This is an automated email from the ASF dual-hosted git repository.
desruisseaux pushed a commit to branch geoapi-4.0
in repository https://gitbox.apache.org/repos/asf/sis.git
The following commit(s) were added to refs/heads/geoapi-4.0 by this push:
new 2dff54f First draft of BandedSampleConverter (not yet tested).
2dff54f is described below
commit 2dff54f7fdaa3dac143f289d1fa5471bbc04d844
Author: Martin Desruisseaux <[email protected]>
AuthorDate: Fri Jan 3 20:24:24 2020 +0100
First draft of BandedSampleConverter (not yet tested).
---
.../coverage/j2d/BandedSampleConverter.java | 149 ++++++
.../sis/internal/coverage/j2d/Transferer.java | 574 +++++++++++++++++++++
2 files changed, 723 insertions(+)
diff --git
a/core/sis-feature/src/main/java/org/apache/sis/internal/coverage/j2d/BandedSampleConverter.java
b/core/sis-feature/src/main/java/org/apache/sis/internal/coverage/j2d/BandedSampleConverter.java
new file mode 100644
index 0000000..a94da76
--- /dev/null
+++
b/core/sis-feature/src/main/java/org/apache/sis/internal/coverage/j2d/BandedSampleConverter.java
@@ -0,0 +1,149 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.sis.internal.coverage.j2d;
+
+import java.awt.Dimension;
+import java.awt.image.Raster;
+import java.awt.image.WritableRaster;
+import java.awt.image.RenderedImage;
+import java.awt.image.BandedSampleModel;
+import org.opengis.referencing.operation.MathTransform1D;
+import org.opengis.referencing.operation.TransformException;
+import org.apache.sis.image.ComputedImage;
+import org.apache.sis.util.Workaround;
+
+
+/**
+ * An image where each sample value is computed independently of other sample
values and independently
+ * of neighbor points. Values are computed by a separated {@link
MathTransform1D} for each band
+ * (by contrast, an {@code InterleavedSampleConverter} would handle all sample
values as a coordinate tuple).
+ * Current implementation makes the following simplifications:
+ *
+ * <ul>
+ * <li>The image has exactly one source.</li>
+ * <li>Image layout (minimum coordinates, image size, tile grid) is the same
than source image layout,
+ * unless the source has too large tiles in which case {@link ImageLayout}
automatically subdivides
+ * the tile grid in smaller tiles.</li>
+ * <li>Image is computed and stored on a band-by-band basis using a {@link
BandedSampleModel}.</li>
+ * <li>Calculation is performed on {@code float} or {@code double}
numbers.</li>
+ * </ul>
+ *
+ * Subclasses may relax those restrictions at the cost of more complex {@link
#computeTile(int, int)}
+ * implementation. Those restrictions may also be relaxed in future versions
of this class.
+ *
+ * @author Martin Desruisseaux (Geomatys)
+ * @version 1.1
+ * @since 1.1
+ * @module
+ */
+public abstract class BandedSampleConverter extends ComputedImage {
+ /**
+ * The transfer functions to apply on each band of the source image.
+ */
+ private final MathTransform1D[] converters;
+
+ /**
+ * Creates a new image of the given data type which will compute values
using the given converters.
+ *
+ * @param source the image for which to convert sample values.
+ * @param layout object to use for computing tile size, or {@code
null} for the default.
+ * @param targetType the type of this image resulting from conversion of
given image.
+ * @param converters the transfer functions to apply on each band of the
source image.
+ */
+ public BandedSampleConverter(final RenderedImage source, final ImageLayout
layout,
+ final int targetType, final
MathTransform1D... converters)
+ {
+ super(createSampleModel(targetType, converters.length, layout,
source), source);
+ this.converters = converters;
+ }
+
+ /**
+ * Returns the sample model to use for this image. This is a workaround
for RFE #4093999
+ * ("Relax constraint on placement of this()/super() call in
constructors").
