lineAngle

LINEANGLE Computes angle between two straight lines.

   A = lineAngle(LINE);
   Returns the angle between horizontal, right-axis and the given line.
   Angle is given in radians, between 0 and 2*pi, in counter-clockwise
   direction.

   A = lineAngle(LINE1, LINE2);
   Returns the directed angle between the two lines. Angle is given in
   radians between 0 and 2*pi, in counter-clockwise direction.

   See also
   lines2d, angles2d, createLine, normalizeAngle

   ---------
   author : David Legland
   INRA - TPV URPOI - BIA IMASTE
   created the 31/10/2003.

0001 function theta = lineAngle(varargin)
0002 %LINEANGLE Computes angle between two straight lines.
0003 %
0004 %   A = lineAngle(LINE);
0005 %   Returns the angle between horizontal, right-axis and the given line.
0006 %   Angle is given in radians, between 0 and 2*pi, in counter-clockwise
0007 %   direction.
0008 %
0009 %   A = lineAngle(LINE1, LINE2);
0010 %   Returns the directed angle between the two lines. Angle is given in
0011 %   radians between 0 and 2*pi, in counter-clockwise direction.
0012 %
0013 %   See also
0014 %   lines2d, angles2d, createLine, normalizeAngle
0015 %
0016 %   ---------
0017 %   author : David Legland
0018 %   INRA - TPV URPOI - BIA IMASTE
0019 %   created the 31/10/2003.
0020 %
0021 
0022 %   HISTORY
0023 %   2004-02-19 added support for multiple lines.
0024 %   2011-01-20 use bsxfun
0025 
0026 nargs = length(varargin);
0027 if nargs == 1
0028     % angle of one line with horizontal
0029     line = varargin{1};
0030     theta = mod(atan2(line(:,4), line(:,3)) + 2*pi, 2*pi);
0031     
0032 elseif nargs==2
0033     % angle between two lines
0034     theta1 = lineAngle(varargin{1});
0035     theta2 = lineAngle(varargin{2});
0036     theta = mod(bsxfun(@minus, theta2, theta1)+2*pi, 2*pi);
0037 end