/*
* Geotoolkit.org - An Open Source Java GIS Toolkit
* http://www.geotoolkit.org
*
* (C) 2001-2012, Open Source Geospatial Foundation (OSGeo)
* (C) 2009-2012, Geomatys
*
* 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.geotoolkit.coverage.grid;
import java.awt.RenderingHints;
import java.awt.color.ColorSpace;
import java.awt.image.*; // Numerous imports here.
import java.awt.image.renderable.ParameterBlock;
import java.util.*;
import java.util.logging.Logger;
import java.util.logging.LogRecord;
import javax.media.jai.JAI;
import javax.media.jai.ROI;
import javax.media.jai.RenderedOp;
import javax.media.jai.ImageLayout;
import javax.media.jai.NullOpImage;
import javax.media.jai.PlanarImage;
import javax.media.jai.LookupTableJAI;
import javax.media.jai.operator.FormatDescriptor;
import javax.media.jai.operator.LookupDescriptor;
import org.opengis.util.InternationalString;
import org.opengis.coverage.grid.GridCoverage;
import org.opengis.referencing.operation.MathTransform1D;
import org.opengis.referencing.operation.TransformException;
import org.opengis.referencing.operation.NoninvertibleTransformException;
import org.geotoolkit.factory.Hints;
import org.apache.sis.util.ArraysExt;
import org.apache.sis.measure.NumberRange;
import org.apache.sis.util.logging.Logging;
import org.geotoolkit.coverage.Category;
import org.geotoolkit.coverage.GridSampleDimension;
import org.geotoolkit.coverage.processing.AbstractCoverageProcessor;
import org.geotoolkit.resources.Errors;
import org.geotoolkit.resources.Loggings;
import org.geotoolkit.resources.Vocabulary;
import org.geotoolkit.internal.coverage.CoverageUtilities;
import static java.lang.Double.NaN;
import static java.lang.Double.isNaN;
import static java.lang.Double.doubleToRawLongBits;
import static org.apache.sis.util.collection.Containers.isNullOrEmpty;
import org.geotoolkit.image.color.ColorUtilities;
import org.geotoolkit.image.internal.ImageUtilities;
/**
* Holds the different views of a {@link GridCoverage2D}. Those views are handled in a separated
* class because the same instance may be shared by more than one {@link GridCoverage2D}. Because
* views are associated with potentially big images, sharing them when possible is a big memory
* and CPU saver.
*
* @author Martin Desruisseaux (IRD, Geomatys)
* @version 3.11
*
* @since 2.5
* @module
*/
final class ViewsManager {
/**
* Slight number for rounding errors in floating point comparison.
*/
private static final float EPS = 1E-5f;
/**
* The views. The coverage that created this {@code ViewsManager} must be stored under
* the {@link ViewType#NATIVE} key.
*
* /!\ Valid views for the coverage are determined at built, and identified using image properties. If user asks for
* a non-managed type of view, an attempt will be done to satisfy him, but in ABSOLUTELY no case queried view type
* will be added to the managed types. It would violate immutability and coherence of underlying data.
*/
private final Map<ViewType,GridCoverage2D> views;
/**
* List of coherent view which can be extracted from source data.
*/
final Set<ViewType> viewTypes;
/**
* Constructs a map of views.
*
* @param coverage The coverage that created this {@code ViewsManager}.
*/
private ViewsManager(final GridCoverage2D coverage) {
views = new EnumMap<>(ViewType.class);
boolean geophysics = true; // 'true' only if all bands are geophysics.
boolean photographic = true; // 'true' only if no band have category.
boolean rendered = true; // 'true' only if all bands are on unsigned samples, and we are not in geophysics mode.
final int numBands = coverage.getNumSampleDimensions();
scan: for (int i=0; i<numBands; i++) {
final GridSampleDimension band = coverage.getSampleDimension(i);
if (band != null) {
if (isNullOrEmpty(band.getCategories())) {
// No category. The image is treated as photographic.
continue;
}
photographic = false;
final GridSampleDimension packed = band.geophysics(false);
if (band != packed) {
for (final Category category : packed.getCategories()) {
if (category.isQuantitative()) {
// Preserves the geophysics value if at least one category
// is quantitative. Otherwise it will be set to 'false'.
