/*
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.
*/
/*
* AlgoDependentLine.java
*
* Created on 29. Oktober 2001
*/
package org.geogebra.common.kernel.algos;
import org.geogebra.common.kernel.Construction;
import org.geogebra.common.kernel.StringTemplate;
import org.geogebra.common.kernel.arithmetic.Equation;
import org.geogebra.common.kernel.arithmetic.ExpressionNode;
import org.geogebra.common.kernel.arithmetic.ExpressionValue;
import org.geogebra.common.kernel.arithmetic.Inspecting;
import org.geogebra.common.kernel.arithmetic.NumberValue;
import org.geogebra.common.kernel.arithmetic.Polynomial;
import org.geogebra.common.kernel.geos.GeoLine;
import org.geogebra.common.kernel.geos.GeoPoint;
/**
*
* @author Markus
*/
public class AlgoDependentLine extends AlgoElement
implements EvaluateAtPoint, DependentAlgo {
private Equation equation;
private ExpressionValue[] ev = new ExpressionValue[3]; // input
private GeoLine g; // output
/**
* Creates new AlgoDependentLine
*
* @param cons
* construction
* @param equ
* equation
*/
public AlgoDependentLine(Construction cons, Equation equ) {
super(cons, false); // don't add to construction list yet
equation = equ;
equation.initEquation();
// Log.debug("Start algo");
// Log.debug(equation.getLHS());
// Log.debug(equation.getRHS());
Polynomial lhs = equ.getNormalForm();
ev[0] = lhs.getCoefficient("x");
ev[1] = lhs.getCoefficient("y");
ev[2] = lhs.getConstantCoefficient();
// Log.debug(lhs);
// Log.debug(ev[0]);
// check coefficients
for (int i = 0; i < 3; i++) {
if (!ev[i].inspect(Inspecting.dynamicGeosFinder)) {
ev[i] = ev[i].evaluate(StringTemplate.defaultTemplate);
}
// check that coefficient is a number: this may throw an exception
ExpressionValue eval = ev[i]
.evaluate(StringTemplate.defaultTemplate);
((NumberValue) eval).getDouble();
}
// if we get here, all is ok: let's add this algorithm to the
// construction list
cons.addToConstructionList(this, false);
g = new GeoLine(cons);
setInputOutput(); // for AlgoElement
// compute value of dependent number
compute();
}
@Override
public Algos getClassName() {
return Algos.Expression;
}
// for AlgoElement
@Override
protected void setInputOutput() {
input = equation.getGeoElementVariables();
setOutputLength(1);
setOutput(0, g);
setDependencies(); // done by AlgoElement
}
/**
* @return resulting line
*/
public GeoLine getLine() {
return g;
}
// calc the current value of the arithmetic tree
@Override
public final void compute() {
try {
g.x = ev[0].evaluateDouble();
g.y = ev[1].evaluateDouble();
g.z = ev[2].evaluateDouble();
// other algos might use the startPoint so we have to update it
if (g.getStartPoint() != null) {
g.setStandardStartPoint();
}
} catch (Throwable e) {
g.setUndefined();
}
}
@Override
final public String toString(StringTemplate tpl) {
if (g.getDefinition() != null) {
return g.getDefinition().toString(tpl);
}
return equation.toString(tpl);
}
@Override
final public double evaluate(GeoPoint P) {
double mat0 = ev[0].evaluateDouble(); // x\u00b2
double mat1 = ev[1].evaluateDouble(); // y\u00b2
double mat2 = ev[2].evaluateDouble(); // constant
return P.x * mat0 + P.y * mat1 + P.z * mat2;
}
@Override
public ExpressionNode getExpression() {
return null;
}
}