Java(TM) 2 Platform, Standard Edition, v1.2.2 API Specification: Class ColorModel - JDK 5 Documentation v1.2.2, Java 2 SDK 英文文档

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java.awt.image
Class ColorModel

java.lang.Object
  |
  +--java.awt.image.ColorModel

Direct Known Subclasses:: ComponentColorModel, IndexColorModel, PackedColorModel

public abstract class ColorModel
extends Object
implements Transparency

The ColorModel abstract class encapsulates the methods for translating a pixel value to color components (for example, red, green, and blue) and an alpha component. In order to render an image to the screen, a printer, or another image, pixel values must be converted to color and alpha components. As arguments to or return values from methods of this class, pixels are represented as 32-bit ints or as arrays of primitive types. The number, order, and interpretation of color components for a ColorModel is specified by its ColorSpace. A ColorModel used with pixel data that does not include alpha information treats all pixels as opaque, which is an alpha value of 1.0.

This ColorModel class supports two representations of pixel values. A pixel value can be a single 32-bit int or an array of primitive types. The Java(tm) Platform 1.0 and 1.1 APIs represented pixels as single byte or single int values. For purposes of the ColorModel class, pixel value arguments were passed as ints. The Java(tm) Platform 1.2 API introduced additional classes for representing images. With BufferedImage or RenderedImage objects, based on Raster and SampleModel classes, pixel values might not be conveniently representable as a single int. Consequently, ColorModel now has methods that accept pixel values represented as arrays of primitive types. The primitive type used by a particular ColorModel object is called its transfer type.

ColorModel objects used with images for which pixel values are not conveniently representable as a single int throw an IllegalArgumentException when methods taking a single int pixel argument are called. Subclasses of ColorModel must specify the conditions under which this occurs. This does not occur with DirectColorModel or IndexColorModel objects.

Currently, the transfer types supported by the Java(tm) 2D API are DataBuffer.TYPE_BYTE, DataBuffer.TYPE_USHORT, and DataBuffer.TYPE_INT. The transfer type for a particular ColorModel object is specified when the object is created, either explicitly or by default. All subclasses of ColorModel must specify what the possible transfer types are and how the number of elements in the primitive arrays representing pixels is determined.

For BufferedImages, the transfer type of its Raster and of the Raster object's SampleModel (available from the getTransferType methods of these classes) must match that of the ColorModel. The number of elements in an array representing a pixel for the Raster and SampleModel (available from the getNumDataElements methods of these classes) must match that of the ColorModel.

The algorithm used to convert from pixel values to color and alpha components varies by subclass. For example, there is not necessarily a one-to-one correspondence between samples obtained from the SampleModel of a BufferedImage object's Raster and color/alpha components. Even when there is such a correspondence, the number of bits in a sample is not necessarily the same as the number of bits in the corresponding color/alpha component. Each subclass must specify how the translation from pixel values to color/alpha components is done.

Methods in the ColorModel class use two different representations of color and alpha components. In the unnormalized form, 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 pixel values for a particular ColorModel represent color samples premultiplied by the alpha sample, unnormalized color component values are also premultiplied. In the normalized form, each component is a float value between 0.0 and 1.0. Normalized color component values are not premultiplied.

See Also:: IndexColorModel, ComponentColorModel, PackedColorModel, DirectColorModel, Image, BufferedImage, RenderedImage, ColorSpace, SampleModel, Raster, DataBuffer

Field Summary

protected int pixel_bits
          The total number of bits in the pixel.

protected int transferType
          Data type of the array used to represent pixel values.

Fields inherited from interface java.awt.Transparency

BITMASK, OPAQUE, TRANSLUCENT

Constructor Summary

ColorModel(int bits)
          Constructs a ColorModel that translates pixels of the specified number of bits to color/alpha components.

protected ColorModel(int pixel_bits, int[] bits, ColorSpace cspace, boolean hasAlpha, boolean isAlphaPremultiplied, int transparency, int transferType)
          Constructs a ColorModel that translates pixel values to color/alpha components.

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)
          Tests if the specified Object is an instance of ColorModel and if it equals this ColorModel.

void finalize()
          Disposes of system resources associated with this ColorModel once this ColorModel is no longer referenced.

abstract 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, provided that pixel values of this ColorModel represent color and alpha information as separate spatial bands (e.g.

abstract 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.

ColorSpace getColorSpace()
          Returns the ColorSpace associated with this ColorModel.