continue scan;
}
}
}
geophysics = false;
if (band.isRangeSigned()) {
rendered = false;
}
}
}
final ViewType type;
if (photographic) {
// Must be tested first because 'geophysics' is 'true' as well in this case.
type = ViewType.PHOTOGRAPHIC;
} else if (geophysics) {
type = ViewType.GEOPHYSICS;
rendered = false;
} else {
type = ViewType.PACKED;
}
views.put(type, coverage);
if (rendered) {
views.put(ViewType.RENDERED, coverage);
}
views.put(ViewType.NATIVE, coverage.getNativeView());
viewTypes = Collections.unmodifiableSet(views.keySet());
}
/**
* Returns a shared map of views <em>or</em> constructs a new one. In order to check if we can
* share the views with one of the sources, the source must have identical image, geometry and
* sample dimensions. As a safety, we do not allow views sharing for arbitrary classes of
* {@link Calculator2D} (this is checked by {@code viewClass}).
*
* @param coverage The coverage that wants to create a {@code ViewsManager}.
*/
static ViewsManager create(final GridCoverage2D coverage) {
final Class<? extends GridCoverage2D> viewClass = coverage.getViewClass();
if (viewClass != null) {
Collection<GridCoverage> sources = coverage.getSources();
while (sources != null) {
Collection<GridCoverage> next = null;
for (final GridCoverage source : sources) {
if (source instanceof GridCoverage2D) {
final GridCoverage2D candidate = (GridCoverage2D) source;
if (Objects.equals(coverage.image, candidate.image) &&
Objects.equals(coverage.gridGeometry, candidate.gridGeometry) &&
Arrays .equals(coverage.sampleDimensions, candidate.sampleDimensions) &&
candidate.getViewClass() == viewClass)
// The CRS is checked with the GridGeometry2D.
{
return candidate.copyViewsTo(coverage);
}
}
final Collection<GridCoverage> more = source.getSources();
if (!isNullOrEmpty(more)) {
if (next == null) {
next = new LinkedHashSet<>(more);
} else {
next.addAll(more);
}
}
}
sources = next;
}
}
return new ViewsManager(coverage);
}
/**
* Invoked by {@linkplain GridCoverage2D#view} for getting a view.
* <p>
* <strong>NOTE:</strong> {@link GridCoverage2D#toString()} requires that this method is
* synchronized on {@code this}.
*/
public synchronized GridCoverage2D get(final GridCoverage2D caller, final ViewType type,
final Hints userHints)
{
GridCoverage2D coverage = views.get(type);
if (coverage != null) {
return coverage;
}
coverage = views.get(ViewType.NATIVE);
if (coverage == null) {
// TODO: localize.
throw new IllegalStateException("This coverage has been disposed.");
}
switch (type) {
case RENDERED: coverage = rendered(caller, userHints); break;
case PACKED: coverage = geophysics(coverage, false, userHints); break;
case GEOPHYSICS: coverage = geophysics(coverage, true, userHints); break;
case PHOTOGRAPHIC: coverage = photographic(coverage, userHints); break;
default: {
/*
* We don't want a case for:
* - SAME because it should be handled by "GridCoverage2D.view(...)"
* - NATIVE because it should be handled by "views.get(type)".
*
* Getting there with one of the above type is an error.
*/
throw new IllegalArgumentException(Errors.format(
Errors.Keys.IllegalArgument_2, "type", type));
}
}
coverage = caller.specialize(coverage);
if (caller.copyViewsTo(coverage) != this) {
throw new AssertionError(); // Should never happen.
}
views.put(type, coverage);
return coverage;
}
/**
* Invoked by {@link #create} when a photographic view needs to be created. This method
* reformats the {@linkplain ColorModel color model} to a {@linkplain ComponentColorModel
* component color model} preserving transparency. The new color model is typically backed
* by an RGB {@linkplain ColorSpace color space}, but not necessarily. It could be YMCB as well.
