Need some pointers please :)

Question

Hi,
I've been given an application which I have to modify to edit a 'raw' image, so far I have been able to implement the loading of the image, but I am stuck with editing it.
The there are 3 classes to the application, rawimage, skelappipcanvas and skelappipframe.
So far as to my understanding, the rawimage class loads the raw image into a pixel array and then converts it into an image which is then displayed on the canvas. The frame contains the menu.
What I have to do is edit the picture, by manipulating the array, adding 5 to all values in the array for example. I understand that the best way to do that is to create a function and call that function when I select the menu option.
My problem is that im not sure how to implement the editing of the array..any pointers would be greatly appreciated. I have posted the code below..sorry for the amount of text.
RawImage Class:
import java.awt.*;
import java.awt.image.*;
import java.awt.event.*;
import java.util.*;
import java.io.*;
public class RawImage
public int imWidth = 640; // default image width
public int imHeight = 480; // default image height
public int imDepth = 256; // default image depth
public short rawPixelArray2D[][]; // array of image pixels
// (to contain grey-scale bitmap)
private Image dispIm; // display image
private int imConvBuf[]; // buffer for converting between raw image bitmap and display image object
// buffer entries are pixel colour values computed using colour model
private ColorModel colMod = ColorModel.getRGBdefault(); //colour model of display image
* Constructs and initialises a grey-scale image object
* @param filename name of input file.
* @since JDK1.1
public RawImage(String filename)
rawPixelArray2D = new short[imHeight][imWidth]; // create pixel array
imConvBuf = new int[imHeight * imWidth];
load(filename); // read data from file into raw bitmap array
arrayToDispImage(); // convert raw bitmap into display image object
* Constructs and initialises a grey-scale image object
* @param rawGreyBitMap 2D array containing raw bitmap.
* @param width width of 2D array.
* @param height height of 2D array.
* @since JDK1.1
public RawImage(short rawGreyBitMap[][], int width, int height)
rawPixelArray2D = rawGreyBitMap;
imWidth = width;
imHeight = height;
imConvBuf = new int[imHeight * imWidth];
arrayToDispImage(); // convert raw bitmap into display image object
* Displays image
* @param none.
* @since JDK1.1
public void display(Graphics gc)
gc.drawImage(dispIm, 0, 0, null);
* Loads image from file
* @param filename name of input file.
* @since JDK1.1
public void load(String filename)
// load pixel array from file
try
DataInputStream inputStream =
new DataInputStream(new FileInputStream(filename));
try
// read each byte from binary file into raw bitmap
for (int row = 0; row < imHeight; ++row)
for (int col = 0; col < imWidth; ++col)
rawPixelArray2D[row][col] = (short) inputStream.readUnsignedByte();
catch(EOFException e)
System.out.println("File shorter than expected. End of reading from file " + filename);
inputStream.close();
catch(FileNotFoundException e)
System.out.println("Cannot find file " + filename);
catch(IOException e2)
System.out.println("Error reading input from file " + filename);
* Saves image to file
* @param filename name of input file.
* @since JDK1.1
public void save(String filename)
// save pixel array to file
try
DataOutputStream outputStream =
new DataOutputStream(new FileOutputStream(filename));
// write each byte from raw bitmap into binary file
for (int row = 0; row < imHeight; ++row)
for (int col = 0; col < imWidth; ++col)
outputStream.writeByte( (int) rawPixelArray2D[row][col] );
outputStream.close();
catch(IOException e)
System.out.println("Error writing output to file " + filename);
* Converts raw grey pixel array into display Image object
* @param none.
