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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.

The parameter, "backgroundValues", is defined to fill the background with the user-specified background values. These background values will be translated into background colors by the ColorModel when the image is displayed. With the default value, {0.0}, of this parameter, the background pixels are filled with 0s. If the provided array length is smaller than the number of bands, the first element of the provided array is used for all the bands. If the provided values are out of the data range of the destination image, they will be clamped into the proper range.

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 the user-specified background values.

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.

It should be noted that this operation automatically adds a value of Boolean.TRUE for the JAI.KEY_REPLACE_INDEX_COLOR_MODEL to the given configuration so that the operation is performed on the pixel values instead of being performed on the indices into the color map if the source(s) have an IndexColorModel. This addition will take place only if a value for the JAI.KEY_REPLACE_INDEX_COLOR_MODEL has not already been provided by the user. Note that the configuration Map is cloned before the new hint is added to it. The operation can be smart about the value of the JAI.KEY_REPLACE_INDEX_COLOR_MODEL RenderingHints, i.e. while the default value for the JAI.KEY_REPLACE_INDEX_COLOR_MODEL is Boolean.TRUE, in some cases the operator could set the default.

"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 identity transform
interpolation javax.media.jai.Interpolation InterpolationNearest
backgroundValues double[] {0.0}

See Also:
AffineTransform, Interpolation, OperationDescriptor, Serialized Form

Fields inherited from class javax.media.jai.OperationDescriptorImpl
resources, sourceNames, supportedModes
 
Fields inherited from interface javax.media.jai.OperationDescriptor
NO_PARAMETER_DEFAULT
 
Constructor Summary
AffineDescriptor()
          Constructor.
 
Method Summary
static RenderedOp create(RenderedImage source0, AffineTransform transform, Interpolation interpolation, double[] backgroundValues, RenderingHints hints)
          Performs interpolated affine transform on an image.
static RenderableOp createRenderable(RenderableImage source0, AffineTransform transform, Interpolation interpolation, double[] backgroundValues, RenderingHints hints)
          Performs interpolated affine transform on an image.
 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
Following copied from class: javax.media.jai.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
Following copied from class: javax.media.jai.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)

create

public static RenderedOp create(RenderedImage source0,
                                AffineTransform transform,
                                Interpolation interpolation,
                                double[] backgroundValues,
                                RenderingHints hints)
Performs interpolated affine transform on an image.

Creates a ParameterBlockJAI from all supplied arguments except hints and invokes JAI.create(String,ParameterBlock,RenderingHints).

Parameters:
source0 - RenderedImage source 0.
transform - The affine transform matrix. May be null.
interpolation - The interpolation method. May be null.
backgroundValues - The user-specified background values. May be null.
hints - The RenderingHints to use. May be null.
Returns:
The RenderedOp destination.
Throws:
IllegalArgumentException - if source0 is null.
See Also:
JAI, ParameterBlockJAI, RenderedOp

createRenderable

public static RenderableOp createRenderable(RenderableImage source0,
                                            AffineTransform transform,
                                            Interpolation interpolation,
                                            double[] backgroundValues,
                                            RenderingHints hints)
Performs interpolated affine transform on an image.

Creates a ParameterBlockJAI from all supplied arguments except hints and invokes JAI.createRenderable(String,ParameterBlock,RenderingHints).

Parameters:
source0 - RenderableImage source 0.
transform - The affine transform matrix. May be null.
interpolation - The interpolation method. May be null.
backgroundValues - The user-specified background values. May be null.
hints - The RenderingHints to use. May be null.
Returns:
The RenderableOp destination.
Throws:
IllegalArgumentException - if source0 is null.
See Also:
JAI, ParameterBlockJAI, RenderableOp
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