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[] getComponentSize()
          Returns an array of the number of bits per color/alpha component.

int getComponentSize(int componentIdx)
          Returns the number of bits for the specified 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 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.

abstract 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.

int getNumColorComponents()
          Returns the number of color components in this ColorModel.

int getNumComponents()
          Returns the number of components, including alpha, in this ColorModel.

int getPixelSize()
          Returns the number of bits per pixel described by this ColorModel.

abstract 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.

static ColorModel getRGBdefault()
          Returns a DirectColorModel that describes the default format for integer RGB values used in many of the methods in the AWT image interfaces for the convenience of the programmer.

int getTransparency()
          Returns the transparency.

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 hasAlpha()
          Returns whether or not alpha is supported in this ColorModel.

boolean isAlphaPremultiplied()
          Returns whether or not the alpha has been premultiplied in the pixel values to be translated by this ColorModel.

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

boolean isCompatibleSampleModel(SampleModel sm)
          Checks if the SampleModel is compatible with this ColorModel.

String toString()
          Returns the String representation of the contents of this ColorModelobject.

Methods inherited from class java.lang.Object

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

Field Detail

pixel_bits

protected int pixel_bits

The total number of bits in the pixel.

transferType

protected int transferType

Data type of the array used to represent pixel values.

Constructor Detail

ColorModel

public ColorModel(int bits)

Constructs a ColorModel that translates pixels of the specified number of bits to color/alpha components. The color space is the default RGB ColorSpace, which is sRGB. Pixel values are assumed to include alpha information. If color and alpha information are represented in the pixel value as separate spatial bands, the color bands are assumed not to be premultiplied with the alpha value. The transparency type is java.awt.Transparency.TRANSLUCENT. The transfer type will be the smallest of DataBuffer.TYPE_BYTE, DataBuffer.TYPE_USHORT, or DataBuffer.TYPE_INT that can hold a single pixel (or DataBuffer.TYPE_UNDEFINED if bits is greater than 32). Since this constructor has no information about the number of bits per color and alpha component, any subclass calling this constructor should override any method that requires this information.

Parameters:: bits - the number of bits of a pixel
Throws:: IllegalArgumentException - if the number of bits in bits is less than 1

ColorModel

protected ColorModel(int pixel_bits,
                     int[] bits,
                     ColorSpace cspace,
                     boolean hasAlpha,
                     boolean isAlphaPremultiplied,
                     int transparency,
                     int transferType)

Constructs a ColorModel that translates pixel values to color/alpha components. Color components will be in the specified ColorSpace. pixel_bits is the number of bits in the pixel values. The bits array specifies the number of significant bits per color and alpha component. Its length should be 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. hasAlpha indicates whether or not alpha information is present. The boolean isAlphaPremultiplied specifies how to interpret pixel values in which color and alpha information are represented as separate spatial bands. 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 transfer type is the type of primitive array used to represent pixel values. Note that the bits array contains the number of significant bits per color/alpha component after the translation from pixel values. For example, for an IndexColorModel with pixel_bits equal to 16, the bits array might have four elements with each element set to 8.

Parameters:: pixel_bits - the number of bits in the pixel values; bits - array that specifies the number of significant bits per color and alpha component; cspace - the specified ColorSpace; hasAlpha - true if alpha information is present; false otherwise; isAlphaPremultiplied - true if color samples are assumed to be premultiplied by the alpha samples; false otherwise; transparency - what alpha values can be represented by this color model; transferType - the type of the array used to represent pixel values
Throws:: IllegalArgumentException - if the length of the bit array is less than the number of color or alpha components in this ColorModel
See Also:: Transparency

Method Detail

getRGBdefault

public static ColorModel getRGBdefault()

Returns a DirectColorModel that describes the default format for integer RGB values used in many of the methods in the AWT image interfaces for the convenience of the programmer. The color space is the default ColorSpace, sRGB. The format for the RGB values is an integer with 8 bits each of alpha, red, green, and blue color components ordered correspondingly from the most significant byte to the least significant byte, as in: 0xAARRGGBB. Color components are not premultiplied by the alpha component. This format does not necessarily represent the native or the most efficient ColorModel for a particular device or for all images. It is merely used as a common color model format.

Returns:: a DirectColorModelobject describing default RGB values.

hasAlpha

public final boolean hasAlpha()

Returns whether or not alpha is supported in this ColorModel.

