The MIMP

You are free to add private or protected instance variables that do not appear in the UML above. You are also free to add private helper methods. See below for detailed requirements for each class.

The Image Class

The Image class acts as an abstract base class for both RgbImage and GrayscaleImage. The Image class stores individual pixels as small arrays containing the necessary integer values to represent either the color or brightness of a single image location. These pixel arrays will have three entries for RgbImages and only one entry for GrayscaleImages. The number of entries required to represent a pixel is referred to as the number of "channels".

Under this representation, the pixel data for any image may be stored as a three-dimensional array, where the first dimension corresponds to the row (i.e. y-coordinate), the second dimension corresponds to the column (i.e. x-coordinate), and the third dimension corresponds to the channel. For example, the following statement accesses the red channel of the pixel at 20th row and 50th column of some image:

int red = pixels[20][50][0];    // Channel 0 corresponds to red.

int green = pixels[20][50][1];  // Channel 1 corresponds to green.
int blue = pixels[20][50][2];   // Channel 2 corresponds to blue.

Under this representation we can think of a grayscale image as a color image with only one color channel:

int brightness = pixels[20][50][0];    // Channel 0 corresponds to brightness.
int b = pixels[20][50][1];             // This will cause an ArrayIndexOutOfBoundsException!

Note that this representation places pixel coordinate (x=0, y=0) at the upper-left corner of the image.

Detailed Requirements

• setPixelValue - This method should clip all values so that they remain in the range 0-255. In other words, values above 255 should be converted to 255, and values below 0 should be converted to 0. This requirement will also apply to all of the pixel value setter methods in both subclasses: it should not be possible for any image to contain pixel values outside of the range 0-255. This method, and all of the pixel getters and setters for this project, should throw an ArrayIndexOutOfBoundsException if the pixel coordinate is invalid.

The required behavior for the remaining methods in the Image class should be clear from the signatures.

The GrayscaleImage Class

Detailed Requirements

• Two argument constructor - The two argument constructor should initialize a white image of the appropriate size. Both this constructor and the three-argument constructor must throw an IllegalArgumentException if either the height or width is less than 1.
• Three argument constructor - In addition to the size parameters, the three argument constructor takes an initial brightness value that should be assigned to all pixels.
• Copy constructor - This method should produce a deep copy of the image.
• getPixelValue, setPixelValue - These methods don't add any additional functionality beyond what is provided by the superclass methods they overload. These are convenience methods that make it possible to access pixel values without explicitly specifying that channel 0 should be used.
• toString - The format for the toString method should be "<GrayscaleImage width=w height=h>" where w and h are the height and width of the image. For example: "<GrayscaleImage width=640 height=480>" would be the correct string for any image that is 640 pixels wide and 480 pixels high.
• toStringDebug -The toStringDebug method is designed to facilitate debugging by returning an easy-to-read string representation of an image. The following string illustrates the correct format for a tiny 4x3 pixel image:

  <GrayscaleImage width=4 height=3>
  	[1]	[2]	[3]	[4]
  	[5]	[6]	[7]	[8]
  	[9]	[10]	[11]	[12]
  

  Use tab characters ("\t") to indent your pixel values and separate the columns in your string. Note that the Web-CAT submission tests will require an exact match to this formatting, including white-space and newline characters.

The RgbImage Class

• Two argument constructor - The two argument constructor should initialize a white image of the appropriate size. Both this constructor and the three-argument constructor must throw an IllegalArgumentException if either the height or width is less than 1.
• Three argument constructor - In addition to the size parameters, the three argument constructor takes a Color object that should be used to initialize all pixels.
• Copy constructor - This method should produce a deep copy of the image.
• getRed, setRed, getBlue, etc. - These methods don't add any functionality beyond that provided by the getPixelValue and setPixelValue methods defined in the superclass. These are convenience methods that make it possible to access pixel color components without specifying color channels numerically.
• toString - The format for the toString method should be "<RgbImage width=w height=h>" where w and h are the height and width of the image. For example: "<RgbImage width=640 height=480>" would be the correct string for any image that is 640 pixels wide and 480 pixels high.
• toStringDebug -The toStringDebug method is designed to facilitate debugging by returning an easy-to-read string representation of an image. The following string illustrates the correct format for a tiny 4x3 pixel image:

  <RgbImage width=4 height=3>
  	[1, 101, 201]	[2, 102, 202]	[3, 103, 203]	[4, 104, 204]
  	[5, 105, 205]	[6, 106, 206]	[7, 107, 207]	[8, 108, 208]
  	[9, 109, 209]	[10, 110, 210]	[11, 111, 211]	[12, 112, 212]
  

  Each bracketed triple corresponds to the color of a single pixel, where the first entry is the red value, the second is the green value and the third is the blue value. There should be a comma and a single space between each entry in the triple. Use tab characters ("\t") to indent your pixel values and separate the columns in your string.

The ImageTransforms Class

ImageTransforms is a utility class that contains static methods for performing basic image transformations. Note that none of the methods defined in ImageTransforms modify the existing image. In each case a new image is returned that is a result of applying the requested transform.

Detailed Requirements