/*
* GeoTools - The Open Source Java GIS Toolkit
* http://geotools.org
*
* (C) 2004-2008, Open Source Geospatial Foundation (OSGeo)
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation;
* version 2.1 of the License.
*
* This library 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
* Lesser General Public License for more details.
*/
package org.geotools.geometry.jts;
// JTS dependencies
import com.vividsolutions.jts.geom.Coordinate;
import com.vividsolutions.jts.geom.CoordinateSequence;
import com.vividsolutions.jts.geom.CoordinateSequenceFactory;
import com.vividsolutions.jts.geom.impl.CoordinateArraySequenceFactory;
import org.opengis.geometry.MismatchedDimensionException;
// OpenGIS dependencies
import org.opengis.referencing.operation.MathTransform;
import org.opengis.referencing.operation.TransformException;
/**
* A default implementation of {@linkplain CoordinateSequenceTransformer coordinate sequence
* transformer}. This transformer applies the coordinate transformations immediately (which
* means that caller are immediately notified if a transformation fails).
* <p>
* This transformer support {@linkplain MathTransform math transform} with up to 3 source
* or target dimensions. This transformer is not thread-safe.
*
* @since 2.1
*
*
* @source $URL$
* @version $Id$
* @author Andrea Aime
* @author Martin Desruisseaux
*/
public class DefaultCoordinateSequenceTransformer implements CoordinateSequenceTransformer {
/**
* A buffer for coordinate transformations. We choose a length which is divisible by
* both 2 and 3, since JTS coordinates may be up to three-dimensional. If the number
* of coordinates point to transform is greater than the buffer capacity, then the
* buffer will be flushed to the destination array before to continue. We avoid to
* create a buffer as large than the number of point to transforms, because it would
* consume a large amount of memory for big geometries.
*/
private final transient double[] buffer = new double[96];
/**
* The coordinate sequence factory to use.
*/
private final CoordinateSequenceFactory csFactory;
/**
* Constructs a default coordinate sequence transformer.
*/
public DefaultCoordinateSequenceTransformer() {
csFactory = CoordinateArraySequenceFactory.instance();
}
public DefaultCoordinateSequenceTransformer(CoordinateSequenceFactory csFactory) {
this.csFactory = csFactory;
}
/**
* {@inheritDoc}
*/
public CoordinateSequence transform(final CoordinateSequence sequence,
final MathTransform transform) throws TransformException {
final int sourceDim = transform.getSourceDimensions();
final int targetDim = transform.getTargetDimensions();
final int size = sequence.size();
final Coordinate[] tcs = new Coordinate[size];
final int bufferCapacity = buffer.length / Math.max(sourceDim, targetDim);
int remainingBeforeFlush = Math.min(bufferCapacity, size);
int ib = 0; // Index in the buffer array.
int it = 0; // Index in the target sequence.
// create a target CS so that the dimensions not contemplated in the source CS
// are copied over (think Z or M with a 2d CRS)
int targetCSDim = targetDim + (sequence.getDimension() - sourceDim);
CoordinateSequence result = csFactory.create(sequence.size(), targetCSDim);
for (int i = 0; i < size; i++) {
switch (sourceDim) {
default:
throw new MismatchedDimensionException();
case 3:
buffer[ib + 2] = sequence.getOrdinate(i, 2); // Fall through
case 2:
buffer[ib + 1] = sequence.getY(i); // Fall through
case 1:
buffer[ib] = sequence.getX(i); // Fall through
case 0:
break;
}
ib += sourceDim;
if (--remainingBeforeFlush == 0) {
/*
* The buffer is full, or we just copied the last coordinates.
* Transform the coordinates and flush to the destination array.
*/
assert (ib % sourceDim) == 0;
final int n = ib / sourceDim;
transform.transform(buffer, 0, buffer, 0, n);
ib = 0;
for (int j = 0; j < n; j++) {
//final Coordinate t;
// copy the transformed portion
int oi = 0;
for (; oi < targetDim; oi++) {
result.setOrdinate(it, oi, buffer[ib++]);
}
// copy over the non transformed portion
for (; oi < targetCSDim; oi++) {
result.setOrdinate(it, oi, sequence.getOrdinate(it, oi + (targetDim - sourceDim)));
}
// force to NaN eventual extra ordinates the sequence has (some are fixed size, wont'
// care about us trying to tell them a size). This works around a bug in the default
// JTS coordinate sequence implementation
for (; oi < result.getDimension(); oi++) {
result.setOrdinate(it, oi, Double.NaN);
}
it++;
}
assert ib == (n * targetDim);
ib = 0;
remainingBeforeFlush = Math.min(bufferCapacity, size - (i + 1));
}
}
assert it == tcs.length : tcs.length - it;
return result;
}
}