Returns:: true if alpha is supported in this ColorModel; false otherwise.

isAlphaPremultiplied

public final boolean isAlphaPremultiplied()

Returns whether or not the alpha has been premultiplied in the pixel values to be translated by this ColorModel. If the boolean is true, this ColorModel is to be used to interpret pixel values in which color and alpha information are represented as separate spatial bands, and color samples are assumed to have been multiplied by the alpha sample.

Returns:: true if the alpha values are premultiplied in the pixel values to be translated by this ColorModel; false otherwise.

getPixelSize

public int getPixelSize()

Returns the number of bits per pixel described by this ColorModel.

Returns:: the number of bits per pixel.

getComponentSize

public int getComponentSize(int componentIdx)

Returns the number of bits for the specified color/alpha component. Color components are indexed in the order 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. If this ColorModel supports alpha, the alpha component corresponds to the index following the last color component.

Parameters:: componentIdx - the index of the color/alpha component
Returns:: the number of bits for the color/alpha component at the specified index.
Throws:: ArrayIndexOutOfBoundsException - if componentIdx is greater than the number of components or less than zero

getComponentSize

public int[] getComponentSize()

Returns an array of the number of bits per color/alpha component. The array contains the color components in the order specified by the ColorSpace, followed by the alpha component, if present.

Returns:: an array of the number of bits per color/alpha component

getTransparency

public int getTransparency()

Returns the transparency. Returns either OPAQUE, BITMASK, or TRANSLUCENT.

Specified by:: getTransparency in interface Transparency

Returns:: the transparency of this ColorModel.
See Also:: Transparency.OPAQUE, Transparency.BITMASK, Transparency.TRANSLUCENT

getNumComponents

public int getNumComponents()

Returns the number of components, including alpha, in this ColorModel. This is equal to the number of color components, optionally plus one, if there is an alpha component.

Returns:: the number of components in this ColorModel

getNumColorComponents

public int getNumColorComponents()

Returns the number of color components in this ColorModel. This is the number of components returned by ColorSpace.getNumComponents().

Returns:: the number of color components in this ColorModel.
See Also:: ColorSpace.getNumComponents()

getRed

public abstract 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. An IllegalArgumentException is thrown if pixel values for this ColorModel are not conveniently representable as a single int. The returned value is not a pre-multiplied value. For example, if the alpha is premultiplied, this method divides it out before returning the value. If the alpha value is 0, the red value is 0.

Parameters:: pixel - a specified pixel
Returns:: the value of the red component of the specified pixel.

getGreen

public abstract 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. An IllegalArgumentException is thrown if pixel values for this ColorModel are not conveniently representable as a single int. The returned value is a non pre-multiplied value. For example, if the alpha is premultiplied, this method divides it out before returning the value. If the alpha value is 0, the green value is 0.

Parameters:: pixel - the specified pixel
Returns:: the value of the green component of the specified pixel.

getBlue

public abstract 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. An IllegalArgumentException is thrown if pixel values for this ColorModel are not conveniently representable as a single int. The returned value is a non pre-multiplied value, for example, if the alpha is premultiplied, this method divides it out before returning the value. If the alpha value is 0, the blue value is 0.

Parameters:: pixel - the specified pixel
Returns:: the value of the blue component of the specified pixel.

getAlpha

public abstract 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. An IllegalArgumentException is thrown if pixel values for this ColorModel are not conveniently representable as a single int.

Parameters:: pixel - the specified pixel
Returns:: the value of alpha component of the specified pixel.

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 pixel value is specified as an int. An IllegalArgumentException thrown if pixel values for this ColorModel are not conveniently representable as a single int. The returned value is in a non pre-multiplied format. For example, if the alpha is premultiplied, this method divides it out of the color components. If the alpha value is 0, the color values are 0.

Parameters:: pixel - the specified pixel
Returns:: the RGB value of the color/alpha components of the specified pixel.
See Also:: 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 is a non pre-multiplied value. For example, if alpha is premultiplied, this method divides it out before returning the value. If the alpha value is 0, the red value is 0. If inData is not a primitive array of type transferType, a ClassCastException is thrown. An ArrayIndexOutOfBoundsException is thrown if inData is not large enough to hold a pixel value for this ColorModel. If this transferType is not supported, a UnsupportedOperationException will be thrown.

