The test program below demonstrates the bug, which is that when you
change the "viewBox" attribute on the top level <svg> node, the JSVGCanvas
redraws the image the height and width specified in the SVG document
rather than using the height and width of the Swing container.

The result is that even though the "viewBox" attribute is being changed
to an equivalent value to what it was before (previous value plus space),
the image shifts dramatically on the screen.

Perhaps a call to this.computeRenderingTransform() is missing somewhere
from SVGSVGElementBridge.java ??  If you subclass JSVGCanvas, and invoke
this method after the DOM change, the image "snaps back" to where it
should be.

--------------------------- CUT HERE --------------------------

import java.awt.Dimension;
import java.awt.GraphicsEnvironment;
import java.awt.Point;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
import java.io.File;

import javax.swing.JFrame;
import javax.swing.SwingUtilities;

import org.apache.batik.bridge.UpdateManager;
import org.apache.batik.bridge.UpdateManagerEvent;
import org.apache.batik.bridge.UpdateManagerListener;
import org.apache.batik.swing.JSVGCanvas;
import org.apache.batik.swing.gvt.GVTTreeRendererEvent;
import org.apache.batik.swing.gvt.GVTTreeRendererListener;
import org.apache.batik.swing.svg.GVTTreeBuilderEvent;
import org.apache.batik.swing.svg.GVTTreeBuilderListener;
import org.apache.batik.swing.svg.SVGDocumentLoaderEvent;
import org.apache.batik.swing.svg.SVGDocumentLoaderListener;
import org.apache.batik.swing.svg.SVGLoadEventDispatcherEvent;
import org.apache.batik.swing.svg.SVGLoadEventDispatcherListener;
import org.apache.batik.util.RunnableQueue;
import org.apache.log4j.BasicConfigurator;
import org.apache.log4j.ConsoleAppender;
import org.apache.log4j.Level;
import org.apache.log4j.Logger;
import org.apache.log4j.PatternLayout;
import org.w3c.dom.svg.SVGDocument;
import org.w3c.dom.svg.SVGElement;

public class ViewBoxTest extends WindowAdapter implements
  SVGDocumentLoaderListener, GVTTreeBuilderListener,
  SVGLoadEventDispatcherListener, GVTTreeRendererListener,
  UpdateManagerListener {

    private final Logger log = Logger.getLogger(getClass());
    private final String url;
    private final JFrame frame;
    private final JSVGCanvas canvas;

    private SVGDocument dom;

    public ViewBoxTest(String url) {
        this.url = url;
        frame = new JFrame("ViewBoxTest: "
          + url.substring(url.lastIndexOf('/') + 1));
        canvas = new JSVGCanvas(null, true, true);
        canvas.setDocumentState(JSVGCanvas.ALWAYS_DYNAMIC);
        canvas.addSVGDocumentLoaderListener(this);
        canvas.addGVTTreeBuilderListener(this);
        canvas.addGVTTreeRendererListener(this);
        canvas.addSVGLoadEventDispatcherListener(this);
        canvas.addUpdateManagerListener(this);
        canvas.setFocusable(true);
        frame.addWindowListener(this);
    }

    public void go() {
        canvas.setURI(this.url);
    }

    public void cancel() {
        System.err.println("Something went wrong");
    }

    protected void updateSVG(final Runnable rable) {
        UpdateManager updateManager = canvas.getUpdateManager();
        updateManager.getUpdateRunnableQueue().invokeLater(
          new Runnable() {
            public void run() {
                try {
                    rable.run();
                } catch (Throwable t) {
                    t.printStackTrace(System.err);
                    System.exit(1);
                }
            }
        });
    }

    protected void ready() {

        // Get SVG DOM
        this.dom = canvas.getSVGDocument();

        // Create mutator
        final Runnable mutator = new Runnable() {
            public void run() {
                SVGElement svg = (SVGElement)dom.getDocumentElement();
                String oldViewBox = svg.getAttribute("viewBox");
                String newViewBox = oldViewBox + " ";
                System.out.println("CHANGING VIEWBOX from \""
                    + oldViewBox + "\" to \"" + newViewBox + "\"");
                svg.setAttribute("viewBox", newViewBox);
            }
        };

        // Start thread to pause and then mutate
        new Thread() {
            public void run() {
                try {
                    Thread.sleep(2000);
                } catch (InterruptedException e) {
                }
                updateSVG(mutator);
            }
        }.start();
    }

    public void showFrame() {
        SwingUtilities.invokeLater(new Runnable() {
            public void run() {
                frame.getContentPane().add(canvas);
                // NOTE: change size this to see different effects
                frame.setPreferredSize(new java.awt.Dimension(800, 800));
                frame.pack();
                Dimension size = frame.getSize();
                Point center = GraphicsEnvironment
                  .getLocalGraphicsEnvironment().getCenterPoint();
                int x = (int)(center.getX() - size.getWidth() / 2);
                int y = (int)(center.getY() - size.getHeight() / 2);
                frame.setLocation(new Point(x, y));
                frame.setVisible(true);
                frame.toFront();
            }
        });
    }

