java::awt::image::ColorModel Class Reference

Inheritance diagram for java::awt::image::ColorModel:

Inheritance graph
java::lang::Objectjava::lang::Interfacejava::awt::Transparency
[legend]
Collaboration diagram for java::awt::image::ColorModel:

Collaboration graph
java::lang::Objectjava::lang::Interfacejava::lang::ObjectRefjava::awt::Transparencyjava::lang::Comparable
[legend]

List of all members.


Detailed Description

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) 2 Platform 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 2D(tm) API are DataBuffer.TYPE_BYTE, DataBuffer.TYPE_USHORT, DataBuffer.TYPE_INT, DataBuffer.TYPE_SHORT, DataBuffer.TYPE_FLOAT, and DataBuffer.TYPE_DOUBLE. Most rendering operations will perform much faster when using ColorModels and images based on the first three of these types. In addition, some image filtering operations are not supported for ColorModels and images based on the latter three types. 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 - a normalized form and an unnormalized form. In the normalized form, each component is a float value between some minimum and maximum values. For the alpha component, the minimum is 0.0 and the maximum is 1.0. For color components the minimum and maximum values for each component can be obtained from the ColorSpace object. These values will often be 0.0 and 1.0 (e.g. normalized component values for the default sRGB color space range from 0.0 to 1.0), but some color spaces have component values with different upper and lower limits. These limits can be obtained using the getMinValue and getMaxValue methods of the ColorSpace class. Normalized color component values are not premultiplied. All ColorModels must support the normalized form.

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. The unnormalized form is used only with instances of ColorModel whose ColorSpace has minimum component values of 0.0 for all components and maximum values of 1.0 for all components. The unnormalized form for color and alpha components can be a convenient representation for ColorModels whose normalized component values all lie between 0.0 and 1.0. In such cases the integral value 0 maps to 0.0 and the value 2n - 1 maps to 1.0. In other cases, such as when the normalized component values can be either negative or positive, the unnormalized form is not convenient. Such ColorModel objects throw an IllegalArgumentException when methods involving an unnormalized argument are called. Subclasses of ColorModel must specify the conditions under which this occurs.

See also:
IndexColorModel

ComponentColorModel

PackedColorModel

DirectColorModel

java.awt.Image

BufferedImage

RenderedImage

java.awt.color.ColorSpace

SampleModel

Raster

DataBuffer

Version:
10 Feb 1997

Public Member Functions

jboolean hasAlpha () const
 Returns whether or not alpha is supported in this ColorModel.
jboolean isAlphaPremultiplied () const
 Returns whether or not the alpha has been premultiplied in the pixel values to be translated by this ColorModel.
jint getTransferType () const
 Returns the transfer type of this ColorModel.
Ref< ColorSpacegetColorSpace () const
 Returns the ColorSpace associated with this ColorModel.
virtual jint getPixelSize () const
 Returns the number of bits per pixel described by this ColorModel.
virtual jint getComponentSize (jint componentIdx) const
 Returns the number of bits for the specified color/alpha component.
virtual const Array
< jint > & 
getComponentSize () const
 Returns an array of the number of bits per color/alpha component.
virtual jint getTransparency () const
 Returns the transparency.
virtual jint getNumComponents () const
 Returns the number of components, including alpha, in this ColorModel.
virtual jint getNumColorComponents () const
 Returns the number of color components in this ColorModel.
virtual jint getRed (jint pixel) const =0
 Returns the red color component for the specified pixel, scaled from 0 to 255 in the default RGB ColorSpace, sRGB.
virtual jint getGreen (jint pixel) const =0
 Returns the green color component for the specified pixel, scaled from 0 to 255 in the default RGB ColorSpace, sRGB.
virtual jint getBlue (jint pixel) const =0
 Returns the blue color component for the specified pixel, scaled from 0 to 255 in the default RGB ColorSpace, sRGB.
virtual jint getAlpha (jint pixel) const =0
 Returns the alpha component for the specified pixel, scaled from 0 to 255.
virtual jint getRGB (jint pixel) const
 Returns the color/alpha components of the pixel in the default RGB color model format.
virtual jint getRed (const Object &inData) const
 Returns the red color component for the specified pixel, scaled from 0 to 255 in the default RGB ColorSpace, sRGB.
virtual jint getGreen (const Object &inData) const
 Returns the green color component for the specified pixel, scaled from 0 to 255 in the default RGB ColorSpace, sRGB.
virtual jint getBlue (const Object &inData) const
 Returns the blue color component for the specified pixel, scaled from 0 to 255 in the default RGB ColorSpace, sRGB.
virtual jint getAlpha (const Object &inData) const
 Returns the alpha component for the specified pixel, scaled from 0 to 255.
virtual jint getRGB (const Object &inData) const
 Returns the color/alpha components for the specified pixel in the default RGB color model format.
virtual jboolean equals (const Object &obj) const
 Tests if the specified Object is an instance of ColorModel and if it equals this ColorModel.
virtual jint hashCode () const
 Returns the hash code for this ColorModel.
virtual String toString () const
 Returns the String representation of the contents of this ColorModelobject.

