Package org.apache.sis.referencing.operation.transform

Class ProjectiveTransform

java.lang.Object
org.apache.sis.io.wkt.FormattableObject
org.apache.sis.referencing.operation.transform.AbstractMathTransform
org.apache.sis.referencing.operation.transform.AbstractLinearTransform
org.apache.sis.referencing.operation.transform.ProjectiveTransform
All Implemented Interfaces:
Serializable, ExtendedPrecisionMatrix, Parameterized, LinearTransform, LenientComparable, org.opengis.referencing.operation.MathTransform, org.opengis.referencing.operation.Matrix
Direct Known Subclasses:
ProjectiveTransform2D
class ProjectiveTransform extends AbstractLinearTransform implements ExtendedPrecisionMatrix
A usually affine, or otherwise a projective transform for the generic cases. This implementation is used for cases other than identity, 1D, 2D or axis swapping.

A projective transform is capable of mapping an arbitrary quadrilateral into another arbitrary quadrilateral, while preserving the straightness of lines. In the special case where the transform is affine, the parallelism of lines in the source is preserved in the output.

Since:
0.5
Version:
1.2
See Also:

  • Field Details

    • serialVersionUID

      private static final long serialVersionUID
      Serial number for inter-operability with different versions.
      See Also:

    • numRow

      private final int numRow
      The number of rows.

    • numCol

      private final int numCol
      The number of columns.

    • elt

      private final double[] elt
      Elements of the matrix. Column indices vary fastest.

      This array may have twice the normal length (numRow × numCol), in which case the second half contains the error terms in double-double arithmetic.

  • Constructor Details

    • ProjectiveTransform

      protected ProjectiveTransform(org.opengis.referencing.operation.Matrix matrix)
      Constructs a transform from the specified matrix. The matrix is usually square and affine, but this is not enforced.
      Parameters:
      matrix - the matrix.

  • Method Details

    • optimize

      final LinearTransform optimize()
      If a more efficient implementation of this math transform can be used, returns it. Otherwise returns this unchanged.

    • getSourceDimensions

      public final int getSourceDimensions()
      Gets the dimension of input points.
      Specified by:
      getSourceDimensions in interface org.opengis.referencing.operation.MathTransform
      Specified by:
      getSourceDimensions in class AbstractMathTransform
      Returns:
      the number of dimensions of input points.
      See Also:

    • getTargetDimensions

      public final int getTargetDimensions()
      Gets the dimension of output points.
      Specified by:
      getTargetDimensions in interface org.opengis.referencing.operation.MathTransform
      Specified by:
      getTargetDimensions in class AbstractMathTransform
      Returns:
      the number of dimensions of output points.
      See Also:

    • getNumRow

      public final int getNumRow()
      Gets the number of rows in the matrix.
      Specified by:
      getNumRow in interface org.opengis.referencing.operation.Matrix
      Overrides:
      getNumRow in class AbstractLinearTransform

    • getNumCol

      public final int getNumCol()
      Gets the number of columns in the matrix.
      Specified by:
      getNumCol in interface org.opengis.referencing.operation.Matrix
      Overrides:
      getNumCol in class AbstractLinearTransform

    • getExtendedElements

      public final double[] getExtendedElements()
      Returns a copy of matrix elements, including error terms if any.
      Specified by:
      getExtendedElements in interface ExtendedPrecisionMatrix
      Returns:
      a copy of matrix elements, potentially followed by error terms.

    • getElement

      public final double getElement(int row, int column)
      Returns the matrix element at the given index.
      Specified by:
      getElement in interface org.opengis.referencing.operation.Matrix

    • isIdentity

      public final boolean isIdentity()
      Tests whether this transform does not move any points.
      Note: this method should always returns false, since MathTransforms.linear(…) should have created specialized implementations for identity cases. Nevertheless we perform the full check as a safety, in case someone instantiated this class directly instead of using a factory method.
      Specified by:
      isIdentity in interface org.opengis.referencing.operation.MathTransform
      Specified by:
      isIdentity in interface org.opengis.referencing.operation.Matrix
      Overrides:
      isIdentity in class AbstractMathTransform

    • transform

      public final org.opengis.referencing.operation.Matrix transform(double[] srcPts, int srcOff, double[] dstPts, int dstOff, boolean derivate)
      Converts a single coordinate tuple in a list of coordinate values, and optionally computes the derivative at that location.
      Specified by:
      transform in class AbstractMathTransform
      Parameters:
      srcPts - the array containing the source coordinates (cannot be null).
      srcOff - the offset to the point to be transformed in the source array.
      dstPts - the array into which the transformed coordinates is returned. May be the same than srcPts. May be null if only the derivative matrix is desired.
      dstOff - the offset to the location of the transformed point that is stored in the destination array.
      derivate - true for computing the derivative, or false if not needed.
      Returns:
      the matrix of the transform derivative at the given source position, or null if the derivate argument is false.
      See Also:

    • transform

      public final void transform(double[] srcPts, int srcOff, double[] dstPts, int dstOff, int numPts)
      Transforms an array of floating point coordinates by this matrix. Point coordinates must have a dimension equal to Matrix.getNumCol()-1. For example, for square matrix of size 4×4, coordinate points are three-dimensional and stored in the arrays starting at the specified offset (srcOff) in the order [x₀, y₀, z₀, x₁, y₁, z₁..., xn, yn, zn].
      Specified by:
      transform in interface org.opengis.referencing.operation.MathTransform
      Overrides:
      transform in class AbstractMathTransform
      Parameters:
      srcPts - the array containing the source point coordinates.
      srcOff - the offset to the first point to be transformed in the source array.
      dstPts - the array into which the transformed point coordinates are returned.
      dstOff - the offset to the location of the first transformed point that is stored in the destination array. The source and destination array sections can overlap.
      numPts - the number of points to be transformed.

    • transform

      public final void transform(float[] srcPts, int srcOff, float[] dstPts, int dstOff, int numPts)
      Transforms an array of floating point coordinates by this matrix. Point coordinates must have a dimension equal to Matrix.getNumCol() - 1. For example, for square matrix of size 4×4, coordinate points are three-dimensional and stored in the arrays starting at the specified offset (srcOff) in the order [x₀, y₀, z₀, x₁, y₁, z₁..., xn, yn, zn].
      Specified by:
      transform in interface org.opengis.referencing.operation.MathTransform
      Overrides:
      transform in class AbstractMathTransform
      Parameters:
      srcPts - the array containing the source point coordinates.
      srcOff - the offset to the first point to be transformed in the source array.
      dstPts - the array into which the transformed point coordinates are returned.
      dstOff - the offset to the location of the first transformed point that is stored in the destination array. The source and destination array sections can overlap.
      numPts - the number of points to be transformed.

    • transform

      public final void transform(double[] srcPts, int srcOff, float[] dstPts, int dstOff, int numPts)
      Transforms an array of floating point coordinates by this matrix.
      Specified by:
      transform in interface org.opengis.referencing.operation.MathTransform
      Overrides:
      transform in class AbstractMathTransform
      Parameters:
      srcPts - the array containing the source point coordinates.
      srcOff - the offset to the first point to be transformed in the source array.
      dstPts - the array into which the transformed point coordinates are returned.
      dstOff - the offset to the location of the first transformed point that is stored in the destination array.
      numPts - the number of points to be transformed.

    • transform

      public final void transform(float[] srcPts, int srcOff, double[] dstPts, int dstOff, int numPts)
      Transforms an array of floating point coordinates by this matrix.
      Specified by:
      transform in interface org.opengis.referencing.operation.MathTransform
      Overrides:
      transform in class AbstractMathTransform
      Parameters:
      srcPts - the array containing the source point coordinates.
      srcOff - the offset to the first point to be transformed in the source array.
      dstPts - the array into which the transformed point coordinates are returned.
      dstOff - the offset to the location of the first transformed point that is stored in the destination array.
      numPts - the number of points to be transformed.

    • derivative

      public final org.opengis.referencing.operation.Matrix derivative(org.opengis.geometry.DirectPosition point)
      Gets the derivative of this transform at a point. For an affine transform, the derivative is the same everywhere and the given point is ignored. For a perspective transform, the given point is used.
      Specified by:
      derivative in interface org.opengis.referencing.operation.MathTransform
      Overrides:
      derivative in class AbstractMathTransform
      Parameters:
      point - the coordinate tuple where to evaluate the derivative.
      Returns:
      the derivative at the specified point (never null).

    • computeHashCode

      protected int computeHashCode()
      Computes a hash value for this transform. This method is invoked by AbstractMathTransform.hashCode() when first needed.
      Overrides:
      computeHashCode in class AbstractMathTransform
      Returns:
      the hash code value. This value may change between different execution of the Apache SIS library.

    • equalsSameClass

      protected boolean equalsSameClass(Object object)
      Compares this math transform with an object which is known to be an instance of the same class.
      Specified by:
      equalsSameClass in class AbstractLinearTransform
      Parameters:
      object - the object to compare with this transform.
      Returns:
      true if the given object is considered equals to this math transform.