Parameters:: inData - an array of pixel values
Returns:: the value of the red component of the specified pixel.
Throws:: ClassCastException - if inData is not a primitive array of type transferType; ArrayIndexOutOfBoundsException - if inData is not large enough to hold a pixel value for this ColorModel; UnsupportedOperationException - if this tranferType is not supported by this ColorModel

getGreen

public int getGreen(Object inData)

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 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. For example, if the alpha is premultiplied, this method divides it out before returning the value. If the alpha value is 0, the green value is 0. If inData is not a primitive array of type transferType, a ClassCastException is thrown. An ArrayIndexOutOfBoundsException is thrown if inData is not large enough to hold a pixel value for this ColorModel. If this transferType is not supported, a UnsupportedOperationException will be thrown.

Parameters:: inData - an array of pixel values
Returns:: the value of the green component of the specified pixel.
Throws:: ClassCastException - if inData is not a primitive array of type transferType; ArrayIndexOutOfBoundsException - if inData is not large enough to hold a pixel value for this ColorModel; UnsupportedOperationException - if this tranferType is not supported by this ColorModel

getBlue

public int getBlue(Object inData)

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 by an array of data elements of type transferType passed in as an object reference. The returned value is a non pre-multiplied value. For example, 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. If inData is not a primitive array of type transferType, a ClassCastException is thrown. An ArrayIndexOutOfBoundsException is thrown if inData is not large enough to hold a pixel value for this ColorModel. If this transferType is not supported, a UnsupportedOperationException will be thrown.

Parameters:: inData - an array of pixel values
Returns:: the value of the blue component of the specified pixel.
Throws:: ClassCastException - if inData is not a primitive array of type transferType; ArrayIndexOutOfBoundsException - if inData is not large enough to hold a pixel value for this ColorModel; UnsupportedOperationException - if this tranferType is not supported by this ColorModel

getAlpha

public int getAlpha(Object inData)

Returns the alpha component for the specified pixel, scaled from 0 to 255. The pixel value is specified by an array of data elements of type transferType passed in as an object reference. If inData is not a primitive array of type transferType, a ClassCastException is thrown. An ArrayIndexOutOfBoundsException is thrown if inData is not large enough to hold a pixel value for this ColorModel. If this transferType is not supported, a UnsupportedOperationException will be thrown.

Parameters:: inData - the specified pixel
Returns:: the alpha component of the specified pixel, scaled from 0 to 255.
Throws:: ClassCastException - if inData is not a primitive array of type transferType; ArrayIndexOutOfBoundsException - if inData is not large enough to hold a pixel value for this ColorModel; UnsupportedOperationException - if this tranferType is not supported by this ColorModel

getRGB

public int getRGB(Object inData)

Returns the color/alpha components for the specified pixel in the default RGB color model format. 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. If inData is not a primitive array of type transferType, a ClassCastException is thrown. An ArrayIndexOutOfBoundsException is thrown if inData is not large enough to hold a pixel value for this ColorModel. The returned value will be in a non pre-multiplied format, i.e. if the alpha is premultiplied, this method will divide it out of the color components (if the alpha value is 0, the color values will be 0).

Parameters:: inData - the specified pixel
Returns:: the color and alpha components of the specified pixel.
See Also:: 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 WritableRaster.setDataElements(int, int, java.lang.Object) method of a WritableRaster object. If the pixel variable is null, a new array will be 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. If this transferType is not supported, a UnsupportedOperationException will be thrown.

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 ColorModel.
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 this method is not supported by this ColorModel
See Also:: WritableRaster.setDataElements(int, int, java.lang.Object), SampleModel.setDataElements(int, int, java.lang.Object, java.awt.image.DataBuffer)

getComponents

public int[] getComponents(int pixel,
                           int[] components,
                           int offset)

Returns an array of unnormalized color/alpha components given a pixel in this ColorModel. The pixel value is specified as an int. An IllegalArgumentException will be thrown if pixel values for this ColorModel are not conveniently representable as a single int. For example, this method can be used to retrieve the components for a specific pixel value in a DirectColorModel. If the components array is null, a new array will be allocated. The components array will be returned. 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).

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.
Throws:: UnsupportedOperationException - if this method is not supported by this ColorModel

getComponents

public int[] getComponents(Object pixel,
                           int[] components,
                           int offset)

Returns an array of unnormalized color/alpha components given a 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. This method can be used to retrieve the components for a specific pixel value in any ColorModel. If the components array is null, a new array will be allocated. The components array will be returned. 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).

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:: UnsupportedOperationException - if this method is not supported by this ColorModel

getUnnormalizedComponents

public 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. Unnormalized components are unsigned integral values between 0 and 2ⁿ - 1, where n is the number of bits for a particular component. Normalized components are float values between 0.0 and 1.0. If the components array is null, a new array will be allocated. The components array will be returned. 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). An IllegalArgumentException is thrown if the normComponents array is not large enough to hold all the color and alpha components starting at normOffset.

