java - drawOval 的意外行为

Question

我遇到了drawOval函数的问题。我用它来画圆，但结果看起来不像圆。我认为这种行为是在 Jpanel 达到一定高度后发生的。向下滚动直到最后，您可以得到如下图所示的结果。有谁能解释一下吗？

Result after Execute the sample program

import java.awt.*;
import java.awt.geom.*;
import javax.swing.*;

public class TestMain
{
    public static void main(String[] args)
    {
        JFrame f = new JFrame();
        f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        JScrollPane jsp = new JScrollPane();
        jsp.setViewportView(new TestPanel());
        f.getContentPane().add(jsp);
        f.setSize(500,400);
        f.setLocation(200,200);
        f.setVisible(true);
    }
}

class TestPanel extends JPanel
{
    public TestPanel()
    {
        setPreferredSize(new Dimension(1960 , 77660240));
        setBackground(Color.white);
    }

    protected void paintComponent(Graphics g)
    {
        super.paintComponent(g);
        Graphics2D g2 = (Graphics2D)g;
        g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING,
                            RenderingHints.VALUE_ANTIALIAS_ON);
        g2.drawRect(30, 77660141, 100, 20);
        g2.drawOval(15, 77660141, 10, 10);
        g2.draw(new Ellipse2D.Double(140, 77660141,
                             10,
                             10));
        g2.draw(new Ellipse2D.Double(160, 77660141,
                             10,
                             10));
        g2.draw(new Ellipse2D.Double(180, 77660141,
                             10,
                             10));
        g2.draw(new Ellipse2D.Double(200, 77660141,
                             30,
                             30));
    }
}

Answer 1

将面板的尺寸更改为更合理的值，例如:1000，它将正常工作。