# Class IndexColorModel

java.lang.Object
java.awt.image.ColorModel
java.awt.image.IndexColorModel

All Implemented Interfaces:
  `Transparency`

public class IndexColorModel extends ColorModel
The `IndexColorModel` class is a `ColorModel` class that works with pixel values consisting of a single sample that is an index into a fixed colormap in the default sRGB color space. The colormap specifies red, green, blue, and optional alpha components corresponding to each index. All components are represented in the colormap as 8-bit unsigned integral values. Some constructors allow the caller to specify "holes" in the colormap by indicating which colormap entries are valid and which represent unusable colors via the bits set in a `BigInteger` object. This color model is similar to an X11 PseudoColor visual.

Some constructors provide a means to specify an alpha component for each pixel in the colormap, while others either provide no such means or, in some cases, a flag to indicate whether the colormap data contains alpha values. If no alpha is supplied to the constructor, an opaque alpha component (alpha = 1.0) is assumed for each entry. An optional transparent pixel value can be supplied that indicates a pixel to be made completely transparent, regardless of any alpha component supplied or assumed for that pixel value. Note that the color components in the colormap of an `IndexColorModel` objects are never pre-multiplied with the alpha components.

The transparency of an `IndexColorModel` object is determined by examining the alpha components of the colors in the colormap and choosing the most specific value after considering the optional alpha values and any transparent index specified. The transparency value is `Transparency.OPAQUE` only if all valid colors in the colormap are opaque and there is no valid transparent pixel. If all valid colors in the colormap are either completely opaque (alpha = 1.0) or completely transparent (alpha = 0.0), which typically occurs when a valid transparent pixel is specified, the value is `Transparency.BITMASK`. Otherwise, the value is `Transparency.TRANSLUCENT`, indicating that some valid color has an alpha component that is neither completely transparent nor completely opaque (0.0 < alpha < 1.0).

If an `IndexColorModel` object has a transparency value of `Transparency.OPAQUE`, then the `hasAlpha` and `getNumComponents` methods (both inherited from `ColorModel`) return false and 3, respectively. For any other transparency value, `hasAlpha` returns true and `getNumComponents` returns 4.

The values used to index into the colormap are taken from the least significant n bits of pixel representations where n is based on the pixel size specified in the constructor. For pixel sizes smaller than 8 bits, n is rounded up to a power of two (3 becomes 4 and 5,6,7 become 8). For pixel sizes between 8 and 16 bits, n is equal to the pixel size. Pixel sizes larger than 16 bits are not supported by this class. Higher order bits beyond n are ignored in pixel representations. Index values greater than or equal to the map size, but less than 2n, are undefined and return 0 for all color and alpha components.

For those methods that use a primitive array pixel representation of type `transferType`, the array length is always one. The transfer types supported are `DataBuffer.TYPE_BYTE` and `DataBuffer.TYPE_USHORT`. A single int pixel representation is valid for all objects of this class, since it is always possible to represent pixel values used with this class in a single int. Therefore, methods that use this representation do not throw an `IllegalArgumentException` due to an invalid pixel value.

Many of the methods in this class are final. The reason for this is that the underlying native graphics code makes assumptions about the layout and operation of this class and those assumptions are reflected in the implementations of the methods here that are marked final. You can subclass this class for other reasons, but you cannot override or modify the behaviour of those methods.

See Also:
  - `ColorModel`
  - `ColorSpace`
  - `DataBuffer`

## Field Summary

### Fields declared in class ColorModel

`pixel_bits, transferType`

### Fields declared in interface Transparency

`BITMASK, OPAQUE, TRANSLUCENT`

## Constructor Summary

Constructors
Constructor
Description
`IndexColorModel(int bits, int size, byte[] r, byte[] g, byte[] b)`
Constructs an `IndexColorModel` from the specified arrays of red, green, and blue components.
`IndexColorModel(int bits, int size, byte[] r, byte[] g, byte[] b, byte[] a)`
Constructs an `IndexColorModel` from the given arrays of red, green, blue and alpha components.
`IndexColorModel(int bits, int size, byte[] r, byte[] g, byte[] b, int trans)`
Constructs an `IndexColorModel` from the given arrays of red, green, and blue components.
`IndexColorModel(int bits, int size, byte[] cmap, int start, boolean hasalpha)`
Constructs an `IndexColorModel` from a single array of interleaved red, green, blue and optional alpha components.
`IndexColorModel(int bits, int size, byte[] cmap, int start, boolean hasalpha, int trans)`
Constructs an `IndexColorModel` from a single array of interleaved red, green, blue and optional alpha components.
`IndexColorModel(int bits, int size, int[] cmap, int start, boolean hasalpha, int trans, int transferType)`
Constructs an `IndexColorModel` from an array of ints where each int is comprised of red, green, blue, and optional alpha components in the default RGB color model format.
`IndexColorModel(int bits, int size, int[] cmap, int start, int transferType, BigInteger validBits)`
Constructs an `IndexColorModel` from an `int` array where each `int` is comprised of red, green, blue, and alpha components in the default RGB color model format.

