vertical_copy_area(screen, firstline, nlines, amount) TScreen *screen; int firstline;		 int nlines; int amount;
vertical_copy_area( TScreen *screen, int firstline,		 int nlines, int amount)
vertical_copy_area(screen, firstline, nlines, amount)    TScreen *screen;    int firstline;		/* line on screen to start copying at */    int nlines;    int amount;			/* number of lines to move up (neg=down) */{    if(nlines > 0) {	int src_x = OriginX(screen);	int src_y = firstline * FontHeight(screen) + screen->border;	copy_area(screen, src_x, src_y,		  (unsigned)Width(screen), nlines*FontHeight(screen),		  src_x, src_y - amount*FontHeight(screen));    }}