*/
@SuppressWarnings("fallthrough")
private static GridCoverage2D photographic(final GridCoverage2D coverage, final Hints userHints) {
final RenderedImage image = coverage.getRenderedImage();
final ColorModel cm = image.getColorModel();
/*
* If the image already use a component color model (not necessarily backed by
* RGB color space - it could be CYMB as well), then there is nothing to do.
*/
if (cm instanceof ComponentColorModel) {
return coverage;
}
final int dataType;
final ColorSpace cs;
final LookupTableJAI lookup;
/*
* If the color model is indexed. Converts to RGB or gray scale using a single "Lookup"
* operation. Color space will be RGB or GRAY, and type will be DataBuffer.TYPE_BYTE.
*/
if (cm instanceof IndexColorModel) {
final IndexColorModel icm = (IndexColorModel) cm;
final int mapSize = icm.getMapSize();
final byte[][] data;
if (ColorUtilities.isGrayPalette(icm, false)) {
final byte[] gray = new byte[mapSize];
icm.getGreens(gray);
if (icm.hasAlpha()) {
final byte[] alpha = new byte[mapSize];
icm.getAlphas(alpha);
data = new byte[][] { gray, alpha };
} else {
data = new byte[][] { gray };
}
cs = ColorSpace.getInstance(ColorSpace.CS_GRAY);
} else {
data = new byte[cm.getNumComponents()][mapSize];
switch (data.length) {
default: // Should not occurs, but keep as a paranoiac check.
case 4: icm.getAlphas(data[3]);
case 3: icm.getBlues (data[2]);
case 2: icm.getGreens(data[1]);
case 1: icm.getReds (data[0]);
case 0: break;
}
cs = icm.getColorSpace();
}
dataType = DataBuffer.TYPE_BYTE;
lookup = new LookupTableJAI(data);
} else {
lookup = null;
cs = cm.getColorSpace();
dataType = (cm instanceof DirectColorModel) ? DataBuffer.TYPE_BYTE :
image.getSampleModel().getTransferType();
}
/*
* Gets the rendering hints to be given to the image operation.
*/
final ColorModel targetCM;
final SampleModel targetSM;
targetCM = new ComponentColorModel(cs,
cm.hasAlpha(), // If true, supports transparency.
cm.isAlphaPremultiplied(), // If true, alpha is premultiplied.
cm.getTransparency(), // What alpha values can be represented.
dataType); // Type of primitive array used to represent pixel.
targetSM = targetCM.createCompatibleSampleModel(image.getWidth(), image.getHeight());
RenderingHints hints = ImageUtilities.getRenderingHints(image);
if (hints == null) {
hints = new RenderingHints(null);
}
ImageLayout layout = (ImageLayout) hints.get(JAI.KEY_IMAGE_LAYOUT);
if (layout == null) {
layout = new ImageLayout();
}
layout.setColorModel (targetCM);
layout.setSampleModel(targetSM);
hints.put(JAI.KEY_IMAGE_LAYOUT, layout);
/*
* Creates the image, than the coverage.
*/
final RenderedOp view;
if (lookup != null) {
view = LookupDescriptor.create(image, lookup, hints);
} else {
view = FormatDescriptor.create(image, dataType, hints);
}
assert view.getColorModel() instanceof ComponentColorModel;
return createView(coverage, view, null, 2, userHints);
}
/**
* Invoked by {@link #create} when a geophysics or packed view needs to be created.
*
* {@note <b>Historic</b>: In JDK 4 and 5, images using a <code>ComponentSampleModel</code> -
* as created by <code>IndexColorModel</code> - were much slower at rendering time than images
* using a <code>PixelInterleavedSampleModel</code> - as created by <code>BufferedImage</code>
* for type <code>TYPE_BYTE_INDEXED</code>. Consequently the Geotk code had a patch replacing
* the former color model by the later one. This patch has been removed in later Geotk version
* since a micro-benchmarking with JDK6 and 7 didn't show any performance difference anymore.}
*
* @todo The "Piecewise" operation is disabled because javac 1.4.1_01 generate illegal
* bytecode. This bug is fixed in javac 1.4.2-beta. However, we still have an
* ArrayIndexOutOfBoundsException in JAI code...
