别以为Swing有双缓冲就够了，变态时三缓冲是很有必要的

import java.awt.geom.Point2D;
import java.util.ArrayList;
import java.util.List;

import org.eclipse.swt.SWT;
import org.eclipse.swt.events.PaintEvent;
import org.eclipse.swt.events.PaintListener;
import org.eclipse.swt.graphics.GC;
import org.eclipse.swt.graphics.Image;
import org.eclipse.swt.graphics.Rectangle;
import org.eclipse.swt.graphics.Transform;
import org.eclipse.swt.layout.FillLayout;
import org.eclipse.swt.widgets.Canvas;
import org.eclipse.swt.widgets.Display;
import org.eclipse.swt.widgets.Shell;

import util.GeometryUtil;

public class GrowingSWT
{
    private final Shell shell;
    private final Canvas canvas;

    private List<Point2D> ps = new ArrayList<Point2D>();
    private boolean stopped = false;
    Image image = null;
    int type = 1;

    private final Runnable timer = new Runnable() {
        public void run()
        {
            shell.getDisplay().timerExec(500, timer);
            grow();
            canvas.redraw();
        }
    };

    GrowingSWT(final Display display)
    {
        shell = new Shell(display, SWT.DOUBLE_BUFFERED | SWT.SHELL_TRIM);
        shell.setLayout(new FillLayout());
        canvas = new Canvas(shell, SWT.NULL);
        canvas.addPaintListener(new PaintListener() {
            public void paintControl(PaintEvent e)
            {
                long time = System.currentTimeMillis();
                if (type == 1) {
                    e.gc.drawImage(getBuffer(false), 0, 0);
                } else {
                    render(e.gc);
                }
                time = System.currentTimeMillis() - time;
                if (time > 10) {
                    System.out.println(time);
                }
            }

        });
        ps.add(new Point2D.Double(0, 0));
        ps.add(new Point2D.Double(800, 0));
        display.timerExec(500, timer);
    }

    Image getBuffer( boolean withRefresh)
    {
        Rectangle bounds = canvas.getBounds();
        if (image == null || !image.getBounds().equals(bounds)) {
            image = new Image(shell.getDisplay(), bounds);
            renderWithBuffer(image);
        } else if (withRefresh) {
            renderWithBuffer(image);
        }
        return image;
    }
    public void grow()
    {
        if (stopped) {
            return;
        }

        List<Point2D> temp = new ArrayList<Point2D>();
        temp.add(ps.get(0));

        for (int i = 0; i < ps.size() - 1; ++i) {
            Point2D p0 = ps.get(i);
            Point2D p4 = ps.get(i + 1);
            double len = GeometryUtil.distanceOfPoints(p0, p4);

            if (len < 0.1) {
                // 当线条长度小于1时，就停止再增长
                System.out.println(ps.size());
                shell.getDisplay().timerExec(-1, timer);
                return;
            }

            Point2D p1 = GeometryUtil.extentPoint(p0, p4, len / 3);
            Point2D p3 = GeometryUtil.extentPoint(p0, p4, len * 2 / 3);
            Point2D p2 = GeometryUtil.rotate(p3.getX(), p3.getY(), p1.getX(), p1.getY(), 60);

            temp.add(p1);
            temp.add(p2);
            temp.add(p3);
            temp.add(p4);
        }

        ps = null;
        ps = temp;
        temp = null;
        if (type == 1) {
            getBuffer(true);
        }
    }

    private void renderWithBuffer(Image image)
    {
        GC _gc = new GC(image);
        render(_gc);
        _gc.dispose();
    }

    private void render(GC gc)
    {
        Display display = shell.getDisplay();
        gc.setBackground(display.getSystemColor(SWT.COLOR_BLACK));
        Rectangle bounds = canvas.getBounds();
        gc.fillRectangle(bounds);
        gc.setAdvanced(true);
        gc.setAntialias(SWT.ON);

        Transform transform = new Transform(display);
        transform.translate(0, bounds.height - 20);
        gc.setTransform(transform);

        gc.setForeground(display.getSystemColor(SWT.COLOR_WHITE));
        for (int i = 0; i < ps.size() - 1; ++i) {
            Point2D sp = ps.get(i);
            Point2D ep = ps.get(i + 1);
            gc.drawLine((int) sp.getX(), -(int) sp.getY(), (int) ep.getX(), -(int) ep.getY());
        }
    }

    public static void main(String[] args)
    {
        Display display = Display.getDefault();
        Shell shell = new GrowingSWT(display).shell;
        shell.setSize(800, 400);
        shell.open();
        while (!shell.isDisposed()) {
            if (!display.readAndDispatch()) {
                display.sleep();
            }
        }
    }

}