Static Public Member Functions

static ColorModelgetRGBdefault ()
 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.

Protected Member Functions

 ColorModel (jint bits)
 Constructs a ColorModel that translates pixels of the specified number of bits to color/alpha components.
 ColorModel (jint pixel_bits, const Array< jint > &bits, const Ref< ColorSpace > &cspace, jboolean hasAlpha, jboolean isAlphaPremultiplied, jint transparency, jint transferType)
 Constructs a ColorModel that translates pixel values to color/alpha components.

Protected Attributes

ObjectRef impl
 REGISTER_MEMBERS

Constructor & Destructor Documentation

java::awt::image::ColorModel::ColorModel ( jint  bits  )  [protected]

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
Exceptions:
IllegalArgumentException if the number of bits in bits is less than 1

java::awt::image::ColorModel::ColorModel ( jint  pixel_bits,
const Array< jint > &  bits,
const Ref< ColorSpace > &  cspace,
jboolean  hasAlpha,
jboolean  isAlphaPremultiplied,
jint  transparency,
jint  transferType 
) [protected]

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
Exceptions:
IllegalArgumentException if the length of the bit array is less than the number of color or alpha components in this ColorModel, or if the transparency is not a valid value.
IllegalArgumentException if the sum of the number of bits in bits is less than 1 or if any of the elements in bits is less than 0.
See also:
java.awt.Transparency


Member Function Documentation

static ColorModel& java::awt::image::ColorModel::getRGBdefault (  )  [static]

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.

jboolean java::awt::image::ColorModel::hasAlpha (  )  const

Returns whether or not alpha is supported in this ColorModel.

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

jboolean java::awt::image::ColorModel::isAlphaPremultiplied (  )  const

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.

jint java::awt::image::ColorModel::getTransferType (  )  const

Returns the transfer type of this ColorModel.

The transfer type is the type of primitive array used to represent pixel values as arrays.

Returns:
the transfer type.

Ref<ColorSpace> java::awt::image::ColorModel::getColorSpace (  )  const

Returns the ColorSpace associated with this ColorModel.

Returns:
the ColorSpace of this ColorModel.

virtual jint java::awt::image::ColorModel::getPixelSize (  )  const [virtual]

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

Returns:
the number of bits per pixel.

virtual jint java::awt::image::ColorModel::getComponentSize ( jint  componentIdx  )  const [virtual]

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.
Exceptions:
ArrayIndexOutOfBoundsException if componentIdx is greater than the number of components or less than zero
NullPointerException if the number of bits array is null

virtual const Array<jint>& java::awt::image::ColorModel::getComponentSize (  )  const [virtual]

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

virtual jint java::awt::image::ColorModel::getTransparency (  )  const [virtual]

Returns the transparency.

Returns either OPAQUE, BITMASK, or TRANSLUCENT.

