Comments on: JTable setRowHeight causes slow repainting

By: Nick

Nick — Tue, 18 Oct 2011 23:30:17 +0000

Hi the TimingRepaintManager is actually a very simple inner class in the test code linked to the original blog post, replicated again below

It’s very possible to write a similar class which times painting for JTable component specifically rather than all repainting – and indeed since we have had a lot of table painting performance issues in the past, we have written a repaint manager which throttles painting for all JTables, letting the other repaints go through unthrottled. That’s worthy of another post in its own right, if I can get time to write it. RepaintManager is quite a powerful class, and can be customised.

//record the total time spent repainting
private static class TimingRepaintManager extends RepaintManager {
private volatile long totalTime;

public void paintDirtyRegions() {
long startTime = System.currentTimeMillis();
super.paintDirtyRegions();
totalTime += System.currentTimeMillis() - startTime;
}

public long getTotalRepaintTime() {
return totalTime;
}

public void resetTotalRepaintTime() {
this.totalTime = 0;
}
}

By: Ole

Ole — Tue, 18 Oct 2011 22:30:45 +0000

Thanks for your interesting article. Can you elaborate a bit more on this TimingRepaintManager of yours? Is the source code available? Thanks a lot.

By: Nick

Nick — Thu, 17 Dec 2009 14:43:34 +0000

Thanks Dave, I’ll check that out later

By: Dave

Dave — Thu, 17 Dec 2009 14:33:47 +0000

I tried your workaround and it vastly improved performance but caused some repainting issues. I believe the calculation of the y coordinate for the dirty region is sometimes incorrect ( because it isn’t adjusted like the height is)

I’ve changed this:
dirtyRegion = new Rectangle(0, start * getRowHeight(),getColumnModel().getTotalColumnWidth(), 0);

To this:
int rowStart = 0;
for ( int row=0; row < start; row++ ) {
rowStart += getRowHeight(row);
}
dirtyRegion = new Rectangle(0, rowStart, getColumnModel().getTotalColumnWidth(), 0);

Would be interested to hear if you agree or not.

By: Dave

Dave — Thu, 17 Dec 2009 13:31:57 +0000

Thanks Nick. Yes I have seen the same issue. I think it is a big problem, especially if the data in your table is frequently updated. Please could you update the post if your hear anything from Sun?

By: Nick

Nick — Fri, 11 Dec 2009 15:22:57 +0000

Hi Dave

I submitted the report etc. but never received anything back from Sun… you don’t get a bug id until they process it but it was a long time ago now. Perhaps I should try submitting it again. Have you seen this problem too?

Nick

By: Dave

Dave — Fri, 11 Dec 2009 13:47:31 +0000

Thanks for the post Nick. What is the status of the bug report you submitted to sun? Do you have a link to it?