/*
* GeoTools - The Open Source Java GIS Toolkit
* http://geotools.org
*
* (C) 2007-2008, 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.gce;
import java.io.IOException;
import javax.imageio.ImageReadParam;
import javax.imageio.ImageReader;
import org.geotools.coverage.grid.io.DecimationPolicy;
import org.geotools.coverage.grid.io.OverviewPolicy;
import org.geotools.factory.Hints;
import org.geotools.gce.OverviewsController.OverviewLevel;
import org.geotools.gce.RasterManager.SpatialDomainManager;
import org.geotools.geometry.GeneralEnvelope;
import org.geotools.util.Utilities;
import org.opengis.referencing.operation.TransformException;
/**
* Class that fills up properly read params given a {@link RasterLayerRequest}, an {@link OverviewsController}
* @author Simone Giannecchini, GeoSolutions SAS
*
*
*
* @source $URL$
*/
public class ReadParamsController {
/**
* This method is responsible for evaluating possible subsampling factors
* once the best resolution level has been found, in case we have support
* for levels, or starting from the original coverage in case there are
* no levels available.
*
* Anyhow this method should not be called directly but subclasses should
* make use of the setReadParams method instead in order to transparently
* look for levels.
*
* @param levelIndex
* @param readParameters
* @param requestedRes
*/
private static void performDecimation(
final SpatialDomainManager spatialDomainManager,
final double[] requestedResolution,
final int levelIndex,
final ImageReadParam readParameters,
final OverviewsController overviewsController
) {
// the read parameters cannot be null
Utilities.ensureNonNull("readParameters", readParameters);
Utilities.ensureNonNull("spatialDomainManager", spatialDomainManager);
Utilities.ensureNonNull("overviewsController", overviewsController);
// get the requested resolution
if (requestedResolution == null) {
// if there is no requested resolution we don't do any
// subsampling
readParameters.setSourceSubsampling(1, 1, 0, 0);
return;
}
double selectedRes[] = new double[2];
final OverviewLevel level = overviewsController.resolutionsLevels.get(levelIndex);
selectedRes[0] = level.resolutionX;
selectedRes[1] = level.resolutionY;
final int rasterWidth, rasterHeight;
if (levelIndex == 0) {
// highest resolution
rasterWidth = spatialDomainManager.coverageRasterArea.width;
rasterHeight = spatialDomainManager.coverageRasterArea.height;
} else {
// work on levels
// TODO this is bad side effect of how the Overviews are managed
// right now. There are two problems here,
// first we are assuming that we are working with LON/LAT,
// second is that we are getting just an approximation of
// raster dimensions. The solution is to have the rater
// dimensions on each level and to confront raster dimensions,
// which means working
rasterWidth = (int) Math.round(spatialDomainManager.coverageBBox.getSpan(0)/ selectedRes[0]);
rasterHeight = (int) Math.round(spatialDomainManager.coverageBBox.getSpan(1)/ selectedRes[1]);
}
// /////////////////////////////////////////////////////////////////////
// DECIMATION ON READING
// Setting subsampling factors with some checks
// 1) the subsampling factors cannot be zero
// 2) the subsampling factors cannot be such that the w or h are
// zero
// /////////////////////////////////////////////////////////////////////
int subSamplingFactorX = (int) Math.floor(requestedResolution[0] / selectedRes[0]);
subSamplingFactorX = subSamplingFactorX == 0 ? 1 : subSamplingFactorX;
while (rasterWidth / subSamplingFactorX <= 0 && subSamplingFactorX >= 0)
subSamplingFactorX--;
subSamplingFactorX = subSamplingFactorX <= 0 ? 1 : subSamplingFactorX;
int subSamplingFactorY = (int) Math.floor(requestedResolution[1] / selectedRes[1]);
subSamplingFactorY = subSamplingFactorY == 0 ? 1 : subSamplingFactorY;
while (rasterHeight / subSamplingFactorY <= 0 && subSamplingFactorY >= 0)
subSamplingFactorY--;
subSamplingFactorY = subSamplingFactorY <= 0 ? 1 : subSamplingFactorY;
readParameters.setSourceSubsampling(subSamplingFactorX, subSamplingFactorY, 0, 0);
}
/**
* This method is responsible for preparing the read param for doing an
* {@link ImageReader#read(int, ImageReadParam)}. It sets the passed
* {@link ImageReadParam} in terms of decimation on reading using the
* provided requestedEnvelope and requestedDim to evaluate the needed
* resolution. It also returns and {@link Integer} representing the index of
* the raster to be read when dealing with multipage raster.
*
* @param overviewPolicy
* it can be one of {@link Hints#VALUE_OVERVIEW_POLICY_IGNORE},
* {@link Hints#VALUE_OVERVIEW_POLICY_NEAREST},
* {@link Hints#VALUE_OVERVIEW_POLICY_QUALITY} or
* {@link Hints#VALUE_OVERVIEW_POLICY_SPEED}. It specifies the
* policy to compute the levels level upon request.
* @param readParams
* an instance of {@link ImageReadParam} for setting the
* subsampling factors.
* @param requestedEnvelope
* the {@link GeneralEnvelope} we are requesting.
* @param requestedDim
* the requested dimensions.
* @return the index of the raster to read in the underlying data sourceFile.
* @throws IOException
* @throws TransformException
*/
static int setReadParams(
final double[] requestedResolution,
OverviewPolicy overviewPolicy,
DecimationPolicy decimationPolicy,
final ImageReadParam readParams,
final RasterManager rasterManager,
final OverviewsController overviewController)
throws IOException, TransformException {
Utilities.ensureNonNull("readParams", readParams);
Utilities.ensureNonNull("RasterManager", rasterManager);
Utilities.ensureNonNull("overviewsController", overviewController);
if (overviewPolicy == null){
overviewPolicy = OverviewPolicy.getDefaultPolicy();
}
if (decimationPolicy == null){
decimationPolicy = DecimationPolicy.getDefaultPolicy();
}
// Default image index 0
int imageChoice = 0;
// default values for subsampling
readParams.setSourceSubsampling(1, 1, 0, 0);
// requested to ignore levels
if (overviewPolicy.equals(OverviewPolicy.IGNORE) && decimationPolicy.equals(DecimationPolicy.DISALLOW))
return imageChoice;
if (!overviewPolicy.equals(OverviewPolicy.IGNORE)) {
imageChoice = overviewController.pickOverviewLevel(overviewPolicy, requestedResolution);
}
// DECIMATION ON READING
if (!decimationPolicy.equals(DecimationPolicy.DISALLOW)) {
ReadParamsController.performDecimation(rasterManager.spatialDomainManager,requestedResolution,imageChoice, readParams, overviewController);
}
return imageChoice;
}
}