package com.vividsolutions.jtstest.testbuilder.model;
import java.util.List;
import com.vividsolutions.jts.geom.Envelope;
import com.vividsolutions.jts.geom.Geometry;
import com.vividsolutions.jtstest.testbuilder.topostretch.TopologyStretcher;
public class GeometryStretcherView
{
/**
* The maximum number of vertices which can be shown.
* This is chosen to ensure reasonable performance for rendering.
*/
private static final int MAX_VERTICES_IN_MASK = 500;
/**
* The nearness tolerance in view pixels.
* This is chosen to be as large as possible
* (which minimizes change to geometries)
* but small enough that points which appear
* to be coincident on the screen at a given zoom level
* will be magnified.
*
*/
public static final double NEARNESS_TOL_IN_VIEW = 1;
private GeometryEditModel geomModel;
private Geometry[] stretchGeom = new Geometry[2];
private List[] stretchCoords;
private boolean isViewPerformant = true;
private Envelope maskEnv = null;
private double stretchSize = 5.0;
private double nearnessTol = 0.5;
public GeometryStretcherView(GeometryEditModel geomEditModel)
{
this.geomModel = geomEditModel;
}
public GeometryContainer getContainer(int i)
{
return new StretchedGeometryContainer(i);
}
/**
* Sets the amount by which vertices will be stretched
* (in geometry units).
*
* @param stretchSize
*/
public void setStretchSize(double stretchSize)
{
this.stretchSize = stretchSize;
}
public void setNearnessTolerance(double nearnessTol)
{
this.nearnessTol = nearnessTol;
}
public void setEnvelope(Envelope maskEnv)
{
this.maskEnv = maskEnv;
// clear cache
stretchGeom = null;
}
public boolean isViewPerformant()
{
updateCache();
return isViewPerformant;
}
public Geometry getStretchedGeometry(int index)
{
updateCache();
return stretchGeom[index];
}
public List getStretchedVertices(int index)
{
updateCache();
return stretchCoords[index];
}
private synchronized void updateCache()
{
if (! isCacheValid()) {
Geometry g0 = geomModel.getGeometry(0);
Geometry g1 = geomModel.getGeometry(1);
TopologyStretcher stretcher = new TopologyStretcher(g0, g1);
// check if view is valid (performant enough) to render
if (maskEnv != null) {
isViewPerformant = stretcher.numVerticesInMask(maskEnv) < MAX_VERTICES_IN_MASK;
}
if (! isViewPerformant)
return;
stretchGeom = stretcher.stretch(nearnessTol, stretchSize, maskEnv);
stretchCoords = stretcher.getModifiedCoordinates();
}
}
private boolean isCacheValid()
{
if (stretchGeom == null) {
stretchGeom = new Geometry[2];
return false;
}
// don't bother checking this any more, since stretchView is always created new
//if (geomModel.getGeometry(0) != stretchGeom[0]) return false;
//if (geomModel.getGeometry(1) != stretchGeom[1]) return false;
return true;
}
private class StretchedGeometryContainer implements GeometryContainer
{
private int index;
public StretchedGeometryContainer(int index)
{
this.index = index;
}
public Geometry getGeometry()
{
return getStretchedGeometry(index);
}
}
}