问在Java中绘制虚线时的性能问题

EN

public void foo(Graphics2D g2d, Shape shape)
{
    Stroke stroke = BasicStroke(1, BasicStroke.CAP_BUTT, BasicStroke.JOIN_BEVEL, 10, new float[]{10}, 0);

    g2d.setStroke(stroke);

    g2d.draw(shape);
}

import java.awt.BasicStroke;
import java.awt.Color;
import java.awt.EventQueue;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Rectangle;
import java.awt.Shape;
import java.awt.Stroke;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.KeyEvent;
import java.awt.event.KeyListener;

import javax.swing.JFrame;
import javax.swing.JPanel;

class Scale
{
    private static int _scale = 1;

    public static int getScale()
    {
        return _scale;
    }

    public static void setScale(int scale)
    {
        _scale = scale;
    }
}

class Surface extends JPanel implements ActionListener
{
    private static Surface _surface;

    boolean isBlue = false;

    private Surface()
    {
    }

    public static Surface getInstance()
    {
        if (_surface == null)
        {
            _surface = new Surface();
        }

        return _surface;
    }

    private void doDrawing(Graphics g)
    {
        Shape rectangle = new Rectangle(0, 0, 600 * Scale.getScale(), 400 * Scale.getScale());
        Graphics2D g2d = (Graphics2D) g.create();

        g2d.setColor(Color.blue);

        Stroke stroke = new BasicStroke(10, BasicStroke.CAP_BUTT, BasicStroke.JOIN_BEVEL, 10.0f, new float[]{10.0f}, 0);
        g2d.setStroke(stroke);

        // Adding a clip don't seem to do the trick :(
        g2d.clip(new Rectangle(0, 0, 100, 100));

        long startTime = System.nanoTime();
        g2d.draw(rectangle);
        long elapseTime = System.nanoTime() - startTime;

        // Printing the time it took each time I render my shape. As the size increase, the time increase. If the shape decrease, the time decrease as well.
        System.out.println(elapseTime);

        g2d.dispose();
    }

    @Override
    public void paintComponent(Graphics g)
    {
        super.paintComponent(g);
        doDrawing(g);
    }

    @Override
    public void actionPerformed(ActionEvent e)
    {
        repaint();
    }
}

public class MainFrame extends JFrame implements KeyListener
{
    public MainFrame()
    {
        initUI();

        setFocusable(true);
        addKeyListener(this);
    }

    public static void main(String[] args)
    {

        EventQueue.invokeLater(new Runnable()
        {
            @Override
            public void run()
            {
                MainFrame ex = new MainFrame();
                ex.setVisible(true);
            }
        });
    }

    private void initUI()
    {
        final Surface surface = Surface.getInstance();
        add(surface);

        setTitle("My boggus apps");
        setSize(600, 400);
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    }


    @Override
    public void keyTyped(final KeyEvent e)
    {

    }

    @Override
    public void keyPressed(final KeyEvent e)
    {
        int key = e.getKeyCode();

        if (key == KeyEvent.VK_UP)
        {
            Scale.setScale(Scale.getScale() * 2);

            if (Scale.getScale() > 200000)
            {
                Scale.setScale(200000);
            }

            Surface.getInstance().repaint();
        }
        else if (key == KeyEvent.VK_DOWN)
        {
            Scale.setScale(Scale.getScale() / 2);

            if (Scale.getScale() < 1)
            {
                Scale.setScale(1);
            }

            Surface.getInstance().repaint();
        }
        else
        {
            System.out.println(key);
        }
    }

    @Override
    public void keyReleased(final KeyEvent e)
    {

    }
}