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Standard interfaces implemented throughout the library.

There is a newer version: 24.2-oss84-1

/*
 *    GeoTools - The Open Source Java GIS Toolkit
 *    http://geotools.org
 *
 *    (C) 2011, Open Source Geospatial Foundation (OSGeo)
 *    (C) 2008, Open Geospatial Consortium Inc.
 *
 *    All Rights Reserved. http://www.opengis.org/legal/
 */
package org.opengis.style;

import org.opengis.annotation.Extension;
import org.opengis.annotation.XmlElement;
import org.opengis.filter.expression.Expression;

/**
 * The ContrastEnhancement object defines contrast enhancement for a channel of a false-color image
 * or for a color image.
 *
 * 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.
 *
 * @version Symbology Encoding
 *     Implementation Specification 1.1.0
 * @author Open Geospatial Consortium
 * @author Ian Turton, CCG
 * @author Johann Sorel (Geomatys)
 * @since GeoAPI 2.2
 */
@XmlElement("ContrastEnhancement")
public interface ContrastEnhancement {

    /** We use a codeList to enable more enchancement type possibilities. */
    @XmlElement("Normalize,Histogram,Logarithmic,Exponential")
    public ContrastMethod getMethod();

    /**
     * A "GammaValue" tells 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 to control gamma adjustment, null or Expression.NIL handled as the value
     *     1.0
     */
    @XmlElement("GammaValue")
    Expression getGammaValue();

    /**
     * calls the visit method of a StyleVisitor
     *
     * @param visitor the style visitor
     */
    @Extension
    Object accept(StyleVisitor visitor, Object extraData);
}