AutoCad凸度反推弧的圆心和起始结束角.pdf

AutoCad 凸度反推弧的圆心和起始结束角 /******************************************************************** created: 2012/09/12 created: 12:9:2012 11:25 file base: main file ext: cpp author: scenic purpose: 由起点和终点以及凸度求圆弧的圆心 *********************************************************************/ #include stdio.h #include stdlib.h #include math.h #define PI 3.141593 #define RESOLUTION 0.000001 typedef struct point { double x; double y; double z; }Point,*PPoint; typedef struct arc { double sx; double sy; double sz; double ex; double ey; double ez; double r; double cx; double cy; double cz; double startangle; double endangle; }ARC,*PARC; int getArcR(Point startpoint ,Point endpoint ,double bulge,PARC parc); int getArcR(Point startpoint ,Point endpoint ,double bulge,PARC parc) { double x1(0.0),y1(0.0),x2(0.0),y2(0.0),arcangle(0.0);//圆弧起始点和终止点, 以及所包的角度 x1=startpoint.x; y1=startpoint.y; x2=endpoint.x; y2=endpoint.y; parc-sx=startpoint.x; parc-sy=startpoint.y; parc-sz=0.0; parc-ex=endpoint.x; parc-ey=endpoint.y; parc-ez=0.0; arcangle=4*atan(fabs(bulge)); //弧包含的弧度 printf(arcangle= %f \n,arcangle*180/PI); if((-RESOLUTIONarcangle)(arcangleRESOLUTION)) { printf(LINE (x1= %f,y1=%f) (x2=%f,y2=%f) \n,x1,y1,x2,y2); return 1; } double chordlength; //弦长 chordlength=sqrt(pow((x1-x2),2)+pow((y1-y2),2)); double radius; //圆弧半径 radius=(0.5*chordlength)/(sin(0.5*arcangle)); printf(r= %f\n,radius); if((-RESOLUTION(radius))((radius)RESOLUTION)) { printf(startpoint cant be same as endpoint \n); return 1; } //已知圆上两点和半径，求圆心坐标 double verticalinterval;//圆心到弦垂距 verticalinterval=sqrt( radius* radius-chordlength*chordlength/4); double cx,cy;//圆心坐标 double midx,midy; /