drawCenteredEdge

DRAWCENTEREDEDGE Draw an edge centered on a point.
   
   Draws a centered edge, defined by a center, a length and an orientation
   (in degrees). This function can be used to draw principal axes of an
   ellipse or of an oriented box.


   drawCenteredEdge(EDGE)
   Draws an edge centered on a point. EDGE has format [XC YC L THETA],
   with (Xc, YC) being edge center, L being the edge length, and THETA
   beigng the edge orientation, in degrees (counted Counter-clockwise from
   horizontal).
   Input argument can also be a N-by-4 array, in that can several edges
   are drawn.

   drawCenteredEdge(CENTER, L, THETA)
   Specifies argument in seperate inputs.

   drawCenteredEdge(..., NAME, VALUE)
   Also specifies drawing options by using one or several parameter name -
   value pairs (see doc of plot function for details).

   drawCenteredEdge(AX, ...)
   Specifies the axis to draw the edge on.

   H = drawCenteredEdge(...)
   Returns handle(s) to the created edges(s).

   Example
     % Draw an ellipse with its two axes
     figure(1); clf;
     center = [50 40];
     r1 = 30; r2 = 10;
     theta = 20;
     elli = [center r1 r2 theta];
     drawEllipse(elli, 'linewidth', 2);
     axis([0 100 0 100]); axis equal;
     hold on;
     edges = [center 2*r1 theta ; center 2*r2 theta+90];
     drawCenteredEdge(edges, 'linewidth', 2, 'color', 'g');
 
   See also:
   edges2d, drawOrientedBox, drawEllipse, centeredEdgeToEdge, drawEdge

   ---------
   author : David Legland
   INRA - TPV URPOI - BIA IMASTE
   created the 05/08/2005.

0001 function varargout = drawCenteredEdge(varargin)
0002 %DRAWCENTEREDEDGE Draw an edge centered on a point.
0003 %
0004 %   Draws a centered edge, defined by a center, a length and an orientation
0005 %   (in degrees). This function can be used to draw principal axes of an
0006 %   ellipse or of an oriented box.
0007 %
0008 %
0009 %   drawCenteredEdge(EDGE)
0010 %   Draws an edge centered on a point. EDGE has format [XC YC L THETA],
0011 %   with (Xc, YC) being edge center, L being the edge length, and THETA
0012 %   beigng the edge orientation, in degrees (counted Counter-clockwise from
0013 %   horizontal).
0014 %   Input argument can also be a N-by-4 array, in that can several edges
0015 %   are drawn.
0016 %
0017 %   drawCenteredEdge(CENTER, L, THETA)
0018 %   Specifies argument in seperate inputs.
0019 %
0020 %   drawCenteredEdge(..., NAME, VALUE)
0021 %   Also specifies drawing options by using one or several parameter name -
0022 %   value pairs (see doc of plot function for details).
0023 %
0024 %   drawCenteredEdge(AX, ...)
0025 %   Specifies the axis to draw the edge on.
0026 %
0027 %   H = drawCenteredEdge(...)
0028 %   Returns handle(s) to the created edges(s).
0029 %
0030 %   Example
0031 %     % Draw an ellipse with its two axes
0032 %     figure(1); clf;
0033 %     center = [50 40];
0034 %     r1 = 30; r2 = 10;
0035 %     theta = 20;
0036 %     elli = [center r1 r2 theta];
0037 %     drawEllipse(elli, 'linewidth', 2);
0038 %     axis([0 100 0 100]); axis equal;
0039 %     hold on;
0040 %     edges = [center 2*r1 theta ; center 2*r2 theta+90];
0041 %     drawCenteredEdge(edges, 'linewidth', 2, 'color', 'g');
0042 %
0043 %   See also:
0044 %   edges2d, drawOrientedBox, drawEllipse, centeredEdgeToEdge, drawEdge
0045 %
0046 %   ---------
0047 %   author : David Legland
0048 %   INRA - TPV URPOI - BIA IMASTE
0049 %   created the 05/08/2005.
0050 %
0051 
0052 %   HISTORY
0053 %   2007-06-15 update doc, clean up code
0054 %   2011-05-18 use angle in degrees, cleanup code and doc
0055 %   2011-10-11 add management of axes handle
0056 
0057 
0058 %% process input variables
0059 
0060 if nargin < 1
0061     error('Function requires an input argument');
0062 end
0063 
0064 % extract handle of axis to draw on
0065 if isAxisHandle(varargin{1})
0066     ax = varargin{1};
0067     varargin(1) = [];
0068 else
0069     ax = gca;
0070 end
0071 
0072 var = varargin{1};
0073 if size(var, 2) == 4
0074     % manage edge in single parameter
0075     len     = var(:, 3);
0076     theta   = var(:, 4);
0077     center  = var(:, 1:2);
0078 
0079     N = size(center, 1);    
0080     varargin(1) = [];
0081 
0082 elseif length(varargin) >= 3
0083     % parameters given in different arguments
0084     
0085     % size of data
0086     center  = varargin{1};
0087     len     = varargin{2};
0088     theta   = varargin{3};
0089     varargin(1:3) = [];
0090 
0091     % ensure all data have same size
0092     NP = size(center, 1);
0093     NL = size(len, 1);
0094     ND = size(theta, 1);
0095     N  = max([NP NL ND]);
0096     if N > 1
0097         if NP == 1, center = repmat(center, [N 1]); end
0098         if NL == 1, len = repmat(len, [N 1]); end
0099         if ND == 1, theta = repmat(theta, [N 1]); end
0100     end
0101     
0102 end
0103 
0104 % extract drawing options
0105 options = varargin(:);
0106 
0107 
0108 %% Draw edges
0109 
0110 % coordinates of center point
0111 xc = center(:, 1);
0112 yc = center(:, 2);
0113 
0114 % convert angle to radians
0115 theta = theta * pi / 180;
0116 
0117 % computation shortcuts
0118 cot = cos(theta);
0119 sit = sin(theta);
0120 
0121 % compute starting and ending points
0122 x1 = xc - len .* cot / 2;
0123 x2 = xc + len .* cot / 2;
0124 y1 = yc - len .* sit / 2;
0125 y2 = yc + len .* sit / 2;
0126 
0127 
0128 % draw the edges
0129 h = zeros(N, 1);
0130 for i = 1:N
0131     h(i) = plot(ax, [x1(i) x2(i)], [y1(i) y2(i)]);
0132 end
0133 
0134 % apply style to edges
0135 if ~isempty(options) > 0
0136     for i = 1:N
0137         set(h(i), options{:});
0138     end
0139 end
0140 
0141 
0142 %% Format output
0143 
0144 % process output arguments
0145 if nargout > 0
0146     varargout = {h};
0147 end