java.awt.image
Class ComponentColorModel

java.lang.Object   
  java.awt.image.ColorModel   
      java.awt.image.ComponentColorModel

All Implemented Interfaces:

Transparency

public class ComponentColorModel
extends ColorModel   

A ColorModel class that works with pixel values that represent color and alpha information as separate samples and that store each sample in a separate data element. This class can be used with an arbitrary ColorSpace. The number of color samples in the pixel values must be same as the number of color components in the ColorSpace. There may be a single alpha sample.

For those methods that use a primitive array pixel representation of type transferType, the array length is the same as the number of color and alpha samples. Color samples are stored first in the array followed by the alpha sample, if present. The order of the color samples is specified by the ColorSpace. Typically, this order reflects the name of the color space type. For example, for TYPE_RGB, index 0 corresponds to red, index 1 to green, and index 2 to blue.

The translation from pixel sample values to color/alpha components for display or processing purposes is based on a one-to-one correspondence of samples to components. Depending on the transfer type used to create an instance of ComponentColorModel, the pixel sample values represented by that instance may be signed or unsigned and may be of integral type or float or double (see below for details). The translation from sample values to normalized color/alpha components must follow certain rules. For float and double samples, the translation is an identity, i.e. normalized component values are equal to the corresponding sample values. For integral samples, the translation should be only a simple scale and offset, where the scale and offset constants may be different for each component. The result of applying the scale and offset constants is a set of color/alpha component values, which are guaranteed to fall within a certain range. Typically, the range for a color component will be the range defined by the getMinValue and getMaxValue methods of the ColorSpace class. The range for an alpha component should be 0.0 to 1.0.

Instances of ComponentColorModel created with transfer types DataBuffer.TYPE_BYTE, DataBuffer.TYPE_USHORT, and DataBuffer.TYPE_INT have pixel sample values which are treated as unsigned integral values. The number of bits in a color or alpha sample of a pixel value might not be the same as the number of bits for the corresponding color or alpha sample passed to the ComponentColorModel(ColorSpace, int[], boolean, boolean, int, int) constructor. In that case, this class assumes that the least significant n bits of a sample value hold the component value, where n is the number of significant bits for the component passed to the constructor. It also assumes that any higher-order bits in a sample value are zero. Thus, sample values range from 0 to 2ⁿ - 1. This class maps these sample values to normalized color component values such that 0 maps to the value obtained from the ColorSpace's getMinValue method for each component and 2ⁿ - 1 maps to the value obtained from getMaxValue. To create a ComponentColorModel with a different color sample mapping requires subclassing this class and overriding the getNormalizedComponents(Object, float[], int) method. The mapping for an alpha sample always maps 0 to 0.0 and 2ⁿ - 1 to 1.0.

For instances with unsigned sample values, the unnormalized color/alpha component representation is only supported if two conditions hold. First, sample value value 0 must map to normalized component value 0.0 and sample value 2ⁿ - 1 to 1.0. Second the min/max range of all color components of the ColorSpace must be 0.0 to 1.0. In this case, the component representation is the n least significant bits of the corresponding sample. Thus each component is an unsigned integral value between 0 and 2ⁿ - 1, where n is the number of significant bits for a particular component. If these conditions are not met, any method taking an unnormalized component argument will throw an IllegalArgumentException.

Instances of ComponentColorModel created with transfer types DataBuffer.TYPE_SHORT, DataBuffer.TYPE_FLOAT, and DataBuffer.TYPE_DOUBLE have pixel sample values which are treated as signed short, float, or double values. Such instances do not support the unnormalized color/alpha component representation, so any methods taking such a representation as an argument will throw an IllegalArgumentException when called on one of these instances. The normalized component values of instances of this class have a range which depends on the transfer type as follows: for float samples, the full range of the float data type; for double samples, the full range of the float data type (resulting from casting double to float); for short samples, from approximately -maxVal to +maxVal, where maxVal is the per component maximum value for the ColorSpace (-32767 maps to -maxVal, 0 maps to 0.0, and 32767 maps to +maxVal). A subclass may override the scaling for short sample values to normalized component values by overriding the getNormalizedComponents(Object, float[], int) method. For float and double samples, the normalized component values are taken to be equal to the corresponding sample values, and subclasses should not attempt to add any non-identity scaling for these transfer types.

