class range_view_annotator
{
public:
    range_view_annotator(int range) {
        orig_colours.init(-1);
        if ( range < 0 )
            return;
        for ( radius_iterator ri(you.pos(), LOS_RADIUS); ri; ++ri )
        {
            if (grid_is_solid(*ri) && grid_distance(you.pos(), *ri) > range)
            {
                orig_colours(*ri - you.pos() + coord_def(9,9)) =
                    env.grid_colours( *ri );
                env.grid_colours(*ri) = DARKGREY;
            }
        }
        viewwindow(true, false);
    }
    ~range_view_annotator() {
        coord_def c;
        for ( c.x = 0; c.x < 19; ++c.x )
        {
            for ( c.y = 0; c.y < 19; ++c.y )
            {
                const int old_colour = orig_colours(c);
                if ( old_colour != -1 )
                    env.grid_colours(you.pos()+c-coord_def(9,9)) = old_colour;
            }
        }
        viewwindow(true, false);
    }
private:
    FixedArray<int,19,19> orig_colours;
};

    range_view_annotator rva(range);