## Method Summary

Modifier and Type
Method
Description
`BufferedImage`
`convertToIntDiscrete(Raster raster, boolean forceARGB)`
Returns a new `BufferedImage` of TYPE_INT_ARGB or TYPE_INT_RGB that has a `Raster` with pixel data computed by expanding the indices in the source `Raster` using the color/alpha component arrays of this `ColorModel`.
`SampleModel`
`createCompatibleSampleModel(int w, int h)`
Creates a `SampleModel` with the specified width and height that has a data layout compatible with this `ColorModel`.
`WritableRaster`
`createCompatibleWritableRaster(int w, int h)`
Creates a `WritableRaster` with the specified width and height that has a data layout (`SampleModel`) compatible with this `ColorModel`.
`boolean`
`equals(Object obj)`
Tests if the specified `Object` is an instance of `IndexColorModel` and if it equals this `IndexColorModel`
`final int`
`getAlpha(int pixel)`
Returns the alpha component for the specified pixel, scaled from 0 to 255.
`final void`
`getAlphas(byte[] a)`
Copies the array of alpha transparency components into the specified array.
`final int`
`getBlue(int pixel)`
Returns the blue color component for the specified pixel, scaled from 0 to 255 in the default RGB ColorSpace, sRGB.
`final void`
`getBlues(byte[] b)`
Copies the array of blue color components into the specified array.
`int[]`
`getComponents(int pixel, int[] components, int offset)`
Returns an array of unnormalized color/alpha components for a specified pixel in this `ColorModel`.
`int[]`
`getComponents(Object pixel, int[] components, int offset)`
Returns an array of unnormalized color/alpha components for a specified pixel in this `ColorModel`.
`int[]`
`getComponentSize()`
Returns an array of the number of bits for each color/alpha component.
`int`
`getDataElement(int[] components, int offset)`
Returns a pixel value represented as an int in this `ColorModel` given an array of unnormalized color/alpha components.
`Object`
`getDataElements(int[] components, int offset, Object pixel)`
Returns a data element array representation of a pixel in this `ColorModel` given an array of unnormalized color/alpha components.
`Object`
`getDataElements(int rgb, Object pixel)`
Returns a data element array representation of a pixel in this ColorModel, given an integer pixel representation in the default RGB color model.
`final int`
`getGreen(int pixel)`
Returns the green color component for the specified pixel, scaled from 0 to 255 in the default RGB ColorSpace, sRGB.
`final void`
`getGreens(byte[] g)`
Copies the array of green color components into the specified array.
`final int`
`getMapSize()`
Returns the size of the color/alpha component arrays in this `IndexColorModel`.
`final int`
`getRed(int pixel)`
Returns the red color component for the specified pixel, scaled from 0 to 255 in the default RGB ColorSpace, sRGB.
`final void`
`getReds(byte[] r)`
Copies the array of red color components into the specified array.
`final int`
`getRGB(int pixel)`
Returns the color/alpha components of the pixel in the default RGB color model format.
`final void`
`getRGBs(int[] rgb)`
Converts data for each index from the color and alpha component arrays to an int in the default RGB ColorModel format and copies the resulting 32-bit ARGB values into the specified array.
`int`
`getTransparency()`
Returns the transparency.
`final int`
`getTransparentPixel()`
Returns the index of a transparent pixel in this `IndexColorModel` or -1 if there is no pixel with an alpha value of 0.
`BigInteger`
`getValidPixels()`
Returns a `BigInteger` that indicates the valid/invalid pixels in the colormap.
`int`
`hashCode()`
Returns the hash code for IndexColorModel.
`boolean`
`isCompatibleRaster(Raster raster)`
Returns `true` if `raster` is compatible with this `ColorModel` or `false` if it is not compatible with this `ColorModel`.
`boolean`
`isCompatibleSampleModel(SampleModel sm)`
Checks if the specified `SampleModel` is compatible with this `ColorModel`.
`boolean`
`isValid()`
Returns whether or not all of the pixels are valid.
`boolean`
`isValid(int pixel)`
Returns whether or not the pixel is valid.
`String`
`toString()`
Returns the `String` representation of the contents of this `ColorModel` object.

