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

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 % ------
0048 % Author: David Legland
0049 % E-mail: david.legland@inrae.fr
0050 % Created: 2005-08-05
0051 % Copyright 2005-2024 INRA - TPV URPOI - BIA IMASTE
0052 
0053 %% process input variables
0054 
0055 if nargin < 1
0056     error('Function requires an input argument');
0057 end
0058 
0059 % extract handle of axis to draw on
0060 if isAxisHandle(varargin{1})
0061     ax = varargin{1};
0062     varargin(1) = [];
0063 else
0064     ax = gca;
0065 end
0066 
0067 var = varargin{1};
0068 if size(var, 2) == 4
0069     % manage edge in single parameter
0070     len     = var(:, 3);
0071     theta   = var(:, 4);
0072     center  = var(:, 1:2);
0073 
0074     N = size(center, 1);    
0075     varargin(1) = [];
0076 
0077 elseif length(varargin) >= 3
0078     % parameters given in different arguments
0079     
0080     % size of data
0081     center  = varargin{1};
0082     len     = varargin{2};
0083     theta   = varargin{3};
0084     varargin(1:3) = [];
0085 
0086     % ensure all data have same size
0087     NP = size(center, 1);
0088     NL = size(len, 1);
0089     ND = size(theta, 1);
0090     N  = max([NP NL ND]);
0091     if N > 1
0092         if NP == 1, center = repmat(center, [N 1]); end
0093         if NL == 1, len = repmat(len, [N 1]); end
0094         if ND == 1, theta = repmat(theta, [N 1]); end
0095     end
0096     
0097 end
0098 
0099 % extract drawing options
0100 options = varargin(:);
0101 
0102 
0103 %% Draw edges
0104 
0105 % coordinates of center point
0106 xc = center(:, 1);
0107 yc = center(:, 2);
0108 
0109 % convert angle to radians
0110 theta = theta * pi / 180;
0111 
0112 % computation shortcuts
0113 cot = cos(theta);
0114 sit = sin(theta);
0115 
0116 % compute starting and ending points
0117 x1 = xc - len .* cot / 2;
0118 x2 = xc + len .* cot / 2;
0119 y1 = yc - len .* sit / 2;
0120 y2 = yc + len .* sit / 2;
0121 
0122 % save hold state
0123 holdState = ishold(ax);
0124 hold(ax, 'on');
0125 
0126 
0127 % draw the edges
0128 h = zeros(N, 1);
0129 for i = 1:N
0130     h(i) = plot(ax, [x1(i) x2(i)], [y1(i) y2(i)]);
0131 end
0132 
0133 % apply style to edges
0134 if ~isempty(options) > 0
0135     for i = 1:N
0136         set(h(i), options{:});
0137     end
0138 end
0139 
0140 
0141 %% Format output
0142 
0143 % restore hold state
0144 if ~holdState
0145     hold(ax, 'off');
0146 end
0147 
0148 % process output arguments
0149 if nargout > 0
0150     varargout = {h};
0151 end