Animations using java

[spoiler title=’Picture.java’]

import java.awt.Color;
import java.awt.FileDialog;
import java.awt.Toolkit;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.KeyEvent;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import java.net.URL;
import javax.imageio.ImageIO;
import javax.swing.ImageIcon;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JMenu;
import javax.swing.JMenuBar;
import javax.swing.JMenuItem;
import javax.swing.KeyStroke;


/**
 *  This class provides methods for manipulating individual pixels of
 *  an image. The original image can be read from a .jpg, .gif,
 *  or .png file or the user can create a blank image of a given size.
 *  This class includes methods for displaying the image in a window on
 *  the screen or saving it to a file.
 *

• Pixel (x, y) is column x and row y. * By default, the origin (0, 0) is upper left, which is a common convention * in image processing. * The method setOriginLowerLeft() change the origin to the lower left. *

• For additional documentation, see * Section 3.1 of * Introduction to Programming in Java: An Interdisciplinary Approach * by Robert Sedgewick and Kevin Wayne. * * @author Robert Sedgewick * @author Kevin Wayne */ public final class Picture implements ActionListener { private BufferedImage image; // the rasterized image private JFrame frame; // on-screen view private String filename; // name of file private boolean isOriginUpperLeft = true; // location of origin private final int width, height; // width and height /** * Initializes a blank width-by-height picture, with width columns * and height rows, where each pixel is black. * * @param width the width of the picture * @param height the height of the picture */ public Picture(int width, int height) { if (width < 0) throw new IllegalArgumentException(“width must be nonnegative”); if (height < 0) throw new IllegalArgumentException(“height must be nonnegative”); this.width = width; this.height = height; image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB); // set to TYPE_INT_ARGB to support transparency filename = width + “-by-” + height; } /** * Initializes a new picture that is a deep copy of the argument picture. * * @param picture the picture to copy */ public Picture(Picture picture) { width = picture.width(); height = picture.height(); image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB); filename = picture.filename; for (int col = 0; col < width(); col++) for (int row = 0; row < height(); row++) image.setRGB(col, row, picture.get(col, row).getRGB()); } /** * Initializes a picture by reading from a file or URL. * * @param filename the name of the file (.png, .gif, or .jpg) or URL. */ public Picture(String filename) { this.filename = filename; try { // try to read from file in working directory File file = new File(filename); if (file.isFile()) { image = ImageIO.read(file); } // now try to read from file in same directory as this .class file else { URL url = getClass().getResource(filename); if (url == null) { url = new URL(filename); } image = ImageIO.read(url); } if (image == null) { throw new IllegalArgumentException(“Invalid image file: ” + filename); } width = image.getWidth(null); height = image.getHeight(null); } catch (IOException e) { // e.printStackTrace(); throw new RuntimeException(“Could not open file: ” + filename); } } /** * Initializes a picture by reading in a .png, .gif, or .jpg from a file. * * @param file the file */ public Picture(File file) { try { image = ImageIO.read(file); } catch (IOException e) { e.printStackTrace(); throw new RuntimeException(“Could not open file: ” + file); } if (image == null) { throw new RuntimeException(“Invalid image file: ” + file); } width = image.getWidth(null); height = image.getHeight(null); filename = file.getName(); } /** * Returns a JLabel containing this picture, for embedding in a JPanel, * JFrame or other GUI widget. * * @return the JLabel */ public JLabel getJLabel() { if (image == null) return null; // no image available ImageIcon icon = new ImageIcon(image); return new JLabel(icon); } /** * Sets the origin to be the upper left pixel. This is the default. */ public void setOriginUpperLeft() { isOriginUpperLeft = true; } /** * Sets the origin to be the lower left pixel. */ public void setOriginLowerLeft() { isOriginUpperLeft = false; } /** * Displays the picture in a window on the screen. */ public void show() { // create the GUI for viewing the image if needed if (frame == null) { frame = new JFrame(); JMenuBar menuBar = new JMenuBar(); JMenu menu = new JMenu(“File”); menuBar.add(menu); JMenuItem menuItem1 = new