Fung-Calc

00001 /***************************************************************************
00002                           zerofunction.cpp  -  description
00003                              -------------------
00004     begin                : Tue Nov 19 2002
00005     copyright            : (C) 2002 by Fungmeista
00006     email                : mizunoami44@sourceforge.net
00007  ***************************************************************************/
00008 
00009 /***************************************************************************
00010  *                                                                         *
00011  *   This program is free software; you can redistribute it and/or modify  *
00012  *   it under the terms of the GNU General Public License as published by  *
00013  *   the Free Software Foundation; either version 2 of the License, or     *
00014  *   (at your option) any later version.                                   *
00015  *                                                                         *
00016  ***************************************************************************/
00017 
00018 #include "zerofunction.h"
00019 
00020 #include <qobject.h>
00021 #include <qpoint.h>
00022 
00023 #include "fungparser.h"
00024 #include "fungmath.h"
00025 
00026 ZeroFunction::ZeroFunction(BasicGraph *graph, int expressions) : MathFunction(graph,expressions)
00027 {
00028     
00029 }
00030 ZeroFunction::~ZeroFunction()
00031 {
00032 }
00033 
00034 void ZeroFunction::calculate_and_draw(QPainter *painter)
00035 {
00036     double x,y,y_next,x_next;
00037     found = false;
00038     for (int i=lowerBounds.x(); i<upperBounds.x(); i++)
00039     {
00040         x = toGraphXCoord(i);
00041         double d[] = {x,animatorValue()};
00042         y = expression->Eval(d);
00043 
00044         x_next = toGraphXCoord(i+1);
00045         double d_next[] = {x_next,animatorValue()};
00046         y_next = expression->Eval(d_next);
00047 
00048         if ( ( y <= 0 && y_next >= 0 ) || ( y >= 0 && y_next <= 0 ) )
00049         {
00050             _x = ( ABS(y) < ABS(y_next) ) ? x : x_next; 
00051             found = true;
00052             break;
00053         } 
00054     }
00055 
00056     if (found)
00057     {
00058         QString s = QString(QObject::tr("Zero = ( %1, 0 )")).arg(_x);
00059         setResult(s);
00060     }
00061     else
00062     {
00063         QString s(QObject::tr("No zero"));
00064         setResult(s);
00065     }
00066 
00067     draw_stored(painter);
00068 }
00069 
00070 void ZeroFunction::draw_stored(QPainter *painter)
00071 {
00072     if (found)
00073         drawSelectedPoint( _x, 0, painter );
00074 }