+ */
+ @Workaround(library="JDK", version="1.8")
+ private static BandedSampleModel createSampleModel(final int targetType,
+ final int numBands, ImageLayout layout, final RenderedImage source)
+ {
+ if (layout == null) {
+ layout = ImageLayout.DEFAULT;
+ }
+ final Dimension tile = layout.suggestTileSize(source);
+ return new BandedSampleModel(targetType, tile.width, tile.height,
numBands);
+ }
+
+ /**
+ * Returns the minimum <var>x</var> coordinate (inclusive) of this image.
+ * This is the the same value than the source image (not necessarily zero).
+ *
+ * @return the minimum <var>x</var> coordinate (column) of this image.
+ */
+ @Override
+ public int getMinX() {
+ return getSource(0).getMinX();
+ }
+
+ /**
+ * Returns the minimum <var>y</var> coordinate (inclusive) of this image.
+ * This is the the same value than the source image (not necessarily zero).
+ *
+ * @return the minimum <var>y</var> coordinate (row) of this image.
+ */
+ @Override
+ public int getMinY() {
+ return getSource(0).getMinY();
+ }
+
+ /**
+ * Returns the minimum tile index in the <var>x</var> direction.
+ * This is the the same value than the source image (not necessarily zero).
+ *
+ * @return the minimum tile index in the <var>x</var> direction.
+ */
+ @Override
+ public int getMinTileX() {
+ return getSource(0).getMinTileX();
+ }
+
+ /**
+ * Returns the minimum tile index in the <var>y</var> direction.
+ * This is the the same value than the source image (not necessarily zero).
+ *
+ * @return the minimum tile index in the <var>y</var> direction.
+ */
+ @Override
+ public int getMinTileY() {
+ return getSource(0).getMinTileY();
+ }
+
+ /**
+ * Computes the tile at specified indices.
+ *
+ * @param tileX the column index of the tile to compute.
+ * @param tileY the row index of the tile to compute.
+ * @return computed tile for the given indices (can not be null).
+ * @throws TransformException if an error occurred while converting a
sample value.
+ */
+ @Override
+ protected Raster computeTile(final int tileX, final int tileY) throws
TransformException {
+ final Raster source = getSource(0).getTile(tileX, tileY);
+ final WritableRaster target = createTile(tileX, tileY);
+ final Transferer transfer = Transferer.suggest(source, target);
+ transfer.compute(converters);
+ return target;
+ }
+}
diff --git
a/core/sis-feature/src/main/java/org/apache/sis/internal/coverage/j2d/Transferer.java
b/core/sis-feature/src/main/java/org/apache/sis/internal/coverage/j2d/Transferer.java
new file mode 100644
index 0000000..8ccda79
--- /dev/null
+++
b/core/sis-feature/src/main/java/org/apache/sis/internal/coverage/j2d/Transferer.java
@@ -0,0 +1,574 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.sis.internal.coverage.j2d;
+
+import java.awt.Rectangle;
+import java.awt.image.Raster;
+import java.awt.image.WritableRaster;
+import java.awt.image.SampleModel;
+import java.awt.image.ComponentSampleModel;
+import java.awt.image.DataBuffer;
+import java.awt.image.DataBufferFloat;
+import java.awt.image.DataBufferDouble;
+import org.apache.sis.internal.util.Numerics;
+import org.opengis.referencing.operation.MathTransform1D;
+import org.opengis.referencing.operation.TransformException;
+
+
+/**
+ * Strategy for reading and writing data between two rasters, with a
computation between them.
+ * Some strategies are to write directly in the destination raster, other
strategies are to use
+ * an intermediate buffer. This class has the following constraints:
+ *
+ * <ul>
+ * <li>Source values can not be modified. Calculations must be done either
directly in the
+ * target raster, or in a temporary buffer.</li>
+ * <li>Direct access to the {@link DataBuffer} arrays may disable video card
acceleration.
+ * This class assumes that it is acceptable for {@code float} and {@code
double} types,
+ * and to be avoided for integer types.</li>
+ * </ul>
+ *
+ * @author Martin Desruisseaux (Geomatys)
+ * @version 1.1
+ * @since 1.1
+ * @module
+ */
+abstract class Transferer {
+ /**
+ * The image tile from which to read sample values.
