javax.media.jai.operator
Class AffineDescriptor

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

All Implemented Interfaces:

OperationDescriptor, RegistryElementDescriptor, Serializable

public class AffineDescriptor

extends OperationDescriptorImpl

An OperationDescriptor describing the "Affine" operation.

The Affine operation performs (possibly filtered) affine mapping on a rendered or renderable source image.

The relationship between the source and the destination pixels is defined as follows. For each pixel (x, y) of the destination, the source value at the fractional subpixel position (x', y') is constructed by means of an Interpolation object and written to the destination. The mapping between the destination pixel (x, y) and the source position (x', y') is given by:

    x' = m[0][0] * x + m[0][1] * y + m[0][2]
    y' = m[1][0] * x + m[1][1] * y + m[1][2]
 

where m is a 3x2 transform matrix that inverts the matrix supplied as the "transform" argument.

When interpolations which require padding the source such as Bilinear or Bicubic interpolation are specified, the source needs to be extended such that it has the extra pixels needed to compute all the destination pixels. This extension is performed via the BorderExtender class. The type of Border Extension can be specified as a RenderingHint to the JAI.create method.

If no BorderExtender is specified (is null), the source will not be extended. The transformed image size is still the same as if the source had been extended. However, since there is insufficient source to compute all the destination pixels, only that subset of the destination image's pixels which can be computed will be written in the destination. The rest of the destination will be set to zeros.

It may be noted that the minX, minY, width and height hints as specified through the JAI.KEY_IMAGE_LAYOUT hint in the RenderingHints object are not honored, as this operator calculates the destination image bounds itself. The other ImageLayout hints, like tileWidth and tileHeight, however are honored.

"Affine" defines a PropertyGenerator that performs an identical transformation on the "ROI" property of the source image, which can be retrieved by calling the getProperty method with "ROI" as the property name.

Resource List

Name	Value
GlobalName	Affine
LocalName	Affine
Vendor	com.sun.media.jai
Description	Performs interpolated affine transform on an image.
DocURL	http://java.sun.com/products/java-media/jai/forDevelopers/jai-apidocs/javax/media/jai/operator/AffineDescriptor.html
Version	1.0
arg0Desc	The affine transform matrix.
arg1Desc	The interpolation method.

Parameter List

Name	Class Type	Default Value
transform	java.awt.geom.AffineTransform	NO_PARAMETER_DEFAULT
interpolation	javax.media.jai.Interpolation	InterpolationNearest

See Also:

AffineTransform, Interpolation, OperationDescriptor, Serialized Form

Fields inherited from class javax.media.jai.OperationDescriptorImpl

resources, sourceNames, supportedModes

Constructor Summary

AffineDescriptor()
Constructor.

Method Summary

PropertyGenerator[]	getPropertyGenerators() Returns an array of PropertyGenerators implementing property inheritance for the "Affine" operation.
boolean	isRenderableSupported() Returns true since renderable operation is supported.
protected boolean	validateParameters(ParameterBlock args, StringBuffer message) Validates the input parameters.

Methods inherited from class javax.media.jai.OperationDescriptorImpl

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

AffineDescriptor

public AffineDescriptor()

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)

getPropertyGenerators

public PropertyGenerator[] getPropertyGenerators()

Returns an array of PropertyGenerators implementing property inheritance for the "Affine" operation.

Overrides:

getPropertyGenerators in class OperationDescriptorImpl

Returns:

An array of property generators.

validateParameters

protected boolean validateParameters(ParameterBlock args,
                                     StringBuffer message)

Validates the input parameters.

In addition to the standard checks performed by the superclass method, this method checks that "transform" is invertible.

Overrides:

validateParameters in class OperationDescriptorImpl

Tags copied from class: OperationDescriptorImpl

Throws:

IllegalArgumentException - if args is null.

IllegalArgumentException - if msg is null and the validation fails.

See Also:

OperationDescriptorImpl.validateParameters(java.lang.String, java.awt.image.renderable.ParameterBlock, java.lang.StringBuffer)