Class Pict

java.lang.Object
  Pict

public class Pict
extends java.lang.Object

This utility class contains static methods to translate between images and 2-D arrays.

To convert a image's filename or URL to an array of int:

     int[][] myPixels;
     myPixels =  Pict.fileToPixelsBW( "http://www.radford.edu/~itec120/2012fall-ibarland/Lectures/lect01-ufo/muse.jpeg" );
     Pict.displayPixels( myPixels );   // Bring up a window with the image.
     myPixels[13][23] = 255;           // Set location (13,23) to white.
     myPixels[14][23] =   0;           // Set location (14,23) to black.
     Pict.displayPixels( myPixels );   // Look for the modified pixel.
   

Note that once you have displayed an image, modifying the array won't retroactively change that image; you'll have to call displayPixels again after making any modifications to see a new image.

Optional/Challenge:

If you want to deal with color images, you can use imageToPixelsColor, which will return an array of java.awt.Color objects. See the Java API for details, but the most useful color methods are getRed(), setRed(int), and similarly for green and blue. To display a color image (if you have a 2-D array of Colors), call displayPixels( Color[][] ).

Pict

public Pict()

displayPixels

public static void displayPixels(java.awt.Color[][] pixels)

Given an array of Colors, draw it as a Color image. (Of course, subsequent changes to the array won't retroactively change this image.)

Parameters:

pixels - A 2-D array of java.awt.Colors.

displayPixels

public static void displayPixels(int[][] pixels)

Given an array of grayscale values in [0,256), draw it as a black-and-white image. (Of course, subsequent changes to the array won't retroactively change this image.)

Parameters:

pixels - A 2-D array of grayscale values in [0,256).

fileToPixelsBW

public static int[][] fileToPixelsBW(java.lang.String filenameOrURL)

Given a filename or URL, return a 2-D array of grayscale values in [0,256).

Parameters:

filenameOrURL - A string like "H:\MyFile.jpeg" or "http://www.radford.edu/someUser/somePict.jpg"

Returns:

The 2-D array of grayscale values representing the indicated picture. Will cause a run-time exception if the file/URL can't be opened.

fileToPixelsColor

public static java.awt.Color[][] fileToPixelsColor(java.lang.String filenameOrURL)

Given a filename or URL, return a 2-D array of java.awt.Colors.

Parameters:

filenameOrURL - A string like "H:\MyFile.jpeg" or "http://www.radford.edu/someUser/somePict.jpg"

Returns:

The 2-D array of grayscale values representing the indicated picture. Will cause a run-time exception if the file/URL can't be opened.

main

public static void main(java.lang.String[] args)

A test method, which just displays three images: A color version, a black-and-white version, and a tiny 4x3 image.