Returns:
the transparency of this ColorModel.
See also:
Transparency::OPAQUE

Transparency::BITMASK

Transparency::TRANSLUCENT

Implements java::awt::Transparency.

virtual jint java::awt::image::ColorModel::getNumComponents (  )  const [virtual]

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

virtual jint java::awt::image::ColorModel::getNumColorComponents (  )  const [virtual]

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

virtual jint java::awt::image::ColorModel::getRed ( jint  pixel  )  const [pure virtual]

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.

virtual jint java::awt::image::ColorModel::getGreen ( jint  pixel  )  const [pure virtual]

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.

virtual jint java::awt::image::ColorModel::getBlue ( jint  pixel  )  const [pure virtual]

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.

virtual jint java::awt::image::ColorModel::getAlpha ( jint  pixel  )  const [pure virtual]

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.

virtual jint java::awt::image::ColorModel::getRGB ( jint  pixel  )  const [virtual]

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:
ColorModel::getRGBdefault

virtual jint java::awt::image::ColorModel::getRed ( const Object inData  )  const [virtual]

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. Since ColorModel is an abstract class, any instance must be an instance of a subclass. Subclasses inherit the implementation of this method and if they don't override it, this method throws an exception if the subclass uses a transferType other than DataBuffer.TYPE_BYTE, DataBuffer.TYPE_USHORT, or DataBuffer.TYPE_INT.

Parameters:
inData an array of pixel values
Returns:
the value of the red component of the specified pixel.
Exceptions:
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

virtual jint java::awt::image::ColorModel::getGreen ( const Object inData  )  const [virtual]

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. Since ColorModel is an abstract class, any instance must be an instance of a subclass. Subclasses inherit the implementation of this method and if they don't override it, this method throws an exception if the subclass uses a transferType other than DataBuffer.TYPE_BYTE, DataBuffer.TYPE_USHORT, or DataBuffer.TYPE_INT.

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

virtual jint java::awt::image::ColorModel::getBlue ( const Object inData  )  const [virtual]

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. Since ColorModel is an abstract class, any instance must be an instance of a subclass. Subclasses inherit the implementation of this method and if they don't override it, this method throws an exception if the subclass uses a transferType other than DataBuffer.TYPE_BYTE, DataBuffer.TYPE_USHORT, or DataBuffer.TYPE_INT.

Parameters:
inData an array of pixel values
Returns:
the value of the blue component of the specified pixel.
Exceptions:
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

virtual jint java::awt::image::ColorModel::getAlpha ( const Object inData  )  const [virtual]

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. Since ColorModel is an abstract class, any instance must be an instance of a subclass. Subclasses inherit the implementation of this method and if they don't override it, this method throws an exception if the subclass uses a transferType other than DataBuffer.TYPE_BYTE, DataBuffer.TYPE_USHORT, or DataBuffer.TYPE_INT.

Parameters:
inData the specified pixel
Returns:
the alpha component of the specified pixel, scaled from 0 to 255.
Exceptions:
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

virtual jint java::awt::image::ColorModel::getRGB ( const Object inData  )  const [virtual]

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:
ColorModel::getRGBdefault

virtual jboolean java::awt::image::ColorModel::equals ( const Object obj  )  const [virtual]

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

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.

Reimplemented from java::lang::Object.

virtual jint java::awt::image::ColorModel::hashCode (  )  const [virtual]

Returns the hash code for this ColorModel.

Returns:
a hash code for this ColorModel.

Reimplemented from java::lang::Object.

virtual String java::awt::image::ColorModel::toString (  )  const [virtual]

Returns the String representation of the contents of this ColorModelobject.

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

Reimplemented from java::lang::Object.


Member Data Documentation

ObjectRef java::awt::image::ColorModel::impl [protected]

java::awt::image::ColorModel::REGISTER_MEMBERS [protected]

Reimplemented from java::awt::Transparency.


The documentation for this class was generated from the following file:
Generated on Fri May 16 11:56:22 2008 for CrossPlatformJavaLikeC++API by  doxygen 1.5.3