#include <stdlib.h>
#include <grass/raster.h>
#include <grass/display.h>

int black_and_white_line (int screen_x, int screen_y,
	int cur_screen_x, int cur_screen_y)
{
	R_standard_color(D_translate_color(DEFAULT_FG_COLOR)) ;
	R_move_abs(cur_screen_x, cur_screen_y) ;
	R_cont_abs(screen_x, screen_y) ;
	R_standard_color(D_translate_color(DEFAULT_BG_COLOR)) ;
	if(abs(screen_y-cur_screen_y) <= abs(screen_x-cur_screen_x))
	{
		R_move_abs(cur_screen_x, cur_screen_y-1) ;
		R_cont_abs(screen_x, screen_y-1) ;
	}
	else
	{
		R_move_abs(cur_screen_x+1, cur_screen_y) ;
		R_cont_abs(screen_x+1, screen_y) ;
	}
	
	R_stabilize() ;

	return 0;
}