+ */
+ protected final Raster source;
+
+ /**
+ * The image tile where to write sample values after processing.
+ */
+ protected final WritableRaster target;
+
+ /**
+ * Coordinates of the region to read and write. This class assumes that
+ * {@link #source} and {@link #target} share the same coordinate system.
+ */
+ protected final Rectangle region;
+
+ /**
+ * The band to read and write. This class assumes that {@link #source} and
+ * {@link #target} have the same number of bands and bands in same order.
+ */
+ protected int band;
+
+ /**
+ * Creates a new instance for transferring data between the two specified
rasters.
+ *
+ * @param source image tile from which to read sample values.
+ * @param target image tile where to write sample values after
processing.
+ */
+ protected Transferer(final Raster source, final WritableRaster target) {
+ this.source = source;
+ this.target = target;
+ this.region = target.getBounds();
+ }
+
+ /**
+ * Sets {@code region.height} to the height of the buffer where values are
stored
+ * during data transfer and where {@link MathTransform1D} operations are
applied.
+ * If this {@code Transferer} does not use an intermediate buffer (i.e. if
it
+ * copies values directly in the target buffer and processes them
in-place),
+ * then this method should leave {@link #region} unchanged.
+ *
+ * <p>The default implementation does nothing. This is the most
conservative approach
+ * since it does not require {@code Transferer} to split data processing
in strips,
+ * at the cost of more memory consumption if this {@code Transferer} does
not write
+ * data directly in the target tile.</p>
+ *
+ * @return {@code region.y + region.height}.
+ *
+ * @see ImageUtilities#prepareTransferRegion(Rectangle, int)
+ */
+ int prepareTransferRegion() {
+ return Math.addExact(region.y, region.height);
+ }
+
+ /**
+ * Computes all sample values from the source tile and writes the result
in the target tile.
+ * This method invokes {@link #computeStrip(MathTransform1D)} repetitively
for sub-regions of the tile.
+ *
+ * @param converters the converters to apply on each band.
+ * @throws TransformException if an error occurred during calculation.
+ */
+ public final void compute(final MathTransform1D[] converters) throws
TransformException {
+ final int afterLastRow = prepareTransferRegion();
+ final int ymin = region.y;
+ final int maxHeight = region.height; // Computed by
`prepareTransferRegion()`.
+ for (band=0; band < converters.length; band++) {
+ final MathTransform1D converter = converters[band];
+ region.y = ymin;
+ do {
+ region.height = Math.min(maxHeight, afterLastRow - region.y);
+ computeStrip(converter);
+ } while ((region.y += region.height) < afterLastRow);
+ }
+ }
+
+ /**
+ * Reads sample values from the {@linkplain #source} tile, applies the
given operation for current
+ * {@linkplain #region} and {@linkplain #band}, then writes results in the
{@linkplain #target} tile.
+ * The {@linkplain #region} and the {@linkplain #band} number must be set
before to invoke this method.
+ *
+ * @param converter the operation to apply on sample values in current
region and current band number.
+ * @throws TransformException if an error occurred during calculation.
+ */
+ abstract void computeStrip(final MathTransform1D converter) throws
TransformException;
+
+ /**
+ * Returns the number of elements in {@link #region}. This is a helper
method for subclass implementations.
+ */
+ final int length() {
+ return Math.multiplyExact(region.width, region.height);
+ }
+
+
+
+
+ /**
+ * Read {@code double} values from the source and write {@code double}
values directly in the target raster,
+ * without intermediate buffer. This strategy is possible only when the
target raster uses the {@code double}
+ * type for storing sample values. This operation is executed in one step,
without subdivisions in strips.
+ */
+ private static final class DoubleToDirect extends Transferer {
+ /** Data buffer of target raster. */
+ private final DataBufferDouble buffer;
+
+ /** Creates a new instance for transferring data between the two
specified rasters. */
+ DoubleToDirect(final Raster source, final WritableRaster target) {
+ super(source, target);
+ buffer = (DataBufferDouble) target.getDataBuffer();
+ }
+
+ /** Copies source values directly in the target, then applies the
conversion in-place. */
+ @Override void computeStrip(final MathTransform1D converter) throws
TransformException {
+ final double[] data = buffer.getData(band);
+ source.getSamples(region.x, region.y, region.width, region.height,
band, data);
+ converter.transform(data, 0, data, 0, length());
+ }
+ }
+
+
+
+
+ /**
+ * Read {@code float} values from the source and write {@code float}
values directly in the target raster,
+ * without intermediate buffer. This strategy is possible only when the
target raster uses the {@code float}
+ * type for storing sample values. This operation is executed in one step,
without subdivisions in strips.