### Methods declared in class ColorModel

`coerceData, getAlpha, getAlphaRaster, getBlue, getColorSpace, getComponentSize, getDataElement, getDataElements, getGreen, getNormalizedComponents, getNormalizedComponents, getNumColorComponents, getNumComponents, getPixelSize, getRed, getRGB, getRGBdefault, getTransferType, getUnnormalizedComponents, hasAlpha, isAlphaPremultiplied`

### Methods declared in class Object

`clone, finalize, getClass, notify, notifyAll, wait, wait, wait`

## Constructor Details

### IndexColorModel

public IndexColorModel(int bits, int size, byte[] r, byte[] g, byte[] b)
Constructs an `IndexColorModel` from the specified arrays of red, green, and blue components. Pixels described by this color model all have alpha components of 255 unnormalized (1.0 normalized), which means they are fully opaque. All of the arrays specifying the color components must have at least the specified number of entries. The `ColorSpace` is the default sRGB space. Since there is no alpha information in any of the arguments to this constructor, the transparency value is always `Transparency.OPAQUE`. The transfer type is the smallest of `DataBuffer.TYPE_BYTE` or `DataBuffer.TYPE_USHORT` that can hold a single pixel.

Parameters:
  `bits` - the number of bits each pixel occupies
  `size` - the size of the color component arrays
  `r` - the array of red color components
  `g` - the array of green color components
  `b` - the array of blue color components
Throws:
  `IllegalArgumentException` - if `bits` is less than 1 or greater than 16
  `IllegalArgumentException` - if `size` is less than 1

### IndexColorModel

public IndexColorModel(int bits, int size, byte[] r, byte[] g, byte[] b, int trans)
Constructs an `IndexColorModel` from the given arrays of red, green, and blue components. Pixels described by this color model all have alpha components of 255 unnormalized (1.0 normalized), which means they are fully opaque, except for the indicated pixel to be made transparent. All of the arrays specifying the color components must have at least the specified number of entries. The `ColorSpace` is the default sRGB space. The transparency value may be `Transparency.OPAQUE` or `Transparency.BITMASK` depending on the arguments, as specified in the class description above. The transfer type is the smallest of `DataBuffer.TYPE_BYTE` or `DataBuffer.TYPE_USHORT` that can hold a single pixel.

Parameters:
  `bits` - the number of bits each pixel occupies
  `size` - the size of the color component arrays
  `r` - the array of red color components
  `g` - the array of green color components
  `b` - the array of blue color components
  `trans` - the index of the transparent pixel
Throws:
  `IllegalArgumentException` - if `bits` is less than 1 or greater than 16
  `IllegalArgumentException` - if `size` is less than 1

### IndexColorModel

public IndexColorModel(int bits, int size, byte[] r, byte[] g, byte[] b, byte[] a)
Constructs an `IndexColorModel` from the given arrays of red, green, blue and alpha components. All of the arrays specifying the components must have at least the specified number of entries. The `ColorSpace` is the default sRGB space. The transparency value may be any of `Transparency.OPAQUE`, `Transparency.BITMASK`, or `Transparency.TRANSLUCENT` depending on the arguments, as specified in the class description above. The transfer type is the smallest of `DataBuffer.TYPE_BYTE` or `DataBuffer.TYPE_USHORT` that can hold a single pixel.

Parameters:
  `bits` - the number of bits each pixel occupies
  `size` - the size of the color component arrays
  `r` - the array of red color components
  `g` - the array of green color components
  `b` - the array of blue color components
  `a` - the array of alpha value components
Throws:
  `IllegalArgumentException` - if `bits` is less than 1 or greater than 16
  `IllegalArgumentException` - if `size` is less than 1

### IndexColorModel

public IndexColorModel(int bits, int size, byte[] cmap, int start, boolean hasalpha)
Constructs an `IndexColorModel` from a single array of interleaved red, green, blue and optional alpha components. The array must have enough values in it to fill all of the needed component arrays of the specified size. The `ColorSpace` is the default sRGB space. The transparency value may be any of `Transparency.OPAQUE`, `Transparency.BITMASK`, or `Transparency.TRANSLUCENT` depending on the arguments, as specified in the class description above. The transfer type is the smallest of `DataBuffer.TYPE_BYTE` or `DataBuffer.TYPE_USHORT` that can hold a single pixel.

