space.c

<B>Digital的Unix操作系统VAX 4.2源码</B>

#ifndef lint
static char SccsId[] = " @(#)space.c	4.1	(ULTRIX)	7/2/90";
#endif not(lint)

/*
 * Modification History
 *
 * 	April-11-1989, Pradeep Chetal
 *	Added changes from 4.3Tahoe BSD for lots of new drivers
 */

/*
 * Copyright (c) 1980 Regents of the University of California.
 * All rights reserved.  The Berkeley software License Agreement
 * specifies the terms and conditions for redistribution.
 */

#ifndef lint
static char sccsid[] = "@(#)space.c	5.2 (Berkeley) 4/30/85";
#endif not lint


#include "aed.h"

/*---------------------------------------------------------
 *	Space sets up the world-to-screen transformation so
 *	that the rectangular area described by (x0, y0) and
 *	(x1, y1) will all be on-screen.
 *
 *	Results:	None.
 *
 *	Side Effects:
 *	Our own variables scale, xbot, and ybot are changed.
 *---------------------------------------------------------
 */
space(x0, y0, x1, y1)
int x0, y0, x1, y1;
{
    int xscale, yscale, xsize, ysize;
    xscale = (GRXMAX<<12)/(x1-x0);
    yscale = (GRYMAX<<12)/(y1-y0);
    if (xscale > yscale) scale = yscale;
    else scale = xscale;
    scale = (scale*9)/10 - 1;
    if (scale<1) scale = 1;
    xsize = (2048*GRXMAX)/scale + 1;
    xbot = (x1+x0)/2 - xsize;
    ysize = (2048*GRYMAX)/scale + 1;
    ybot = (y1+y0)/2 - ysize;
}