Application: gvSIG desktop » gvSIG tools: ToolBox

package es.unex.sextante.vectorTools.medialAxis;

import java.util.ArrayList;

import com.vividsolutions.jts.geom.Coordinate;

import com.vividsolutions.jts.geom.GeometryFactory;

import com.vividsolutions.jts.geom.LineString;

import com.vividsolutions.jts.geom.MultiLineString;

import com.vividsolutions.jts.geom.Polygon;

import es.unex.sextante.additionalInfo.AdditionalInfoVectorLayer;

import es.unex.sextante.core.GeoAlgorithm;

import es.unex.sextante.core.Sextante;

import es.unex.sextante.dataObjects.IFeature;

import es.unex.sextante.dataObjects.IFeatureIterator;

import es.unex.sextante.dataObjects.IVectorLayer;

import es.unex.sextante.dataObjects.vectorFilters.BoundingBoxFilter;

import es.unex.sextante.exceptions.GeoAlgorithmExecutionException;

import es.unex.sextante.exceptions.RepeatedParameterNameException;

import es.unex.sextante.outputs.OutputVectorLayer;

import gishur.core.SimpleList;

import gishur.x.XPoint;

import gishur.x.XPolygon;

import gishur.x.XSegment;

import gishur.x.voronoi.Skeleton;

public class MedialAxisAlgorithm

         extends

            GeoAlgorithm {

   public static final String LAYER  = "LAYER";

   public static final String RESULT = "RESULT";

   @Override

   public boolean processAlgorithm() throws GeoAlgorithmExecutionException {

      int i = 0;

      final IVectorLayer layerIn = m_Parameters.getParameterValueAsVectorLayer(LAYER);

      if (!m_bIsAutoExtent) {

         layerIn.addFilter(new BoundingBoxFilter(m_AnalysisExtent));

      }

      final IVectorLayer result = getNewVectorLayer(RESULT, Sextante.getText("Medial_Axis"), IVectorLayer.SHAPE_TYPE_LINE,

               layerIn.getFieldTypes(), layerIn.getFieldNames());

      final IFeatureIterator iter = layerIn.iterator();

      final int iTotal = layerIn.getShapesCount();

      while (iter.hasNext() && setProgress(i, iTotal)) {

         final IFeature feature = iter.next();

         final MultiLineString axis = getMedialAxis(((Polygon) feature.getGeometry().getGeometryN(0)));

         result.addFeature(axis, feature.getRecord().getValues());

         i++;

      }

      iter.close();

      return !m_Task.isCanceled();

   }

   @Override

   public void defineCharacteristics() {

      setName(Sextante.getText("Medial_Axis"));

      setGroup(Sextante.getText("Tools_for_polygon_layers"));

      try {

         m_Parameters.addInputVectorLayer(LAYER, Sextante.getText("Polygons"), AdditionalInfoVectorLayer.SHAPE_TYPE_POLYGON, true);

         addOutputVectorLayer(RESULT, Sextante.getText("Medial_Axis"), OutputVectorLayer.SHAPE_TYPE_LINE);

      }

      catch (final RepeatedParameterNameException e) {

         Sextante.addErrorToLog(e);

      }

   }

   private MultiLineString getMedialAxis(final Polygon poly) {

      final ArrayList<LineString> list = new ArrayList<LineString>();

      final GeometryFactory gf = new GeometryFactory();

      final Coordinate[] coords = poly.getExteriorRing().getCoordinates();

      final XPoint xpoints[] = new XPoint[coords.length];

      for (int i = 0; i < coords.length; i++) {

         xpoints[i] = new XPoint(coords[i].x, coords[i].y);

      }

      final XPolygon xpoly = new XPolygon(xpoints);

      final Skeleton skeleton = new Skeleton(xpoly);

      skeleton.execute();

      final SimpleList lines = skeleton.getLines(false);

      final Object[] array = lines.convertValuesToArray();

      for (int i = 0; i < array.length; i++) {

         final XSegment segment = (XSegment) array[i];

         System.out.println(segment.toString());

         final Coordinate[] segmentCoords = new Coordinate[] {

                  new Coordinate(segment.getStartPoint().x, segment.getStartPoint().y),

                  new Coordinate(segment.getEndPoint().x, segment.getEndPoint().y) };

         list.add(gf.createLineString(segmentCoords));

      }

      return gf.createMultiLineString(list.toArray(new LineString[0]));

   }

}