Parameters:
  `bits` - the number of bits each pixel occupies
  `size` - the size of the color component arrays
  `cmap` - the array of color components
  `start` - the starting offset of the first color component
  `hasalpha` - indicates whether alpha values are contained in the `cmap` array
Throws:
  `IllegalArgumentException` - if `bits` is less than 1 or greater than 16
  `IllegalArgumentException` - if `size` is less than 1

### IndexColorModel

public IndexColorModel(int bits, int size, byte[] cmap, int start, boolean hasalpha, int trans)
Constructs an `IndexColorModel` from a single array of interleaved red, green, blue and optional alpha components. The specified transparent index represents a pixel that is made entirely transparent regardless of any alpha value specified for it. The array must have enough values in it to fill all of the needed component arrays of the specified size. The `ColorSpace` is the default sRGB space. The transparency value may be any of `Transparency.OPAQUE`, `Transparency.BITMASK`, or `Transparency.TRANSLUCENT` depending on the arguments, as specified in the class description above. The transfer type is the smallest of `DataBuffer.TYPE_BYTE` or `DataBuffer.TYPE_USHORT` that can hold a single pixel.

Parameters:
  `bits` - the number of bits each pixel occupies
  `size` - the size of the color component arrays
  `cmap` - the array of color components
  `start` - the starting offset of the first color component
  `hasalpha` - indicates whether alpha values are contained in the `cmap` array
  `trans` - the index of the fully transparent pixel
Throws:
  `IllegalArgumentException` - if `bits` is less than 1 or greater than 16
  `IllegalArgumentException` - if `size` is less than 1

### IndexColorModel

public IndexColorModel(int bits, int size, int[] cmap, int start, boolean hasalpha, int trans, int transferType)
Constructs an `IndexColorModel` from an array of ints where each int is comprised of red, green, blue, and optional alpha components in the default RGB color model format. The specified transparent index represents a pixel that is made entirely transparent regardless of any alpha value specified for it. The array must have enough values in it to fill all of the needed component arrays of the specified size. The `ColorSpace` is the default sRGB space. The transparency value may be any of `Transparency.OPAQUE`, `Transparency.BITMASK`, or `Transparency.TRANSLUCENT` depending on the arguments, as specified in the class description above.

Parameters:
  `bits` - the number of bits each pixel occupies
  `size` - the size of the color component arrays
  `cmap` - the array of color components
  `start` - the starting offset of the first color component
  `hasalpha` - indicates whether alpha values are contained in the `cmap` array
  `trans` - the index of the fully transparent pixel
  `transferType` - the data type of the array used to represent pixel values. The data type must be either `DataBuffer.TYPE_BYTE` or `DataBuffer.TYPE_USHORT`.
Throws:
  `IllegalArgumentException` - if `bits` is less than 1 or greater than 16
  `IllegalArgumentException` - if `size` is less than 1
  `IllegalArgumentException` - if `transferType` is not one of `DataBuffer.TYPE_BYTE` or `DataBuffer.TYPE_USHORT`

### IndexColorModel

public IndexColorModel(int bits, int size, int[] cmap, int start, int transferType, BigInteger validBits)
Constructs an `IndexColorModel` from an `int` array where each `int` is comprised of red, green, blue, and alpha components in the default RGB color model format. The array must have enough values in it to fill all of the needed component arrays of the specified size. The `ColorSpace` is the default sRGB space. The transparency value may be any of `Transparency.OPAQUE`, `Transparency.BITMASK`, or `Transparency.TRANSLUCENT` depending on the arguments, as specified in the class description above. The transfer type must be one of `DataBuffer.TYPE_BYTE` `DataBuffer.TYPE_USHORT`. The `BigInteger` object specifies the valid/invalid pixels in the `cmap` array. A pixel is valid if the `BigInteger` value at that index is set, and is invalid if the `BigInteger` bit at that index is not set.

