total_progress = new Canvas(transfer_group, SWT.NONE);
GridData grid_data = new GridData(GridData.FILL_HORIZONTAL);
grid_data.heightHint = 20;
total_progress.setLayoutData(grid_data);
gap_list_painter = new GapListPainter(download_session.getGapList(),
download_session.getFileSize());
gap_list_painter.setMarginWidth(0);
total_progress.addPaintListener(new PaintListener() {
public void paintControl(PaintEvent arg0) {
gap_list_painter.draw(arg0.gc, 0, 0, arg0.width, arg0.height);