+ */
+ private static final class FloatToDirect extends Transferer {
+ /** Data buffer of target raster. */
+ private final DataBufferFloat buffer;
+
+ /** Creates a new instance for transferring data between the two
specified rasters. */
+ FloatToDirect(final Raster source, final WritableRaster target) {
+ super(source, target);
+ buffer = (DataBufferFloat) target.getDataBuffer();
+ }
+
+ /** Copies source values directly in the target, then applies the
conversion in-place. */
+ @Override void computeStrip(final MathTransform1D converter) throws
TransformException {
+ final float[] data = buffer.getData(band);
+ source.getSamples(region.x, region.y, region.width, region.height,
band, data);
+ converter.transform(data, 0, data, 0, length());
+ }
+ }
+
+
+
+
+ /*
+ * TODO: provide an IntegerToDirect class which would use the
SampleModel.getSamples(…, int[]) method
+ * instead than SampleModel.getSamples(…, float[]). The reason is that the
former method is optimized
+ * in Java2D while the later is not. We would not provide that
optimisation for double target type
+ * because it is less commonly used.
+ */
+
+
+
+
+ /**
+ * Read {@code double} values from the source raster and write {@code
double} values in a temporary buffer.
+ * Note that reading and writing data has {@code double} does not imply
that raster data type must be that type.
+ * The temporary buffer will be written in the target raster as a
separated step. The use of a temporary buffer
+ * is needed when the target raster does not use the {@code double} type,
or does not use a layout that allows
+ * us to write directly in the raster array.
+ *
+ * <div class="note"><b>Note:</b>
+ * having a source raster with {@code double} data type does not remove
the need to use a temporary buffer,
+ * because we can not modify the source data. We still need to allocate a
temporary array for collecting the
+ * operation results before final writing in the target array.</div>
+ */
+ private static final class DoubleToDouble extends Transferer {
+ /** Temporary buffer where to copy data and apply operation. */
+ private double[] buffer;
+
+ /** Creates a new instance for transferring data between the two
specified rasters. */
+ DoubleToDouble(final Raster source, final WritableRaster target) {
+ super(source, target);
+ }
+
+ /** Subdivides the region to process in smaller strips, for smaller
{@linkplain #buffer}. */
+ @Override int prepareTransferRegion() {
+ return ImageUtilities.prepareTransferRegion(region,
DataBuffer.TYPE_DOUBLE);
+ }
+
+ /** Copies source values in temporary buffer, applies conversion then
copies to target. */
+ @Override void computeStrip(final MathTransform1D converter) throws
TransformException {
+ buffer = source.getSamples(region.x, region.y, region.width,
region.height, band, buffer);
+ converter.transform(buffer, 0, buffer, 0, length());
+ target.setSamples(region.x, region.y, region.width, region.height,
band, buffer);
+ }
+ }
+
+
+
+
+ /**
+ * Read {@code float} values from the source raster and write {@code
float} values in a temporary buffer.
+ * Note that reading and writing data has {@code float} does not imply
that raster data type must be that type.
+ * The temporary buffer will be written in the target raster as a
separated step. The use of a temporary buffer
+ * is needed when the target raster does not use the {@code float} type,
or does not use a layout that allows
+ * us to write directly in the raster array.