Parameters:
  `bits` - the number of bits each pixel occupies
  `size` - the size of the color component array
  `cmap` - the array of color components
  `start` - the starting offset of the first color component
  `transferType` - the specified data type
  `validBits` - a `BigInteger` object. If a bit is set in the BigInteger, the pixel at that index is valid. If a bit is not set, the pixel at that index is considered invalid. If null, all pixels are valid. Only bits from 0 to the map size are considered.
Throws:
  `IllegalArgumentException` - if `bits` is less than 1 or greater than 16
  `IllegalArgumentException` - if `size` is less than 1
  `IllegalArgumentException` - if `transferType` is not one of `DataBuffer.TYPE_BYTE` or `DataBuffer.TYPE_USHORT`
Since:
  1.3

## Method Details

### getTransparency

public int getTransparency()
Returns the transparency. Returns either OPAQUE, BITMASK, or TRANSLUCENT

Specified by:
  `getTransparency` in interface `Transparency`
Overrides:
  `getTransparency` in class `ColorModel`
Returns:
  the transparency of this `IndexColorModel`
See Also:
  - `Transparency.OPAQUE`
  - `Transparency.BITMASK`
  - `Transparency.TRANSLUCENT`

### getComponentSize

public int[] getComponentSize()
Returns an array of the number of bits for each color/alpha component. The array contains the color components in the order red, green, blue, followed by the alpha component, if present.

Overrides:
  `getComponentSize` in class `ColorModel`
Returns:
  an array containing the number of bits of each color and alpha component of this `IndexColorModel`

### getMapSize

public final int getMapSize()
Returns the size of the color/alpha component arrays in this `IndexColorModel`.

Returns:
  the size of the color and alpha component arrays.

### getTransparentPixel

public final int getTransparentPixel()
Returns the index of a transparent pixel in this `IndexColorModel` or -1 if there is no pixel with an alpha value of 0. If a transparent pixel was explicitly specified in one of the constructors by its index, then that index will be preferred, otherwise, the index of any pixel which happens to be fully transparent may be returned.

Returns:
  the index of a transparent pixel in this `IndexColorModel` object, or -1 if there is no such pixel

### getReds

public final void getReds(byte[] r)
Copies the array of red color components into the specified array. Only the initial entries of the array as specified by `getMapSize` are written.

Parameters:
  `r` - the specified array into which the elements of the array of red color components are copied

### getGreens

public final void getGreens(byte[] g)
Copies the array of green color components into the specified array. Only the initial entries of the array as specified by `getMapSize` are written.

Parameters:
  `g` - the specified array into which the elements of the array of green color components are copied

### getBlues

public final void getBlues(byte[] b)
Copies the array of blue color components into the specified array. Only the initial entries of the array as specified by `getMapSize` are written.

Parameters:
  `b` - the specified array into which the elements of the array of blue color components are copied

### getAlphas

public final void getAlphas(byte[] a)
Copies the array of alpha transparency components into the specified array. Only the initial entries of the array as specified by `getMapSize` are written.

Parameters:
  `a` - the specified array into which the elements of the array of alpha components are copied

### getRGBs

public final void getRGBs(int[] rgb)
Converts data for each index from the color and alpha component arrays to an int in the default RGB ColorModel format and copies the resulting 32-bit ARGB values into the specified array. Only the initial entries of the array as specified by `getMapSize` are written.

Parameters:
  `rgb` - the specified array into which the converted ARGB values from this array of color and alpha components are copied.

### getRed

public final int getRed(int pixel)
Returns the red color component for the specified pixel, scaled from 0 to 255 in the default RGB ColorSpace, sRGB. The pixel value is specified as an int. Only the lower n bits of the pixel value, as specified in the class description above, are used to calculate the returned value. The returned value is a non pre-multiplied value.

Specified by:
  `getRed` in class `ColorModel`
Parameters:
  `pixel` - the specified pixel
Returns:
  the value of the red color component for the specified pixel

### getGreen

public final int getGreen(int pixel)
Returns the green color component for the specified pixel, scaled from 0 to 255 in the default RGB ColorSpace, sRGB. The pixel value is specified as an int. Only the lower n bits of the pixel value, as specified in the class description above, are used to calculate the returned value. The returned value is a non pre-multiplied value.

Specified by:
  `getGreen` in class `ColorModel`
Parameters:
  `pixel` - the specified pixel
Returns:
  the value of the green color component for the specified pixel

### getBlue

public final int getBlue(int pixel)
Returns the blue color component for the specified pixel, scaled from 0 to 255 in the default RGB ColorSpace, sRGB. The pixel value is specified as an int. Only the lower n bits of the pixel value, as specified in the class description above, are used to calculate the returned value. The returned value is a non pre-multiplied value.

