demoapplet.java

一个一元曲线多项式数值演示例子

package numbercruncher.graphutils;

import java.applet.*;

import java.awt.*;

/**
 * The base applet for all demo applets.
 */
public abstract class DemoApplet
    extends Applet {
  private DemoPanel demoPanel; // demo panel

  /**
   * Constructor.
   * @param demoPanel the demo panel
   */
  protected DemoApplet(DemoPanel demoPanel) {
    this.demoPanel = demoPanel;
  }

  /**
   * Applet initializer.
   */
  public void init() {
    // Add the demo panel.
    setLayout(new BorderLayout());
    add( (Panel) demoPanel, BorderLayout.CENTER);

    // Initialize the demo.
    demoPanel.initializeDemo();
  }

  /**
   * Applet starter.
   */
  public void start() {
//	repaint();
    paint(this.getGraphics());
  }

  /**
   * Applet stopper.
   */
  public void stop() {
    demoPanel.closeDemo();
  }

  /**
   * Update the display without repainting the background.
   * @param g the graphics context
   */
  public void update(Graphics g) {
    paint(g);
  }

  /**
   * Redraw the contents of the demo panel.
   * @param g the graphics context
   */
  public void paint(Graphics g) {
    demoPanel.draw();
  }
}