usr/src/lib/libcurses/overlay.c

# include       "curses.h"
# include       <ctype.h>

# define        min(a,b)        (a < b ? a : b)
# define        max(a,b)        (a < b ? a : b)

/*
 *      This routine writes win1 on win2 non-destructively.
 */
overlay(win1, win2)
reg WINDOW      *win1, *win2; {

        reg char        *sp, *end;
        reg int         x, y, endy, endx, starty, startx, y_top,
                        y_bot, x_left, x_right;

# ifdef DEBUG
        fprintf(outf, "OVERLAY(%0.2o, %0.2o);\n", win1, win2);
# endif
        y_top = max(win1->_begy, win2->_begy);
        y_bot = min(win1->_maxy, win2->_maxy);
        x_left = max(win1->_begx, win2->_begx);
        x_right = min(win1->_maxx, win2->_maxx);
        starty = y_top - win1->_begy;
        startx = x_left - win1->_begx;
        endy = y_bot - win1->_begy;
        endx = x_right - win1->_begx;
        for (y = starty; y < endy; y++) {
                end = &win1->_y[y][endx];
                x = startx + win1->_begx;
                for (sp = &win1->_y[y][startx]; sp <= end; sp++) {
                        if (!isspace(*sp))
                                mvwaddch(win2, y + win1->_begy, x, *sp);
                        x++;
                }
        }
}