Instances of ComponentColorModel created with transfer types DataBuffer.TYPE_SHORT, DataBuffer.TYPE_FLOAT, and DataBuffer.TYPE_DOUBLE use all the bits of all sample values. Thus all color/alpha components have 16 bits when using DataBuffer.TYPE_SHORT, 32 bits when using DataBuffer.TYPE_FLOAT, and 64 bits when using DataBuffer.TYPE_DOUBLE. When the ComponentColorModel(ColorSpace, int[], boolean, boolean, int, int) form of constructor is used with one of these transfer types, the bits array argument is ignored.

It is possible to have color/alpha sample values which cannot be reasonably interpreted as component values for rendering. This can happen when ComponentColorModel is subclassed to override the mapping of unsigned sample values to normalized color component values or when signed sample values outside a certain range are used. (As an example, specifying an alpha component as a signed short value outside the range 0 to 32767, normalized range 0.0 to 1.0, can lead to unexpected results.) It is the responsibility of applications to appropriately scale pixel data before rendering such that color components fall within the normalized range of the ColorSpace (obtained using the getMinValue and getMaxValue methods of the ColorSpace class) and the alpha component is between 0.0 and 1.0. If color or alpha component values fall outside these ranges, rendering results are indeterminate.

Methods that use a single int pixel representation throw an IllegalArgumentException, unless the number of components for the ComponentColorModel is one and the component value is unsigned -- in other words, a single color component using a transfer type of DataBuffer.TYPE_BYTE, DataBuffer.TYPE_USHORT, or DataBuffer.TYPE_INT and no alpha.

A ComponentColorModel can be used in conjunction with a ComponentSampleModel, a BandedSampleModel, or a PixelInterleavedSampleModel to construct a BufferedImage.

See Also:

ColorModel , ColorSpace , ComponentSampleModel , BandedSampleModel , PixelInterleavedSampleModel , BufferedImage

Field Summary

Fields inherited from class java.awt.image.ColorModel

pixel_bits, transferType

Fields inherited from interface java.awt.Transparency

BITMASK , OPAQUE , TRANSLUCENT

Constructor Summary

ComponentColorModel (ColorSpace colorSpace, boolean hasAlpha, boolean isAlphaPremultiplied, int transparency, int transferType)
Constructs a ComponentColorModel from the specified parameters.

ComponentColorModel (ColorSpace colorSpace, int[] bits, boolean hasAlpha, boolean isAlphaPremultiplied, int transparency, int transferType)
Constructs a ComponentColorModel from the specified parameters.

Method Summary

ColorModel	coerceData (WritableRaster raster, boolean isAlphaPremultiplied) Forces the raster data to match the state specified in the isAlphaPremultiplied variable, assuming the data is currently correctly described by 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) Compares this color model with another for equality.
int	getAlpha (int pixel) Returns the alpha component for the specified pixel, scaled from 0 to 255.
int	getAlpha (Object inData) Returns the alpha component for the specified pixel, scaled from 0 to 255.
WritableRaster	getAlphaRaster (WritableRaster raster) Returns a Raster representing the alpha channel of an image, extracted from the input Raster.
int	getBlue (int pixel) Returns the blue color component for the specified pixel, scaled from 0 to 255 in the default RGB ColorSpace, sRGB.
int	getBlue (Object inData) Returns the blue color component for the specified pixel, scaled from 0 to 255 in the default RGB ColorSpace, sRGB.
int[]	getComponents (int pixel, int[] components, int offset) Returns an array of unnormalized color/alpha components given a pixel in this ColorModel.
int[]	getComponents (Object pixel, int[] components, int offset) Returns an array of unnormalized color/alpha components given a pixel in this ColorModel.
int	getDataElement (float[] normComponents, int normOffset) Returns a pixel value represented as an int in this ColorModel, given an array of normalized color/alpha components.
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 (float[] normComponents, int normOffset, Object obj) Returns a data element array representation of a pixel in this ColorModel, given an array of normalized color/alpha components.
Object	getDataElements (int[] components, int offset, Object obj) 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.
int	getGreen (int pixel) Returns the green color component for the specified pixel, scaled from 0 to 255 in the default RGB ColorSpace, sRGB.
int	getGreen (Object inData) Returns the green color component for the specified pixel, scaled from 0 to 255 in the default RGB ColorSpace, sRGB.
float[]	getNormalizedComponents (int[] components, int offset, float[] normComponents, int normOffset) Returns an array of all of the color/alpha components in normalized form, given an unnormalized component array.
float[]	getNormalizedComponents (Object pixel, float[] normComponents, int normOffset) Returns an array of all of the color/alpha components in normalized form, given a pixel in this ColorModel.
int	getRed (int pixel) Returns the red color component for the specified pixel, scaled from 0 to 255 in the default RGB ColorSpace, sRGB.
int	getRed (Object inData) Returns the red color component for the specified pixel, scaled from 0 to 255 in the default RGB ColorSpace, sRGB.
int	getRGB (int pixel) Returns the color/alpha components of the pixel in the default RGB color model format.
int	getRGB (Object inData) Returns the color/alpha components for the specified pixel in the default RGB color model format.
int[]	getUnnormalizedComponents (float[] normComponents, int normOffset, int[] components, int offset) Returns an array of all of the color/alpha components in unnormalized form, given a normalized component array.
boolean	isCompatibleRaster (Raster raster) Returns true if raster is compatible with this ColorModel; false if it is not.
boolean	isCompatibleSampleModel (SampleModel sm) Checks whether or not the specified SampleModel is compatible with this ColorModel.

