Fung-Calc

00001 /***************************************************************************
00002                           meanvaluefunction.cpp  -  description
00003                              -------------------
00004     begin                : Sun Dec 29 2002
00005     copyright            : (C) 2002 by Fungmeista
00006     email                : mizunoami44@users.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 "meanvaluefunction.h"
00019 
00020 #include <qpainter.h>
00021 #include <qpoint.h>
00022 #include <qobject.h>
00023 
00024 #include "basicgraph.h"
00025 #include "fungparser.h"
00026 
00027 MeanValueFunction::MeanValueFunction(BasicGraph *graph,int expressions) : MathFunction(graph,expressions)
00028 {
00029 }
00030 MeanValueFunction::~MeanValueFunction()
00031 {
00032 }
00033 
00034 void MeanValueFunction::calculate_and_draw(QPainter* painter)
00035 {
00036     if ( lowerBounds.x() > upperBounds.x() ) //bounds check
00037     {
00038         QString s( QObject::tr("Invalid bounds") );
00039         setResult( s );
00040         return;
00041     }
00042 
00043     found = false;
00044     double slope = (toGraphYCoord(upperBounds.y()) - toGraphYCoord(lowerBounds.y())) / (toGraphXCoord(upperBounds.x()) - toGraphXCoord(lowerBounds.x()));
00045     for(int i=lowerBounds.x(); i<=upperBounds.x(); i++)
00046     {
00047         double x = toGraphXCoord(i);
00048         double x_next = toGraphXCoord(i+1);
00049 
00050         double d[] = {x,animatorValue()};
00051         double d_next[] = {x_next,animatorValue()};
00052 
00053         double y = expression->Eval(d);
00054         double y_next = expression->Eval(d_next);
00055 
00056         double slope_search = (y - y_next) / (x - x_next);
00057         if ( (slope_search <= slope + 0.1) && (slope_search >= slope - 0.1) )
00058         {
00059             point_x = x;
00060             point_y = y;
00061             found = true;
00062             break;
00063         }
00064     }
00065 
00066     double b = -(slope * point_x - point_y);
00067 
00068     double _x1 = toGraphXCoord(0);
00069     double _y1 = _x1*slope + b;
00070 
00071     double _x2 = toGraphXCoord(basicgraph->width());
00072     double _y2 = _x2*slope + b;
00073 
00074     x1 = toPixelXCoord(_x1);
00075     y1 = toPixelYCoord(_y1);
00076     x2 = toPixelXCoord(_x2);
00077     y2 = toPixelYCoord(_y2);
00078 
00079     if (found)
00080     {
00081         QString s = QString(QObject::tr("Mean Value = %1")).arg(point_x);
00082         setResult(s);
00083     }
00084     else
00085     {
00086         QString s = QObject::tr("None found");
00087         setResult(s);
00088     }
00089 
00090     draw_stored(painter);
00091 }
00092 
00093 void MeanValueFunction::draw_stored(QPainter* painter)
00094 {
00095     if (found)
00096     {
00097         painter->drawLine(x1,y1,x2,y2); //draw a line tangent to the point found
00098         drawSelectedPoint(point_x,point_y,painter);
00099     }
00100 }