Specified by:
  `getBlue` in class `ColorModel`
Parameters:
  `pixel` - the specified pixel
Returns:
  the value of the blue color component for the specified pixel

### getAlpha

public final int getAlpha(int pixel)
Returns the alpha component for the specified pixel, scaled from 0 to 255. The pixel value is specified as an int. Only the lower n bits of the pixel value, as specified in the class description above, are used to calculate the returned value.

Specified by:
  `getAlpha` in class `ColorModel`
Parameters:
  `pixel` - the specified pixel
Returns:
  the value of the alpha component for the specified pixel

### getRGB

public final int getRGB(int pixel)
Returns the color/alpha components of the pixel in the default RGB color model format. The pixel value is specified as an int. Only the lower n bits of the pixel value, as specified in the class description above, are used to calculate the returned value. The returned value is in a non pre-multiplied format.

Overrides:
  `getRGB` in class `ColorModel`
Parameters:
  `pixel` - the specified pixel
Returns:
  the color and alpha components of the specified pixel
See Also:
  - `ColorModel.getRGBdefault()`

### getDataElements

public Object getDataElements(int rgb, Object pixel)
Returns a data element array representation of a pixel in this ColorModel, given an integer pixel representation in the default RGB color model. This array can then be passed to the `setDataElements` method of a `WritableRaster` object. If the pixel variable is `null`, a new array is allocated. If `pixel` is not `null`, it must be a primitive array of type `transferType`; otherwise, a `ClassCastException` is thrown. An `ArrayIndexOutOfBoundsException` is thrown if `pixel` is not large enough to hold a pixel value for this `ColorModel`. The pixel array is returned.

Since `IndexColorModel` can be subclassed, subclasses inherit the implementation of this method and if they don't override it then they throw an exception if they use an unsupported `transferType`.

Overrides:
  `getDataElements` in class `ColorModel`
Parameters:
  `rgb` - the integer pixel representation in the default RGB color model
  `pixel` - the specified pixel
Returns:
  an array representation of the specified pixel in this `IndexColorModel`.
Throws:
  `ClassCastException` - if `pixel` is not a primitive array of type `transferType`
  `ArrayIndexOutOfBoundsException` - if `pixel` is not large enough to hold a pixel value for this `ColorModel`
  `UnsupportedOperationException` - if `transferType` is invalid
See Also:
  - `WritableRaster.setDataElements(int, int, Object)`
  - `SampleModel.setDataElements(int, int, Object, DataBuffer)`

### getComponents

public int[] getComponents(int pixel, int[] components, int offset)
Returns an array of unnormalized color/alpha components for a specified pixel in this `ColorModel`. The pixel value is specified as an int. If the `components` array is `null`, a new array is allocated that contains `offset + getNumComponents()` elements. The `components` array is returned, with the alpha component included only if `hasAlpha` returns true. Color/alpha components are stored in the `components` array starting at `offset` even if the array is allocated by this method. An `ArrayIndexOutOfBoundsException` is thrown if the `components` array is not `null` and is not large enough to hold all the color and alpha components starting at `offset`.

Overrides:
  `getComponents` in class `ColorModel`
Parameters:
  `pixel` - the specified pixel
  `components` - the array to receive the color and alpha components of the specified pixel
  `offset` - the offset into the `components` array at which to start storing the color and alpha components
Returns:
  an array containing the color and alpha components of the specified pixel starting at the specified offset.
See Also:
  - `ColorModel.hasAlpha()`
  - `ColorModel.getNumComponents()`

### getComponents

public int[] getComponents(Object pixel, int[] components, int offset)
Returns an array of unnormalized color/alpha components for a specified pixel in this `ColorModel`. The pixel value is specified by an array of data elements of type `transferType` passed in as an object reference. If `pixel` is not a primitive array of type `transferType`, a `ClassCastException` is thrown. An `ArrayIndexOutOfBoundsException` is thrown if `pixel` is not large enough to hold a pixel value for this `ColorModel`. If the `components` array is `null`, a new array is allocated that contains `offset + getNumComponents()` elements. The `components` array is returned, with the alpha component included only if `hasAlpha` returns true. Color/alpha components are stored in the `components` array starting at `offset` even if the array is allocated by this method. An `ArrayIndexOutOfBoundsException` is also thrown if the `components` array is not `null` and is not large enough to hold all the color and alpha components starting at `offset`.