Methods inherited from class java.awt.image.ColorModel

finalize , getColorSpace , getComponentSize , getComponentSize , getNumColorComponents , getNumComponents , getPixelSize , getRGBdefault , getTransferType , getTransparency , hasAlpha , hashCode , isAlphaPremultiplied , toString

Methods inherited from class java.lang.Object

clone , getClass , notify , notifyAll , wait , wait , wait

Constructor Detail

ComponentColorModel

public ComponentColorModel(ColorSpace    colorSpace,
                           int[] bits,
                           boolean hasAlpha,
                           boolean isAlphaPremultiplied,
                           int transparency,
                           int transferType)

Constructs a ComponentColorModel from the specified parameters. Color components will be in the specified ColorSpace. The supported transfer types are DataBuffer.TYPE_BYTE, DataBuffer.TYPE_USHORT, DataBuffer.TYPE_INT, DataBuffer.TYPE_SHORT, DataBuffer.TYPE_FLOAT, and DataBuffer.TYPE_DOUBLE. If not null, the bits array specifies the number of significant bits per color and alpha component and its length should be at least the number of components in the ColorSpace if there is no alpha information in the pixel values, or one more than this number if there is alpha information. When the transferType is DataBuffer.TYPE_SHORT, DataBuffer.TYPE_FLOAT, or DataBuffer.TYPE_DOUBLE the bits array argument is ignored. hasAlpha indicates whether alpha information is present. If hasAlpha is true, then the boolean isAlphaPremultiplied specifies how to interpret color and alpha samples in pixel values. If the boolean is true, color samples are assumed to have been multiplied by the alpha sample. The transparency specifies what alpha values can be represented by this color model. The acceptable transparency values are OPAQUE, BITMASK or TRANSLUCENT. The transferType is the type of primitive array used to represent pixel values.

Parameters:

colorSpace - The ColorSpace associated with this color model.

bits - The number of significant bits per component. May be null, in which case all bits of all component samples will be significant. Ignored if transferType is one of DataBuffer.TYPE_SHORT, DataBuffer.TYPE_FLOAT, or DataBuffer.TYPE_DOUBLE, in which case all bits of all component samples will be significant.

hasAlpha - If true, this color model supports alpha.

isAlphaPremultiplied - If true, alpha is premultiplied.

transparency - Specifies what alpha values can be represented by this color model.

transferType - Specifies the type of primitive array used to represent pixel values.

Throws:

IllegalArgumentException - If the bits array argument is not null, its length is less than the number of color and alpha components, and transferType is one of DataBuffer.TYPE_BYTE, DataBuffer.TYPE_USHORT, or DataBuffer.TYPE_INT.

IllegalArgumentException - If transferType is not one of DataBuffer.TYPE_BYTE, DataBuffer.TYPE_USHORT, DataBuffer.TYPE_INT, DataBuffer.TYPE_SHORT, DataBuffer.TYPE_FLOAT, or DataBuffer.TYPE_DOUBLE.

See Also:

ColorSpace , Transparency

ComponentColorModel

public ComponentColorModel(ColorSpace    colorSpace,
                           boolean hasAlpha,
                           boolean isAlphaPremultiplied,
                           int transparency,
                           int transferType)

Constructs a ComponentColorModel from the specified parameters. Color components will be in the specified ColorSpace. The supported transfer types are DataBuffer.TYPE_BYTE, DataBuffer.TYPE_USHORT, DataBuffer.TYPE_INT, DataBuffer.TYPE_SHORT, DataBuffer.TYPE_FLOAT, and DataBuffer.TYPE_DOUBLE. The number of significant bits per color and alpha component will be 8, 16, 32, 16, 32, or 64, respectively. The number of color components will be the number of components in the ColorSpace. There will be an alpha component if hasAlpha is true. If hasAlpha is true, then the boolean isAlphaPremultiplied specifies how to interpret color and alpha samples in pixel values. If the boolean is true, color samples are assumed to have been multiplied by the alpha sample. The transparency specifies what alpha values can be represented by this color model. The acceptable transparency values are OPAQUE, BITMASK or TRANSLUCENT. The transferType is the type of primitive array used to represent pixel values.