* @since JDK1.1
private void arrayToDispImage()
for (int row = 0; row < imHeight; row++)
int colOffset = row * imWidth;
for (int col = 0; col < imWidth; col++)
imConvBuf[col + colOffset] =
0xFF000000 | (rawPixelArray2D[row][col] << 16)
| (rawPixelArray2D[row][col] << 8)
| rawPixelArray2D[row][col];
MemoryImageSource MemSource = new MemoryImageSource(imWidth, imHeight, colMod,
imConvBuf, 0, imWidth);
dispIm = Toolkit.getDefaultToolkit().createImage(MemSource);
SkelAppIPCanvas class:
import java.awt.*;
import java.awt.event.*;
import java.util.*;
public class SkelAppIPCanvas extends Canvas
private int xCanvasCentre = 0; // coordinates of centre of canvas
private int yCanvasCentre = 0;
private RawImage image = null; // image
* Constructs and initialises a canvas object
* @param none.
* @since JDK1.1
public SkelAppIPCanvas()
super(); // call parent's constructor
addListenersToCanvas(); // add event listeners
* Adds listeners to canvas
* @param none.
* @since JDK1.1
public void addListenersToCanvas()
// add mouse listener
addMouseListener( // use argument which is an object of an anonymous subclass of MouseAdapter
new MouseAdapter()
public void mousePressed(MouseEvent event)
serviceMouseEvent(MouseEvent.MOUSE_PRESSED, event.getX(), event.getY());
public void mouseClicked(MouseEvent event)
serviceMouseEvent(MouseEvent.MOUSE_CLICKED, event.getX(), event.getY());
public void mouseReleased(MouseEvent event)
serviceMouseEvent(MouseEvent.MOUSE_RELEASED, event.getX(), event.getY());
// add mouse motion listener
addMouseMotionListener( // use argument which is an object of an anonymous subclass of MouseMotionAdapter
new MouseMotionAdapter()
public void mouseDragged(MouseEvent event)
serviceMouseEvent(MouseEvent.MOUSE_DRAGGED, event.getX(), event.getY());
public void mouseMoved(MouseEvent event)
serviceMouseEvent(MouseEvent.MOUSE_MOVED, event.getX(), event.getY());
// add key listener
addKeyListener( // use argument which is an object of an anonymous subclass of KeyAdapter
new KeyAdapter()
public void keyPressed(KeyEvent event)
// service keyboard event
serviceKeyEvent(event);
* Gets the coordinates of the centre of the canvas.
* @param none.
* @since JDK1.1
public Point getCanvasCentre()
updateCanvasCentre();
return new Point(xCanvasCentre, yCanvasCentre);
* Updates the coordinates of the centre of the canvas.
* @param none.
* @since JDK1.1
public void updateCanvasCentre()
Dimension canvasDimensions = getSize();
xCanvasCentre = canvasDimensions.width / 2;
yCanvasCentre = canvasDimensions.height / 2;
* |
* PAINT MESSAGE SERVICING |
* |
// CUSTOMISE THE "TO DO" COMMENTS AS APPROPRIATE
* Updates canvas area.
* @param graphicsContext a Graphics object.
* @since JDK1.1
public void paint(Graphics graphicsContext)
// Display currently loaded image
if (image != null)
image.display(graphicsContext);
* |
* "ARROW KEYS" SERVICING |
* |
// CUSTOMISE THE "TO DO" COMMENTS AS APPROPRIATE
* Services "arrow keys" events (NOTE: for some reason the key listener gets
* decoupled from the canvas object after the window has been minimised.)
* @param event a key-event object.
* @since JDK1.1
public void serviceKeyEvent(KeyEvent event)
switch(event.getKeyCode())
case KeyEvent.VK_UP:
// TO DO: service up-key as approriate
break;
case KeyEvent.VK_LEFT:
// TO DO: service left-key as approriate
break;
case KeyEvent.VK_DOWN:
// TO DO: service down-key as approriate
break;
case KeyEvent.VK_RIGHT:
// TO DO: service right-key as approriate
break;
default:
// TO DO: service "all-other-keys" as approriate
break;
* |
* MOUSE SERVICING |
* |
// CUSTOMISE THE "TO DO" COMMENTS AS APPROPRIATE
* Services mouse events.
* @param eventID ID of mouse event.
* @param xMousePosition x coordinate of cursor at occurence mouse event.
* @param yMousePosition y coordinate of cursor at occurence mouse event.