Since `IndexColorModel` can be subclassed, subclasses inherit the implementation of this method and if they don't override it then they throw an exception if they use an unsupported `transferType`.

Overrides:
  `getComponents` in class `ColorModel`
Parameters:
  `pixel` - the specified pixel
  `components` - an array that receives the color and alpha components of the specified pixel
  `offset` - the index into the `components` array at which to begin storing the color and alpha components of the specified pixel
Returns:
  an array containing the color and alpha components of the specified pixel starting at the specified offset.
Throws:
  `ArrayIndexOutOfBoundsException` - if `pixel` is not large enough to hold a pixel value for this `ColorModel` or if the `components` array is not `null` and is not large enough to hold all the color and alpha components starting at `offset`
  `ClassCastException` - if `pixel` is not a primitive array of type `transferType`
  `UnsupportedOperationException` - if `transferType` is not one of the supported transfer types
See Also:
  - `ColorModel.hasAlpha()`
  - `ColorModel.getNumComponents()`

### getDataElement

public int getDataElement(int[] components, int offset)
Returns a pixel value represented as an int in this `ColorModel` given an array of unnormalized color/alpha components. An `ArrayIndexOutOfBoundsException` is thrown if the `components` array is not large enough to hold all of the color and alpha components starting at `offset`. Since `ColorModel` can be subclassed, subclasses inherit the implementation of this method and if they don't override it then they throw an exception if they use an unsupported transferType.

Overrides:
  `getDataElement` in class `ColorModel`
Parameters:
  `components` - an array of unnormalized color and alpha components
  `offset` - the index into `components` at which to begin retrieving the color and alpha components
Returns:
  an `int` pixel value in this `ColorModel` corresponding to the specified components.
Throws:
  `ArrayIndexOutOfBoundsException` - if the `components` array is not large enough to hold all of the color and alpha components starting at `offset`
  `UnsupportedOperationException` - if `transferType` is invalid

### getDataElements

public Object getDataElements(int[] components, int offset, Object pixel)
Returns a data element array representation of a pixel in this `ColorModel` given an array of unnormalized color/alpha components. This array can then be passed to the `setDataElements` method of a `WritableRaster` object. An `ArrayIndexOutOfBoundsException` is thrown if the `components` array is not large enough to hold all of the color and alpha components starting at `offset`. If the pixel variable is `null`, a new array is allocated. If `pixel` is not `null`, it must be a primitive array of type `transferType`; otherwise, a `ClassCastException` is thrown. An `ArrayIndexOutOfBoundsException` is thrown if pixel is not large enough to hold a pixel value for this `ColorModel`.

Since `IndexColorModel` can be subclassed, subclasses inherit the implementation of this method and if they don't override it then they throw an exception if they use an unsupported `transferType`

Overrides:
  `getDataElements` in class `ColorModel`
Parameters:
  `components` - an array of unnormalized color and alpha components
  `offset` - the index into `components` at which to begin retrieving color and alpha components
  `pixel` - the `Object` representing an array of color and alpha components
Returns:
  an `Object` representing an array of color and alpha components.
Throws:
  `ClassCastException` - if `pixel` is not a primitive array of type `transferType`
  `ArrayIndexOutOfBoundsException` - if `pixel` is not large enough to hold a pixel value for this `ColorModel` or the `components` array is not large enough to hold all of the color and alpha components starting at `offset`
  `UnsupportedOperationException` - if `transferType` is not one of the supported transfer types
See Also:
  - `WritableRaster.setDataElements(int, int, Object)`
  - `SampleModel.setDataElements(int, int, Object, DataBuffer)`

### createCompatibleWritableRaster

public WritableRaster createCompatibleWritableRaster(int w, int h)
Creates a `WritableRaster` with the specified width and height that has a data layout (`SampleModel`) compatible with this `ColorModel`. This method only works for color models with 16 or fewer bits per pixel.

Since `IndexColorModel` can be subclassed, any subclass that supports greater than 16 bits per pixel must override this method.