*/
private static GridCoverage2D geophysics(final GridCoverage2D coverage, final boolean toGeo,
final Hints userHints)
{
/*
* STEP 1 - Gets the source image and prepare the target bands (sample dimensions).
* As a slight optimization, we skip the "Null" operation since such image
* may be the result of some operation (e.g. "Colormap").
*/
RenderedImage image = coverage.image;
while (image instanceof NullOpImage) {
final NullOpImage op = (NullOpImage) image;
if (op.getNumSources() != 1) {
break;
}
image = op.getSourceImage(0);
}
final SampleModel sourceModel = image.getSampleModel();
final int numBands = sourceModel.getNumBands();
final GridSampleDimension[] sourceBands = coverage.sampleDimensions;
final GridSampleDimension[] targetBands = sourceBands.clone();
assert targetBands.length == numBands : targetBands.length;
for (int i=0; i<targetBands.length; i++) {
targetBands[i] = targetBands[i].geophysics(toGeo);
}
/*
* If the target bands are equal to the source bands, then there is nothing to do.
* Otherwise, we call "nativeBands" the ones that are not geophysics (i.e. the ones
* that may contain a MathTransform1D different than the identity transform).
*/
if (Arrays.equals(sourceBands, targetBands)) {
return coverage;
}
final int visibleBand = CoverageUtilities.getVisibleBand(image);
final GridSampleDimension[] nativeBands = toGeo ? sourceBands : targetBands;
/*
* Computes immediately the "geophysics to native" transforms. If all transforms are the
* identity one, then we will return the coverage unchanged. The transforms that can't be
* obtained will be set to null, which is understood by LookupTableFactory.create(...) as
* "Lookup operation not allowed".
*/
boolean isIdentity = true;
MathTransform1D[] transforms = new MathTransform1D[numBands];
for (int i=0; i<numBands; i++) {
MathTransform1D transform = nativeBands[i].getSampleToGeophysics();
if (transform!=null && !toGeo) try {
transform = transform.inverse(); // We want the geophysics to native transform.
} catch (NoninvertibleTransformException e) {
transform = null;
isIdentity = false;
}
transforms[i] = transform;
isIdentity &= transform.isIdentity();
}
if (isIdentity) {
return coverage;
}
/*
* STEP 2 - Computes the layout for the destination RenderedImage. We will use the same
* layout than the parent image, except for tile size if the parent image had
* only one big tile, and for the color model and sample model (since we are
* reformating data in the process of this operation).
*/
ImageLayout layout = ImageUtilities.getImageLayout(image);
final ColorModel colors = targetBands[visibleBand].getColorModel(visibleBand, numBands);
final SampleModel targetModel = colors.createCompatibleSampleModel(
layout.getTileWidth(image), layout.getTileHeight(image));
layout = layout.setSampleModel(targetModel).setColorModel(colors);
ParameterBlock param = new ParameterBlock().addSource(image);
RenderingHints hints = new RenderingHints(JAI.KEY_IMAGE_LAYOUT, layout);
hints.put(JAI.KEY_REPLACE_INDEX_COLOR_MODEL, Boolean.FALSE);
hints.put(JAI.KEY_TRANSFORM_ON_COLORMAP, Boolean.FALSE);
String operation = null; // Will be set in step 3 or 4.
/*
* STEP 3 - Checks if the transcoding could be done with the JAI's "Lookup" operation. This
* is probably the fastest operation available for going to the geophysics view.
* Note that the transforms array may contains null elements, which will cause
* LookupTableFactory.create(...) to returns null.
*/
if (transforms != null) try {
final int sourceType = sourceModel.getDataType();
final int targetType = targetModel.getDataType();
LookupTableJAI table = LookupTableFactory.create(sourceType, targetType, transforms);
if (table != null) {
operation = "Lookup";
param = param.add(table);
}
} catch (TransformException exception) {
/*
* A value can't be transformed. Fallback on "Rescale" or "Piecewise" operations. We
* don't log yet because the more general operations are likely to fail for the same
* reason and we don't want to log the same TransformException twice.
