Source Code Cross Referenced for ContrastEnhancementImpl.java in  » GIS » GeoTools-2.4.1 » org » geotools » styling » Java Source Code / Java DocumentationJava Source Code and Java Documentation

001:        /*
002:         *    GeoTools - OpenSource mapping toolkit
003:         *    http://geotools.org
004:         *    (C) 2002-2006, GeoTools Project Managment Committee (PMC)
005:         *    (C) 2002, Centre for Computational Geography
006:         *    
007:         *    This library is free software; you can redistribute it and/or
008:         *    modify it under the terms of the GNU Lesser General Public
009:         *    License as published by the Free Software Foundation;
010:         *    version 2.1 of the License.
011:         *
012:         *    This library is distributed in the hope that it will be useful,
013:         *    but WITHOUT ANY WARRANTY; without even the implied warranty of
014:         *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
015:         *    Lesser General Public License for more details.
016:         *
017:         * Created on 13 November 2002, 13:52
018:         */
019:        package org.geotools.styling;
020:
021:        import org.geotools.event.AbstractGTComponent;
022:        import org.geotools.factory.CommonFactoryFinder;
023:        import org.geotools.factory.GeoTools;
024:        import org.opengis.filter.FilterFactory;
025:        import org.opengis.filter.expression.Expression;
026:
027:        /**
028:         * The ContrastEnhancement object defines contrast enhancement for a channel of
029:         * a false-color image or for a color image. Its format is:
030:         * <pre>
031:         * &lt;xs:element name="ContrastEnhancement"&gt;
032:         *   &lt;xs:complexType&gt;
033:         *     &lt;xs:sequence&gt;
034:         *       &lt;xs:choice minOccurs="0"&gt;
035:         *         &lt;xs:element ref="sld:Normalize"/&gt;
036:         *         &lt;xs:element ref="sld:Histogram"/&gt;
037:         *       &lt;/xs:choice&gt;
038:         *       &lt;xs:element ref="sld:GammaValue" minOccurs="0"/&gt;
039:         *     &lt;/xs:sequence&gt;
040:         *   &lt;/xs:complexType&gt;
041:         * &lt;/xs:element&gt;
042:         * &lt;xs:element name="Normalize"&gt;
043:         *   &lt;xs:complexType/&gt;
044:         * &lt;/xs:element&gt;
045:         * &lt;xs:element name="Histogram"&gt;
046:         *   &lt;xs:complexType/&gt;
047:         * &lt;/xs:element&gt;
048:         * &lt;xs:element name="GammaValue" type="xs:double"/&gt;
049:         * </pre>
050:         * In the case of a color image, the relative grayscale brightness of a pixel
051:         * color is used. ?Normalize? means to stretch the contrast so that the
052:         * dimmest color is stretched to black and the brightest color is stretched to
053:         * white, with all colors in between stretched out linearly. ?Histogram? means
054:         * to stretch the contrast based on a histogram of how many colors are at each
055:         * brightness level on input, with the goal of producing equal number of
056:         * pixels in the image at each brightness level on output.  This has the
057:         * effect of revealing many subtle ground features. A ?GammaValue? tells how
058:         * much to brighten (value greater than 1.0) or dim (value less than 1.0) an
059:         * image. The default GammaValue is 1.0 (no change). If none of Normalize,
060:         * Histogram, or GammaValue are selected in a ContrastEnhancement, then no
061:         * enhancement is performed.
062:         *
063:         * @author iant
064:         * @source $URL: http://svn.geotools.org/geotools/tags/2.4.1/modules/library/main/src/main/java/org/geotools/styling/ContrastEnhancementImpl.java $
065:         */
066:        public class ContrastEnhancementImpl extends AbstractGTComponent
067:                implements  ContrastEnhancement {
068:
069:            private static final java.util.logging.Logger LOGGER = org.geotools.util.logging.Logging
070:                    .getLogger("org.geotools.core");
071:            private FilterFactory filterFactory;
072:            private Expression gamma;
073:            private Expression type;
074:
075:            public ContrastEnhancementImpl() {
076:                this (CommonFactoryFinder.getFilterFactory(GeoTools
077:                        .getDefaultHints()));
078:            }
079:
080:            public ContrastEnhancementImpl(FilterFactory factory) {
081:                filterFactory = factory;
082:            }
083:
084:            public void setFilterFactory(FilterFactory factory) {
085:                filterFactory = factory;
086:            }
087:
088:            public Expression getGammaValue() {
089:                return gamma;
090:            }
091:
092:            public Expression getType() {
093:                return type;
094:            }
095:
096:            public void setGammaValue(Expression gamma) {
097:                this .gamma = gamma;
098:                fireChanged();
099:            }
100:
101:            public void setHistogram() {
102:                type = filterFactory.literal("HISTOGRAM");
103:                fireChanged();
104:            }
105:
106:            public void setNormalize() {
107:                type = filterFactory.literal("NORMALIZE");
108:                fireChanged();
109:            }
110:
111:            public void setType(Expression type) {
112:                this.type = type;
113:                fireChanged();
114:            }
115:        }