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intersectionfunction.cpp
00001 /*************************************************************************** 00002 intersectionfunction.cpp - description 00003 ------------------- 00004 begin : Tue Nov 12 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 <cmath> 00019 00020 #include "intersectionfunction.h" 00021 00022 IntersectionFunction::IntersectionFunction(BasicGraph *graph, int expressions) : MathFunction(graph,expressions) 00023 { 00024 } 00025 IntersectionFunction::~IntersectionFunction() 00026 { 00027 } 00028 00029 void IntersectionFunction::calculate_and_draw(QPainter *) 00030 { 00031 00032 } 00033 /* 00034 void Intersect_Lines(float x0,float y0,float x1,float y1, 00035 float x2,float y2,float x3,float y3, 00036 float *xi,float *yi) 00037 { 00038 00039 float a1,b1,c1, // constants of linear equations 00040 a2,b2,c2, 00041 det_inv, // the inverse of the determinant of the coefficient 00042 //matrix 00043 m1,m2; // the slopes of each line 00044 00045 // compute slopes, note the cludge for infinity, however, this will 00046 // be close enough 00047 00048 if ((x1-x0)!=0) 00049 m1 = (y1-y0)/(x1-x0); 00050 else 00051 m1 = (float)1e+10; // close enough to infinity 00052 00053 if ((x3-x2)!=0) 00054 m2 = (y3-y2)/(x3-x2); 00055 else 00056 m2 = (float)1e+10; // close enough to infinity 00057 00058 // compute constants 00059 00060 a1 = m1; 00061 a2 = m2; 00062 00063 b1 = -1; 00064 b2 = -1; 00065 00066 c1 = (y0-m1*x0); 00067 c2 = (y2-m2*x2); 00068 00069 // compute the inverse of the determinate 00070 00071 det_inv = 1/(a1*b2 - a2*b1); 00072 00073 // use Kramers rule to compute xi and yi 00074 00075 *xi=((b1*c2 - b2*c1)*det_inv); 00076 *yi=((a2*c1 - a1*c2)*det_inv); 00077 00078 } // end Intersect_Lines 00079 00080 */