www.pudn.com > 医学算法.rar > trace.c

#include	
#include	

/*
	trace - trace through single ellipse

	Carl Crawford
	Purdue University
	W. Lafayette, IN. 47907

	Jan. 15, 1981
*/

float	a = 2.0;	/* semi - major axis */
float	b = 1.0;	/* semi - minor axis */
float   theta = 00.0;   /* rotation of ellipse */
float   tau = 1.8;      /* transducer position */
float   width = .3;     /* width of transducer */
int	dev = 3;	/* plot device */
int	print;		/* 1=don't print program status */
float	pi = 3.14159265;/* pi in the face */
int     tang;           /* 1 = draw tangent to center line */
float   sc      1.0;    /* scale factor */

char    *table[] = {
		"a",
		"b",
		"theta",
		"tau",
		"width",
		"dev",
		0
	};

main(argc,argv)
	int	argc;
	char	**argv;
{
	char	c;
	float   g,dg,cost,sint,x,y,at;
	float   x1,y1,x2,y2,t1,t2;
	register int	i;

	while(argv++ , --argc){
		if(argv[0][0] == '-')while(c = *++*argv)switch(c){

			case 'p':	/* print flag */
				print = 1;
				break;
			case 't':       /* tangent */
				tang = 1;
				break;
			case 'h':
				sc /= 2;
				break;
			default:
				fprintf(stderr,"bad flag: -%c\n",c);
				exit(1);
			}
		else
			switch(i = comm(*argv)){

			case 1:
				a = atof(*argv + 2);
				break;
			case 2:
				b = atof(*argv + 2);
				break;
			case 3:
				theta = atof(*argv + 6);
				break;
			case 4:
				tau = atof(*argv + 4);
				break;
			case 5:
				width = atof(*argv + 6);
				break;
			case 6:
				dev = atoi(*argv + 4);
				break;
		}
	}

	if(!print){
		printf("TRACE DATA\n\n");
		printf("a = %f\n",a);
		printf("b = %f\n",b);
		printf("theta = %f\n",theta);
		printf("tau = %f\n",tau);
		printf("width = %f\n",width);
	}

	theta *= pi / 180.0;

	plots(dev,0);
	factor(sc);
	plot(5.0,5.0,-3);


	lplot(5.0,0.0,-5.0,0.0);/* draw axes */
	lplot(0.0,5.0,0.0,-5.0);
	cost = cos(theta);
	sint = sin(theta);
	lplot(4.0*sint,4.0*cost,-4.0*sint,-4.0*cost);
	lplot(4.0*cost,-4.0*sint,-4.0*cost,4.0*sint);

	g = 0.0;		/* draw ellipse */
	dg = (pi + pi) / 199.0;
	for(i=0;i<200;i++){
		x = a * cos(g);
		y = b * sin(g);
		plot(x*cost+y*sint,-x*sint+y*cost,2 + !i);
		g += dg;
	}

	lplot(-5.0,-4.0,5.0,-4.0);      /* draw transducer axis */
	lplot(tau,-4.0,tau,4.0);
	lplot(tau + width * 0.5,-4.0,tau + width * 0.5,4.0);
	lplot(tau - width * 0.5,-4.0,tau - width * 0.5,4.0);

	if(tang){       /* draw tangents */
		at = a * a * cost * cost + b * b * sint * sint;
		if(at >= fabs(tau)){
			t1 = a * a * tau * cost;
			t2 = a * b * sint * sqrt(at - tau * tau);
			x1 = (t1 - t2) / at;
			x2 = (t1 + t2) / at;
			y1 = b * sqrt(1- x1 * x1 / a / a);
			y2 = -b * sqrt(1- x2 * x2 / a / a);
			symbol(x1*cost+y1*sint,-x1*sint+y1*cost,.1,"x",0.0);
			symbol(x2*cost+y2*sint,-x2*sint+y2*cost,.1,"x",0.0);
		}
	}

	plot(0.0,0.0,999);
}


comm(s)
	char	*s;
{
	register	int	i,j,r;

	for(i=0;table[i];i++){
		for(j=0;(r=table[i][j]) == s[j] && r;j++);
		if(r == 0 && s[j] == '=' && s[j+1] )return(i+1);
	}
	fprintf(stderr,"bad option: %s\n",s);
	exit(1);
}