    // SVGDocumentLoaderListener methods

    public void documentLoadingStarted(SVGDocumentLoaderEvent e) {
        log.debug("Document loading started");
    }

    public void documentLoadingCompleted(SVGDocumentLoaderEvent e) {
        log.debug("Document loading completed");
    }

    public void documentLoadingCancelled(SVGDocumentLoaderEvent e) {
        log.debug("Document loading canceled");
    }

    public void documentLoadingFailed(SVGDocumentLoaderEvent e) {
        log.debug("Document loading failed: " + e);
        cancel();
    }

    // GVTTreeBuilderListener methods

    public void gvtBuildStarted(GVTTreeBuilderEvent e) {
        log.debug("GVT build started");
    }

    public void gvtBuildCompleted(GVTTreeBuilderEvent e) {
        log.debug("GVT build completed");
        showFrame();
    }

    public void gvtBuildCancelled(GVTTreeBuilderEvent e) {
        log.debug("GVT build canceled");
    }

    public void gvtBuildFailed(GVTTreeBuilderEvent e) {
        log.debug("GVT build failed: " + e);
        cancel();
    }

    // GVTTreeRendererListener methods

    public void gvtRenderingPrepare(GVTTreeRendererEvent e) {
        log.debug("GVT rendering preparing");
    }

    public void gvtRenderingStarted(GVTTreeRendererEvent e) {
        log.debug("GVT rendering started");
    }

    public void gvtRenderingCompleted(GVTTreeRendererEvent e) {
        log.debug("GVT rendering complete");
        ready();
    }

    public void gvtRenderingCancelled(GVTTreeRendererEvent e) {
        log.debug("GVT rendering canceled");
    }

    public void gvtRenderingFailed(GVTTreeRendererEvent e) {
        log.debug("GVT rendering failed: " + e);
        cancel();
    }

    // SVGLoadEventDispatcherListener methods

    public void svgLoadEventDispatchCancelled(SVGLoadEventDispatcherEvent e) {
        log.debug("Load event dispatch cancelled");
    }

    public void svgLoadEventDispatchCompleted(SVGLoadEventDispatcherEvent e) {
        log.debug("Load event dispatch completed");
    }

    public void svgLoadEventDispatchFailed(SVGLoadEventDispatcherEvent e) {
        log.debug("Load event dispatch failed: " + e);
    }

    public void svgLoadEventDispatchStarted(SVGLoadEventDispatcherEvent e) {
        log.debug("Load event dispatch started");
    }

    // UpdateManagerListener

    public void managerStarted(UpdateManagerEvent e) {
        log.debug("Update manager started");
    }

    public void managerSuspended(UpdateManagerEvent e) {
        log.debug("Update manager suspended");
    }

    public void managerResumed(UpdateManagerEvent e) {
        log.debug("Update manager resumed");
    }

    public void managerStopped(UpdateManagerEvent e) {
        log.debug("Update manager stopped");
    }

    public void updateStarted(UpdateManagerEvent e) {
        //log.debug("Update manager started");
    }

    public void updateCompleted(UpdateManagerEvent e) {
        //log.debug("Update manager completed");
    }

    public void updateFailed(UpdateManagerEvent e) {
        log.debug("Update manager failed: " + e);
    }

    // WindowListener methods

    public void windowClosing(WindowEvent e) {
        System.exit(0);
    }

    public static void main(String[] args) throws Exception {
        ConsoleAppender consoleAppender = new ConsoleAppender(
          new PatternLayout(PatternLayout.TTCC_CONVERSION_PATTERN),
          ConsoleAppender.SYSTEM_ERR);
        consoleAppender.setThreshold(Level.DEBUG);
        BasicConfigurator.configure(consoleAppender);
        if (args.length == 0) {
            args = new String[] {
              "http://svn.apache.org/repos/asf/xmlgraphics/batik/trunk"
              + "/samples/tests/spec/coordinates/percentagesAndUnits.svg"
            };
        } else if (args.length != 1) {
            System.err.println("Usage: java ViewBoxTest [file | URL]");
            System.exit(1);
        }
        File file = new File(args[0]);
        if (file.exists())
            args[0] = file.toURL().toString();
        new ViewBoxTest(args[0]).go();
    }
}