* @since JDK1.1
public void serviceMouseEvent(int eventID, int xMousePosition, int yMousePosition)
switch(eventID)
case MouseEvent.MOUSE_CLICKED:
// TO DO: service MOUSE_CLICKED as approriate
break;
case MouseEvent.MOUSE_DRAGGED:
// TO DO: service MOUSE_DRAGGED as approriate
break;
case MouseEvent.MOUSE_PRESSED:
// TO DO: service MOUSE_PRESSED as approriate
break;
case MouseEvent.MOUSE_RELEASED:
// TO DO: service MOUSE_RELEASED as approriate
break;
case MouseEvent.MOUSE_MOVED:
// TO DO: service MOUSE_MOVED as approriate
break;
default:
// TO DO: service "all-other-mouse-states" as approriate
break;
* Loads image from file.
* @param filename name of the file.
* @since JDK1.1
public void loadRawImage(String filename)
image = new RawImage(filename); // load raw image from file
repaint(); // trigger a screen refresh for displaying image just loaded
* Saves image to file.
* @param filename name of the file.
* @since JDK1.1
public void saveRawImage(String filename)
// save raw image to file
image.save(filename);
SkelAppIPFrame class:
import java.awt.*;
import java.awt.event.*;
public class SkelAppIPFrame extends Frame
// drawing area
private SkelAppIPCanvas displayCanvas;
// menu items
private MenuItem fileOpen, saveAs, exitApp,
/* VARIABLES FOR STUDENT MENUS */
studentMenu1_1, studentMenu1_2, studentMenu1_3, studentMenu1_4,
studentMenu2_1_1, studentMenu2_1_2, studentMenu2_1_3,
studentMenu2_2_1, studentMenu2_2_2;
/* END OF VARIABLES FOR STUDENT MENUS */
//image
private RawImage image = null;
* Creates a window
* @param commandArgs command line arguments for application.
* @since JDK1.1
public static void main(String [] commandArgs)
new SkelAppIPFrame();
* Constructs a window (frame + canvas + menu)
* @param none.
* @since JDK1.1
public SkelAppIPFrame()
// set frame title
super("IP Programming Framework");
// add window listener
addWindowListenerToFrame();
// add menu
addMenu();
// set frame size
Dimension screenDimensions = getToolkit().getScreenSize();
setSize(screenDimensions.width, screenDimensions.height);
// add canvas in centre of frame
displayCanvas = new SkelAppIPCanvas();
add("Center", displayCanvas);
// show frame
show();
* Gets the name of the input file entered by the user.
* @param none.
* @since JDK1.0
private String getInputFileName()
return getFileName("File Open", FileDialog.LOAD);
* Gets the name of the output file entered by the user.
* @param none.
* @since JDK1.0
private String getOutputFileName()
return getFileName("File Save", FileDialog.SAVE);
* Gets the name of the input or output file entered by the user.
* @param title a string specifying the title of the dialog box.
* @param mode an integer specifying the mode (file open or save dialog box).
* @since JDK1.0
private String getFileName(String title, int mode)
FileDialog fileDlg = new FileDialog(this, title, mode);
fileDlg.setDirectory("");
fileDlg.setFile("");
fileDlg.show();
String folderName = fileDlg.getDirectory();
String fileNameBuffer = fileDlg.getFile();
String fileName = null;
// get file name if it has been specified by user
if (fileNameBuffer != null)
fileName = folderName + fileNameBuffer;
return fileName;
* Adds a window listener to the window frame
* @param none.
* @since JDK1.1
public void addWindowListenerToFrame()
addWindowListener( // use argument which is an object of an anonymous subclass of WindowAdapter
new WindowAdapter()
public void windowClosing(WindowEvent e)
System.exit(0);
* Adds a menu to the window frame
* @param none.
