org.geotoolkit.referencing.operation.transform
Class AffineTransform2D

Object
  AffineTransform
      XAffineTransform
          AffineTransform2D

All Implemented Interfaces:

Serializable, Cloneable, Formattable, LinearTransform, Parameterized, LenientComparable, MathTransform, MathTransform2D

@Immutable
public class AffineTransform2D
extends XAffineTransform
implements MathTransform2D, LinearTransform, Parameterized, Formattable, Cloneable

Transforms two-dimensional coordinate points using an affine transform. This class both extends AffineTransform and implements MathTransform2D, so it can be used as a bridge between Java2D and the referencing module. Note that this bridge role involve a tricky issue with the equals method, hopefully to occur only in exceptional corner cases.

See any of the following providers for a list of programmatic parameters:

• Affine
• LongitudeRotation

Since:

1.2

Version:

3.18

Author:

Martin Desruisseaux (IRD, Geomatys)

See Also:

ProjectiveTransform, Serialized Form

Module:

referencing/geotk-referencing (download)

View source code for this class

Field Summary

Fields inherited from class AffineTransform

TYPE_FLIP, TYPE_GENERAL_ROTATION, TYPE_GENERAL_SCALE, TYPE_GENERAL_TRANSFORM, TYPE_IDENTITY, TYPE_MASK_ROTATION, TYPE_MASK_SCALE, TYPE_QUADRANT_ROTATION, TYPE_TRANSLATION, TYPE_UNIFORM_SCALE

Constructor Summary

AffineTransform2D(AffineTransform transform)
Constructs a new affine transform with the same coefficient than the specified transform.

AffineTransform2D(double m00, double m10, double m01, double m11, double m02, double m12)
Constructs a new AffineTransform2D from 6 values representing the 6 specifiable entries of the 3×3 transformation matrix.

Method Summary

protected void	checkPermission() Throws an UnsupportedOperationException when a mutable method is invoked, since AffineTransform2D must be immutable.
AffineTransform	clone() Returns a new affine transform which is a modifiable copy of this transform.
Shape	createTransformedShape(Shape shape) Transforms the specified shape.
Matrix	derivative(DirectPosition point) Gets the derivative of this transform at a point.
Matrix	derivative(Point2D point) Gets the derivative of this transform at a point.
boolean	equals(Object object) Compares this affine transform with the given object for equality.
boolean	equals(Object object, ComparisonMode mode) Compares this affine transform with the given object for equality.
String	formatWKT(Formatter formatter) Format the inner part of a Well Known Text (WKT) element.
Matrix	getMatrix() Returns this transform as an affine transform matrix.
ParameterDescriptorGroup	getParameterDescriptors() Returns the parameter descriptors for this math transform.
ParameterValueGroup	getParameterValues() Returns the matrix elements as a group of parameters values.
int	getSourceDimensions() Gets the dimension of input points, which is fixed to 2.
int	getTargetDimensions() Gets the dimension of output points, which is fixed to 2.
MathTransform2D	inverse() Creates the inverse transform of this object.
String	toString() Returns the WKT representation of this transform.
String	toWKT() Returns the WKT for this transform.
DirectPosition	transform(DirectPosition ptSrc, DirectPosition ptDst) Transforms the specified ptSrc and stores the result in ptDst.

Methods inherited from class XAffineTransform

concatenate, getFlip, getRotation, getScale, getScaleInstance, getScaleX0, getScaleY0, getSwapXY, inverseDeltaTransform, inverseTransform, invert, isIdentity, isIdentity, preConcatenate, quadrantRotate, quadrantRotate, rotate, rotate, rotate, rotate, roundIfAlmostInteger, scale, setToIdentity, setToQuadrantRotation, setToQuadrantRotation, setToRotation, setToRotation, setToRotation, setToRotation, setToScale, setToShear, setToTranslation, setTransform, setTransform, shear, transform, transform, translate

Methods inherited from class AffineTransform

createInverse, deltaTransform, deltaTransform, getDeterminant, getMatrix, getQuadrantRotateInstance, getQuadrantRotateInstance, getRotateInstance, getRotateInstance, getRotateInstance, getRotateInstance, getScaleInstance, getScaleX, getScaleY, getShearInstance, getShearX, getShearY, getTranslateInstance, getTranslateX, getTranslateY, getType, hashCode, inverseTransform, inverseTransform, isIdentity, transform, transform, transform, transform, transform, transform

Methods inherited from class Object

finalize, getClass, notify, notifyAll, wait, wait, wait

Methods inherited from interface MathTransform2D

transform

Methods inherited from interface LinearTransform

isIdentity

Methods inherited from interface MathTransform

isIdentity, transform, transform, transform, transform

Constructor Detail

AffineTransform2D

public AffineTransform2D(AffineTransform transform)

Constructs a new affine transform with the same coefficient than the specified transform.

Parameters:

transform - The affine transform to copy.

AffineTransform2D

public AffineTransform2D(double m00,
                         double m10,
                         double m01,
                         double m11,
                         double m02,
                         double m12)

Constructs a new AffineTransform2D from 6 values representing the 6 specifiable entries of the 3×3 transformation matrix. Those values are given unchanged to the super class constructor.

Parameters:

m00 - the X coordinate scaling.

m10 - the Y coordinate shearing.

m01 - the X coordinate shearing.

m11 - the Y coordinate scaling.

m02 - the X coordinate translation.

m12 - the Y coordinate translation.

Since:

2.5

Method Detail

checkPermission

protected final void checkPermission()
                              throws UnsupportedOperationException

Throws an UnsupportedOperationException when a mutable method is invoked, since AffineTransform2D must be immutable.

