/*
* GeoTools - The Open Source Java GIS Toolkit
* http://geotools.org
*
* (C) 2002-2008, Open Source Geospatial Foundation (OSGeo)
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation;
* version 2.1 of the License.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*/
package org.geotools.renderer.shape;
import java.util.Stack;
import org.geotools.filter.visitor.AbstractFilterVisitor;
import com.vividsolutions.jts.geom.Envelope;
import com.vividsolutions.jts.geom.Geometry;
import com.vividsolutions.jts.geom.GeometryFactory;
/**
* Visits a filter and extracts the minimum bounds that the filter requires.
*
* @author jones
*
*
*
* @source $URL$
*/
public class BoundsExtractor extends AbstractFilterVisitor{
private Stack/*<Envelope>*/ envelopeStack=new Stack/*<Envelope>*/();
private final Envelope original;
private Envelope notEnvelope;
private final static GeometryFactory factory=new GeometryFactory();
public BoundsExtractor(Envelope bbox) {
original=bbox;
}
public BoundsExtractor(int minx, int maxx, int miny, int maxy) {
this(new Envelope(minx, maxx, miny, maxy));
}
/**
* @return the intersecton of the new bbox and the original
*/
public Envelope getIntersection() {
Envelope bbox=null;
if( !envelopeStack.isEmpty())
bbox=(Envelope) envelopeStack.peek();
if( original==null ){
return bbox==null?new Envelope():bbox;
}
if( bbox!=null )
return bbox.intersection(original);
if( notEnvelope!=null ){
return intersectionWithNotEnvelope(original);
}
return original;
}
/**
* @return the intersecton of the new bbox and the original
*/
public Envelope getFilterEnvelope() {
if( envelopeStack.isEmpty() )
return new Envelope();
return (Envelope) envelopeStack.peek();
}
public Envelope getNotEnvelope() {
return notEnvelope==null?new Envelope():notEnvelope;
}
// /*
// * @see org.geotools.filter.FilterVisitor#visit(org.geotools.filter.LogicFilter)
// */
// public void visit(LogicFilter filter) {
//
// if (filter != null) {
// switch (filter.getFilterType()) {
// case FilterType.LOGIC_OR: {
// Iterator i = filter.getFilterIterator();
// while (i.hasNext()) {
// Filter tmp = (Filter) i.next();
// tmp.accept(this);
// }
// Envelope bbox=new Envelope();
// while( !envelopeStack.isEmpty() ){
// Envelope env = (Envelope) envelopeStack.pop();
// bbox.expandToInclude(env);
// }
// if( notEnvelope!=null ){
// if( bbox.contains(notEnvelope) ){
// // or contains all of notEnvelope so notEnvelope is meaningless
// notEnvelope=null;
// }else{
// // lets err on the side of caution and we can safely ignore the or... This will
// // be a little big but that's ok.
// bbox=new Envelope();
// }
// }
//
// if( !bbox.isNull() )
// envelopeStack.push(bbox);
// break;
// }
// case FilterType.LOGIC_AND: {
// Iterator i = filter.getFilterIterator();
// while (i.hasNext()) {
// Filter tmp = (Filter) i.next();
// tmp.accept(this);
// }
// if( !envelopeStack.isEmpty() ){
// Envelope bbox = null;
// while( !envelopeStack.isEmpty() ){
// Envelope env = (Envelope) envelopeStack.pop();
// if( bbox==null ){
// bbox=env;
// }else{
// bbox=bbox.intersection(env);
// }
// }
// if( notEnvelope!=null && bbox!=null){
// if( notEnvelope.contains(bbox) ){
// // this mean that nothing valid since we are ANDING
// // and area with an area that is guaranteed to be empty
// // Erring on the side of caution for now
// notEnvelope=bbox;
// bbox=null;
// }else{
// bbox = intersectionWithNotEnvelope(bbox);
// notEnvelope=null;
// }
// }
// if( bbox!=null && !bbox.isNull() )
// envelopeStack.push(bbox);
// }
//
// break;
// }
// case FilterType.LOGIC_NOT:
// Iterator i = filter.getFilterIterator();
// Filter tmp = (Filter) i.next();
// tmp.accept(this);
// if( !envelopeStack.isEmpty() ){
// notEnvelope=(Envelope) envelopeStack.pop();
// assert envelopeStack.isEmpty();
// }else if( notEnvelope!=null || !notEnvelope.isNull()){
// envelopeStack.push(notEnvelope);
// notEnvelope=null;
// }
// default:
// break;
// }
//
// }
// }
//
private Envelope intersectionWithNotEnvelope(Envelope bbox) {
Geometry notGeom = factory.toGeometry(notEnvelope);
Geometry andGeom = factory.toGeometry(bbox);
Envelope envelopeInternal = andGeom.difference(notGeom).getEnvelopeInternal();
bbox = envelopeInternal;
return bbox;
}
//
// public void visit(LiteralExpression expression) {
// Object literal = expression.getLiteral();
// if (literal instanceof Geometry) {
// Geometry geom = (Geometry) literal;
// envelopeStack.push(geom.getEnvelopeInternal());
// }
// }
}