Simple Java image processing program __java

Import Java.awt.BorderLayout;
Import Java.awt.Image;
Import java.awt.event.ActionEvent;
Import Java.awt.event.ActionListener;
Import Java.awt.image.BufferedImage;
Import Java.awt.image.ColorModel;
Import Java.awt.image.MemoryImageSource;
Import Java.awt.image.PixelGrabber;
Import Java.io.File;
Import java.io.IOException;
Import java.util.LinkedList;

Import Javax.imageio.ImageIO;
Import Javax.swing.ImageIcon;
Import Javax.swing.JFileChooser;
Import Javax.swing.JFrame;
Import Javax.swing.JLabel;
Import Javax.swing.JMenu;
Import Javax.swing.JMenuBar;
Import Javax.swing.JMenuItem;
Import Javax.swing.JOptionPane;
Import Javax.swing.JScrollPane;

public class Myshowimage extends JFrame {

To save the pixel matrix for the current operation
private int currentpixarray[] = null;

The path of the image
Private String filestring = null;
Label used to display the image
Private JLabel Imagelabel = null;

Loaded images
Private BufferedImage newimage;

The height and width of the image
private int h,w;

Save History operation Image Matrix
private LinkedList < int [] > imagestack = new LinkedList < int [] > ();
private LinkedList < int [] > tempimagestack = new LinkedList < int [] > ();





Public Myshowimage (String title) {
Super (title);
this. SetSize (800, 600);
this. Setdefaultcloseoperation (Jframe.exit_on_close);

Create a Menu
JMenuBar JB = new JMenuBar ();
JMenu filemenu = new JMenu ("file");
Jb.add (Filemenu);

JMenuItem Openimagemenuitem = new JMenuItem ("open image");
Filemenu.add (Openimagemenuitem);
Openimagemenuitem.addactionlistener (New Openlistener ());

JMenuItem exitmenu = new JMenuItem ("Exit");
Filemenu.add (Exitmenu);
Exitmenu.addactionlistener (new ActionListener () {
public void actionperformed (ActionEvent e) {
System.exit (0);
}
});

JMenu operatemenu = new JMenu ("image processing");
Jb.add (Operatemenu);

JMenuItem Rgbtograymenuitem = new JMenuItem ("Grayscale image conversion");
Operatemenu.add (Rgbtograymenuitem);
Rgbtograymenuitem.addactionlistener (New Rgbtograyactionlistener ());

JMenuItem Balancemenuitem = new JMenuItem ("balanced");
Operatemenu.add (Balancemenuitem);
Balancemenuitem.addactionlistener (New Balanceactionlistener ());

JMenu frontandbackmenu = new JMenu ("Historical operation");
Jb.add (Frontandbackmenu);

JMenuItem Backmenuitem = new JMenuItem ("Back");
Frontandbackmenu.add (Backmenuitem);
Backmenuitem.addactionlistener (New Backactionlistener ());

JMenuItem Frontmenuitem = new JMenuItem ("forward");
Frontandbackmenu.add (Frontmenuitem);
Frontmenuitem.addactionlistener (New Frontactionlistener ());

this. Setjmenubar (JB);

Imagelabel = new JLabel ("");
JScrollPane pane = new JScrollPane (Imagelabel);
this. Add (Pane,borderlayout.center);

this. setvisible (true);

}

Private class Openlistener implements actionlistener{
public void actionperformed (ActionEvent e) {
JFileChooser JC = new JFileChooser ();
int returnvalue = Jc.showopendialog (null);
if (returnvalue = = jfilechooser.approve_option) {
File selectedfile = Jc.getselectedfile ();
if (selectedfile!= null) {
filestring = Selectedfile.getabsolutepath ();
try {
NewImage = Imageio.read (new File (filestring));
W = newimage.getwidth ();
h = newimage.getheight ();
Currentpixarray = Getpixarray (newimage,w,h);
Imagestack.clear ();
Tempimagestack.clear ();
Imagestack.addlast (Currentpixarray);
Imagelabel.seticon (New ImageIcon (newimage));

catch (IOException ex) {
System.out.println (ex);
}

}
}
Myshowimage. this. repaint ();
MyShowImage.this.pack ();
}
}


Menu Listener///////////
Private class Rgbtograyactionlistener implements actionlistener{

public void actionperformed (ActionEvent e) {
int [] Resultarray = Rgbtogray (Currentpixarray);
Imagestack.addlast (resultarray);
Currentpixarray = Resultarray;
ShowImage (resultarray);
Tempimagestack.clear ();
}

}

Private class Balanceactionlistener implements actionlistener{

public void actionperformed (ActionEvent e) {
int [] Resultarray = balance (Currentpixarray);
Imagestack.addlast (resultarray);
Currentpixarray = Resultarray;
ShowImage (resultarray);
Tempimagestack.clear ();
}

}

Private class Backactionlistener implements actionlistener{

public void actionperformed (ActionEvent e) {
if (Imagestack.size () <= 1) {
Joptionpane.showmessagedialog (NULL, "The processing of this picture has no back history operation", "hint",
Joptionpane.information_message);
} else {
Tempimagestack.addlast (Imagestack.removelast ());
Currentpixarray = Imagestack.getlast ();
ShowImage (Currentpixarray);
}
}

}

Private class Frontactionlistener implements actionlistener{

public void actionperformed (ActionEvent e) {
if (Tempimagestack.size () < 1) {
Joptionpane.showmessagedialog (NULL, "The processing of this picture has no advance history operation", "hint",
Joptionpane.information_message);
} else {
Currentpixarray = Tempimagestack.removefirst ();
Imagestack.addlast (Currentpixarray);
ShowImage (Currentpixarray);
}
}

}


Get Image pixel matrix/////////
private int []getpixarray (Image im, int w, int h) {
int [] pix = new int [w * h];
PixelGrabber pg = NULL;
try {
pg = new PixelGrabber (IM, 0, 0, W, h, Pix, 0, W);
if (Pg.grabpixels ()!= true)
try {
throw new Java.awt.AWTException ("PG Error" + pg.status ());
catch (Exception eq) {
Eq.printstacktrace ();
}
catch (Exception ex) {
Ex.printstacktrace ();

}
return pix;
}



Show Picture///////////
private void ShowImage (int [] srcpixarray) {
Image pic = createimage (new MemoryImageSource (W,h,srcpixarray, 0