circleArcToPolyline

CIRCLEARCTOPOLYLINE Convert a circle arc into a series of points.

   P = circleArcToPolyline(ARC, N);
   convert the circle ARC into a series of N points. 
   ARC is given in the format: [XC YC R THETA1 DTHETA]
   where XC and YC define the center of the circle, R its radius, THETA1
   is the start of the arc and DTHETA is the angle extent of the arc. Both
   angles are given in degrees. 
   N is the number of vertices of the resulting polyline, default is 65.

   The result is a N-by-2 array containing coordinates of the N points. 

   [X Y] = circleArcToPolyline(ARC, N);
   Return the result in two separate arrays with N lines and 1 column.


   See also:
   circles2d, circleToPolygon, drawCircle, drawPolygon


 ---------
 author : David Legland
 created the 22/05/2006.
 Copyright 2010 INRA - Cepia Software Platform.

0001 function varargout = circleArcToPolyline(arc, N)
0002 %CIRCLEARCTOPOLYLINE Convert a circle arc into a series of points.
0003 %
0004 %   P = circleArcToPolyline(ARC, N);
0005 %   convert the circle ARC into a series of N points.
0006 %   ARC is given in the format: [XC YC R THETA1 DTHETA]
0007 %   where XC and YC define the center of the circle, R its radius, THETA1
0008 %   is the start of the arc and DTHETA is the angle extent of the arc. Both
0009 %   angles are given in degrees.
0010 %   N is the number of vertices of the resulting polyline, default is 65.
0011 %
0012 %   The result is a N-by-2 array containing coordinates of the N points.
0013 %
0014 %   [X Y] = circleArcToPolyline(ARC, N);
0015 %   Return the result in two separate arrays with N lines and 1 column.
0016 %
0017 %
0018 %   See also:
0019 %   circles2d, circleToPolygon, drawCircle, drawPolygon
0020 %
0021 %
0022 % ---------
0023 % author : David Legland
0024 % created the 22/05/2006.
0025 % Copyright 2010 INRA - Cepia Software Platform.
0026 %
0027 
0028 % HISTORY
0029 % 2011-03-30 use angles in degrees, add default value for N
0030 % 2011-12-09 rename to circleArcToPolyline
0031 
0032 
0033 % default value for N
0034 if nargin < 2
0035     N = 65;
0036 end
0037 
0038 % vector of positions
0039 t0 = deg2rad(arc(4));
0040 t1 = t0 + deg2rad(arc(5));
0041 t = linspace(t0, t1, N)';
0042 
0043 % compute coordinates of vertices
0044 x = arc(1) + arc(3) * cos(t);
0045 y = arc(2) + arc(3) * sin(t);
0046 
0047 % format output
0048 if nargout <= 1
0049     varargout = {[x y]};
0050 else
0051     varargout = {x, y};
0052 end