/*	$OpenBSD: lib_overlay.c,v 1.5 1998/01/17 16:27:35 millert Exp $	*/


/***************************************************************************
*                            COPYRIGHT NOTICE                              *
****************************************************************************
*                ncurses is copyright (C) 1992-1995                        *
*                          Zeyd M. Ben-Halim                               *
*                          zmbenhal@netcom.com                             *
*                          Eric S. Raymond                                 *
*                          esr@snark.thyrsus.com                           *
*                                                                          *
*        Permission is hereby granted to reproduce and distribute ncurses  *
*        by any means and for any fee, whether alone or as part of a       *
*        larger distribution, in source or in binary form, PROVIDED        *
*        this notice is included with any such distribution, and is not    *
*        removed from any of its header files. Mention of ncurses in any   *
*        applications linked with it is highly appreciated.                *
*                                                                          *
*        ncurses comes AS IS with no warranty, implied or expressed.       *
*                                                                          *
***************************************************************************/


/*
**	lib_overlay.c
**
**	The routines overlay(), copywin(), and overwrite().
**
*/

#include <curses.priv.h>

MODULE_ID("Id: lib_overlay.c,v 1.11 1997/12/19 17:04:06 xtang Exp $")

static int overlap(const WINDOW *const s, WINDOW *const d, int const flag)
{
int sminrow, smincol, dminrow, dmincol, dmaxrow, dmaxcol;

	T(("overlap : sby %d, sbx %d, smy %d, smx %d, dby %d, dbx %d, dmy %d, dmx %d",
		s->_begy, s->_begx, s->_maxy, s->_maxx,
		d->_begy, d->_begx, d->_maxy, d->_maxx));

	if (!s || !d)
		returnCode(ERR);

	sminrow = max(s->_begy, d->_begy) - s->_begy;
	smincol = max(s->_begx, d->_begx) - s->_begx;
	dminrow = max(s->_begy, d->_begy) - d->_begy;
	dmincol = max(s->_begx, d->_begx) - d->_begx;
	dmaxrow = min(s->_maxy+s->_begy, d->_maxy+d->_begy) - d->_begy;
	dmaxcol = min(s->_maxx+s->_begx, d->_maxx+d->_begx) - d->_begx;

	return(copywin(s, d,
		       sminrow, smincol, dminrow, dmincol, dmaxrow, dmaxcol,
		       flag));
}

/*
**
**	overlay(win1, win2)
**
**
**	overlay() writes the overlapping area of win1 behind win2
**	on win2 non-destructively.
**
**/

int overlay(const WINDOW *win1, WINDOW *win2)
{
	T((T_CALLED("overlay(%p,%p)"), win1, win2));
	returnCode(overlap(win1, win2, TRUE));
}

/*
**
**	overwrite(win1, win2)
**
**
**	overwrite() writes the overlapping area of win1 behind win2
**	on win2 destructively.
**
**/

int overwrite(const WINDOW *win1, WINDOW *win2)
{
	T((T_CALLED("overwrite(%p,%p)"), win1, win2));
	returnCode(overlap(win1, win2, FALSE));
}

int copywin(const WINDOW *src, WINDOW *dst,
	int sminrow, int smincol,
	int dminrow, int dmincol, int dmaxrow, int dmaxcol,
	int over)
{
int sx, sy, dx, dy;
bool touched;
chtype bk = AttrOf(dst->_bkgd);
chtype mask = ~(chtype)((bk&A_COLOR) ? A_COLOR : 0);

	T((T_CALLED("copywin(%p, %p, %d, %d, %d, %d, %d, %d, %d)"),
		src, dst, sminrow, smincol, dminrow, dmincol, dmaxrow, dmaxcol, over));

	if (!src || !dst)
	  returnCode(ERR);

	/* make sure rectangle exists in source */
	if ((sminrow + dmaxrow - dminrow) > (src->_maxy + 1) ||
	    (smincol + dmaxcol - dmincol) > (src->_maxx + 1)) {
		returnCode(ERR);
	}

	T(("rectangle exists in source"));

	/* make sure rectangle fits in destination */
	if (dmaxrow > dst->_maxy || dmaxcol > dst->_maxx) {
		returnCode(ERR);
	}

	T(("rectangle fits in destination"));

	for (dy = dminrow, sy = sminrow; dy <= dmaxrow; sy++, dy++) {
	   touched = FALSE;
	   for(dx=dmincol, sx=smincol; dx <= dmaxcol; sx++, dx++)
	   {
		if (over)
		{
		   if ((TextOf(src->_line[sy].text[sx]) != ' ') &&
                       (dst->_line[dy].text[dx]!=src->_line[sy].text[sx]))
		   {
			dst->_line[dy].text[dx] =
					(src->_line[sy].text[sx] & mask) | bk;
			touched = TRUE;
		   }
	        }
		else {
		   if (dst->_line[dy].text[dx] != src->_line[sy].text[sx])
		   {
			dst->_line[dy].text[dx] = src->_line[sy].text[sx];
			touched = TRUE;
                   }
                }
           }
	   if (touched)
	   {
	      touchline(dst,0,getmaxy(dst));
	   }
	}
	T(("finished copywin"));
	returnCode(OK);
}