org.geotools.styling.ContrastEnhancement Maven / Gradle / Ivy

Go to download

Show more of this group Show more artifacts with this name
Show all versions of gt-main Show documentation

The main module contains the GeoTools public interfaces that are used by other GeoTools modules (and GeoTools applications). Where possible we make use industry standard terms as provided by OGC and ISO standards. The formal GeoTools public api consists of gt-metadata, jts and the gt-main module. The main module contains the default implementations that are available provided to other GeoTools modules using our factory system. Factories are obtained from an appropriate FactoryFinder, giving applications a chance configure the factory used using the Factory Hints facilities. FilterFactory ff = CommonFactoryFinder.getFilterFactory(); Expression expr = ff.add( expression1, expression2 ); If you find yourself using implementation specific classes chances are you doing it wrong: Expression expr = new AddImpl( expression1, expressiom2 );

The newest version!

/*
 *    GeoTools - The Open Source Java GIS Toolkit
 *    http://geotools.org
 *
 *    (C) 2002-2015, 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.styling;

import java.util.Map;
import org.opengis.filter.expression.Expression;
import org.opengis.style.ContrastMethod;

/**
 * The ContrastEnhancement object defines contrast enhancement for a channel of a false-color image
 * or for a color image. Its format is:
 *
 *  * <xs:element name="ContrastEnhancement">
 *   <xs:complexType>
 *     <xs:sequence>
 *       <xs:choice minOccurs="0">
 *         <xs:element ref="sld:Normalize"/>
 *         <xs:element ref="sld:Histogram"/>
 *       </xs:choice>
 *       <xs:element ref="sld:GammaValue" minOccurs="0"/>
 *     </xs:sequence>
 *   </xs:complexType>
 * </xs:element>
 * <xs:element name="Normalize">
 *   <xs:complexType/>
 * </xs:element>
 * <xs:element name="Histogram">
 *   <xs:complexType/>
 * </xs:element>
 * <xs:element name="GammaValue" type="xs:double"/>
 * 
 *
 * In the case of a color image, the relative grayscale brightness of a pixel color is used.
 * ?Normalize? means to stretch the contrast so that the dimmest color is stretched to black and the
 * brightest color is stretched to white, with all colors in between stretched out linearly.
 * ?Histogram? means to stretch the contrast based on a histogram of how many colors are at each
 * brightness level on input, with the goal of producing equal number of pixels in the image at each
 * brightness level on output. This has the effect of revealing many subtle ground features. A
 * ?GammaValue? tells how much to brighten (value greater than 1.0) or dim (value less than 1.0) an
 * image. The default GammaValue is 1.0 (no change). If none of Normalize, Histogram, or GammaValue
 * are selected in a ContrastEnhancement, then no enhancement is performed.
 *
 * @author iant
 */
public interface ContrastEnhancement extends org.opengis.style.ContrastEnhancement {
    /** Used to set the contrast enhancement method used. */
    public void setMethod(ContrastMethod method);

    /**
     * @param gamma How much to brighten (greater than 1) or dim (less than 1) this channel; use 1.0
     *     to indicate no change.
     */
    public void setGammaValue(Expression gamma);

    /**
     * How much to brighten (values greater than 1.0) or dim (values less than 1.0) an image. The
     * default GammaValue is 1.0 (no change).
     *
     * @return Expression, if null a value of 1.0 is assumed indicating no change
     */
    public Expression getGammaValue();

    /**
     * Return vendor options relating to the enhancement method
     *
     * @return a Map containing expressions with string keys.
     */
    public Map getOptions();
    /**
     * check if vendor option key is available
     *
     * @param key - the name of the option to check
     * @return true if present
     */
    public boolean hasOption(String key);

    /**
     * Store a vendor option
     *
     * @param key - the name of the option
     * @param value an expression that evaluates to it's value
     */
    public void addOption(String key, Expression value);

    /** Traversal of the style data structure. */
    public void accept(StyleVisitor visitor);

    /** @param options a Map of VendorOptions */
    public void setOptions(Map options);

    /** @return An expression for the matching VendorOption */
    public Expression getOption(String string);

    /**
     * Convenience method to allow users to pass in a {@link ContrastEnhancementMethod} to update
     * {@link Method} and {@link Options} in one go.
     *
     * @param method the {@link ContrastEnhancementMethod} that underlies this enhancement
     */
    public void setMethod(ContrastMethodStrategy method);
}