001 /*
002 * GeoAPI - Java interfaces for OGC/ISO standards
003 * http://www.geoapi.org
004 *
005 * Copyright (C) 2004-2012 Open Geospatial Consortium, Inc.
006 * All Rights Reserved. http://www.opengeospatial.org/ogc/legal
007 *
008 * Permission to use, copy, and modify this software and its documentation, with
009 * or without modification, for any purpose and without fee or royalty is hereby
010 * granted, provided that you include the following on ALL copies of the software
011 * and documentation or portions thereof, including modifications, that you make:
012 *
013 * 1. The full text of this NOTICE in a location viewable to users of the
014 * redistributed or derivative work.
015 * 2. Notice of any changes or modifications to the OGC files, including the
016 * date changes were made.
017 *
018 * THIS SOFTWARE AND DOCUMENTATION IS PROVIDED "AS IS," AND COPYRIGHT HOLDERS MAKE
019 * NO REPRESENTATIONS OR WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED
020 * TO, WARRANTIES OF MERCHANTABILITY OR FITNESS FOR ANY PARTICULAR PURPOSE OR THAT
021 * THE USE OF THE SOFTWARE OR DOCUMENTATION WILL NOT INFRINGE ANY THIRD PARTY
022 * PATENTS, COPYRIGHTS, TRADEMARKS OR OTHER RIGHTS.
023 *
024 * COPYRIGHT HOLDERS WILL NOT BE LIABLE FOR ANY DIRECT, INDIRECT, SPECIAL OR
025 * CONSEQUENTIAL DAMAGES ARISING OUT OF ANY USE OF THE SOFTWARE OR DOCUMENTATION.
026 *
027 * The name and trademarks of copyright holders may NOT be used in advertising or
028 * publicity pertaining to the software without specific, written prior permission.
029 * Title to copyright in this software and any associated documentation will at all
030 * times remain with copyright holders.
031 */
032 package org.opengis.style;
033
034 import org.opengis.annotation.Extension;
035 import org.opengis.filter.expression.Expression;
036 import org.opengis.annotation.XmlElement;
037
038
039 /**
040 * A Halo is a type of Fill that is applied to the backgrounds of font glyphs. The use of
041 * halos greatly improves the readability of text labels.
042 *
043 * @version <A HREF="http://www.opengeospatial.org/standards/symbol">Symbology Encoding Implementation Specification 1.1.0</A>
044 * @author Open Geospatial Consortium
045 * @author Johann Sorel (Geomatys)
046 * @author Chris Dillard (SYS Technologies)
047 * @since GeoAPI 2.2
048 */
049 @XmlElement("Halo")
050 public interface Halo {
051
052 /**
053 * Returns the object that indicates how the halo area around the text
054 * should be filled.
055 *
056 * The default halo fill is solid white (Color
057 * “#FFFFFF”). The glyph’s fill is plotted on top of the halo. The default font fill is solid
058 * black (Color “#000000”).
059 *
060 * @return Fill or null
061 */
062 @XmlElement("Fill")
063 Fill getFill();
064
065 /**
066 * Returns the expression that will be evaluated to get the pixel radius of
067 * the halo around the text.
068 *
069 * The Radius element gives the absolute size of a halo radius in pixels encoded as a
070 * floating-point number. The radius is taken from the outside edge of a font glyph to extend
071 * the area of coverage of the glyph (and the inside edge of “holes” in the glyphs). The halo
072 * of a text label is considered to be a single shape. The default radius is one pixel.
073 * Negative values are not allowed.
074 *
075 * @return Expression or null
076 */
077 @XmlElement("Radius")
078 Expression getRadius();
079
080 /**
081 * calls the visit method of a StyleVisitor
082 *
083 * @param visitor the style visitor
084 */
085 @Extension
086 Object accept(StyleVisitor visitor, Object extraData);
087
088 }