+ */
+ private static final class FloatToFloat extends Transferer {
+ /** Temporary buffer where to copy data and apply operation. */
+ private float[] buffer;
+
+ /** Creates a new instance for transferring data between the two
specified rasters. */
+ FloatToFloat(final Raster source, final WritableRaster target) {
+ super(source, target);
+ }
+
+ /** Subdivides the region to process in smaller strips, for smaller
{@linkplain #buffer}. */
+ @Override int prepareTransferRegion() {
+ return ImageUtilities.prepareTransferRegion(region,
DataBuffer.TYPE_FLOAT);
+ }
+
+ /** Copies source values in temporary buffer, applies conversion then
copies to target. */
+ @Override void computeStrip(final MathTransform1D converter) throws
TransformException {
+ buffer = source.getSamples(region.x, region.y, region.width,
region.height, band, buffer);
+ converter.transform(buffer, 0, buffer, 0, length());
+ target.setSamples(region.x, region.y, region.width, region.height,
band, buffer);
+ }
+ };
+
+
+
+
+ /**
+ * Read {@code double} values from the source raster and write {@code int}
values in a temporary buffer.
+ * The floating point values will be rounded and clamped to the range of
the integer type.
+ * Note that we do not provide any direct version for integer types
because direct access
+ * to {@link DataBuffer} array disable Java2D acceleration on video card.
+ */
+ private static class DoubleToInteger extends Transferer {
+ /** Temporary buffer where to copy data and apply operation. */
+ protected double[] buffer;
+
+ /** Temporary buffer where to round data before transfer to target
raster. */
+ protected int[] transfer;
+
+ /** Creates a new instance for transferring data between the two
specified rasters. */
+ DoubleToInteger(final Raster source, final WritableRaster target) {
+ super(source, target);
+ }
+
+ /** Subdivides the region to process in smaller strips, for smaller
{@linkplain #buffer}. */
+ @Override final int prepareTransferRegion() {
+ return ImageUtilities.prepareTransferRegion(region,
DataBuffer.TYPE_DOUBLE);
+ }
+
+ /** Copies source values in temporary buffer, applies conversion then
copies to target. */
+ @Override final void computeStrip(final MathTransform1D converter)
throws TransformException {
+ final int length = length();
+ buffer = source.getSamples(region.x, region.y, region.width,
region.height, band, buffer);
+ converter.transform(buffer, 0, buffer, 0, length);
+ if (transfer == null) transfer = new int[length];
+ clamp(length);
+ target.setSamples(region.x, region.y, region.width, region.height,
band, transfer);
+ }
+
+ /** Clamps data to the range of target integer type. */
+ void clamp(final int length) {
+ for (int i=0; i<length; i++) {
+ transfer[i] = Numerics.clamp(Math.round(buffer[i]));
+ }
+ }
+ }
+
+
+
+
+ /**
+ * Read {@code double} values from the source raster and write signed
{@code short} values in a temporary buffer.
+ * The floating point values will be rounded and clamped to the range of
the integer type.
+ */
+ private static final class DoubleToShort extends DoubleToInteger {
+ /** Creates a new instance for transferring data between the two
specified rasters. */
+ DoubleToShort(final Raster source, final WritableRaster target) {
+ super(source, target);
+ }
+
+ /** Clamps data to the range of target integer type. */
+ @Override void clamp(final int length) {
+ for (int i=0; i<length; i++) {
+ transfer[i] = (int) Math.max(Short.MIN_VALUE,
Math.min(Short.MAX_VALUE, Math.round(buffer[i])));
+ }
+ }
+ }
+
+
+
+
+ /**
+ * Read {@code double} values from the source raster and write unsigned
{@code short} values in a temporary buffer.
+ * The floating point values will be rounded and clamped to the range of
the integer type.
+ */
+ private static final class DoubleToUShort extends DoubleToInteger {
+ /** Creates a new instance for transferring data between the two
specified rasters. */
+ DoubleToUShort(final Raster source, final WritableRaster target) {
+ super(source, target);
+ }
+
+ /** Clamps data to the range of target integer type. */
+ @Override void clamp(final int length) {
+ for (int i=0; i<length; i++) {
+ transfer[i] = (int) Math.max(0, Math.min(0xFFFF,
Math.round(buffer[i])));
+ }
+ }
+ }
+
+
+
+
+ /**
+ * Read {@code double} values from the source raster and write unsigned
{@code byte} values in a temporary buffer.
