triazole();
StructureDiagramGenerator sdg = new StructureDiagramGenerator();
sdg.setMolecule(triazole);
sdg.generateCoordinates();
triazole = sdg.getMolecule();
// generators make the image elements
List generators = new ArrayList();
generators.add(new BasicSceneGenerator());
generators.add(new BasicBondGenerator());
generators.add(new BasicAtomGenerator());
// the renderer needs to have a toolkit-specific font manager
AtomContainerRenderer renderer =
new AtomContainerRenderer(generators, new AWTFontManager());
// the call to 'setup' only needs to be done on the first paint
renderer.setup(triazole, drawArea);
// paint the background
Graphics2D g2 = (Graphics2D)image.getGraphics();
g2.setColor(Color.WHITE);
g2.fillRect(0, 0, WIDTH, HEIGHT);
// the paint method also needs a toolkit-specific renderer
renderer.paint(triazole, new AWTDrawVisitor(g2));
ImageIO.write((RenderedImage)image, "PNG", new File("triazole.png"));