arrowicon.java

来自「java swing 开发代码」· Java 代码 · 共 50 行

// ArrowIcon.java
// A simple implementation of the Icon interface that can make
// Up and Down arrows.
//

package	jswing.ch16;

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

public class ArrowIcon implements Icon {

  public static final int UP = 0;
  public static final int DOWN = 1;
  
  private int direction;
  private Polygon pagePolygon = new Polygon(new int[] { 2, 4, 4, 10, 10, 2 },
                                    new int[] { 4, 4, 2,  2, 12, 12},
				    6);
  private int[] arrowX = { 4, 9, 6 };
  private Polygon arrowUpPolygon = 
                  new Polygon(arrowX, new int[] { 10, 10, 4 }, 3);
  private Polygon arrowDownPolygon = 
                  new Polygon(arrowX, new int[] { 6, 6, 11 }, 3);

  public ArrowIcon(int which) {
    direction = which;
  }

  public int getIconWidth() { return 14; }
  public int getIconHeight() { return 14; }

  public void paintIcon(Component c, Graphics g, int x, int y) {
    g.setColor(Color.black);
    pagePolygon.translate(x, y);
    g.drawPolygon(pagePolygon);
    pagePolygon.translate(-x, -y);
    if (direction == UP) {
      arrowUpPolygon.translate(x, y);
      g.fillPolygon(arrowUpPolygon);
      arrowUpPolygon.translate(-x, -y);
    }
    else {
      arrowDownPolygon.translate(x, y);
      g.fillPolygon(arrowDownPolygon);
      arrowDownPolygon.translate(-x, -y);
    }
  }
}