Parameters:: normComponents - an array containing normalized components; normOffset - the offset into the normComponents array at which to start retrieving normalized components; components - an array that receives the components from normComponents; offset - the index into components at which to begin storing normalized components from normComponents
Returns:: an array containing unnormalized color and alpha components.
Throws:: UnsupportedOperationException - if this method is not supported by this ColorModel

getNormalizedComponents

public 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. Unnormalized components are unsigned integral values between 0 and 2ⁿ - 1, where n is the number of bits for a particular component. Normalized components are float values between 0.0 and 1.0. If the normComponents array is null, a new array will be allocated. The normComponents array will be returned. Color/alpha components are stored in the normComponents array starting at normOffset (even if the array is allocated by this method). An ArrayIndexOutOfBoundsException is thrown if the normComponents array is not null and is not large enough to hold all the color and alpha components (starting at normOffset). An IllegalArgumentException is thrown if the components array is not large enough to hold all the color and alpha components starting at offset.

Parameters:: components - an array containing unnormalized components; offset - the offset into the components array at which to start retrieving unnormalized components; normComponents - an array that receives the components from components; normOffset - the index into normComponents at which to begin storing unnormalized components from components
Returns:: an array containing normalized color and alpha components.
Throws:: UnsupportedOperationException - if this method is not supported by this ColorModel

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. This method will throw an IllegalArgumentException if pixel values for this ColorModel are not conveniently representable as a single int. An ArrayIndexOutOfBoundsException is thrown if the components array is not large enough to hold all the color and alpha components (starting at offset).

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:: IllegalArgumentException - if pixel values for this ColorModel are not conveniently representable as a single int; ArrayIndexOutOfBoundsException - if the components array is not large enough to hold all of the color and alpha components starting at offset; UnsupportedOperationException - if this method is not supported by this ColorModel

getDataElements

public 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. 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 the color and alpha components (starting at offset). If the obj variable is null, a new array will be allocated. If obj is not null, it must be a primitive array of type transferType; otherwise, a ClassCastException is thrown. An ArrayIndexOutOfBoundsException is thrown if obj is not large enough to hold a pixel value for this 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; obj - the Object representing an array of color and alpha components
Returns:: an Object representing an array of color and alpha components.
Throws:: ClassCastException - if obj is not a primitive array of type transferType; ArrayIndexOutOfBoundsException - if obj 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 this method is not supported by this ColorModel
See Also:: WritableRaster.setDataElements(int, int, java.lang.Object), SampleModel.setDataElements(int, int, java.lang.Object, java.awt.image.DataBuffer)

equals

public boolean equals(Object obj)

Tests if the specified Object is an instance of ColorModel and if it equals this ColorModel.

Overrides:: equals in class Object

Parameters:: obj - the Object to test for equality
Returns:: true if the specified Object is an instance of ColorModel and equals this ColorModel; false otherwise.

getColorSpace

public final ColorSpace getColorSpace()

Returns the ColorSpace associated with this ColorModel.

Returns:: the ColorSpace of this ColorModel.

coerceData

public 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. It may multiply or divide the color raster data by alpha, or do nothing if the data is in the correct state. If the data needs to be coerced, this method will also return an instance of this ColorModel with the isAlphaPremultiplied flag set appropriately. This method will throw a UnsupportedOperationException if it is not supported by this ColorModel.

Parameters:: raster - the WritableRaster data; isAlphaPremultiplied - true if the alpha is premultiplied; false otherwise
Returns:: a ColorModel object that represents the coerced data.

isCompatibleRaster

public boolean isCompatibleRaster(Raster raster)

Returns true if raster is compatible with this ColorModel and false if it is not.

Parameters:: raster - the Raster object to test for compatibility
Returns:: true if raster is compatible with this ColorModel.
Throws:: UnsupportedOperationException - if this method has not been implemented for this ColorModel

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.

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 this method is not supported by this ColorModel
See Also:: WritableRaster, SampleModel

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.

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:: UnsupportedOperationException - if this method is not supported by this ColorModel
See Also:: SampleModel

isCompatibleSampleModel

public boolean isCompatibleSampleModel(SampleModel sm)

Checks if the SampleModel is compatible with this ColorModel.