Parameters:

colorSpace - The ColorSpace associated with this color model.

hasAlpha - If true, this color model supports alpha.

isAlphaPremultiplied - If true, alpha is premultiplied.

transparency - Specifies what alpha values can be represented by this color model.

transferType - Specifies the type of primitive array used to represent pixel values.

Throws:

IllegalArgumentException - If transferType is not one of DataBuffer.TYPE_BYTE, DataBuffer.TYPE_USHORT, DataBuffer.TYPE_INT, DataBuffer.TYPE_SHORT, DataBuffer.TYPE_FLOAT, or DataBuffer.TYPE_DOUBLE.

Since:

1.4

See Also:

ColorSpace , Transparency

Method Detail

getRed

public int getRed(int pixel)

Returns the red color component for the specified pixel, scaled from 0 to 255 in the default RGB ColorSpace, sRGB. A color conversion is done if necessary. The pixel value is specified as an int. The returned value will be a non pre-multiplied value. If the alpha is premultiplied, this method divides it out before returning the value (if the alpha value is 0, the red value will be 0).

Specified by:

getRed in class ColorModel

Parameters:

pixel - The pixel from which you want to get the red color component.

Returns:

The red color component for the specified pixel, as an int.

Throws:

IllegalArgumentException - If there is more than one component in this ColorModel.

IllegalArgumentException - If the component value for this ColorModel is signed

getGreen

public int getGreen(int pixel)

Returns the green color component for the specified pixel, scaled from 0 to 255 in the default RGB ColorSpace, sRGB. A color conversion is done if necessary. The pixel value is specified as an int. The returned value will be a non pre-multiplied value. If the alpha is premultiplied, this method divides it out before returning the value (if the alpha value is 0, the green value will be 0).

Specified by:

getGreen in class ColorModel

Parameters:

pixel - The pixel from which you want to get the green color component.

Returns:

The green color component for the specified pixel, as an int.

Throws:

IllegalArgumentException - If there is more than one component in this ColorModel.

IllegalArgumentException - If the component value for this ColorModel is signed

getBlue

public int getBlue(int pixel)

Returns the blue color component for the specified pixel, scaled from 0 to 255 in the default RGB ColorSpace, sRGB. A color conversion is done if necessary. The pixel value is specified as an int. The returned value will be a non pre-multiplied value. If the alpha is premultiplied, this method divides it out before returning the value (if the alpha value is 0, the blue value will be 0).

Specified by:

getBlue in class ColorModel

Parameters:

pixel - The pixel from which you want to get the blue color component.

Returns:

The blue color component for the specified pixel, as an int.

Throws:

IllegalArgumentException - If there is more than one component in this ColorModel.

IllegalArgumentException - If the component value for this ColorModel is signed

getAlpha

public 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.

Specified by:

getAlpha in class ColorModel

Parameters:

pixel - The pixel from which you want to get the alpha component.

Returns:

The alpha component for the specified pixel, as an int.

Throws:

IllegalArgumentException - If there is more than one component in this ColorModel.

IllegalArgumentException - If the component value for this ColorModel is signed

getRGB

public int getRGB(int pixel)

Returns the color/alpha components of the pixel in the default RGB color model format. A color conversion is done if necessary. The returned value will be in a non pre-multiplied format. If the alpha is premultiplied, this method divides it out of the color components (if the alpha value is 0, the color values will be 0).

Overrides:

getRGB in class ColorModel

Parameters:

pixel - The pixel from which you want to get the color/alpha components.

Returns:

The color/alpha components for the specified pixel, as an int.

Throws:

IllegalArgumentException - If there is more than one component in this ColorModel.

IllegalArgumentException - If the component value for this ColorModel is signed

See Also:

ColorModel.getRGBdefault()

getRed

public int getRed(Object    inData)

Returns the red color component for the specified pixel, scaled from 0 to 255 in the default RGB ColorSpace, sRGB. A color conversion is done if necessary. The pixel value is specified by an array of data elements of type transferType passed in as an object reference. The returned value will be a non pre-multiplied value. If the alpha is premultiplied, this method divides it out before returning the value (if the alpha value is 0, the red value will be 0). Since ComponentColorModel 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:

getRed in class ColorModel