*/
}
/*
* STEP 4 - Check if the transcoding could be done with a JAI's "Rescale" or "Piecewise"
* operations. The "Rescale" operation requires a completely linear relationship
* between the source and the destination sample values. The "Piecewise" operation
* is less strict: piecewise breakpoints are very similar to categories, but the
* transformation for all categories still have to be linear.
*/
if (operation == null) try {
boolean canRescale = true; // 'true' if the "Rescale" operation can be applied.
boolean canPiecewise = true; // 'true' if the "Piecewise" operation can be applied.
boolean conditional = false;// 'true' if isZeroExcluded(...) needs to be invoked.
double[] scales = null; // The first argument for "Rescale".
double[] offsets = null; // The second argument for "Rescale".
float[][][] breakpoints = null; // The only argument for "Piecewise".
testLinear: for (int i=0; i<numBands; i++) {
final List<Category> sources = sourceBands[i].getCategories();
final int numCategories = sources.size();
float[] sourceBreakpoints = null;
float[] targetBreakpoints = null;
double expectedSource = NaN;
double expectedTarget = NaN;
int jbp = 0; // Break point index (vary with j)
for (int j=0; j<numCategories; j++) {
final Category sourceCategory = sources.get(j);
final Category packedCategory = sourceCategory.geophysics(false);
MathTransform1D transform = packedCategory.getSampleToGeophysics();
final double offset, scale;
if (transform == null) {
/*
* A qualitative category was found. Those categories maps NaN values,
* which need the special processing performed by our "SampleTranscode"
* operation. However there is a few special cases where JAI operations
* could still fit:
*
* - In "packed to geophysics" transform, we can still use "Piecewise"
* if the minimum and maximum target value are equals (usually NaN).
*
* - In "geophysics to packed" transform, we can still use "Rescale"
* if the NaN value maps to 0.
*/
if (toGeo) {
canRescale = false;
final NumberRange<?> target = sourceCategory.geophysics(true).getRange();
offset = target.getMinDouble();
if (doubleToRawLongBits(offset) != doubleToRawLongBits(target.getMaxDouble())) {
canPiecewise = false;
break testLinear;
}
scale = 0;
} else {
canPiecewise = false;
assert !packedCategory.equals(sourceCategory) : packedCategory;
final NumberRange<?> range = packedCategory.getRange();
if (range.getMinDouble(true) == 0 && range.getMaxDouble(true) == 0) {
assert isNaN(sourceCategory.getRange().getMinDouble()) : sourceCategory;
conditional = true;
continue;
}
canRescale = false;
break testLinear;
}
} else {
if (!toGeo) {
// We are going to convert geophysics values to packed ones.
transform = transform.inverse();
}
offset = transform.transform(0);
scale = transform.derivative(NaN);
if (isNaN(scale) || isNaN(offset)) {
// One category doesn't use a linear transformation. We can't deal with
// that with "Rescale" or "Piecewise". Fallback on our "SampleTranscode".
canRescale = false;
canPiecewise = false;
break testLinear;
}
}
// Allocates arrays the first time the loop is run up to this point.
// Store scale and offset, and check if they still the same.
if (j == 0) {
if (i == 0) {
scales = new double[numBands];
offsets = new double[numBands];
breakpoints = new float [numBands][][];
}
sourceBreakpoints = new float[numCategories * 2];
targetBreakpoints = new float[numCategories * 2];
breakpoints[i] = new float[][] {sourceBreakpoints, targetBreakpoints};
offsets [i] = offset;
scales [i] = scale;
}
if (offset!=offsets[i] || scale!=scales[i]) {
canRescale = false;
}
// Computes breakpoints.
final NumberRange<?> range = sourceCategory.getRange();
final double minimum = range.getMinDouble(true);
final double maximum = range.getMaxDouble(true);
final float sourceMin = (float) minimum;
final float sourceMax = (float) maximum;
final float targetMin = (float)(minimum * scale + offset);
final float targetMax = (float)(maximum * scale + offset);
assert sourceMin <= sourceMax : range;
if (Math.abs(minimum - expectedSource) <= EPS) {
if (Math.abs(targetMin - expectedTarget) <= EPS || isNaN(expectedTarget)) {
/*
* This breakpoint is identical to the previous one. Do not duplicate;
* overwrites the previous breakpoint since the later is likely to be
* more accurate. Note that we accept NaN in expected (not calculated)
* target values but not in source values, because "Piecewise" performs
* its search on source values, wich must be monotonically increasing.