Parameters:: sm - the specified SampleModel
Returns:: true if the specified SampleModel is compatible with this ColorModel; false otherwise.
Throws:: UnsupportedOperationException - if this method is not supported by this ColorModel
See Also:: SampleModel

finalize

public void finalize()

Disposes of system resources associated with this ColorModel once this ColorModel is no longer referenced.

Overrides:: finalize in class Object

getAlphaRaster

public WritableRaster getAlphaRaster(WritableRaster raster)

Returns a Raster representing the alpha channel of an image, extracted from the input Raster, provided that pixel values of this ColorModel represent color and alpha information as separate spatial bands (e.g. ComponentColorModel and DirectColorModel). This method assumes that Raster objects associated with such a ColorModel store the alpha band, if present, as the last band of image data. Returns null if there is no separate spatial alpha channel associated with this ColorModel. If this is an IndexColorModel which has alpha in the lookup table, this method will return null since there is no spatially discrete alpha channel. This method will create a new Raster (but will share the data array).

Parameters:: raster - the specified Raster
Returns:: a Raster representing the alpha channel of an image, obtained from the specified Raster.

toString

public String toString()

Returns the String representation of the contents of this ColorModelobject.

Overrides:: toString in class Object

Returns:: a String representing the contents of this ColorModel object.

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Field Summary
`protected int`	`pixel_bits` The total number of bits in the pixel.
`protected int`	`transferType` Data type of the array used to represent pixel values.

Constructor Summary
	`ColorModel(int bits)` Constructs a `ColorModel` that translates pixels of the specified number of bits to color/alpha components.
`protected`	`ColorModel(int pixel_bits, int[] bits, ColorSpace cspace, boolean hasAlpha, boolean isAlphaPremultiplied, int transparency, int transferType)` Constructs a `ColorModel` that translates pixel values to color/alpha components.

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)` Tests if the specified `Object` is an instance of `ColorModel` and if it equals this `ColorModel`.
`void`	`finalize()` Disposes of system resources associated with this `ColorModel` once this `ColorModel` is no longer referenced.
`abstract 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`, provided that pixel values of this `ColorModel` represent color and alpha information as separate spatial bands (e.g.
`abstract 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.
`ColorSpace`	`getColorSpace()` Returns the `ColorSpace` associated with this `ColorModel`.
`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[]`	`getComponentSize()` Returns an array of the number of bits per color/alpha component.
`int`	`getComponentSize(int componentIdx)` Returns the number of bits for the specified 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 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.
`abstract 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.
`int`	`getNumColorComponents()` Returns the number of color components in this `ColorModel`.
`int`	`getNumComponents()` Returns the number of components, including alpha, in this `ColorModel`.
`int`	`getPixelSize()` Returns the number of bits per pixel described by this `ColorModel`.
`abstract 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.
`static ColorModel`	`getRGBdefault()` Returns a `DirectColorModel` that describes the default format for integer RGB values used in many of the methods in the AWT image interfaces for the convenience of the programmer.
`int`	`getTransparency()` Returns the transparency.
`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`	`hasAlpha()` Returns whether or not alpha is supported in this `ColorModel`.
`boolean`	`isAlphaPremultiplied()` Returns whether or not the alpha has been premultiplied in the pixel values to be translated by this `ColorModel`.
`boolean`	`isCompatibleRaster(Raster raster)` Returns `true` if `raster` is compatible with this `ColorModel` and `false` if it is not.
`boolean`	`isCompatibleSampleModel(SampleModel sm)` Checks if the `SampleModel` is compatible with this `ColorModel`.
`String`	`toString()` Returns the `String` representation of the contents of this `ColorModel`object.

Java(TM) 2 Platform, Standard Edition, v1.2.2 API Specification: Class ColorModel - JDK 5 Documentation v1.2.2, Java 2 SDK 英文文档

java.awt.image Class ColorModel

pixel_bits

transferType

ColorModel

ColorModel

getRGBdefault

hasAlpha

isAlphaPremultiplied

getPixelSize

getComponentSize

getComponentSize

getTransparency

getNumComponents

getNumColorComponents

getRed

getGreen

getBlue

getAlpha

getRGB

getRed

getGreen

getBlue

getAlpha

getRGB

getDataElements

getComponents

getComponents

getUnnormalizedComponents

getNormalizedComponents

getDataElement

getDataElements

equals

getColorSpace

coerceData

isCompatibleRaster

createCompatibleWritableRaster

createCompatibleSampleModel

isCompatibleSampleModel

finalize

getAlphaRaster

toString

java.awt.image
Class ColorModel