org.locationtech.jts.geom.util

Class AffineTransformationBuilder

java.lang.Object

org.locationtech.jts.geom.util.AffineTransformationBuilder

public class AffineTransformationBuilder
extends Object

Builds an AffineTransformation defined by a set of control vectors. A control vector consists of a source point and a destination point, which is the image of the source point under the desired transformation.

A transformation is well-defined by a set of three control vectors if and only if the source points are not collinear. (In particular, the degenerate situation where two or more source points are identical will not produce a well-defined transformation). A well-defined transformation exists and is unique. If the control vectors are not well-defined, the system of equations defining the transformation matrix entries is not solvable, and no transformation can be determined.

No such restriction applies to the destination points. However, if the destination points are collinear or non-unique, a non-invertible transformations will be generated.

This technique of recovering a transformation from its effect on known points is used in the Bilinear Interpolated Triangulation algorithm for warping planar surfaces.

Author:

Martin Davis

Constructor Summary

Constructors

Constructor and Description
AffineTransformationBuilder(Coordinate src0, Coordinate src1, Coordinate src2, Coordinate dest0, Coordinate dest1, Coordinate dest2) Constructs a new builder for the transformation defined by the given set of control point mappings.

Method Summary

Modifier and Type	Method and Description
AffineTransformation	getTransformation() Computes the AffineTransformation determined by the control point mappings, or null if the control vectors do not determine a well-defined transformation.

Methods inherited from class java.lang.Object

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

Constructor Detail

AffineTransformationBuilder

public AffineTransformationBuilder(Coordinate src0,
                                   Coordinate src1,
                                   Coordinate src2,
                                   Coordinate dest0,
                                   Coordinate dest1,
                                   Coordinate dest2)

Constructs a new builder for the transformation defined by the given set of control point mappings.

Parameters:

src0 - a control point

src1 - a control point

src2 - a control point

dest0 - the image of control point 0 under the required transformation

dest1 - the image of control point 1 under the required transformation

dest2 - the image of control point 2 under the required transformation

Method Detail

getTransformation

public AffineTransformation getTransformation()

Computes the AffineTransformation determined by the control point mappings, or null if the control vectors do not determine a well-defined transformation.

Returns:

an affine transformation, or null if the control vectors do not determine a well-defined transformation