randomPointInBox

RANDOMPOINTINBOX Generate random point within a box.

   PTS = randomPointInBox(BOX)
   Generate a random point within the box BOX. The result is a 1-by-2 row
   vector.

   PTS = randomPointInBox(BOX, N)
   Generates N points within the box. The result is a N-by-2 array.

   BOX has the format:
   BOX = [xmin xmax ymin ymax].

   Example
     % draw points within a box
     box = [10 80 20 60];
     pts =  randomPointInBox(box, 500);
     figure(1); clf; hold on;
     drawBox(box);
     drawPoint(pts, '.');
     axis('equal');
     axis([0 100 0 100]);

   See also
     geom2d, points2d, boxes2d, randomPointInBox3d, randomPointInPolygon

0001 function points = randomPointInBox(box, N, varargin)
0002 %RANDOMPOINTINBOX Generate random point within a box.
0003 %
0004 %   PTS = randomPointInBox(BOX)
0005 %   Generate a random point within the box BOX. The result is a 1-by-2 row
0006 %   vector.
0007 %
0008 %   PTS = randomPointInBox(BOX, N)
0009 %   Generates N points within the box. The result is a N-by-2 array.
0010 %
0011 %   BOX has the format:
0012 %   BOX = [xmin xmax ymin ymax].
0013 %
0014 %   Example
0015 %     % draw points within a box
0016 %     box = [10 80 20 60];
0017 %     pts =  randomPointInBox(box, 500);
0018 %     figure(1); clf; hold on;
0019 %     drawBox(box);
0020 %     drawPoint(pts, '.');
0021 %     axis('equal');
0022 %     axis([0 100 0 100]);
0023 %
0024 %   See also
0025 %     geom2d, points2d, boxes2d, randomPointInBox3d, randomPointInPolygon
0026 %
0027 
0028 % ------
0029 % Author: David Legland
0030 % e-mail: david.legland@inra.fr
0031 % Created: 2007-10-10,    using Matlab 7.4.0.287 (R2007a)
0032 % Copyright 2007 INRA - BIA PV Nantes - MIAJ Jouy-en-Josas.
0033 
0034 if nargin < 2
0035     N = 1;
0036 end
0037 
0038 % extract box bounds
0039 xmin = box(1);
0040 xmax = box(2);
0041 ymin = box(3);
0042 ymax = box(4);
0043 
0044 % compute size of box
0045 dx = xmax - xmin;
0046 dy = ymax - ymin;
0047 
0048 % compute point coordinates
0049 points = [rand(N, 1)*dx+xmin , rand(N, 1)*dy+ymin];