Overrides:
  `createCompatibleWritableRaster` in class `ColorModel`
Parameters:
  `w` - the width to apply to the new `WritableRaster`
  `h` - the height to apply to the new `WritableRaster`
Returns:
  a `WritableRaster` object with the specified width and height.
Throws:
  `UnsupportedOperationException` - if the number of bits in a pixel is greater than 16
See Also:
  - `WritableRaster`
  - `SampleModel`

### isCompatibleRaster

public boolean isCompatibleRaster(Raster raster)
Returns `true` if `raster` is compatible with this `ColorModel` or `false` if it is not compatible with this `ColorModel`.

Overrides:
  `isCompatibleRaster` in class `ColorModel`
Parameters:
  `raster` - the `Raster` object to test for compatibility
Returns:
  `true` if `raster` is compatible with this `ColorModel`; `false` otherwise.

### createCompatibleSampleModel

public SampleModel createCompatibleSampleModel(int w, int h)
Creates a `SampleModel` with the specified width and height that has a data layout compatible with this `ColorModel`.

Overrides:
  `createCompatibleSampleModel` in class `ColorModel`
Parameters:
  `w` - the width to apply to the new `SampleModel`
  `h` - the height to apply to the new `SampleModel`
Returns:
  a `SampleModel` object with the specified width and height.
Throws:
  `IllegalArgumentException` - if `w` or `h` is not greater than 0
See Also:
  - `SampleModel`

### isCompatibleSampleModel

public boolean isCompatibleSampleModel(SampleModel sm)
Checks if the specified `SampleModel` is compatible with this `ColorModel`. If `sm` is `null`, this method returns `false`.

Overrides:
  `isCompatibleSampleModel` in class `ColorModel`
Parameters:
  `sm` - the specified `SampleModel`, or `null`
Returns:
  `true` if the specified `SampleModel` is compatible with this `ColorModel`; `false` otherwise.
See Also:
  - `SampleModel`

### convertToIntDiscrete

public BufferedImage convertToIntDiscrete(Raster raster, boolean forceARGB)
Returns a new `BufferedImage` of TYPE_INT_ARGB or TYPE_INT_RGB that has a `Raster` with pixel data computed by expanding the indices in the source `Raster` using the color/alpha component arrays of this `ColorModel`. Only the lower n bits of each index value in the source `Raster`, as specified in the class description above, are used to compute the color/alpha values in the returned image. If `forceARGB` is `true`, a TYPE_INT_ARGB image is returned regardless of whether or not this `ColorModel` has an alpha component array or a transparent pixel.

Parameters:
  `raster` - the specified `Raster`
  `forceARGB` - if `true`, the returned `BufferedImage` is TYPE_INT_ARGB; otherwise it is TYPE_INT_RGB
Returns:
  a `BufferedImage` created with the specified `Raster`
Throws:
  `IllegalArgumentException` - if the raster argument is not compatible with this IndexColorModel

### isValid

public boolean isValid(int pixel)
Returns whether or not the pixel is valid.

Parameters:
  `pixel` - the specified pixel value
Returns:
  `true` if `pixel` is valid; `false` otherwise.
Since:
  1.3

### isValid

public boolean isValid()
Returns whether or not all of the pixels are valid.

Returns:
  `true` if all pixels are valid; `false` otherwise.
Since:
  1.3

### getValidPixels

public BigInteger getValidPixels()
Returns a `BigInteger` that indicates the valid/invalid pixels in the colormap. A bit is valid if the `BigInteger` value at that index is set, and is invalid if the `BigInteger` value at that index is not set. The only valid ranges to query in the `BigInteger` are between 0 and the map size.

Returns:
  a `BigInteger` indicating the valid/invalid pixels.
Since:
  1.3

### toString

public String toString()
Returns the `String` representation of the contents of this `ColorModel` object.

Overrides:
  `toString` in class `ColorModel`
Returns:
  a `String` representing the contents of this `ColorModel` object.

### equals

public boolean equals(Object obj)
Tests if the specified `Object` is an instance of `IndexColorModel` and if it equals this `IndexColorModel`

Overrides:
  `equals` in class `ColorModel`
Parameters:
  `obj` - the `Object` to test for equality
Returns:
  `true` if the specified `Object` equals this `IndexColorModel`; `false` otherwise.
See Also:
  - `Object.hashCode()`
  - `HashMap`

### hashCode

public int hashCode()
Returns the hash code for IndexColorModel.

Overrides:
  `hashCode` in class `ColorModel`
Returns:
  a hash code for IndexColorModel
See Also:
  - `Object.equals(java.lang.Object)`
  - `System.identityHashCode(Object)`