*/
jbp--;
} else {
// Found a discontinuity!!! The "piecewise" operation is not really
// designed for such case. The behavior between the last breakpoint
// and the current one may not be what the user expected.
assert sourceBreakpoints[jbp-1] < sourceMin : expectedSource;
canPiecewise = false;
}
} else if (j != 0) {
// Found a gap between the last category and the current one. But the
// piecewise operation still work as expected for values not in the gap.
assert !(expectedSource > sourceMin) : expectedSource;
}
sourceBreakpoints[jbp ] = sourceMin;
sourceBreakpoints[jbp+1] = sourceMax;
targetBreakpoints[jbp ] = targetMin;
targetBreakpoints[jbp+1] = targetMax;
jbp += 2;
expectedSource = range.getMaxDouble(false);
expectedTarget = expectedSource * scale + offset;
}
breakpoints[i][0] = sourceBreakpoints = ArraysExt.resize(sourceBreakpoints, jbp);
breakpoints[i][1] = targetBreakpoints = ArraysExt.resize(targetBreakpoints, jbp);
assert ArraysExt.isSorted(sourceBreakpoints, false);
}
if (canRescale && scales!=null && (!conditional || isZeroExcluded(image, scales, offsets))) {
/*
* TODO: JAI BUG? If the type is TYPE_USHORT, its look like that JAI interpret
* 256 as 0 (and same for all value above 256). In order to check if this issue
* still exists, see SampleTranscoderTest.testTypeUShort().
*/
if (sourceModel.getDataType() != DataBuffer.TYPE_USHORT) {
operation = "Rescale";
param = param.add(scales).add(offsets);
}
} else if (canPiecewise && breakpoints!=null) {
// operation = "Piecewise";
// param = param.add(breakpoints);
}
} catch (TransformException exception) {
/*
* At least one category doesn't use a linear relation. Ignores the exception and
* fallback on the next case. We log a message at Level.FINE rather than WARNING
* because this exception may be normal. We pretend that the log come from
* GridCoverage2D.view, which is the public method that invoked this one.
*/
Logging.recoverableException(null, GridCoverage2D.class, "view", exception);
}
/*
* STEP 5 - Transcode the image sample values. The "SampleTranscode" operation is
* registered in the org.geotoolkit.coverage package in the GridSampleDimension
* class.
*/
if (operation == null) {
param = param.add(sourceBands);
operation = "org.geotoolkit.SampleTranscode";
}
final RenderedOp view = JAI.create(operation, param, hints);
return createView(coverage, view, targetBands, toGeo ? 1 : 0, userHints);
}
/**
* Invoked by {@link #create} when a rendered view needs to be created.
*
* @todo Not yet implemented. For now we use the packed view as a close match. Future version
* will needs to make sure that we returns the same instance than PACKED when suitable.
*/
private GridCoverage2D rendered(final GridCoverage2D coverage, final Hints userHints) {
return get(coverage, ViewType.PACKED, userHints);
}
/**
* Creates the view and logs a record.
*/
private static GridCoverage2D createView(final GridCoverage2D coverage, final RenderedOp view,
final GridSampleDimension[] targetBands, final int code, final Hints userHints)
{
final InternationalString name = coverage.getName();
if (GridCoverage2D.LOGGER.isLoggable(AbstractCoverageProcessor.OPERATION)) {
// Logs a message using the same level than grid coverage processor.
final String operation = view.getOperationName();
final String shortName = operation.substring(operation.lastIndexOf('.') + 1);
final Locale locale = coverage.getLocale();
final LogRecord record = Loggings.getResources(locale).getLogRecord(
AbstractCoverageProcessor.OPERATION, Loggings.Keys.SampleTranscode_3, new Object[] {
(name != null) ? name.toString(locale) :
Vocabulary.getResources(locale).getString(Vocabulary.Keys.Untitled),
code, shortName
});
record.setSourceClassName(GridCoverage2D.class.getName());
record.setSourceMethodName("geophysics");
final Logger logger = GridCoverage2D.LOGGER;
record.setLoggerName(logger.getName());
logger.log(record);
}
final GridCoverage[] sources = new GridCoverage[] {coverage};
return new GridCoverage2D(name, view, coverage.gridGeometry, targetBands, sources, null, userHints);
}
/**
* Returns {@code true} if rescaling every pixels in the specified image (excluding NaN) would
* not produce zero value. In case of doubt, this method conservatively returns {@code false}.