+ * The floating point values will be rounded and clamped to the range of
the integer type.
+ */
+ private static final class DoubleToByte extends DoubleToInteger {
+ /** Creates a new instance for transferring data between the two
specified rasters. */
+ DoubleToByte(final Raster source, final WritableRaster target) {
+ super(source, target);
+ }
+
+ /** Clamps data to the range of target integer type. */
+ @Override void clamp(final int length) {
+ for (int i=0; i<length; i++) {
+ transfer[i] = (int) Math.max(0, Math.min(0xFF,
Math.round(buffer[i])));
+ }
+ }
+ }
+
+
+
+
+ /**
+ * Read {@code float} values from the source raster and write {@code int}
values in a temporary buffer.
+ * The floating point values will be rounded and clamped to the range of
the integer type.
+ * Note that we do not provide any direct version for integer types
because direct access
+ * to {@link DataBuffer} array disable Java2D acceleration on video card.
+ */
+ private static class FloatToInteger extends Transferer {
+ /** Temporary buffer where to copy data and apply operation. */
+ protected float[] buffer;
+
+ /** Temporary buffer where to round data before transfer to target
raster. */
+ protected int[] transfer;
+
+ /** Creates a new instance for transferring data between the two
specified rasters. */
+ FloatToInteger(final Raster source, final WritableRaster target) {
+ super(source, target);
+ }
+
+ /** Subdivides the region to process in smaller strips, for smaller
{@linkplain #buffer}. */
+ @Override final int prepareTransferRegion() {
+ return ImageUtilities.prepareTransferRegion(region,
DataBuffer.TYPE_FLOAT);
+ }
+
+ /** Copies source values in temporary buffer, applies conversion then
copies to target. */
+ @Override final void computeStrip(final MathTransform1D converter)
throws TransformException {
+ final int length = length();
+ buffer = source.getSamples(region.x, region.y, region.width,
region.height, band, buffer);
+ converter.transform(buffer, 0, buffer, 0, length);
+ if (transfer == null) transfer = new int[length];
+ clamp(length);
+ target.setSamples(region.x, region.y, region.width, region.height,
band, transfer);
+ }
+
+ /** Clamps data to the range of target integer type. */
+ void clamp(final int length) {
+ for (int i=0; i<length; i++) {
+ transfer[i] = Math.round(buffer[i]);
+ }
+ }
+ }
+
+
+
+
+ /**
+ * Read {@code float} values from the source raster and write signed
{@code short} values in a temporary buffer.
+ * The floating point values will be rounded and clamped to the range of
the integer type.
+ */
+ private static final class FloatToShort extends FloatToInteger {
+ /** Creates a new instance for transferring data between the two
specified rasters. */
+ FloatToShort(final Raster source, final WritableRaster target) {
+ super(source, target);
+ }
+
+ /** Clamps data to the range of target integer type. */
+ @Override void clamp(final int length) {
+ for (int i=0; i<length; i++) {
+ transfer[i] = Math.max(Short.MIN_VALUE,
Math.min(Short.MAX_VALUE, Math.round(buffer[i])));
+ }
+ }
+ }
+
+
+
+
+ /**
+ * Read {@code float} values from the source raster and write unsigned
{@code short} values in a temporary buffer.
+ * The floating point values will be rounded and clamped to the range of
the integer type.
+ */
+ private static final class FloatToUShort extends FloatToInteger {
+ /** Creates a new instance for transferring data between the two
specified rasters. */
+ FloatToUShort(final Raster source, final WritableRaster target) {
+ super(source, target);
+ }
+
+ /** Clamps data to the range of target integer type. */
+ @Override void clamp(final int length) {
+ for (int i=0; i<length; i++) {
+ transfer[i] = Math.max(0, Math.min(0xFFFF,
Math.round(buffer[i])));
+ }
+ }
+ }
+
+
+
+
+ /**
+ * Read {@code float} values from the source raster and write unsigned
{@code byte} values in a temporary buffer.
+ * The floating point values will be rounded and clamped to the range of
the integer type.
