subr.c

来自「<B>Digital的Unix操作系统VAX 4.2源码</B>」· C语言 代码 · 共 161 行

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

#include <stdio.h>
#include "con.h"
abval(q)
{
	return (q>=0 ? q : -q);
}

xconv (xp)
{
	/* x position input is -2047 to +2047, output must be 0 to PAGSIZ*HORZRES */
	xp += 2048;
	/* the computation is newx = xp*(PAGSIZ*HORZRES)/4096 */
	return (xoffset + xp /xscale);
}

yconv (yp)
{
	/* see description of xconv */
	yp += 2048;
	return (yp / yscale);
}

inplot()
{
	stty(OUTF, &PTTY);
	spew(ESC);
	spew (INPLOT);
}

outplot()
{
	spew(ESC);
	spew(ACK);
	spew(ESC);
	spew(ACK);
	fflush(stdout);
	stty (OUTF, &ITTY);
}

spew(ch)
{
	putc(ch, stdout);
}

tobotleft ()
{
	move(-2048,-2048);
}
reset()
{
	outplot();
	exit();
}

float
dist2 (x1, y1, x2, y2)
{
	float t,v;
	t = x2-x1;
	v = y1-y2;
	return (t*t+v*v);
}

swap (pa, pb)
int *pa, *pb;
{
	int t;
	t = *pa;
	*pa = *pb;
	*pb = t;
}

#define DOUBLE 010
#define ADDR 0100
#define COM 060
#define MAXX 070
#define MAXY 07
extern xnow,ynow;
#define SPACES 7
movep(ix,iy){
	int dx,dy,remx,remy,pts,i;
	int xd,yd;
	int addr,command;
	char c;
	if(xnow == ix && ynow == iy)return;
	inplot();
	dx = ix-xnow;
	dy = iy-ynow;
	command = COM|PENUP|((dx<0)<<1)|(dy<0);
	dx = abval(dx);
	dy = abval(dy);
	xd = dx/(SPACES*2);
	yd = dy/(SPACES*2);
	pts = xd<yd?xd:yd;
	if((i=pts)>0){
		c=command|DOUBLE;
		addr=ADDR;
		if(xd>0)addr|=MAXX;
		if(yd>0)addr|=MAXY;
		spew(c);
		while(i--){
			spew(addr);
		}
	}
	if(xd!=yd){
		if(xd>pts){
			i=xd-pts;
			addr=ADDR|MAXX;
		}
		else{
			i=yd-pts;
			addr=ADDR|MAXY;
		}
		c=command|DOUBLE;
		spew(c);
		while(i--){
			spew(addr);
		}
	}
	remx=dx-xd*SPACES*2;
	remy=dy-yd*SPACES*2;
	addr=ADDR;
	i = 0;
	if(remx>7){
		i=1;
		addr|=MAXX;
		remx -= 7;
	}
	if(remy>7){
		i=1;
		addr|=MAXY;
		remy -= 7;
	}
	while(i--){
		spew(command);
		spew(addr);
	}
	if(remx>0||remy>0){
		spew(command);
		spew(ADDR|remx<<3|remy);
	}
	xnow=ix;
	ynow=iy;
	outplot();
	return;
}
xsc(xi){
	int xa;
	xa = (xi - obotx) * scalex + botx;
	return(xa);
}
ysc(yi){
	int ya;
	ya = (yi - oboty) *scaley +boty;
	return(ya);
}