* @since JDK1.1
public void addMenu()
// create and set menu bar
MenuBar frameMenuBar = new MenuBar();
setMenuBar(frameMenuBar);
// create pull-down menu and attach to menu bar
Menu fileMenu = new Menu("File");
frameMenuBar.add(fileMenu);
// create menu items for "File" pull-down menu
fileOpen = new MenuItem( "Open ...", new MenuShortcut(KeyEvent.VK_O) );
saveAs = new MenuItem( "Save As ...", new MenuShortcut(KeyEvent.VK_S) );
exitApp = new MenuItem( "Exit", new MenuShortcut(KeyEvent.VK_X) );
// attach menu items to pull-down menu
fileMenu.add(fileOpen);
fileMenu.addSeparator();
fileMenu.add(saveAs);
fileMenu.addSeparator();
fileMenu.add(exitApp);
// create menu-action listener, and add it to each menu item
SkelApp2DGMenuDispatcher menuListener = new SkelApp2DGMenuDispatcher();
fileOpen.addActionListener(menuListener);
saveAs.addActionListener(menuListener);
exitApp.addActionListener(menuListener);
* |
* MENUS |
* |
// STRINGS THAT WILL APPEAR ON THE MENU
// TODO: CUSTOMISE THE TEXT BETWEEN DOUBLE QUOTES AS APPROPRIATE
String studentMenu1Label = "Menu 1",
studentMenu1_1Label = "lighten",
studentMenu1_2Label = "Your Menu 1.2",
studentMenu1_3Label = "Your Menu 1.3",
studentMenu1_4Label = "Your Menu 1.4",
studentMenu2Label = "Student Menu 2",
studentMenu2_1Label = "Your Menu 2.1",
studentMenu2_1_1Label = "Your Menu 2.1.1",
studentMenu2_1_2Label = "Your Menu 2.1.2",
studentMenu2_1_3Label = "Your Menu 2.1.3",
studentMenu2_2Label = "Your Menu 2.2",
studentMenu2_2_1Label = "Your Menu 2.2.1",
studentMenu2_2_2Label = "Your Menu 2.2.2";
// END OF MENU STRINGS
// create pull-down menus and attach to menu bar
Menu studentMenu1 = new Menu(studentMenu1Label);
Menu studentMenu2 = new Menu(studentMenu2Label);
frameMenuBar.add(studentMenu1);
frameMenuBar.add(studentMenu2);
// create menu items for <studentMenu1> pull-down menu
studentMenu1_1 = new MenuItem( studentMenu1_1Label, new MenuShortcut(KeyEvent.VK_U) );
studentMenu1_2 = new MenuItem( studentMenu1_2Label, new MenuShortcut(KeyEvent.VK_V) );
studentMenu1_3 = new MenuItem( studentMenu1_3Label, new MenuShortcut(KeyEvent.VK_W) );
studentMenu1_4 = new MenuItem( studentMenu1_4Label, new MenuShortcut(KeyEvent.VK_X) );
// create cascading menus for <studentMenu2> pull-down menu
Menu studentMenu2_1 = new Menu(studentMenu2_1Label);
Menu studentMenu2_2 = new Menu(studentMenu2_2Label);
// create menu items for <studentMenu2 | studentMenu2_1> cascaded menu
studentMenu2_1_1 = new MenuItem( studentMenu2_1_1Label, new MenuShortcut(KeyEvent.VK_R) );
studentMenu2_1_2 = new MenuItem( studentMenu2_1_2Label, new MenuShortcut(KeyEvent.VK_S) );
studentMenu2_1_3 = new MenuItem( studentMenu2_1_3Label, new MenuShortcut(KeyEvent.VK_T) );
// attach menu items to <studentMenu2 | studentMenu2_1> cascaded menu
studentMenu2_1.add(studentMenu2_1_1);
studentMenu2_1.add(studentMenu2_1_2);
studentMenu2_1.add(studentMenu2_1_3);
// create cascading menus for <studentMenu2 | studentMenu2_2> cascaded menu
studentMenu2_2_1 = new MenuItem( studentMenu2_2_1Label, new MenuShortcut(KeyEvent.VK_H) );
studentMenu2_2_2 = new MenuItem( studentMenu2_2_2Label, new MenuShortcut(KeyEvent.VK_N) );
// attach menu items to <studentMenu2 | studentMenu2_2> cascaded menu
