Gray

java.lang.Object
- eecs2030.test1.Gray

All Implemented Interfaces:

Comparable<Gray>
```
public final class Gray
extends Object
implements Comparable<Gray>
```
A class that represents gray values for grayscale (black-and-white) images. A gray value can be an integer value between 0 and 255, or a double value between 0.0 and 1.0.

gray value as double gray value as int

0.0 0

1.0 / 255.0 1

2.0 / 255.0 2

3.0 / 255.0 3

... ...

254.0 / 255.0 254

1.0 255

A Gray instance can be created using any double value between 0.0 and 1.0; it is not required that there be an exact match between the double gray value and an int gray value. See toInt(double) for details on how a double gray value is converted to an int gray value.

gray value as double	gray value as int
0.0	0
1.0 / 255.0	1
2.0 / 255.0	2
3.0 / 255.0	3
...	...
254.0 / 255.0	254
1.0	255

Field Summary

Fields
Modifier and Type	Field and Description
`static double`	`MAX_DOUBLE_VALUE` The maximum double gray value.
`static int`	`MAX_INT_VALUE` The maximum int gray value.
`static double`	`MIN_DOUBLE_VALUE` The minimum double gray value.
`static int`	`MIN_INT_VALUE` The minimum int gray value.

Constructor Summary

Constructors
Constructor and Description
`Gray(double g)` Initializes the gray value of this object to `g`.
`Gray(Gray other)` Initializes the gray value of this object by copying another `Gray` object.
`Gray(int g)` Initializes the gray value of this object to `g`.

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`double`	`asDouble()` Returns the gray value of this object as a double.
`int`	`asInt()` Returns the gray value of this object as an int.
`int`	`compareTo(Gray other)` Compares two `Gray` instances by their gray values.
`boolean`	`equals(Object obj)` Compares two `Gray` instances for equality.
`static Gray`	`fromRGB(Color c)` Creates a `Gray` instance from a `Color`.
`static void`	`main(String[] args)`
`static double`	`toDouble(int value)` Converts an integer gray value to its equivalent double gray value.
`static int`	`toInt(double value)` Converts a double gray value to its equivalent int gray value.
`String`	`toString()` Returns a string representation of this `Gray` instance.

Methods inherited from class java.lang.Object
getClass, hashCode, notify, notifyAll, wait, wait, wait

- Field Detail
  - MIN_DOUBLE_VALUE
```
public static final double MIN_DOUBLE_VALUE
```
    The minimum double gray value.
    
    See Also:
    
    Constant Field Values
  - MAX_DOUBLE_VALUE
```
public static final double MAX_DOUBLE_VALUE
```
    The maximum double gray value.
    
    See Also:
    
    Constant Field Values
  - MIN_INT_VALUE
```
public static final int MIN_INT_VALUE
```
    The minimum int gray value.
    
    See Also:
    
    Constant Field Values
  - MAX_INT_VALUE
```
public static final int MAX_INT_VALUE
```
    The maximum int gray value.
    
    See Also:
    
    Constant Field Values
- Constructor Detail
  - Gray
```
public Gray(double g)
```
    Initializes the gray value of this object to g. The value returned by asDouble() will be equal to g:
```
 double g = 0.12345;
 Gray gray = new Gray(g);
 double value = gray.asDouble();   // value is equal to g
 
```
    Parameters:
    
    g - a gray value
    
    Throws:
    
    IllegalArgumentException - if g is less than 0.0 or greater than 1.0
    
    Precondition:
    
    g between 0.0 and 1.0, inclusive
  - Gray
```
public Gray(int g)
```
    Initializes the gray value of this object to g. The value returned by asInt() will be equal to g:
```
 int g = 128;
 Gray gray = new Gray(g);
 int value = gray.asInt();   // value is equal to g
 
```
    Parameters:
    
    g - a gray value between 0 and 255
    
    Throws:
    
    IllegalArgumentException - if g is less than 0 or greater than 255
    
    Precondition:
    
    g between 0 and 255, inclusive
  - Gray
```
public Gray(Gray other)
```
    Initializes the gray value of this object by copying another Gray object.
    