* <p>
* <b>Why this method exists</b><br>
* When a {@link org.opengis.coverage.SampleDimension} describes exactly one linear relationship with one NaN value
* mapping exactly to the index value 0, then the "<cite>geophysics to native</cite>" transform
* can be optimized to the {@code "Rescale"} operation because {@link Float#NaN} casted to the
* {@code int} primitive type equals 0. This case is very common, which make this optimization
* a useful one. Unfortunately there is nothing in {@code "Rescale"} preventing some real number
* (not NaN) to maps to 0 through the normal linear relationship. We need to make sure that the
* range of transformed values doesn't contains 0.
*/
private static boolean isZeroExcluded(final RenderedImage image,
final double[] scales, final double[] offsets)
{
/*
* We can't do any guarantee if pixel values are modifiable.
*/
if (image instanceof WritableRenderedImage) {
return false;
}
/*
* If an "Extrema" operation is used somewhere in the image chain, ensure that it was
* applied on an image with the same pixel values than the image we want to analyze.
* Ensure also that no ROI was defined for the "Extrema" operation.
*/
Object parent = image;
while (parent instanceof PlanarImage) {
final PlanarImage planar = (PlanarImage) image;
if (parent instanceof RenderedOp) {
final RenderedOp op = (RenderedOp) parent;
final String name = op.getOperationName();
if (name.equalsIgnoreCase("Extrema")) {
final int n = op.getNumParameters();
for (int i=0; i<n; i++) {
if (op.getObjectParameter(i) instanceof ROI) {
return false;
}
}
break;
}
if (!name.equalsIgnoreCase("Null") && !name.equalsIgnoreCase("Histogram")) {
return false;
}
}
final int n = planar.getNumSources();
if (n >= 2) return false;
if (n == 0) break;
parent = planar.getSourceObject(0);
}
/*
* Apparently, there is nothing preventing us to query the "extrema" property. Note that
* the above test did not guarantee that this property is defined - only that if defined,
* it looks like suitable. Now ensure that the range after conversion does not includes 0.
*/
final Object property = image.getProperty("extrema");
if (!(property instanceof double[][])) {
return false;
}
final double[][] extrema = (double[][]) property;
if (extrema.length != 2) {
return false;
}
for (int i=0; i<scales.length; i++) {
final double scale = scales [i];
final double offset = offsets[i];
double maximum = extrema[0][i] * scale + offset;
double minimum = extrema[1][i] * scale + offset;
if (minimum > maximum) {
final double tmp = minimum;
minimum = maximum;
maximum = tmp;
}
if (!(minimum > 0 || maximum < 0)) { // Use '!' for catching NaN.
return false;
}
}
return true;
}
/**
* Disposes all views and returns the remaining ones. Disposed views are removed from
* this {@code ViewsManager}, but may be recreated if the user asks them again.
* <p>
* This method is invoked by {@link GridCoverage2D#dispose} method only.
*/
public synchronized Collection<GridCoverage2D> dispose(final boolean force) {
/*
* Following loop will be executed as long as we have been able to dispose at least one
* view. This is because some coverages can be disposed only after their dependency have
* been disposed first. Since we don't know the dependency order, we just try the loop
* again and again. The amount of values (5) is small enough to keep the cost small.
*/
int disposed;
do {
disposed = 0;
for (final Iterator<GridCoverage2D> it=views.values().iterator(); it.hasNext();) {
final GridCoverage2D coverage = it.next();
if (coverage.disposeImage(force)) {
it.remove();
disposed++;
}
}
} while (disposed != 0);
return views.values();
}
}