function d = drectangle ( p, x1, x2, y1, y2 ) %*****************************************************************************80 % %% DRECTANGLE returns the signed distance of one or more points to a rectangle. % % Discussion: % % The formula used here is not quite correct. In particular, it is wrong % at the corners. For a true distance function, compare DRECTANGLE0. % % Licensing: % % (C) 2004 Per-Olof Persson. % See COPYRIGHT.TXT for details. % % Reference: % % Per-Olof Persson and Gilbert Strang, % A Simple Mesh Generator in MATLAB, % SIAM Review, % Volume 46, Number 2, June 2004, pages 329-345. % % Parameters: % % Input, real P(NP,2), the coordinates of a set of nodes. % % Input, real X1, X2, Y1, Y2, the left, right, bottom and top % coordinates of the rectangle. % % Output, real D, the signed distance of the points to the rectangle, % which is negative, 0 or positive depending on whether each point % is inside, or, or outside the rectangle. % d = - min ( min ( min ( -y1+p(:,2), y2-p(:,2) ), -x1+p(:,1) ), x2-p(:,1) ); return end