/****************************************************************//* Overlay() and overwrite() functions of the PCcurses package	*//*								*//****************************************************************//* This version of curses is based on ncurses, a curses version	*//* Originally written by Pavel Curtis at Cornell University.	*//* I have made substantial changes to make it run on IBM PC's,	*//* And therefore consider myself free to make it public domain.	*//*		Bjorn Larsson (...mcvax!enea!infovax!bl)	*//****************************************************************//* 1.0:	Release:					870515	*//****************************************************************//* Modified to run under the MINIX operating system by Don Cope *//* These changes are also released into the public domain.      *//* 							900906  *//****************************************************************/#include <curses.h>#include "curspriv.h"/****************************************************************//* Overlay() overwrites 'win1' upon 'win2', with origins alig-	*//* Ned. Overlay is transparent; blanks from 'win1' are not	*//* Copied to 'win2'.						*//****************************************************************/void overlay(win1, win2)WINDOW *win1, *win2;{  int *minchng;  int *maxchng;  int *w1ptr;  int *w2ptr;  int attrs;  int col;  int line;  int last_line;  int last_col;  last_col = min(win1->_maxx, win2->_maxx);  last_line = min(win1->_maxy, win2->_maxy);  attrs = win2->_attrs & ATR_MSK;  minchng = win2->_minchng;  maxchng = win2->_maxchng;  for (line = 0; line <= last_line; line++) {	register short fc, lc = 0;	w1ptr = win1->_line[line];	w2ptr = win2->_line[line];	fc = _NO_CHANGE;	for (col = 0; col <= last_col; col++) {		if ((*w1ptr & CHR_MSK) != ' ') {			*w2ptr = (*w1ptr & CHR_MSK) | attrs;			if (fc == _NO_CHANGE) fc = col;			lc = col;		}		w1ptr++;		w2ptr++;	}	if (*minchng == _NO_CHANGE) {		*minchng = fc;		*maxchng = lc;	} else if (fc != _NO_CHANGE) {		if (fc < *minchng) *minchng = fc;		if (lc > *maxchng) *maxchng = lc;	}	minchng++;	maxchng++;  }				/* for */}				/* overlay *//****************************************************************//* Overwrite() overwrites 'win1' upon 'win2', with origins	*//* Aligned. Overwrite is non-transparent; blanks from 'win1'	*//* Are copied to 'win2'.					*//****************************************************************/void overwrite(win1, win2)WINDOW *win1, *win2;{  int *minchng;  int *maxchng;  int *w1ptr;  int *w2ptr;  int attrs;  int col;  int line;  int last_line;  int last_col;  last_col = min(win1->_maxx, win2->_maxx);  last_line = min(win1->_maxy, win2->_maxy);  attrs = win2->_attrs & ATR_MSK;  minchng = win2->_minchng;  maxchng = win2->_maxchng;  for (line = 0; line <= last_line; line++) {	register short fc, lc = 0;	w1ptr = win1->_line[line];	w2ptr = win2->_line[line];	fc = _NO_CHANGE;	for (col = 0; col <= last_col; col++) {		if ((*w1ptr & CHR_MSK) != (*w2ptr & CHR_MSK)) {			*w2ptr = (*w1ptr & CHR_MSK) | attrs;			if (fc == _NO_CHANGE) fc = col;			lc = col;		}		w1ptr++;		w2ptr++;	}			/* for */	if (*minchng == _NO_CHANGE) {		*minchng = fc;		*maxchng = lc;	} else if (fc != _NO_CHANGE) {		if (fc < *minchng) *minchng = fc;		if (lc > *maxchng) *maxchng = lc;	}	minchng++;	maxchng++;  }}