Now that we covered the utmost basics of using the CDK-JChemPaint patch (see\n#1 ,\n#2 ,\n#3 ),\nit is time to move on. I am happy to hear that so many people have started using the new rendering architecture, either\nvia the EBI JChemPaint Swing applet/application branch, or via the CDK-JChemPaint patch.
\n\nA couple of issues and questions came up (scaling not working as expected; how to layout reactions; how to get charges\nto show up), and I will look at those shortly. But before I get into those matters, I’ll first show how to use the renderer\nwith a Swing JPanel\n(I’ll do the SWT alternative later). First, we need to subclass the JPanel:
\n\nclass JCPPanel extends JPanel {\n\n IMolecule mol;\n AtomContainerRenderer renderer;\n int width;\n int height;\n\n public JCPPanel(IMolecule mol, int width, int height) {\n super();\n this.setSize(width, height);\n this.mol = mol;\n this.width = width;\n this.height = height;\n\n // generators make the image elements\n List generators = new ArrayList();\n generators.add(new BasicSceneGenerator());\n generators.add(new BasicBondGenerator());\n generators.add(new BasicAtomGenerator());\n\n // the renderer needs to have a toolkit-specific font manager\n renderer = new AtomContainerRenderer(\n generators, new AWTFontManager()\n );\n }\n\n public Dimension getPreferredSize() {\n return new Dimension(width, height);\n }\n\n public void paint(Graphics graphics) {\n // the call to 'setup' only needs to be done on the first paint\n renderer.setup(mol, new Rectangle(getWidth(), getHeight()));\n\n // paint the background\n graphics.setColor(Color.WHITE);\n graphics.fillRect(0, 0, getWidth(), getHeight());\n\n // the paint method also needs a toolkit-specific renderer\n renderer.paint(mol, new AWTDrawVisitor(graphics));\n }\n\n}\nThe panel does not implement resizing, and it could consider caching the image too, to speed things up a bit. But, we’ll use this as a starting point.
\n\nWe can then embed this panel into a JFrame to make a small runable application:
\n\nint WIDTH = 600;\nint HEIGHT = 600;\n\n// create molecule\nIMolecule triazole = MoleculeFactory.make123Triazole();\nStructureDiagramGenerator sdg = new StructureDiagramGenerator();\nsdg.setMolecule(triazole);\nsdg.generateCoordinates();\ntriazole = sdg.getMolecule();\n\n// create the frame\nJFrame frame = new JFrame(\"Swinging CDK-JChemPaint\");\nframe.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);\n\nJCPPanel panel = new JCPPanel(triazole, WIDTH, HEIGHT);\nframe.getContentPane().add(panel);\n\nframe.pack();\nframe.setVisible(true);\nThe result is pretty much the same as with the created PNG, just with a window. But, this should get you started with using the new code base in your\nSwing-based application. If you need an impression on where this can get you, have a look at the\napplet developed by Chris’ team. Likewise, a SWT-based application can be\ndeveloped, of which Bioclipse is a full example. This shows one of the features of this\nnew JChemPaint code base: it is widget set-independent. I am not aware of applications using other widget toolkits yet, though, but I am still\nhoping someone will use QtJambi to create a Qt-based JChemPaint port.
", "summary": "Now that we covered the utmost basics of using the CDK-JChemPaint patch (see #1 , #2 , #3 ), it is time to move on. I am happy to hear that so many people have started using the new rendering architecture, either via the EBI JChemPaint Swing applet/application branch, or via the CDK-JChemPaint patch.", "date_published": "2010-04-18T00:10:00+00:00", "date_modified": "2026-07-17T00:00:00+00:00", "tags": ["cdk","jchempaint"], "authors": [ { "name": "Egon Willighagen", "url": "https://orcid.org/0000-0001-7542-0286" } ] } ] }