+ */
+ private static final class FloatToByte extends FloatToInteger {
+ /** Creates a new instance for transferring data between the two
specified rasters. */
+ FloatToByte(final Raster source, final WritableRaster target) {
+ super(source, target);
+ }
+
+ /** Clamps data to the range of target integer type. */
+ @Override void clamp(final int length) {
+ for (int i=0; i<length; i++) {
+ transfer[i] = Math.max(0, Math.min(0xFF,
Math.round(buffer[i])));
+ }
+ }
+ }
+
+
+
+
+ /**
+ * Suggests a strategy for transferring data from the given source to the
given target.
+ * Some operation can be applied on sample values during the transfer for
producing a
+ * computed image.
+ *
+ * @param source image tile from which to read sample values.
+ * @param target image tile where to write sample values after
processing.
+ * @return object to use for applying the operation.
+ */
+ static Transferer suggest(final Raster source, final WritableRaster
target) {
+ switch (ImageUtilities.getDataType(target)) {
+ case DataBuffer.TYPE_DOUBLE: {
+ if (isDirect(target)) {
+ return new DoubleToDirect(source, target);
+ }
+ break;
+ }
+ case DataBuffer.TYPE_FLOAT: {
+ switch (ImageUtilities.getDataType(source)) {
+ case DataBuffer.TYPE_BYTE:
+ case DataBuffer.TYPE_SHORT:
+ case DataBuffer.TYPE_USHORT: // TODO: consider
using IntegerToDirect here.
+ case DataBuffer.TYPE_FLOAT: {
+ if (isDirect(target)) {
+ return new FloatToDirect(source, target);
+ } else {
+ return new FloatToFloat(source, target);
+ }
+ }
+ /*
+ * TYPE_DOUBLE, TYPE_INT and any unknown types. We handle
TYPE_INT as `double`
+ * because conversion of 32 bits integer to `float` may
lost precision digits.
+ */
+ }
+ break;
+ }
+ case DataBuffer.TYPE_INT: return isFloat(source) ? new
FloatToInteger(source, target) : new DoubleToInteger(source, target);
+ case DataBuffer.TYPE_USHORT: return isFloat(source) ? new
FloatToUShort (source, target) : new DoubleToUShort (source, target);
+ case DataBuffer.TYPE_SHORT: return isFloat(source) ? new
FloatToShort (source, target) : new DoubleToShort (source, target);
+ case DataBuffer.TYPE_BYTE: return isFloat(source) ? new
FloatToByte (source, target) : new DoubleToByte (source, target);
+ }
+ /*
+ * Most conservative fallback, also used for any unknown type.
+ */
+ return new DoubleToDouble(source, target);
+ }
+
+ /**
+ * Returns {@code true} if the given raster use a data type than can be
casted to the {@code float} type
+ * without precision lost. If the type is unknown, then this method
returns {@code false}. Note that this
+ * method also returns {@code false} for {@link DataBuffer#TYPE_INT}
because conversion of 32 bits integer
+ * to the {@code float} type may lost precision digits.
+ */
+ private static boolean isFloat(final Raster source) {
+ switch (ImageUtilities.getDataType(source)) {
+ case DataBuffer.TYPE_BYTE:
+ case DataBuffer.TYPE_USHORT:
+ case DataBuffer.TYPE_SHORT:
+ case DataBuffer.TYPE_FLOAT: return true;
+ default: return false;
+ }
+ }
+
+ /**
+ * Returns {@code true} if the given raster stores sample values at
consecutive locations in each band.
+ * In other words, verifies if the given raster uses a pixel stride of 1
with no gab between lines.
+ * Another condition is that the data buffer must start at offset 0.
+ */
+ private static boolean isDirect(final Raster target) {
+ final SampleModel sm = target.getSampleModel();
+ if (sm instanceof ComponentSampleModel) {
+ final ComponentSampleModel cm = (ComponentSampleModel) sm;
+ if (cm.getPixelStride() == 1 && cm.getScanlineStride() ==
target.getWidth()) {
+ for (final int offset : target.getDataBuffer().getOffsets()) {
+ if (offset != 0) {
+ return false;
+ }
+ }
+ return true;
+ }
+ }
+ return false;
+ }
+}
