/*
GeoGebra - Dynamic Mathematics for Everyone
http://www.geogebra.org
This file is part of GeoGebra.
This program is free software; you can redistribute it and/or modify it
under the terms of the GNU General Public License as published by
the Free Software Foundation.
*/
package org.geogebra.common.kernel.algos;
import org.geogebra.common.kernel.Construction;
import org.geogebra.common.kernel.FixedPathRegionAlgo;
import org.geogebra.common.kernel.Path;
import org.geogebra.common.kernel.StringTemplate;
import org.geogebra.common.kernel.Matrix.Coords;
import org.geogebra.common.kernel.arithmetic.Function;
import org.geogebra.common.kernel.commands.Commands;
import org.geogebra.common.kernel.geos.GeoElement;
import org.geogebra.common.kernel.geos.GeoFunction;
import org.geogebra.common.kernel.geos.GeoPoint;
import org.geogebra.common.kernel.kernelND.GeoPointND;
public class AlgoClosestPoint extends AlgoElement
implements FixedPathRegionAlgo {
private Path path; // input
protected GeoPointND point; // input
protected GeoPointND P; // output
public AlgoClosestPoint(Construction cons, Path path, GeoPointND point) {
super(cons);
this.path = path;
this.point = point;
// create point on path and compute current location
createOutputPoint(cons, path);
setInputOutput(); // for AlgoElement
compute();
addIncidence();
}
/**
* create the output point
*
* @param cons1
* construction
* @param pointPath
* path
*/
protected void createOutputPoint(Construction cons1, Path pointPath) {
P = new GeoPoint(cons1);
((GeoPoint) P).setPath(pointPath);
}
public AlgoClosestPoint(Construction cons, String label, Path path,
GeoPointND point) {
this(cons, path, point);
P.setLabel(label);
}
@Override
public Commands getClassName() {
return Commands.ClosestPoint;
}
// for AlgoElement
@Override
protected void setInputOutput() {
input = new GeoElement[2];
input[0] = path.toGeoElement();
input[1] = point.toGeoElement();
setOutputLength(1);
setOutput(0, (GeoElement) P);
setDependencies(); // done by AlgoElement
}
/**
* @author Tam
*
* for special cases of e.g. AlgoIntersectLineConic
*/
protected void addIncidence() {
((GeoPoint) P).addIncidence((GeoElement) path, false);
}
public GeoPointND getP() {
return P;
}
/**
* set coords of closest point to input point coords
*/
protected void setCoords() {
((GeoPoint) P).setCoords((GeoPoint) point);
}
@Override
public final void compute() {
if (input[0].isDefined() && point.isDefined()) {
if (path instanceof GeoFunction) {
Function fun = ((GeoFunction) path).getFunction()
.deepCopy(kernel);
Coords coords = point.getCoordsInD2();
double val = AlgoDistancePointObject
.getClosestFunctionValueToPoint(fun, coords.getX(),
coords.getY());
((GeoPoint) P).setCoords(val, fun.value(val), 1.0);
} else {
setCoords();
path.pointChanged(P);
}
P.updateCoords();
} else {
P.setUndefined();
}
}
@Override
final public String toString(StringTemplate tpl) {
return getLoc().getPlain("PointOnAClosestToB", input[0].getLabel(tpl),
input[1].getLabel(tpl));
}
@Override
public boolean isChangeable(GeoElement out) {
return false;
}
}