Package org.geotools.referencing.operation.matrix

Class XAffineTransform

Object
AffineTransform
XAffineTransform
All Implemented Interfaces:
Serializable, Cloneable
Direct Known Subclasses:
AffineTransform2D
public class XAffineTransform extends AffineTransform
Utility methods for affine transforms. This class provides two kind of services:

  • A set of public static methods working on any AffineTransform.

  • An abstract base class that override all mutable AffineTransform methods in order to check for permission before changing the transform's state. If checkPermission() is defined to always throw an exception, then XAffineTransform is immutable.

Since:
2.3
Author:
Martin Desruisseaux (IRD), Simone Giannecchini
See Also:

  • Constructor Details

    • XAffineTransform

      public XAffineTransform(AffineTransform tr)
      Constructs a new XAffineTransform that is a copy of the specified AffineTransform object.

    • XAffineTransform

      public XAffineTransform(double m00, double m10, double m01, double m11, double m02, double m12)
      Constructs a new XAffineTransform from 6 values representing the 6 specifiable entries of the 3×3 transformation matrix. Those values are given unchanged to the super class constructor.
      Since:
      2.5

  • Method Details

    • checkPermission

      protected void checkPermission() throws UnsupportedOperationException
      Checks if the caller is allowed to change this XAffineTransform state. If this method is defined to thrown an exception in all case, then this XAffineTransform is immutable.

      The default implementation throws the exception in all case, thus making this instance immutable.

      Throws:
      UnsupportedOperationException - if this affine transform is immutable.

    • translate

      public void translate(double tx, double ty)
      Checks for permission before translating this transform.
      Overrides:
      translate in class AffineTransform

    • rotate

      public void rotate(double theta)
      Checks for permission before rotating this transform.
      Overrides:
      rotate in class AffineTransform

    • rotate

      public void rotate(double theta, double x, double y)
      Checks for permission before rotating this transform.
      Overrides:
      rotate in class AffineTransform

    • scale

      public void scale(double sx, double sy)
      Checks for permission before scaling this transform.
      Overrides:
      scale in class AffineTransform

    • shear

      public void shear(double shx, double shy)
      Checks for permission before shearing this transform.
      Overrides:
      shear in class AffineTransform

    • setToIdentity

      public void setToIdentity()
      Checks for permission before setting this transform.
      Overrides:
      setToIdentity in class AffineTransform

    • setToTranslation

      public void setToTranslation(double tx, double ty)
      Checks for permission before setting this transform.
      Overrides:
      setToTranslation in class AffineTransform

    • setToRotation

      public void setToRotation(double theta)
      Checks for permission before setting this transform.
      Overrides:
      setToRotation in class AffineTransform

    • setToRotation

      public void setToRotation(double theta, double x, double y)
      Checks for permission before setting this transform.
      Overrides:
      setToRotation in class AffineTransform

    • setToScale

      public void setToScale(double sx, double sy)
      Checks for permission before setting this transform.
      Overrides:
      setToScale in class AffineTransform

    • setToShear

      public void setToShear(double shx, double shy)
      Checks for permission before setting this transform.
      Overrides:
      setToShear in class AffineTransform

    • setTransform

      public void setTransform(AffineTransform Tx)
      Checks for permission before setting this transform.
      Overrides:
      setTransform in class AffineTransform

    • setTransform

      public void setTransform(double m00, double m10, double m01, double m11, double m02, double m12)
      Checks for permission before setting this transform.
      Overrides:
      setTransform in class AffineTransform

    • concatenate

      public void concatenate(AffineTransform Tx)
      Checks for permission before concatenating this transform.
      Overrides:
      concatenate in class AffineTransform

    • preConcatenate

      public void preConcatenate(AffineTransform Tx)
      Checks for permission before concatenating this transform.
      Overrides:
      preConcatenate in class AffineTransform

    • isIdentity

      public boolean isIdentity(double tolerance)
      Checks whether or not this XAffineTransform is the identity by using the provided tolerance.
      Parameters:
      tolerance - The tolerance to use for this check.
      Returns:
      true if the transform is identity, false otherwise.
      Since:
      2.3.1

    • isIdentity

      public static boolean isIdentity(AffineTransform tr, double tolerance)
      Returns true if the specified affine transform is an identity transform up to the specified tolerance. This method is equivalent to computing the difference between this matrix and an identity matrix (as created by new AffineTransform()) and returning true if and only if all differences are smaller than or equal to tolerance.

      This method is used for working around rounding error in affine transforms resulting from a computation, as in the example below: 

       [ 1.0000000000000000001  0.0                      0.0 ]
 [ 0.0                    0.999999999999999999999  0.0 ]
 [ 0.0                    0.0                      1.0 ]
      Parameters:
      tr - The affine transform to be checked for identity.
      tolerance - The tolerance value to use when checking for identity. return true if this tranformation is close enough to the identity, false otherwise.
      Since:
      2.3.1

    • transform

      public static Shape transform(AffineTransform transform, Shape shape, boolean overwrite)
      Transforms the given shape. This method is similar to createTransformedShape except that:

      • It tries to preserve the shape kind when possible. For example if the given shape is an instance of RectangularShape and the given transform do not involve rotation, then the returned shape may be some instance of the same class.
      • It tries to recycle the given object if overwrite is true.
      Parameters:
      transform - Affine transform to use.
      shape - The shape to transform.
      overwrite - If true, this method is allowed to overwrite shape with the transform result. If false, then shape is never modified.
      Returns:
      The direct transform of the given shape. May or may not be the same instance than the given shape.
      Since:
      2.5
      See Also:

    • transform

      public static Rectangle2D transform(AffineTransform transform, Rectangle2D bounds, Rectangle2D dest)
      Returns a rectangle which entirely contains the direct transform of bounds. This operation is equivalent to:
      createTransformedShape(bounds).getBounds2D()
      Parameters:
      transform - Affine transform to use.
      bounds - Rectangle to transform. This rectangle will not be modified except if dest is the same reference.
      dest - Rectangle in which to place the result. If null, a new rectangle will be created.
      Returns:
      The direct transform of the bounds rectangle.
      See Also:

    • inverseTransform

      public static Rectangle2D inverseTransform(AffineTransform transform, Rectangle2D bounds, Rectangle2D dest) throws NoninvertibleTransformException
      Returns a rectangle which entirely contains the inverse transform of bounds. This operation is equivalent to:
      createInverse().createTransformedShape(bounds).getBounds2D()
      Parameters:
      transform - Affine transform to use.
      bounds - Rectangle to transform. This rectangle will not be modified.
      dest - Rectangle in which to place the result. If null, a new rectangle will be created.
      Returns:
      The inverse transform of the bounds rectangle.
      Throws:
      NoninvertibleTransformException - if the affine transform can't be inverted.

    • inverseDeltaTransform

      public static Point2D inverseDeltaTransform(AffineTransform transform, Point2D source, Point2D dest) throws NoninvertibleTransformException
      Calculates the inverse affine transform of a point without without applying the translation components.
      Parameters:
      transform - Affine transform to use.
      source - Point to transform. This rectangle will not be modified.
      dest - Point in which to place the result. If null, a new point will be created.
      Returns:
      The inverse transform of the source point.
      Throws:
      NoninvertibleTransformException - if the affine transform can't be inverted.

    • getSwapXY

      public static int getSwapXY(AffineTransform tr)
      Returns an estimation about whatever the specified transform swaps x and y axis. This method assumes that the specified affine transform is built from arbitrary translations, scales or rotations, but no shear. It returns +1 if the (x, y) axis order seems to be preserved, -1 if the transform seems to swap axis to the (y, x) axis order, or 0 if this method can not make a decision.

    • getRotation

      public static double getRotation(AffineTransform tr)
      Returns an estimation of the rotation angle in radians. This method assumes that the specified affine transform is built from arbitrary translations, scales or rotations, but no shear. If a flip has been applied, then this method assumes that the flipped axis is the y one in source CRS space. For a grid to world CRS transform, this is the row number in grid coordinates.
      Parameters:
      tr - The affine transform to inspect.
      Returns:
      An estimation of the rotation angle in radians, or NaN if the angle can not be estimated.

    • getFlip

      public static int getFlip(AffineTransform tr)
      Returns -1 if one axis has been flipped, +1 if no axis has been flipped, or 0 if unknown. A flipped axis in an axis with direction reversed (typically the y axis). This method assumes that the specified affine transform is built from arbitrary translations, scales or rotations, but no shear. Note that it is not possible to determine which of the x or y axis has been flipped.

      This method can be used in order to set the sign of a scale according the flipping state. The example below choose to apply the sign on the y scale, but this is an arbitrary (while common) choice:

      double scaleX0 = getScaleX0(transform); double scaleY0 = getScaleY0(transform); int flip = getFlip(transform); if (flip != 0) { scaleY0 *= flip; // ... continue the process here. }
      This method is similar to the following code, except that this method distinguish between "unflipped" and "unknow" states.
      boolean flipped = (tr.getType() & AffineTransform.TYPE_FLIP) != 0;

    • getScaleX0

      public static double getScaleX0(AffineTransform tr)
      Returns the magnitude of scale factor x by cancelling the effect of eventual flip and rotation. This factor is calculated by .

    • getScaleY0

      public static double getScaleY0(AffineTransform tr)
      Returns the magnitude of scale factor y by cancelling the effect of eventual flip and rotation. This factor is calculated by .

    • getScale

      public static double getScale(AffineTransform tr)
      Returns a global scale factor for the specified affine transform. This scale factor will combines getScaleX0(java.awt.geom.AffineTransform) and getScaleY0(java.awt.geom.AffineTransform). The way to compute such a "global" scale is somewhat arbitrary and may change in a future version.

    • getScaleInstance

      public static AffineTransform getScaleInstance(double sx, double sy, double x, double y)
      Returns an affine transform representing a zoom carried out around a central point (x, y). The transforms will leave the specified (x, y) coordinate unchanged.
      Parameters:
      sx - Scale along x axis.
      sy - Scale along y axis.
      x - x coordinates of the central point.
      y - y coordinates of the central point.
      Returns:
      Affine transform of a zoom which leaves the (x,y) coordinate unchanged.

    • round

      public static void round(AffineTransform tr, double tolerance)
      Checks whether the matrix coefficients are close to whole numbers. If this is the case, these coefficients will be rounded up to the nearest whole numbers. This rounding up is useful, for example, for speeding up image displays. Above all, it is efficient when we know that a matrix has a chance of being close to the similarity matrix.
      Parameters:
      tr - The matrix to round. Rounding will be applied in place.
      tolerance - The maximal departure from integers in order to allow rounding. It is typically a small number like 1E-6.
      Since:
      2.3.1