edu.rit.image

Class GrayImageRow

java.lang.Object

edu.rit.image.GrayImageRow

public class GrayImageRow
extends java.lang.Object

Class GrayImageRow provides one row of a grayscale image. The image row is layered on top of a byte array (type byte[]). Use the setArray() method to specify which array this is. The width of the image row is equal to the number of elements in the underlying array. The image row's underlying array usually is (but does not have to be) one row of an image's underlying matrix.

To read and write the pixels of an image row, use the getIntPixel(), getPixel(), setIntPixel(), and setPixel() methods. These methods represent a pixel value as an integer in the range 0 .. 255 or as a floating point number in the range 0.0 .. 1.0. The image row's interpretation attribute specifies how to map between the numerical pixel value and the shade of gray. If the interpretation is ZERO_IS_WHITE, then a value of 0 or 0.0 represents white and 255 or 1.0 represents black. If the interpretation is ZERO_IS_BLACK, then a value of 0 or 0.0 represents black and 255 or 1.0 represents white. The default interpretation is ZERO_IS_BLACK. To change the interpretation, call the setInterpretation() method.

Changing the contents of the underlying matrix directly will also change the image row. In the underlying matrix, a value of 0 represents black and a value of 255 represents white.

Field Summary

Fields

Modifier and Type	Field and Description
static PJGGrayImage.Interpretation	ZERO_IS_BLACK A pixel value of 0 or 0.0 is black, 255 or 1.0 is white.
static PJGGrayImage.Interpretation	ZERO_IS_WHITE A pixel value of 0 or 0.0 is white, 255 or 1.0 is black.

Constructor Summary

Constructors

Constructor and Description
GrayImageRow(byte[] theArray) Construct a new grayscale image row on top of the given array.

Method Summary

Modifier and Type	Method and Description
void	fill(float val) Set all pixels in this image row to the given value.
void	fill(int val) Set all pixels in this image row to the given value.
byte[]	getArray() Obtain this image row's underlying array.
PJGGrayImage.Interpretation	getInterpretation() Get this image row's interpretation.
int	getIntPixel(int c) Obtain the pixel at the given column in this image row.
float	getPixel(int c) Obtain the pixel at the given column in this image row.
void	setArray(byte[] theArray) Set this image row's underlying array.
void	setInterpretation(PJGGrayImage.Interpretation theInterpretation) Set this image row's interpretation.
void	setIntPixel(int c, int val) Set the pixel at the given column in this image row.
void	setPixel(int c, float val) Set the pixel at the given column in this image row.

Methods inherited from class java.lang.Object

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

Field Detail

ZERO_IS_WHITE

public static final PJGGrayImage.Interpretation ZERO_IS_WHITE

A pixel value of 0 or 0.0 is white, 255 or 1.0 is black.

ZERO_IS_BLACK

public static final PJGGrayImage.Interpretation ZERO_IS_BLACK

A pixel value of 0 or 0.0 is black, 255 or 1.0 is white.

Constructor Detail

GrayImageRow

public GrayImageRow(byte[] theArray)

Construct a new grayscale image row on top of the given array. The image row's interpretation is ZERO_IS_BLACK.

Parameters:

theArray - Underlying array.

Throws:

java.lang.NullPointerException - (unchecked exception) Thrown if theArray is null.

Method Detail

getArray

public byte[] getArray()

Obtain this image row's underlying array.

Returns:

Underlying array.

setArray

public void setArray(byte[] theArray)

Set this image row's underlying array.

Parameters:

theArray - Underlying array.

Throws:

java.lang.NullPointerException - (unchecked exception) Thrown if theArray is null.

getInterpretation

public PJGGrayImage.Interpretation getInterpretation()

Get this image row's interpretation.

Returns:

ZERO_IS_WHITE or ZERO_IS_BLACK.

setInterpretation

public void setInterpretation(PJGGrayImage.Interpretation theInterpretation)

Set this image row's interpretation. If this method is not called, this image row's default interpretation is ZERO_IS_BLACK.

Parameters:

theInterpretation - ZERO_IS_WHITE or ZERO_IS_BLACK.

getIntPixel

public int getIntPixel(int c)

Obtain the pixel at the given column in this image row.

Parameters:

c - Column index.

Returns:

Pixel[c] as an integer in the range 0 .. 255.

Throws:

java.lang.NullPointerException - (unchecked exception) Thrown if the underlying matrix row has not been specified.

java.lang.ArrayIndexOutOfBoundsException - (unchecked exception) Thrown if c is out of bounds.

getPixel

public float getPixel(int c)

Obtain the pixel at the given column in this image row.

Parameters:

c - Column index.

Returns:

Pixel[c] as a floating point number in the range 0.0 .. 1.0.

Throws:

java.lang.NullPointerException - (unchecked exception) Thrown if the underlying matrix row has not been specified.

java.lang.ArrayIndexOutOfBoundsException - (unchecked exception) Thrown if c is out of bounds.

setIntPixel

public void setIntPixel(int c,
                        int val)

Set the pixel at the given column in this image row. If val is outside the range 0 .. 255, it is pinned to the appropriate boundary.

Parameters:

c - Column index.

val - New pixel value as an integer in the range 0 .. 255.

Throws:

java.lang.NullPointerException - (unchecked exception) Thrown if the underlying matrix row has not been specified.

java.lang.ArrayIndexOutOfBoundsException - (unchecked exception) Thrown if c is out of bounds.

setPixel

public void setPixel(int c,
                     float val)

Set the pixel at the given column in this image row. If val is outside the range 0.0 .. 1.0, it is pinned to the appropriate boundary.

Parameters:

c - Column index.

val - New pixel value as a floating point number in the range 0.0 .. 1.0.

Throws:

java.lang.NullPointerException - (unchecked exception) Thrown if the underlying matrix row has not been specified.

java.lang.ArrayIndexOutOfBoundsException - (unchecked exception) Thrown if c is out of bounds.

fill

public void fill(int val)

Set all pixels in this image row to the given value. If val is outside the range 0 .. 255, it is pinned to the appropriate boundary.

Parameters:

val - New pixel value as an integer in the range 0 .. 255.

Throws:

java.lang.NullPointerException - (unchecked exception) Thrown if the underlying matrix row has not been specified.

fill

public void fill(float val)

Set all pixels in this image row to the given value. If val is outside the range 0.0 .. 1.0, it is pinned to the appropriate boundary.

Parameters:

val - New pixel value as a floating point number in the range 0.0 .. 1.0.

Throws:

java.lang.NullPointerException - (unchecked exception) Thrown if the underlying matrix row has not been specified.