Description Kwong Lai 2007-05-09 17:53:54 EDT

Build ID: M20070212-1330

Steps To Reproduce:

I'm noticing significant delays when scrolling near the bottom of my virtual table (8 columns, 50000 rows).

   After some investigation, I've found the delay is caused by calls to setText() in the event handler.

   Using Snippet 144 as a guide (1000000 rows in the table), setText took the following times for these rows:

        row 1      took 0ms
        row 50000  took 2ms
        row 100000 took 3ms
        row 500000 took 16ms
        row 999998 took 39ms

   So the lower down the table I scroll, the longer it takes to setText for each row. 

   This happens regardless of whether I scroll through every row to get to the bottom, or just drag the scroll bar all the way down (without triggering events to the rows in the middle).

   I'm using version 3.2.2.v3236 of the org.eclipse.swt.gtk.linux.x86 plug-in, in case this information helps. I've also included the snippet I used to do the timing at the bottom. 


More information:
-----------------------------------------------

import org.eclipse.swt.SWT;
import org.eclipse.swt.layout.RowData;
import org.eclipse.swt.layout.RowLayout;
import org.eclipse.swt.widgets.Button;
import org.eclipse.swt.widgets.Display;
import org.eclipse.swt.widgets.Event;
import org.eclipse.swt.widgets.Label;
import org.eclipse.swt.widgets.Listener;
import org.eclipse.swt.widgets.Shell;
import org.eclipse.swt.widgets.Table;
import org.eclipse.swt.widgets.TableItem;

public class Snippet144 {

    static final int COUNT = 1000000;

    public static void main(String[] args) {
        Display display = new Display ();
        final Shell shell = new Shell (display);
        shell.setLayout (new RowLayout (SWT.VERTICAL));
        final Table table = new Table (shell, SWT.VIRTUAL | SWT.BORDER);

        table.addListener (SWT.SetData, new Listener () {
            public void handleEvent (Event event) {
                TableItem item = (TableItem) event.item;
                int index = table.indexOf (item);
                long startTime = System.currentTimeMillis();
                item.setText ("Item " + index);
                long timeTaken = System.currentTimeMillis() - startTime;
                System.out.println ("row " + index + " took " + timeTaken +
"ms");
            }
        });
        table.setLayoutData (new RowData (200, 200));
        Button button = new Button (shell, SWT.PUSH);
        button.setText ("Add Items");
        final Label label = new Label(shell, SWT.NONE);
        button.addListener (SWT.Selection, new Listener () {
            public void handleEvent (Event event) {
                long t1 = System.currentTimeMillis ();
                table.setItemCount (COUNT);
                long t2 = System.currentTimeMillis ();
                label.setText ("Items: " + COUNT + ", Time: " + (t2 - t1) +
" (ms)");
                shell.layout ();
            }
        });
        shell.pack ();
        shell.open ();
        while (!shell.isDisposed ()) {
            if (!display.readAndDispatch ()) display.sleep ();
        }
        display.dispose ();
    }
}