JMenuItem(” Save… “); menuItem1.addActionListener(this); menuItem1.setAccelerator(KeyStroke.getKeyStroke(KeyEvent.VK_S, Toolkit.getDefaultToolkit().getMenuShortcutKeyMask())); menu.add(menuItem1); frame.setJMenuBar(menuBar); frame.setContentPane(getJLabel()); // f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); frame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE); frame.setTitle(filename); frame.setResizable(false); frame.pack(); frame.setVisible(true); } // draw frame.repaint(); } /** * Returns the height of the picture. * * @return the height of the picture (in pixels) */ public int height() { return height; } /** * Returns the width of the picture. * * @return the width of the picture (in pixels) */ public int width() { return width; } /** * Returns the color of pixel (col, row). * * @param col the column index * @param row the row index * @return the color of pixel (col, row) * @throws IndexOutOfBoundsException unless both 0 ≤ col < width * and 0 ≤ row < height */ public Color get(int col, int row) { if (col < 0 || col >= width()) throw new IndexOutOfBoundsException(“col must be between 0 and ” + (width()-1) + “: ” + col); if (row < 0 || row >= height()) throw new IndexOutOfBoundsException(“row must be between 0 and ” + (height()-1) + “: ” + col); if (isOriginUpperLeft) return new Color(image.getRGB(col, row)); else return new Color(image.getRGB(col, height – row – 1)); } /** * Sets the color of pixel (col, row) to given color. * * @param col the column index * @param row the row index * @param color the color * @throws IndexOutOfBoundsException unless both 0 ≤ col < width * and 0 ≤ row < height * @throws NullPointerException if color is null */ public void set(int col, int row, Color color) { if (col < 0 || col >= width()) throw new IndexOutOfBoundsException(“col must be between 0 and ” + (width()-1) + “: ” + col); if (row < 0 || row >= height()) throw new IndexOutOfBoundsException(“row must be between 0 and ” + (height()-1) + “: ” + row); if (color == null) throw new NullPointerException(“can’t set Color to null”); if (isOriginUpperLeft) image.setRGB(col, row, color.getRGB()); else image.setRGB(col, height – row – 1, color.getRGB()); } /** * Returns true if this picture is equal to the argument picture. * * @param other the other picture * @return true if this picture is the same dimension as other * and if all pixels have the same color; false otherwise */ public boolean equals(Object other) { if (other == this) return true; if (other == null) return false; if (other.getClass() != this.getClass()) return false; Picture that = (Picture) other; if (this.width() != that.width()) return false; if (this.height() != that.height()) return false; for (int col = 0; col < width(); col++) for (int row = 0; row < height(); row++) if (!this.get(col, row).equals(that.get(col, row))) return false; return true; } /** * This operation is not supported because pictures are mutable. * * @return does not return a value * @throws UnsupportedOperationException if called */ public int hashCode() { throw new UnsupportedOperationException(“hashCode() is not supported because pictures are mutable”); } /** * Saves the picture to a file in a standard image format. * The filetype must be .png or .jpg. * * @param name the name of the file */ public void save(String name) { save(new File(name)); } /** * Saves the picture to a file in a PNG or JPEG image format. * * @param file the file */ public void save(File file) { filename = file.getName(); if (frame != null) frame.setTitle(filename); String suffix = filename.substring(filename.lastIndexOf(‘.’) + 1); suffix = suffix.toLowerCase(); if (suffix.equals(“jpg”) || suffix.equals(“png”)) { try { ImageIO.write(image, suffix, file); } catch (IOException e) { e.printStackTrace(); } } else { System.out.println(“Error: filename must end in .jpg or .png”); } } /** * Opens a save dialog box when the user selects “Save As” from the menu. */ @Override public void actionPerformed(ActionEvent e) { FileDialog chooser = new FileDialog(frame, “Use a .png or .jpg extension”, FileDialog.SAVE); chooser.setVisible(true); if (chooser.getFile() != null) { save(chooser.getDirectory() + File.separator + chooser.getFile()); } } /** * Unit tests this Picture data type. * Reads a picture specified by the command-line argument, * and shows it in a window on the screen. */ public static void main(String[] args) { Picture picture = new Picture(args[0]); System.out.printf(“%d-by-%d\n”, picture.width(), picture.height()); picture.show(); } }

[/spoiler]

Write a java program, YI_Pixels30x30.java to display the RGB colors of the top area of the image in this format:

R     G    B
196   200  105
155   0    50
...