/*
* 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.filter.expression.Expression;
import org.opengis.annotation.XmlElement;
/**
* A Halo is a type of Fill that is applied to the backgrounds of font glyphs. The use of
* halos greatly improves the readability of text labels.
*
*
* @source $URL: http://svn.osgeo.org/geotools/trunk/modules/library/opengis/src/main/java/org/opengis/style/Halo.java $
* @version <A HREF="http://www.opengeospatial.org/standards/symbol">Symbology Encoding Implementation Specification 1.1.0</A>
* @author Open Geospatial Consortium
* @author Johann Sorel (Geomatys)
* @author Chris Dillard (SYS Technologies)
* @since GeoAPI 2.2
*/
@XmlElement("Halo")
public interface Halo {
/**
* Returns the object that indicates how the halo area around the text
* should be filled.
*
* The default halo fill is solid white (Color
* “#FFFFFF”). The glyph’s fill is plotted on top of the halo. The default font fill is solid
* black (Color “#000000”).
*
* @return Fill or null
*/
@XmlElement("Fill")
Fill getFill();
/**
* Returns the expression that will be evaluated to get the pixel radius of
* the halo around the text.
*
* The Radius element gives the absolute size of a halo radius in pixels encoded as a
* floating-point number. The radius is taken from the outside edge of a font glyph to extend
* the area of coverage of the glyph (and the inside edge of “holes” in the glyphs). The halo
* of a text label is considered to be a single shape. The default radius is one pixel.
* Negative values are not allowed.
*
* @return Expression or null
*/
@XmlElement("Radius")
Expression getRadius();
/**
* calls the visit method of a StyleVisitor
*
* @param visitor the style visitor
*/
@Extension
Object accept(StyleVisitor visitor, Object extraData);
}