    Parameters:
    
    other - a Gray object to copy
- Method Detail
  - asInt
```
public int asInt()
```
    Returns the gray value of this object as an int. If this gray object was created using a double value, then that double value is converted to the equivalent int gray value and returned (see toInt(double) for details).
```
 Gray gray = new Gray(192);
 int value = gray.asInt();    // value is equal to 192
 
 gray = new Gray(1.0);
 value = gray.asInt();        // value is equal to 255
 
```
    Returns:
    
    the gray value of this object expressed as an integer
  - asDouble
```
public double asDouble()
```
    Returns the gray value of this object as a double. If this gray object was created using an int value, then that int value is converted to the equivalent double gray value and returned (see toDouble(int) for details).
```
 Gray gray = new Gray(0.5);
 double value = gray.asDouble();    // value is equal to 0.5
 
 gray = new Gray(255);
 value = gray.asDouble();           // value is equal to 1.0
 
```
    Returns:
    
    the gray value of this object expressed as a double
  - toDouble
```
public static double toDouble(int value)
```
    Converts an integer gray value to its equivalent double gray value. The equivalent double value is equal to value / Gray.MAX_DOUBLE_VALUE
    
    Parameters:
    
    value - a gray value between 0 and 255
    
    Returns:
    
    the equivalent double gray value
    
    Throws:
    
    IllegalArgumentException - if value is less than 0 or greater than 255
    
    Precondition:
    
    value between 0 and 255, inclusive
  - toInt
```
public static int toInt(double value)
```
    Converts a double gray value to its equivalent int gray value. The equivalent int value is equal to round(Gray.MAX_DOUBLE_VALUE × value) where round rounds the computed value to the nearest int value.
    
    Parameters:
    
    value - a gray value between 0.0 and 1.0
    
    Returns:
    
    the equivalent int gray value
    
    Throws:
    
    IllegalArgumentException - if value is less than 0.0 or greater than 1.0
    
    Precondition:
    
    value between 0.0 and 1.0, inclusive
  - fromRGB
```
public static Gray fromRGB(Color c)
```
    Creates a Gray instance from a Color. The gray value of a color is given by 0.299 × R + 0.587 × G + 0.114 × B where R is the red value of the color, G is the green value of the color, B is the blue value of the color, and all of R, G, and B are double values between 0.0 and 1.0.
    
    Parameters:
    
    c - a color
    
    Returns:
    
    a Gray instance
  - toString
```
public String toString()
```
    Returns a string representation of this Gray instance. The string is simply the gray value of this instance.
```
 Gray gray = new Gray(18);
 String s = gray.toString();    // s is equal to "18"
 
 gray = new Gray(0.125);
 s = gray.toString();           // s is equal to "0.125"
 
```
    Overrides:
    
    toString in class Object
    
    Returns:
    
    a string representation of this instance
  - compareTo
```
public int compareTo(Gray other)
```
    Compares two Gray instances by their gray values. The instances are compared using their gray values represented as double values (between 0.0 and 1.0). Returns:
    
    -1 if this gray value is less than the other gray value,
    1 if this gray value is greater than the other gray value, and
    0 otherwise.
    
    Specified by:
    
    compareTo in interface Comparable<Gray>
    
    Returns:
    
    -1, 1, or 0 as indicated in the description above
  - equals
```
public boolean equals(Object obj)
```
    Compares two Gray instances for equality. The result is true if and only if the argument is not null and is a Gray instance whose gray value is equal to this instance's gray value. The gray levels are checked for equality by converting them to int values (between 0 and 255) and comparing the two int values.
    
    Overrides:
    
    equals in class Object
    
    Returns:
    
    true if the int gray levels of the two instances are equal, and false otherwise
  - main
```
public static void main(String[] args)
```

Class Gray

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

MIN_DOUBLE_VALUE

MAX_DOUBLE_VALUE

MIN_INT_VALUE

MAX_INT_VALUE

Constructor Detail

Gray

Gray

Gray

Method Detail

asInt

asDouble

toDouble

toInt

fromRGB

toString

compareTo

equals

main