/*
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.Matrix.Coords;
import org.geogebra.common.kernel.geos.GeoElement;
import org.geogebra.common.kernel.geos.GeoNumberValue;
import org.geogebra.common.kernel.geos.GeoPoint;
import org.geogebra.common.kernel.geos.GeoPolygon;
import org.geogebra.common.kernel.kernelND.GeoDirectionND;
import org.geogebra.common.kernel.kernelND.GeoPointND;
/**
* Creates a regular Polygon for two points and the number of vertices.
*
* @author Markus Hohenwarter
*/
public class AlgoPolygonRegular extends AlgoPolygonRegularND {
private Coords centerPointCoords;
/**
* Creates a new regular polygon algorithm
*
* @param c
* construction
* @param labels
* labels[0] for polygon, then labels for segments and then for
* points
* @param A1
* first input point
* @param B1
* second input point
* @param num
* number of vertices
*/
public AlgoPolygonRegular(Construction c, String[] labels, GeoPointND A1,
GeoPointND B1, GeoNumberValue num) {
super(c, labels, A1, B1, num, null);
}
@Override
protected GeoPolygon newGeoPolygon(Construction cons1) {
return new GeoPolygon(cons1);
}
@Override
protected GeoElement newGeoPoint(Construction cons1) {
GeoPoint newPoint = new GeoPoint(cons1);
newPoint.setCoords(0, 0, 1);
return newPoint;
}
@Override
protected void setCenterPoint(int n, double beta) {
double xA = ((GeoPoint) A).inhomX;
double yA = ((GeoPoint) A).inhomY;
double xB = ((GeoPoint) B).inhomX;
double yB = ((GeoPoint) B).inhomY;
// some temp values
double mx = (xA + xB) / 2; // midpoint of AB
double my = (yA + yB) / 2;
// normal vector of AB
double nx = yA - yB;
double ny = xB - xA;
// center point of regular polygon
double tanBetaHalf = Math.tan(beta) / 2;
centerPoint.setCoords(mx + tanBetaHalf * nx, my + tanBetaHalf * ny,
1.0);
centerPointCoords = centerPoint.getInhomCoords();
}
@Override
protected void rotate(GeoPointND point) {
point.rotate(rotAngle, centerPointCoords);
}
// for AlgoElement
@Override
protected void setInputOutput() {
input = new GeoElement[3];
input[0] = (GeoElement) A;
input[1] = (GeoElement) B;
input[2] = num.toGeoElement();
// set dependencies
for (int i = 0; i < input.length; i++) {
input[i].addAlgorithm(this);
}
cons.addToAlgorithmList(this);
// setOutput(); done in compute
// parent of output
getPoly().setParentAlgorithm(this);
}
@Override
final protected void setDirection(GeoDirectionND direction) {
// used only in 3D
}
@Override
public void calcCentroid(GeoPoint p) {
p.setCoords((GeoPoint) centerPoint);
}
}