Overrides:

checkPermission in class XAffineTransform

Throws:

UnsupportedOperationException - Always thrown.

getParameterDescriptors

public ParameterDescriptorGroup getParameterDescriptors()

Returns the parameter descriptors for this math transform.

Specified by:

getParameterDescriptors in interface Parameterized

Returns:

The parameter descriptors for this math transform, or null.

See Also:

OperationMethod.getParameters()

getParameterValues

public ParameterValueGroup getParameterValues()

Returns the matrix elements as a group of parameters values. The number of parameters depends on the matrix size. Only matrix elements different from their default value will be included in this group.

Specified by:

getParameterValues in interface Parameterized

Returns:

A copy of the parameter values for this math transform, or null. Since this method returns a copy of the parameter values, any change to a value will have no effect on this math transform.

See Also:

SingleOperation.getParameterValues()

getSourceDimensions

public final int getSourceDimensions()

Gets the dimension of input points, which is fixed to 2.

Specified by:

getSourceDimensions in interface MathTransform

getTargetDimensions

public final int getTargetDimensions()

Gets the dimension of output points, which is fixed to 2.

Specified by:

getTargetDimensions in interface MathTransform

transform

public DirectPosition transform(DirectPosition ptSrc,
                                DirectPosition ptDst)

Transforms the specified ptSrc and stores the result in ptDst.

Specified by:

transform in interface MathTransform

createTransformedShape

public Shape createTransformedShape(Shape shape)

Transforms the specified shape. This method creates a simpler shape then the default super-class implementation. For example if the given shape is a rectangle and this affine transform has no scale or shear, then the returned shape will be an instance of Rectangle2D.

Specified by:

createTransformedShape in interface MathTransform2D

Overrides:

createTransformedShape in class AffineTransform

Parameters:

shape - Shape to transform.

Returns:

Transformed shape, or shape if this transform is the identity transform.

getMatrix

public Matrix getMatrix()

Returns this transform as an affine transform matrix.

Specified by:

getMatrix in interface LinearTransform

Returns:

A copy of the underlying matrix.

derivative

public Matrix derivative(Point2D point)

Gets the derivative of this transform at a point. For an affine transform, the derivative is the same everywhere.

Specified by:

derivative in interface MathTransform2D

derivative

public Matrix derivative(DirectPosition point)

Gets the derivative of this transform at a point. For an affine transform, the derivative is the same everywhere.

Specified by:

derivative in interface MathTransform

inverse

public MathTransform2D inverse()
                        throws NoninvertibleTransformException

Creates the inverse transform of this object.

Specified by:

inverse in interface MathTransform

Specified by:

inverse in interface MathTransform2D

Throws:

NoninvertibleTransformException - if this transform can't be inverted.

equals

public boolean equals(Object object,
                      ComparisonMode mode)

Compares this affine transform with the given object for equality. This method behaves as documented in the LinearTransform interface, except for the following case: if the given mode is ComparisonMode.STRICT, then this method delegates to equals(Object). The later method has different rules than the ones documented in the LinearTransform interface, because of the AffineTransform inheritance.

Specified by:

equals in interface LinearTransform

Specified by:

equals in interface LenientComparable

Parameters:

object - The object to compare to this.

mode - The strictness level of the comparison.

Returns:

true if both objects are equal.

Since:

3.18

equals

public boolean equals(Object object)

Compares this affine transform with the given object for equality. The comparison is performed in the same way than AffineTransform.equals(Object) with one additional rule: if the other object is also an instance of AffineTransform2D, then the two objects must be of the exact same class.

Most Geotk implementations require that the objects being compared are unconditionally of the same class in order to be considered equal. However many JDK implementations, including AffineTransform, do not have this requirement. Consequently the above condition (i.e. require the same class only if the given object is an AffineTransform2D or a subclass) is necessary in order to preserve the symmetricity contract of Object.equals(java.lang.Object).

A side-effect of this implementation is that the transitivity contract of Object.equals(Object) may be broken is some corner cases. This contract said:

a.equals(b) and b.equals(c) implies a.equals(c)

Assuming that a, b and c are instances of AffineTransform (where "instance of T" means T or any subclass of T), then the transitivity contract is broken if and only if exactly two of those objects are instance of AffineTransform2D and those two objects are not of the same class. Note that this implies that at least one subclass of AffineTransform2D is used.

In the vast majority of cases, the transitivity contract is not broken and the users can ignore this documentation. The transitivity contract is typically not broken either because we usually don't subclass AffineTransform2D, or because we don't mix AffineTransform with AffineTransform2D subclasses in the same collection.

This special case exists in order to allow developers to attach additional information to their own subclass of AffineTransform2D, and still distinguish their specialized subclass from ordinary affine transforms in a pool of MathTransform instances. The main application is the Equirectangular map projection, which can be simplified to an affine transform but still needs to remember the projection parameters.

Specified by:

equals in interface LenientComparable

Overrides:

equals in class AffineTransform

Parameters:

object - The object to compare with this affine transform for equality.

Returns:

true if the given object is of appropriate class (as explained in the above documentation) and the affine transform coefficients are the same.

clone

public AffineTransform clone()

Returns a new affine transform which is a modifiable copy of this transform. This implementation always returns an instance of AffineTransform, not AffineTransform2D, because the later is unmodifiable and cloning it make little sense.

Overrides:

clone in class AffineTransform

formatWKT

public String formatWKT(Formatter formatter)

Format the inner part of a Well Known Text (WKT) element.

Specified by:

formatWKT in interface Formattable

Parameters:

formatter - The formatter to use.

Returns:

The WKT element name.

toWKT

public String toWKT()

Returns the WKT for this transform.

Specified by:

toWKT in interface MathTransform

toString

public String toString()

Returns the WKT representation of this transform.

Overrides:

toString in class AffineTransform