/*
* Open Source Physics software is free software as described near the bottom of this code file.
*
* For additional information and documentation on Open Source Physics please see:
* <http://www.opensourcephysics.org/>
*/
package org.opensourcephysics.numerics;
import java.awt.geom.AffineTransform;
import org.opensourcephysics.controls.XML;
import org.opensourcephysics.controls.XMLControl;
import org.opensourcephysics.controls.XMLLoader;
/**
* Matrix2DTransformation implements 2D affine transformations
*/
public class Matrix2DTransformation implements MatrixTransformation {
private double[] origin = new double[] {0, 0};
private AffineTransform originTransform = new AffineTransform();
private AffineTransform internalTransform = new AffineTransform();
private AffineTransform originInverseTransform = new AffineTransform();
private AffineTransform totalTransform = new AffineTransform();
/**
* Constructs a 2D transformation using the given matrix.
*
* Affine transformations can be applied to 2D coordinates.
* A 2 by 3 matrix sets the rotation and shear.
* A null matrix sets the transformation to the identity transformation.
*
* @param matrix double[][]
*/
public Matrix2DTransformation(double[][] matrix) {
if(matrix!=null) {
internalTransform.setTransform(matrix[0][0], matrix[1][0], matrix[0][1], matrix[1][1], matrix[0][2], matrix[1][2]);
}
update();
}
/**
* Constructor Matrix2DTransformation
* @param transform
*/
public Matrix2DTransformation(AffineTransform transform) {
internalTransform.setTransform(transform);
update();
}
/**
* Creates a 2D transformation representing a rotation about the origin by the given angle.
*
* @param theta double
*
* @return Matrix2DTransformation
*/
public static Matrix2DTransformation rotation(double theta) {
return new Matrix2DTransformation(AffineTransform.getRotateInstance(theta));
}
/**
* Creates a 2D transformation representing a rotation about the origin by the given angle around
* the given axis.
*
* @param theta double
* @param anchorx double
* @param anchory double
* @return Matrix2DTransformation
*/
public static Matrix2DTransformation rotation(double theta, double anchorx, double anchory) {
return new Matrix2DTransformation(AffineTransform.getRotateInstance(theta, anchorx, anchory));
}
public AffineTransform getTotalTransform() {
return totalTransform;
}
/**
* Provides a copy of this transformation.
*/
public Object clone() {
return new Matrix2DTransformation(internalTransform);
}
/**
* Gets the direct homogeneous affine transformation flattened into a 1-d arrray.
*
* If the mat parameter is null a double[6] array is created;
* otherwise the given array is used.
*
* @param mat double[] optional matrix
* @return double[] the matrix
*/
public final double[] getFlatMatrix(double[] mat) {
if(mat==null) {
mat = new double[6];
}
internalTransform.getMatrix(mat);
return mat;
}
/**
* Instantiates a rotation that aligns the first vector with the second vector.
*
* @param v1 double[]
* @param v2 double[]
* @return Matrix2DTransformation
*/
public static Matrix2DTransformation createAlignmentTransformation(double[] v1, double v2[]) {
return new Matrix2DTransformation(AffineTransform.getRotateInstance(Math.atan2(v2[1], v2[0])-Math.atan2(v1[1], v1[0])));
}
/**
* Computes this internalTransform as a concatenation of the origin and the internal internalTransform
*/
private void update() {
totalTransform.setTransform(originTransform);
totalTransform.concatenate(internalTransform);
totalTransform.concatenate(originInverseTransform);
}
/**
* Sets the origin for this rotation.
*
* @param ox double
* @param oy double
*/
public void setOrigin(double ox, double oy) {
origin[0] = ox;
origin[1] = oy;
originTransform = AffineTransform.getTranslateInstance(ox, oy);
originInverseTransform = AffineTransform.getTranslateInstance(-ox, -oy);
update();
}
/**
* Sets the origin for this rotation.
*
* @param origin double[] the new origin
* @return double[]
*/
public double[] setOrigin(double[] origin) {
setOrigin(origin[0], origin[1]);
return origin;
}
/**
* Multiplies (concatenates) this transformation matrix with the given transformation.
*
* @param trans Matrix2DTransformation
*/
public final void multiply(Matrix2DTransformation trans) {
internalTransform.concatenate(trans.internalTransform);
update();
}
/**
* Multiplies this rotation matrix by the given matrix.
*
* @param mat double[][]
*/
public final void multiply(double[][] mat) {
internalTransform.concatenate(new Matrix2DTransformation(mat).internalTransform);
update();
}
/**
* Transforms the given point+.
*
* @param point the coordinates to be transformed
*/
public double[] direct(double[] point) {
totalTransform.transform(point, 0, point, 0, 1);
return point;
}
/**
* Transforms the given point using the inverse transformation (if it exists).
*
* If the transformation is not invertible, then a call to this
* method must throw a UnsupportedOperationException exception.
*
* @param point the coordinates to be transformed
*/
public double[] inverse(double[] point) throws UnsupportedOperationException {
try {
totalTransform.inverseTransform(point, 0, point, 0, 1);
return point;
} catch(java.awt.geom.NoninvertibleTransformException exc) {
throw new UnsupportedOperationException("The inverse matrix does not exist."); //$NON-NLS-1$
}
}
public static XML.ObjectLoader getLoader() {
return new Matrix2DTransformationLoader();
}
protected static class Matrix2DTransformationLoader extends XMLLoader {
public void saveObject(XMLControl control, Object obj) {
Matrix2DTransformation transf = (Matrix2DTransformation) obj;
control.setValue("matrix", transf.getFlatMatrix(null)); //$NON-NLS-1$
control.setValue("origin x", transf.origin); //$NON-NLS-1$
}
public Object createObject(XMLControl control) {
return new Matrix2DTransformation(new AffineTransform());
}
public Object loadObject(XMLControl control, Object obj) {
Matrix2DTransformation transf = (Matrix2DTransformation) obj;
transf.internalTransform.setTransform(new AffineTransform((double[]) control.getObject("matrix"))); //$NON-NLS-1$
transf.setOrigin((double[]) control.getObject("origin")); //$NON-NLS-1$
return obj;
}
}
}
/*
* Open Source Physics software is free software; you can redistribute
* it and/or modify it under the terms of the GNU General Public License (GPL) as
* published by the Free Software Foundation; either version 2 of the License,
* or(at your option) any later version.
* Code that uses any portion of the code in the org.opensourcephysics package
* or any subpackage (subdirectory) of this package must must also be be released
* under the GNU GPL license.
*
* This software is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston MA 02111-1307 USA
* or view the license online at http://www.gnu.org/copyleft/gpl.html
*
* Copyright (c) 2007 The Open Source Physics project
* http://www.opensourcephysics.org
*/