Package stdlib

Class Picture

java.lang.Object
stdlib.Picture
All Implemented Interfaces:
ActionListener, EventListener
public final class Picture extends Object implements ActionListener
This class provides methods for manipulating individual pixels of an image. The original image can be read from a file in JPEG, GIF, or PNG format, 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 to a file.

By default, pixel (x, y) is column x, row y, where (0, 0) is upper left. 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.

  • Constructor Summary

    Constructors
    Constructor
    Description
    Picture(int w, int h)
    Create a blank w-by-h picture, where each pixel is black.
    Picture(File file)
    Create a picture by reading in a .png, .gif, or .jpg from a File.
    Picture(String filename)
    Create a picture by reading in a .png, .gif, or .jpg from the given filename or URL name.
    Picture(Picture pic)
    Copy constructor.

  • Method Summary

    Modifier and Type
    Method
    Description
    void
    actionPerformed(ActionEvent e)
    Opens a save dialog box when the user selects "Save As" from the menu.
    boolean
    equals(Object obj)
    Is this Picture equal to obj?
    Color
    get(int i, int j)
    Return the color of pixel (i, j).
    JLabel
    getJLabel()
    Return a JLabel containing this Picture, for embedding in a JPanel, JFrame or other GUI widget.
    int
    height()
    Return the height of the picture in pixels.
    static void
    main(String[] args)
    Test client.
    void
    save(File file)
    Save the picture to a file in a standard image format.
    void
    save(String name)
    Save the picture to a file in a standard image format.
    void
    set(int i, int j, Color c)
    Set the color of pixel (i, j) to c.
    void
    setOriginLowerLeft()
    Set the origin to be the lower left pixel.
    void
    setOriginUpperLeft()
    Set the origin to be the upper left pixel.
    void
    show()
    Display the picture in a window on the screen.
    int
    width()
    Return the width of the picture in pixels.

    Methods inherited from class java.lang.Object

    getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

  • Constructor Details

    • Picture

      public Picture(int w, int h)
      Create a blank w-by-h picture, where each pixel is black.

    • Picture

      public Picture(Picture pic)
      Copy constructor.

    • Picture

      public Picture(String filename)
      Create a picture by reading in a .png, .gif, or .jpg from the given filename or URL name.

    • Picture

      public Picture(File file)
      Create a picture by reading in a .png, .gif, or .jpg from a File.

  • Method Details

    • getJLabel

      public JLabel getJLabel()
      Return a JLabel containing this Picture, for embedding in a JPanel, JFrame or other GUI widget.

    • setOriginUpperLeft

      public void setOriginUpperLeft()
      Set the origin to be the upper left pixel.

    • setOriginLowerLeft

      public void setOriginLowerLeft()
      Set the origin to be the lower left pixel.

    • show

      public void show()
      Display the picture in a window on the screen.

    • height

      public int height()
      Return the height of the picture in pixels.

    • width

      public int width()
      Return the width of the picture in pixels.

    • get

      public Color get(int i, int j)
      Return the color of pixel (i, j).

    • set

      public void set(int i, int j, Color c)
      Set the color of pixel (i, j) to c.

    • equals

      public boolean equals(Object obj)
      Is this Picture equal to obj?
      Overrides:
      equals in class Object

    • save

      public void save(String name)
      Save the picture to a file in a standard image format. The filetype must be .png or .jpg.

    • save

      public void save(File file)
      Save the picture to a file in a standard image format.

    • actionPerformed

      public void actionPerformed(ActionEvent e)
      Opens a save dialog box when the user selects "Save As" from the menu.
      Specified by:
      actionPerformed in interface ActionListener

    • main

      public static void main(String[] args)
      Test client. Reads a picture specified by the command-line argument, and shows it in a window on the screen.