/*
 *    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 ShadedRelief element selects the application of relief shading (or “hill shading”) to
 * an image for a three-dimensional visual effect.
 *
 * Exact parameters of the shading are system-dependent (for now). If the BrightnessOnly
 * flag is “0” or “false” (false, default), the shading is applied to the layer being rendered as
 * the current RasterSymbolizer. If BrightnessOnly is “1” or “true” (true), the shading is
 * applied to the brightness of the colors in the rendering canvas generated so far by other
 * layers, with the effect of relief-shading these other layers. The default for
 * BrightnessOnly is “0” (false). The ReliefFactor gives the amount of exaggeration to use
 * for the height of the “hills.” A value of around 55 (times) gives reasonable results for
 * Earth-based DEMs. The default value is system-dependent.
 *
 *
 * @source $URL: http://svn.osgeo.org/geotools/trunk/modules/library/opengis/src/main/java/org/opengis/style/ShadedRelief.java $
 * @version <A HREF="http://www.opengeospatial.org/standards/symbol">Symbology Encoding Implementation Specification 1.1.0</A>
 * @author Open Geospatial Consortium
 * @author Ian Turton, CCG
 * @author Johann Sorel (Geomatys)
 * @since GeoAPI 2.2
 */
@XmlElement("ShadedRelief")
public interface ShadedRelief {

    /**
     * indicates if brightnessOnly is true or false. Default is false.
     *
     * @return boolean brightnessOn.
     */
    @XmlElement("BrightnessOnly")
    public boolean isBrightnessOnly();

    /**
     * The ReliefFactor gives the amount of exaggeration to use for the height
     * of the ?hills.?  A value of around 55 (times) gives reasonable results
     * for Earth-based DEMs. The default value is system-dependent.
     *
     * @return an expression which evaluates to a double.
     */
    @XmlElement("ReliefFactor")
    public Expression getReliefFactor();

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