/*
* GeoTools - The Open Source Java GIS Toolkit
* http://geotools.org
*
* (C) 2002-2008, 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.coverage;
import java.awt.image.BufferedImage;
import java.awt.image.DataBuffer;
import java.awt.image.DataBufferByte;
import java.awt.image.RenderedImage;
import java.util.Random;
import javax.media.jai.PlanarImage;
import javax.media.jai.RenderedImageAdapter;
import javax.media.jai.RenderedOp;
import org.opengis.referencing.operation.MathTransform;
import org.opengis.referencing.operation.TransformException;
import org.geotools.coverage.grid.ViewType;
import org.geotools.coverage.grid.GridCoverage2D;
import org.geotools.coverage.grid.GridCoverageFactory;
import org.geotools.referencing.crs.DefaultGeographicCRS;
import org.geotools.referencing.operation.transform.IdentityTransform;
import org.junit.*;
import static org.junit.Assert.*;
/**
* Tests the {@link SampleTranscoder} implementation. Image adapter depends
* heavily on {@link CategoryList}, so this one should be tested first.
*
*
*
* @source $URL$
* @version $Id$
* @author Martin Desruisseaux (IRD)
*/
public final class SampleTranscoderTest {
/**
* Small value for comparaisons. Remind: transformed values are stored in a new image
* using the 'float' data type. So we can't expected as much precision than with a
* 'double' data type.
*/
private static final double EPS = 1E-5;
/**
* Random number generator for this test.
*/
private static final Random random = new Random(6215962897884256696L);
/**
* A sample dimension for a band.
*/
private GridSampleDimension band1;
/**
* Sets up common objects used for all tests.
*/
@Before
public void setUp() {
band1 = new GridSampleDimension("Temperature", new Category[] {
new Category("No data", null, 0),
new Category("Land", null, 1),
new Category("Clouds", null, 2),
new Category("Temperature", null, 3, 100, 0.1, 5),
new Category("Foo", null, 100, 160, -1, 3),
new Category("Tarzan", null, 160)
}, null);
}
/**
* Tests the transformation using a random raster with only one band.
*
* @throws TransformException If an error occured while transforming a value.
*/
@Test
public void testOneBand() throws TransformException {
assertTrue(testOneBand(1, 0) instanceof RenderedImageAdapter);
assertTrue(testOneBand(.8, 2) instanceof RenderedOp);
assertTrue(testOneBand(band1) instanceof RenderedOp);
}
/**
* Tests the transformation using a random raster with only one band.
* A sample dimension with only one category will be used.
*
* @param scale The scale factor.
* @param offset The offset value.
* @return The transformed image.
*/
private RenderedImage testOneBand(final double scale, final double offset) throws TransformException {
final Category category = new Category("Values", null, 0, 256, scale, offset);
return testOneBand(new GridSampleDimension("Measure", new Category[] {category}, null));
}
/**
* Tests the transformation using a random raster with only one band.
*
* @param band The sample dimension for the only band.
* @return The transformed image.
*/
private RenderedImage testOneBand(final GridSampleDimension band) throws TransformException {
final int SIZE = 64;
/*
* Constructs a 64x64 image with random values.
* Samples values are integer in the range 0..160 inclusive.
*/
final BufferedImage source = new BufferedImage(SIZE, SIZE, BufferedImage.TYPE_BYTE_INDEXED);
final DataBufferByte buffer = (DataBufferByte) source.getRaster().getDataBuffer();
final byte[] array = buffer.getData(0);
for (int i=0; i<array.length; i++) {
array[i] = (byte) random.nextInt(161);
}
final MathTransform identity = IdentityTransform.create(2);
final GridCoverageFactory factory = CoverageFactoryFinder.getGridCoverageFactory(null);
GridCoverage2D coverage;
coverage = factory.create("Test", source, DefaultGeographicCRS.WGS84,
identity, new GridSampleDimension[] {band}, null, null);
/*
* Apply the operation. The SampleTranscoder class is suppose to transform our
* integers into real-world values. Check if the result use floating-points.
*/
final RenderedImage target = coverage.view(ViewType.GEOPHYSICS).getRenderedImage();
assertSame(target, PlanarImage.wrapRenderedImage(target));
assertEquals(DataBuffer.TYPE_BYTE, source.getSampleModel().getDataType());
if (coverage.getRenderedImage() != target) {
assertEquals(DataBuffer.TYPE_FLOAT, target.getSampleModel().getDataType());
}
/*
* Now, gets the data as an array and compare it with the expected values.
*/
double[] sourceData = source.getData().getSamples(0, 0, SIZE, SIZE, 0, (double[]) null);
double[] targetData = target.getData().getSamples(0, 0, SIZE, SIZE, 0, (double[]) null);
band.getSampleToGeophysics().transform(sourceData, 0, sourceData, 0, sourceData.length);
CategoryListTest.compare(sourceData, targetData, EPS);
/*
* Construct a new image with the resulting data, and apply an inverse transformation.
* Compare the resulting values with the original data.
*/
RenderedImage back = PlanarImage.wrapRenderedImage(target).getAsBufferedImage();
coverage = factory.create("Test", back, DefaultGeographicCRS.WGS84,
identity, new GridSampleDimension[]{band.geophysics(true)}, null, null);
back = coverage.view(ViewType.PACKED).getRenderedImage();
assertEquals(DataBuffer.TYPE_BYTE, back.getSampleModel().getDataType());
sourceData = source.getData().getSamples(0, 0, SIZE, SIZE, 0, (double[]) null);
targetData = back.getData().getSamples(0, 0, SIZE, SIZE, 0, (double[]) null);
CategoryListTest.compare(sourceData, targetData, 1.0 + EPS);
/*
* Returns the "geophysics view" of the image.
*/
return target;
}
}