studentMenu2_2.add(studentMenu2_2_1);
studentMenu2_2.add(studentMenu2_2_2);
// attach menu items and cascaded menus to pull-down menus
studentMenu1.add(studentMenu1_1);
studentMenu1.add(studentMenu1_2);
studentMenu1.add(studentMenu1_3);
studentMenu1.add(studentMenu1_4);
studentMenu2.add(studentMenu2_1);
studentMenu2.add(studentMenu2_2);
// add action listener for menu items
studentMenu1_1.addActionListener(menuListener);
studentMenu1_2.addActionListener(menuListener);
studentMenu1_3.addActionListener(menuListener);
studentMenu1_4.addActionListener(menuListener);
studentMenu2_1_1.addActionListener(menuListener);
studentMenu2_1_2.addActionListener(menuListener);
studentMenu2_1_3.addActionListener(menuListener);
studentMenu2_2_1.addActionListener(menuListener);
studentMenu2_2_2.addActionListener(menuListener);
* Defines menu dispatcher (as an inner class)
* @since JDK1.1
class SkelApp2DGMenuDispatcher implements ActionListener
* Receives menu-selection events and forwards them for servicing.
* @param event an event.
* @since JDK1.1
public void actionPerformed(ActionEvent event)
if ( event.getSource() instanceof MenuItem )
MenuItem menuItemObject = (MenuItem) event.getSource();
serviceMenuEvent(menuItemObject);
* Services menu-selection event.
* @param menuItemObject a MenuItem object.
* @since JDK1.1
public void serviceMenuEvent(MenuItem menuItemObject)
* |
* MENU SERVICING |
* |
// CUSTOMISE THE "TO DO" COMMENTS AS APPROPRIATE
if (menuItemObject == fileOpen)
String fileName = null;
// launch file-open dialog box and load file if file name has been specified
if ( ( fileName = getInputFileName() ) != null )
// load image from file
displayCanvas.loadRawImage(fileName);
else if (menuItemObject == saveAs)
String fileName = null;
// launch file-save dialog box and save file if file name has been specified
if ( ( fileName = getOutputFileName() ) != null )
// save image to file
displayCanvas.saveRawImage(fileName);
else if (menuItemObject == exitApp)
System.exit(0); // confirmation message box not implemented
else if (menuItemObject == studentMenu1_1)
// TO DO: ADD RELEVANT MENU SERVICING CODE HERE
// FOR <studentMenu1_1>
System.out.println("test");
else if (menuItemObject == studentMenu1_2)
// TO DO: ADD RELEVANT MENU SERVICING CODE HERE
// FOR <studentMenu1_2>
else if (menuItemObject == studentMenu1_3)
// TO DO: ADD RELEVANT MENU SERVICING CODE HERE
// FOR <studentMenu1_3>
else if (menuItemObject == studentMenu1_4)
// TO DO: ADD RELEVANT MENU SERVICING CODE HERE
// FOR <studentMenu1_4>
else if (menuItemObject == studentMenu2_1_1)
// TO DO: ADD RELEVANT MENU SERVICING CODE HERE
// FOR <studentMenu2_1_1>
else if (menuItemObject == studentMenu2_1_2)
// TO DO: ADD RELEVANT MENU SERVICING CODE HERE
// FOR <studentMenu2_1_2>
else if (menuItemObject == studentMenu2_1_3)
// TO DO: ADD RELEVANT MENU SERVICING CODE HERE
// FOR <studentMenu2_1_3>
else if (menuItemObject == studentMenu2_2_1)
// TO DO: ADD RELEVANT MENU SERVICING CODE HERE
// FOR <studentMenu2_2_1>
else if (menuItemObject == studentMenu2_2_2)
// TO DO: ADD RELEVANT MENU SERVICING CODE HERE
// FOR <studentMenu2_2_2>
}

Answer 1

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