Image Viewer GUI
Program Image Viewer
Class OFImage
Class OFImage
import java.awt.*;
import java.awt.image.*;
import javax.swing.*;
public class OFImage extends BufferedImage
{
/**
* Create an OFImage copied from a BufferedImage.
* @param image The image to copy.
*/
public OFImage(BufferedImage image)
{
super(image.getColorModel(), image.copyData(null),
image.isAlphaPremultiplied(), null);
}
/**
* Create an OFImage with specified size and unspecified content.
* @param width The width of the image.
* @param height The height of the image.
*/
public OFImage(int width, int height)
{
super(width, height, TYPE_INT_RGB);
}
/**
* Set a given pixel of this image to a specified color. The
* color is represented as an (r,g,b) value.
* @param x The x position of the pixel.
* @param y The y position of the pixel.
* @param col The color of the pixel.
*/
public void setPixel(int x, int y, Color col)
{
int pixel = col.getRGB();
setRGB(x, y, pixel);
}
/**
* Get the color value at a specified pixel position.
* @param x The x position of the pixel.
* @param y The y position of the pixel.
* @return The color of the pixel at the given position.
*/
public Color getPixel(int x, int y)
{
int pixel = getRGB(x, y);
return new Color(pixel);
}
/**
* Make this image a bit darker.
*/
public void darker()
{
int height = getHeight();
int width = getWidth();
for(int y = 0; y < height; y++) {
for(int x = 0; x < width; x++) {
setPixel(x, y, getPixel(x, y).darker());
}
}
}
/**
* Make this image a bit lighter.
*/
public void lighter()
{
int height = getHeight();
int width = getWidth();
for(int y = 0; y < height; y++) {
for(int x = 0; x < width; x++) {
setPixel(x, y, getPixel(x, y).brighter());
}
}
}
/**
* Perform a three level threshold operation.
* That is: repaint the image with only three color values:
* white, gray, and black.
*/
public void threshold()
{
int height = getHeight();
int width = getWidth();
for(int y = 0; y < height; y++) {
for(int x = 0; x < width; x++) {
Color pixel = getPixel(x, y);
int brightness = (pixel.getRed() + pixel.getBlue() + pixel.getGreen()) / 3;
if(brightness <= 85) {
setPixel(x, y, Color.BLACK);
}
else if(brightness <= 170) {
setPixel(x, y, Color.GRAY);
}
else {
setPixel(x, y, Color.WHITE);
}
}
}
}
Class Image File Manager
import java.awt.image.*;
import javax.imageio.*;
import java.io.*;
public class ImageFileManager
{
// A constant for the image format that this writer uses for writing.
// Available formats are "jpg" and "png".
private static final String IMAGE_FORMAT = "jpg";
/**
* Read an image file from disk and return it as an image. This method
* can read JPG and PNG file formats. In case of any problem (e.g the file
* does not exist, is in an undecodable format, or any other read error)
* this method returns null.
*
* @param imageFile The image file to be loaded.
* @return The image object or null is it could not be read.
*/
public static OFImage loadImage(File imageFile)
{
try {
BufferedImage image = ImageIO.read(imageFile);
if(image == null || (image.getWidth(null) < 0)) {
// we could not load the image - probably invalid file format
return null;
}
return new OFImage(image);
}
catch(IOException exc) {
return null;
}
}
/**
* Write an image file to disk. The file format is JPG. In case of any
* problem the method just silently returns.
*
* @param image The image to be saved.
* @param file The file to save to.
*/
public static void saveImage(OFImage image, File file)
{
try {
ImageIO.write(image, IMAGE_FORMAT, file);
}
catch(IOException exc) {
return;
}
}
Class Image Panel
import java.awt.*;
import javax.swing.*;
import java.awt.image.*;
public class ImagePanel extends JComponent
{
// The current width and height of this panel
private int width, height;
// An internal image buffer that is used for painting. For
// actual display, this image buffer is then copied to screen.
private OFImage panelImage;
/**
* Create a new, empty ImagePanel.
*/
public ImagePanel()
{
width = 360; // arbitrary size for empty panel
height = 240;
panelImage = null;
}
/**
* Set the image that this panel should show.
*
* @param image The image to be displayed.
*/
public void setImage(OFImage image)
{
if(image != null) {
width = image.getWidth();
height = image.getHeight();
panelImage = image;
repaint();
}
}
/**
* Clear the image on this panel.
*/
public void clearImage()
{
Graphics imageGraphics = panelImage.getGraphics();
imageGraphics.setColor(Color.LIGHT_GRAY);
imageGraphics.fillRect(0, 0, width, height);
repaint();
}
// The following methods are redefinitions of methods
// inherited from superclasses.
/**
* Tell the layout manager how big we would like to be.
* (This method gets called by layout managers for placing
* the components.)
*
* @return The preferred dimension for this component.
*/
public Dimension getPreferredSize()
{
return new Dimension(width, height);
}
/**
* This component needs to be redisplayed. Copy the internal image
* to screen. (This method gets called by the Swing screen painter
* every time it want this component displayed.)
*
* @param g The graphics context that can be used to draw on this component.
*/
public void paintComponent(Graphics g)
{
Dimension size = getSize();
g.clearRect(0, 0, size.width, size.height);
if(panelImage != null) {
g.drawImage(panelImage, 0, 0, null);
}
}
Class Image Viewer
import java.awt.*;
import javax.swing.*;
import java.awt.image.*;
public class ImagePanel extends JComponent
{
// The current width and height of this panel
private int width, height;
// An internal image buffer that is used for painting. For
// actual display, this image buffer is then copied to screen.
private OFImage panelImage;
/**
* Create a new, empty ImagePanel.
*/
public ImagePanel()
{
width = 360; // arbitrary size for empty panel
height = 240;
panelImage = null;
}
/**
* Set the image that this panel should show.
*
* @param image The image to be displayed.
*/
public void setImage(OFImage image)
{
if(image != null) {
width = image.getWidth();
height = image.getHeight();
panelImage = image;
repaint();
}
}
/**
* Clear the image on this panel.
*/
public void clearImage()
{
Graphics imageGraphics = panelImage.getGraphics();
imageGraphics.setColor(Color.LIGHT_GRAY);
imageGraphics.fillRect(0, 0, width, height);
repaint();
}
// The following methods are redefinitions of methods
// inherited from superclasses.
/**
* Tell the layout manager how big we would like to be.
* (This method gets called by layout managers for placing
* the components.)
*
* @return The preferred dimension for this component.
*/
public Dimension getPreferredSize()
{
return new Dimension(width, height);
}
/**
* This component needs to be redisplayed. Copy the internal image
* to screen. (This method gets called by the Swing screen painter
* every time it want this component displayed.)
*
* @param g The graphics context that can be used to draw on this component.
*/
public void paintComponent(Graphics g)
{
Dimension size = getSize();
g.clearRect(0, 0, size.width, size.height);
if(panelImage != null) {
g.drawImage(panelImage, 0, 0, null);
}
}
Output
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