line.c

来自「<B>Digital的Unix操作系统VAX 4.2源码</B>」· C语言 代码 · 共 46 行

#ifndef lint
static char sccsid[] = "@(#)line.c	4.1 (Berkeley) 6/27/83";
#endif

#include "con.h"
line(x0,y0,x1,y1){
	iline(xconv(xsc(x0)),yconv(ysc(y0)),xconv(xsc(x1)),yconv(ysc(y1)));
	return;
}
cont(x0,y0){
	iline(xnow,ynow,xconv(xsc(x0)),yconv(ysc(y0)));
	return;
}
iline(cx0,cy0,cx1,cy1){
	int maxp,tt,j,np;
	char chx,chy,command;
	    float xd,yd;
	float dist2(),sqrt();
	movep(cx0,cy0);
	maxp = sqrt(dist2(cx0,cy0,cx1,cy1))/2.;
	xd = cx1-cx0;
	yd = cy1-cy0;
	command = COM|((xd<0)<<1)|(yd<0);
	if(maxp == 0){
		xd=0;
		yd=0;
	}
	else {
		xd /= maxp;
		yd /= maxp;
	}
	inplot();
	spew(command);
	for (tt=0; tt<=maxp; tt++){
		chx= cx0+xd*tt-xnow;
		xnow += chx;
		chx = abval(chx);
		chy = cy0+yd*tt-ynow;
		ynow += chy;
		chy = abval(chy);
		spew(ADDR|chx<<3|chy);
	}
	outplot();
	return;
}