out of memory problem

[Jenny Liu]

Hi,

We plug batik into our system as a java bean to view our svg documents. And we still 
have out of memory problem.  

It can be reproduced by using batik svgbrowser as follows.

1) Open batik browser window.
2) go to http://cec.wustl.edu/~jl2/sample.svg
3) reload
4) reload
5) out of memory

I have some memory usage statistics here (read from memory monitor in tools)

                                                         Memory Usage
open batik browser                                  5,500 k
http://cec.wustl.edu/~jl2/sample.svg    22,000 k
reload                                                      51,000 k
reload                                                   out of memory                

If I manually do garbage collection in between each step, I got

                                                         Memory Usage
open batik browser                                  5,000 k
http://cec.wustl.edu/~jl2/sample.svg    22,700 k
garbage collect                                       22,000 k
reload                                                      58,000 k
garbage collect                                       39,900 k
reload                                                   out of memory                

In our system, we use JScrollPane to hold the svgCanvas, so that when we zoom, we 
still see the whole picture. I added a JScrollPane in batik browser by making a tiny 
change to JSVGViewerFrame.java

        JScrollPane myScrollPane = new JScrollPane(svgCanvas);
        myScrollPane.setPreferredSize(new Dimension(800, 800));
        p2.add(myScrollPane, BorderLayout.CENTER);
        //p2.add(svgCanvas, BorderLayout.CENTER);
        p = new JPanel(new BorderLayout());
        p.add(p2, BorderLayout.CENTER);
        p.add(statusBar = new StatusBar(), BorderLayout.SOUTH);

Then I found I could run out of the memory even quicker

                                                         Memory Usage
open batik browser                                  13,000 k
http://cec.wustl.edu/~jl2/sample.svg    46,000 k
reload                                                   out of memory          

and with garbage collection in between,

                                                         Memory Usage
open batik browser                                  13,000 k
http://cec.wustl.edu/~jl2/sample.svg    47,000 k
garbage collect                                       37,000 k
reload                                                   out of memory                

I think the problem comes from the viewbox attribute in svg file. When the width and 
height is very big, it taks a lot of memory to display. Since our system requires the 
user should be able to see the whole picture of the enlarged svg file, we'll have to 
set the big width and height accordingly.

Doing manually garbage collection does help a bit. In 
/org/apache/batik/apps/svgbrowser/Main.java, I also see garbage collection at the end 
of the rendering. 

        c.addGVTTreeRendererListener(new GVTTreeRendererAdapter() {
            public void gvtRenderingCompleted(GVTTreeRendererEvent e) {
                initDialog.dispose();
                v.dispose();
                System.gc();
                run();
            }
        }); 

Doesn't it seem like the memory leak problem is still out there?

Thanks!

Jenny


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