Java Swing 层次面板(JLayeredPanel) Demo

package com.gloomyfish.layer.demo;
 
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.RenderingHints;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.io.InputStream;
 
import javax.imageio.ImageIO;
import javax.swing.JComponent;
 
public class JBackGroundPanel extends JComponent {
  
  /**
   * 
   */
  private static final long serialVersionUID = 4639168655243672491L;
  private Dimension size;
  private int startx;
  private int starty;
  private BufferedImage image;
  public JBackGroundPanel() {
    super();
    setOpaque(false);
    startx = 30;
    starty = 30;
    if(size == null) {
      size = new Dimension(400, 400);
    }
    this.setBounds(startx, starty, size.width / 2, size.height / 2);
  }
  
  public JBackGroundPanel(int xp, int yp, int width, int height) {
    super();
    setOpaque(false);
    startx = xp;
    starty = yp;
    size = new Dimension(width, height);
    this.setBounds(startx, starty, size.width, size.height);
  }
  
  private void loadImage() {
    try {
      InputStream stream = this.getClass().getResourceAsStream("frame.jpg");
      image = tunningAlpha(ImageIO.read(stream));
      
    } catch (IOException e) {
      System.out.println("Could not load the image resource...");
    }
  }
 
  private BufferedImage tunningAlpha(BufferedImage src) {
    int width = src.getWidth();
        int height = src.getHeight();
 
        int[] inPixels = new int[width*height];
        int[] outPixels = new int[width*height];
        getRGB(src, 0, 0, width, height, inPixels );
        System.arraycopy(inPixels, 0, outPixels, 0, width*height);
        int index = 0;
        for(int row=90; row<height-90; row++) {
          int ta = 0, tr = 0, tg = 0, tb = 0;
          for(int col=90; col<width-90; col++) {
            index = row * width + col;
            ta = (inPixels[index] >> 24) & 0xff;
                tr = (inPixels[index] >> 16) & 0xff;
                tg = (inPixels[index] >> 8) & 0xff;
                tb = inPixels[index] & 0xff;
                ta = 0;
                outPixels[index] = (ta << 24) | (tr << 16) | (tg << 8) | tb;
                
          }
        }
        BufferedImage dest = new BufferedImage(width, height, BufferedImage.TYPE_4BYTE_ABGR);
        setRGB(dest, 0, 0, width, height, outPixels);
        return dest;
  }
 
  protected void paintComponent(Graphics g) {
    super.paintComponent(g);
    Graphics2D g2 = (Graphics2D) g;
    g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
    
    // do something here.....
    if(image == null) {
      loadImage();
    }
    g2.drawImage(image, startx, starty, size.width, size.height, null);
  }
  
  @Override
  public Dimension getPreferredSize() {
    return size;
  } 
  
  public Dimension getMinimumSize() {
    return size;
  }
  
  /**
   * A convenience method for getting ARGB pixels from an image. This tries to avoid the performance
   * penalty of BufferedImage.getRGB unmanaging the image.
   */
  public int[] getRGB( BufferedImage image, int x, int y, int width, int height, int[] pixels ) {
    int type = image.getType();
    if ( type == BufferedImage.TYPE_INT_ARGB || type == BufferedImage.TYPE_INT_RGB )
      return (int [])image.getRaster().getDataElements( x, y, width, height, pixels );
    return image.getRGB( x, y, width, height, pixels, 0, width );
    }
 
  /**
   * A convenience method for setting ARGB pixels in an image. This tries to avoid the performance
   * penalty of BufferedImage.setRGB unmanaging the image.
   */
  public void setRGB( BufferedImage image, int x, int y, int width, int height, int[] pixels ) {
    int type = image.getType();
    if ( type == BufferedImage.TYPE_INT_ARGB || type == BufferedImage.TYPE_INT_RGB )
      image.getRaster().setDataElements( x, y, width, height, pixels );
    else
      image.setRGB( x, y, width, height, pixels, 0, width );
    }
  
}