rect.c

操作系统SunOS 4.1.3版本的源码

#ifndef lint
#ifdef sccs
static	char sccsid[] = "@(#)rect.c 1.1 92/07/30 Copyr 1984 Sun Micro";
#endif
#endif

/*
 * Copyright (c) 1984 by Sun Microsystems, Inc.
 */

/*
 * 	Overview:	Implements the interface described by rect.h
 *			which defines the rectangle structure
 */

#include <sunwindow/rect.h>
#ifndef KERNEL
#include <stdio.h>
#endif /* !KERNEL */

/*
 * Rect geometry functions
 */
rect_intersection(r1, r2, r)
	register struct	rect *r1, *r2, *r;
{
	r->r_left = max(r1->r_left, r2->r_left);
	r->r_top = max(r1->r_top, r2->r_top);
	r->r_width = min(r1->r_left+r1->r_width, r2->r_left+r2->r_width)-
	    r->r_left;
	if (r->r_width < 0) r->r_width = 0;
	r->r_height  = min(r1->r_top+r1->r_height, r2->r_top+r2->r_height)-
	    r->r_top;
	if (r->r_height < 0) r->r_height = 0;
	return;
}

#ifndef KERNEL
bool
rect_clipvector(r, x1arg, y1arg, x2arg, y2arg)
	register struct	rect *r;
	int *x1arg, *y1arg, *x2arg, *y2arg;
{	/*
	 * clip vector 1=>2 to r, return TRUE if visible.
	 * Cohen-Sutherland algorithm.
	 */
	register short x1 = *x1arg, y1 = *y1arg, x2 = *x2arg, y2 = *y2arg;
	register char bits1, bits2, bits;
	coord	t, n, d, p;
	bool	done, accept;

	done = FALSE;
	do {
	    bits1 = 0;
	    if (y1 < r->r_top) bits1 |= 1;
	    if (y1 > rect_bottom(r)) bits1 |= 2;
	    if (x1 > rect_right(r)) bits1 |= 4;
	    if (x1 < r->r_left) bits1 |= 8;
	    bits2 = 0;
	    if (y2 < r->r_top) bits2 |= 1;
	    if (y2 > rect_bottom(r)) bits2 |= 2;
	    if (x2 > rect_right(r)) bits2 |= 4;
	    if (x2 < r->r_left) bits2 |= 8;

	    accept = ((bits1 | bits2) == 0);
	    if (accept) done = TRUE;	/* vector all inside clip volume*/
	    else {
	        accept = ((bits1 & bits2) == 0);
	        if (!accept) done = TRUE;	/* vec all outside clip vol  */
		else {			/* vector needs clip	*/
		    if (bits1 == 0) {	/* make sure v1 is outside	*/
			p = x1; x1 = x2; x2 = p;
			p = y1; y1 = y2; y2 = p;
			bits = bits1;  bits1 = bits2;  bits2 = bits;
			}
		    if (bits1 & 1) {			/* clip above	*/
			n = (r->r_top - y1);
			d = (y2 - y1);
			t = (x2 - x1);
			t *= n;
			t /= d;
			x1 = x1 + t;
			y1 = r->r_top;
			}
		    else if (bits1 & 2) {		/* clip below	*/
			n = (rect_bottom(r) - y1);
			d = (y2 - y1);
			t = (x2 - x1);
			t *= n;
			t /= d;
			x1 = x1 + t;
			y1 = rect_bottom(r);
			}
		    else if (bits1 & 4) {		/* clip right	*/
			n = (rect_right(r) - x1);
			d = (x2 - x1);
			t = (y2 - y1);
			t *= n;
			t /= d;
			y1 = y1 + t;
			x1 = rect_right(r);
			}
		    else if (bits1 & 8) {		/* clip r_left	*/
			n = (r->r_left - x1);
			d = (x2 - x1);
			t = (y2 - y1);
			t *= n;
			t /= d;
			y1 = y1 + t;
			x1 = r->r_left;
			}
		    }
		}
	    } while (!done);
	*x1arg = x1; *y1arg = y1; *x2arg = x2; *y2arg = y2;
	return( accept);
}

bool
rect_order(r1, r2, sortorder)
	struct	rect *r1, *r2;
	int	sortorder;
{	/*
	 * Return true if r1 & r2 are in the specified relationship.
	 */
	switch (sortorder) {
	case RECTS_TOPTOBOTTOM:
		if (r1->r_top <= r2->r_top)
			return(TRUE);
		break;
	case RECTS_BOTTOMTOTOP:
		if (rect_bottom(r1) >= rect_bottom(r2))
			return(TRUE);
		break;
	case RECTS_LEFTTORIGHT:
		if (r1->r_left <= r2->r_left)
			return(TRUE);
		break;
	case RECTS_RIGHTTOLEFT:
		if (rect_right(r1) >= rect_right(r2))
			return(TRUE);
		break;
	case RECTS_UNSORTED:
		return(TRUE);
		break;
	default:
		(void)fprintf(stderr, "Bad sortorder arg in mostRect\n");
		break;
	}
	return(FALSE);
}
#endif !KERNEL

struct	rect
rect_bounding(r1, r2)
	register struct rect *r1, *r2;
{
	struct	rect r;

	if (rect_isnull(r1))
		r = *r2;
	else if (rect_isnull(r2))
		r = *r1;
	else {
		r.r_left = min(r1->r_left, r2->r_left);
		r.r_top = min(r1->r_top, r2->r_top);
		r.r_width = max(r1->r_left+r1->r_width, r2->r_left+r2->r_width)
		     -r.r_left;
		r.r_height = max(r1->r_top+r1->r_height, r2->r_top+r2->r_height)
		    -r.r_top;
	}
	return(r);
}