ovalborder.java

这是JFrame的一些例子(chapter3)。可以参考一下。

import java.awt.*;

import javax.swing.*;
import javax.swing.border.*;

public class OvalBorder implements Border
{
  protected int m_w=6;
  protected int m_h=6;
  protected Color m_topColor = Color.white;
  protected Color m_bottomColor = Color.gray;

  public OvalBorder() {
    m_w=6;
    m_h=6;
  }

  public OvalBorder(int w, int h) {
    m_w=w;
    m_h=h;
  }

  public OvalBorder(int w, int h, Color topColor, 
   Color bottomColor) {
    m_w=w;
    m_h=h;
    m_topColor = topColor;
    m_bottomColor = bottomColor;
  }

  public Insets getBorderInsets(Component c) {
    return new Insets(m_h, m_w, m_h, m_w);
  }

  public boolean isBorderOpaque() { return true; }

  public void paintBorder(Component c, Graphics g, 
   int x, int y, int w, int h) {
    w--;
    h--;
    g.setColor(m_topColor);
    g.drawLine(x, y+h-m_h, x, y+m_h);
    g.drawArc(x, y, 2*m_w, 2*m_h, 180, -90);
    g.drawLine(x+m_w, y, x+w-m_w, y);
    g.drawArc(x+w-2*m_w, y, 2*m_w, 2*m_h, 90, -90);

    g.setColor(m_bottomColor);
    g.drawLine(x+w, y+m_h, x+w, y+h-m_h);
    g.drawArc(x+w-2*m_w, y+h-2*m_h, 2*m_w, 2*m_h, 0, -90);
    g.drawLine(x+m_w, y+h, x+w-m_w, y+h);
    g.drawArc(x, y+h-2*m_h, 2*m_w, 2*m_h, -90, -90);
  }

  public static void main(String[] args) {
    JFrame frame = new JFrame("Custom Border: OvalBorder");
    JLabel label = new JLabel("OvalBorder");
    ((JPanel) frame.getContentPane()).setBorder(new CompoundBorder(
      new EmptyBorder(10,10,10,10), new OvalBorder(10,10)));
    frame.getContentPane().add(label);
    frame.setBounds(0,0,300,150);
    frame.setVisible(true);
  }
}