javax.media.jai.operator
Class FormatDescriptor

java.lang.Object
  |
  +--javax.media.jai.OperationDescriptorImpl
        |
        +--javax.media.jai.operator.FormatDescriptor

All Implemented Interfaces:

OperationDescriptor, RegistryElementDescriptor, Serializable

public class FormatDescriptor

extends OperationDescriptorImpl

An OperationDescriptor describing the "Format" operation.

The "Format" operation performs reformatting on an image. It is capable of casting the pixel values of an image to a given data type, replacing the SampleModel and ColorModel of an image, and restructuring the image's tile grid layout. The pixel values of the destination image are defined by the pseudocode:

dst[x][y][b] = cast(src[x][y][b], dataType)

where "dataType" is one of the constants TYPE_BYTE, TYPE_SHORT, TYPE_USHORT, TYPE_INT, TYPE_FLOAT, or TYPE_DOUBLE from java.awt.image.DataBuffer.

The output SampleModel, ColorModel and tile grid layout are specified by passing an ImageLayout object as a RenderingHint named "ImageLayout". The output image will have a SampleModel compatible with the one specified in the layout hint wherever possible; however, for output data types of float and double a ComponentSampleModel will be used regardless of the value of the hint parameter.

The ImageLayout may also specify a tile grid origin and size which will be respected.

The typecasting performed by the Format function is defined by the following set of expressions, dependent on the data types of the source and destination. Casting an image to its current data type is a no-op. See The Java Language Specification for the definition of type conversions between primitive types.

In most cases, it is not necessary to explictly perform widening typecasts since they will be performed automatically by image operators when handed source images having different datatypes.

Source Type	Destination Type	Action
BYTE	SHORT	(short)(x & 0xff)
BYTE	USHORT	(short)(x & 0xff)
BYTE	INT	(int)(x & 0xff)
BYTE	FLOAT	(float)(x & 0xff)
BYTE	DOUBLE	(double)(x & 0xff)
SHORT	BYTE	(byte)clamp((int)x, 0, 255)
SHORT	USHORT	(short)clamp((int)x, 0, 32767)
SHORT	INT	(int)x
SHORT	FLOAT	(float)x
SHORT	DOUBLE	(double)x
USHORT	BYTE	(byte)clamp((int)x & 0xffff, 0, 255)
USHORT	SHORT	(short)clamp((int)x & 0xffff, 0, 32767)
USHORT	INT	(int)(x & 0xffff)
USHORT	FLOAT	(float)(x & 0xffff)
USHORT	DOUBLE	(double)(x & 0xffff)
INT	BYTE	(byte)clamp(x, 0, 255)
INT	SHORT	(short)clamp(x, -32768, 32767)
INT	USHORT	(short)clamp(x, 0, 65535)
INT	FLOAT	(float)x
INT	DOUBLE	(double)x
FLOAT	BYTE	(byte)clamp((int)x, 0, 255)
FLOAT	SHORT	(short)clamp((int)x, -32768, 32767)
FLOAT	USHORT	(short)clamp((int)x, 0, 65535)
FLOAT	INT	(int)x
FLOAT	DOUBLE	(double)x
DOUBLE	BYTE	(byte)clamp((int)x, 0, 255)
DOUBLE	SHORT	(short)clamp((int)x, -32768, 32767)
DOUBLE	USHORT	(short)clamp((int)x, 0, 65535)
DOUBLE	INT	(int)x
DOUBLE	FLOAT	(float)x

The clamp function may be defined as:

 int clamp(int x, int low, int high) {
     return (x < low) ? low : ((x > high) ? high : x);
 }
 

Resource List

Name	Value
GlobalName	Format
LocalName	Format
Vendor	com.sun.media.jai
Description	Reformats an image.
DocURL	http://java.sun.com/products/java-media/jai/forDevelopers/jai-apidocs/javax/media/jai/operator/FormatDescriptor.html
Version	1.0
arg0Desc	The output data type (from java.awt.image.DataBuffer).

Parameter List

Name	Class Type	Default Value
dataType	java.lang.Integer	DataBuffer.TYPE_BYTE

See Also:

DataBuffer, ImageLayout, OperationDescriptor, Serialized Form

Fields inherited from class javax.media.jai.OperationDescriptorImpl

resources, sourceNames, supportedModes

Constructor Summary

FormatDescriptor()
Constructor.

Method Summary

Number	getParamMaxValue(int index) Returns the maximum legal value of a specified numeric parameter for this operation.
Number	getParamMinValue(int index) Returns the minimum legal value of a specified numeric parameter for this operation.
boolean	isRenderableSupported() Returns true since renderable operation is supported.

Methods inherited from class javax.media.jai.OperationDescriptorImpl

arePropertiesSupported, getDefaultSourceClass, getDestClass, getDestClass, getInvalidRegion, getName, getNumParameters, getNumSources, getParamClasses, getParamDefaults, getParamDefaultValue, getParameterListDescriptor, getParamNames, getPropertyGenerators, getPropertyGenerators, getRenderableDestClass, getRenderableSourceClasses, getResourceBundle, getResources, getSourceClasses, getSourceClasses, getSourceNames, getSupportedModes, isImmediate, isModeSupported, isRenderedSupported, makeDefaultSourceClassList, validateArguments, validateArguments, validateParameters, validateParameters, validateRenderableArguments, validateRenderableSources, validateSources, validateSources

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

FormatDescriptor

public FormatDescriptor()

Constructor.

Method Detail

isRenderableSupported

public boolean isRenderableSupported()

Returns true since renderable operation is supported.

Overrides:

isRenderableSupported in class OperationDescriptorImpl

Tags copied from class: OperationDescriptorImpl

See Also:

OperationDescriptorImpl.isModeSupported(java.lang.String)

getParamMinValue

public Number getParamMinValue(int index)

Returns the minimum legal value of a specified numeric parameter for this operation.

Overrides:

getParamMinValue in class OperationDescriptorImpl

Tags copied from class: OperationDescriptorImpl

Parameters:

index - The index of the parameter to be queried.

Returns:

A Number representing the minimum legal value, or null if the specified parameter is not numeric.

Throws:

IllegalArgumentException - if this operation has no parameters.

ArrayIndexOutOfBoundsException - if there is no parameter corresponding to the specified index.

See Also:

ParameterListDescriptor.getParamValueRange(java.lang.String), ParameterListDescriptor.getEnumeratedParameterValues(java.lang.String), ParameterListDescriptor.isParameterValueValid(java.lang.String, java.lang.Object)

getParamMaxValue

public Number getParamMaxValue(int index)

Returns the maximum legal value of a specified numeric parameter for this operation.

Overrides:

getParamMaxValue in class OperationDescriptorImpl

Tags copied from class: OperationDescriptorImpl

Parameters:

index - The index of the parameter to be queried.

Returns:

A Number representing the maximum legal value, or null if the specified parameter is not numeric.

Throws:

IllegalArgumentException - if this operation has no parameters.

ArrayIndexOutOfBoundsException - if there is no parameter corresponding to the specified index.

See Also:

ParameterListDescriptor.getParamValueRange(java.lang.String), ParameterListDescriptor.getEnumeratedParameterValues(java.lang.String), ParameterListDescriptor.isParameterValueValid(java.lang.String, java.lang.Object)