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.