CREATELINE Create a straight line from 2 points, or from other inputs. Line is represented in a parametric form : [x0 y0 dx dy] x = x0 + t*dx y = y0 + t*dy; L = createLine(p1, p2); Returns the line going through the two given points. L = createLine(x0, y0, dx, dy); Returns the line going through point (x0, y0) and with direction vector(dx, dy). L = createLine(LINE); where LINE is an array of 4 values, creates the line going through the point (LINE(1) LINE(2)), and with direction given by vector (LINE(3) LINE(4)). L = createLine(THETA); Create a polar line originated at (0,0) and with angle THETA in radians. L = createLine(p, THETA); Create a polar line originated at p and with angle THETA in radians. L = createLine(RHO, THETA); Create a polar line with normal theta, and with min distance to origin equal to rho. rho can be negative, in this case, the line is the same as with CREATELINE(-rho, theta+pi), but the orientation is different. Note: in all cases, parameters can be vertical arrays of the same dimension. The result is then an array of lines, of dimensions [N*4]. See also lines2d, createEdge, createRay
0001 function line = createLine(varargin) 0002 %CREATELINE Create a straight line from 2 points, or from other inputs. 0003 % 0004 % Line is represented in a parametric form : [x0 y0 dx dy] 0005 % x = x0 + t*dx 0006 % y = y0 + t*dy; 0007 % 0008 % 0009 % L = createLine(p1, p2); 0010 % Returns the line going through the two given points. 0011 % 0012 % L = createLine(x0, y0, dx, dy); 0013 % Returns the line going through point (x0, y0) and with direction 0014 % vector(dx, dy). 0015 % 0016 % L = createLine(LINE); 0017 % where LINE is an array of 4 values, creates the line going through the 0018 % point (LINE(1) LINE(2)), and with direction given by vector (LINE(3) 0019 % LINE(4)). 0020 % 0021 % L = createLine(THETA); 0022 % Create a polar line originated at (0,0) and with angle THETA in radians. 0023 % 0024 % L = createLine(p, THETA); 0025 % Create a polar line originated at p and with angle THETA in radians. 0026 % 0027 % L = createLine(RHO, THETA); 0028 % Create a polar line with normal theta, and with min distance to origin 0029 % equal to rho. rho can be negative, in this case, the line is the same 0030 % as with CREATELINE(-rho, theta+pi), but the orientation is different. 0031 % 0032 % 0033 % Note: in all cases, parameters can be vertical arrays of the same 0034 % dimension. The result is then an array of lines, of dimensions [N*4]. 0035 % 0036 % 0037 % See also 0038 % lines2d, createEdge, createRay 0039 0040 % ------ 0041 % Author: David Legland 0042 % E-mail: david.legland@inrae.fr 0043 % Created: 2003-10-31 0044 % Copyright 2003-2024 INRA - TPV URPOI - BIA IMASTE 0045 0046 % NOTE : A line can also be represented with a 1*5 array : 0047 % [x0 y0 dx dy t]. 0048 % whith 't' being one of the following : 0049 % - t=0 : line is a singleton (x0,y0) 0050 % - t=1 : line is an edge segment, between points (x0,y0) and (x0+dx, 0051 % y0+dy). 0052 % - t=Inf : line is a Ray, originated from (x0,y0) and going to infinity 0053 % in the direction(dx,dy). 0054 % - t=-Inf : line is a Ray, originated from (x0,y0) and going to infinity 0055 % in the direction(-dx,-dy). 0056 % - t=NaN : line is a real straight line, and contains all points 0057 % verifying the above equation. 0058 % This seems us a convenient way to represent uniformly all kind of lines 0059 % (including edges, rays, and even point). 0060 % 0061 0062 % NOTE2 : Any line object can be represented using a 1x6 array : 0063 % [x0 y0 dx dy t0 t1] 0064 % the first 4 parameters define the supporting line, 0065 % t0 represent the position of the first point on the line, 0066 % and t1 the position of the last point. 0067 % * for edges : t0 = 0, and t1=1 0068 % * for straight lines : t0 = -inf, t1=inf 0069 % * for rays : t0=0, t1=inf (or t0=-inf,t1=0 for inverted ray). 0070 % I propose to call these objects 'lineArc' 0071 0072 if isscalar(varargin) 0073 % Only one input parameter. It can be : 0074 % - line angle 0075 % - array of four parameters 0076 % TODO : add control for arrays of lines. 0077 var = varargin{1}; 0078 0079 if size(var, 2)==4 0080 % 4 parameters of the line in a single array. 0081 line = var; 0082 elseif size(var, 2)==1 0083 % 1 parameter : angle of the line, going through origin. 0084 line = [zeros(size(var)) zeros(size(var)) cos(var) sin(var)]; 0085 else 0086 error('wrong number of dimension for arg1 : can be 1 or 4'); 0087 end 0088 0089 elseif length(varargin)==2 0090 % 2 input parameters. They can be : 0091 % - line angle and signed distance to origin. 0092 % - 2 points, then 2 arrays of 1*2 double. 0093 v1 = varargin{1}; 0094 v2 = varargin{2}; 0095 if size(v1, 2)==2 && size(v2, 2)==1 0096 % first param is point, and second param is angle of line 0097 line = [v1(:,1), v1(:,2) cos(v2) sin(v2)]; 0098 elseif size(v1, 2)==1 0099 % first param is angle of line, and second param is signed distance 0100 % to origin. 0101 line = [v1.*cos(v2) v1.*sin(v2) -sin(v2) cos(v2)]; 0102 elseif size(v1, 2)==3 || size(v2, 2)==3 0103 error('The 1st or 2nd input argument has 3 columns. You may want to try createLine3d.'); 0104 else 0105 % first input parameter is first point, and second input is the 0106 % second point. 0107 line = [v1(:,1), v1(:,2), v2(:,1)-v1(:,1), v2(:,2)-v1(:,2)]; 0108 end 0109 0110 elseif length(varargin)==3 0111 % 3 input parameters : 0112 % first one is a point belonging to the line, 0113 % second and third ones are direction vector of the line (dx and dy). 0114 p = varargin{1}; 0115 line = [p(:,1) p(:,2) varargin{2} varargin{3}]; 0116 0117 elseif length(varargin)==4 0118 % 4 input parameters : 0119 % they are x0, y0 (point belongng to line) and dx, dy (direction vector 0120 % of the line). 0121 % All parameters should have the same size. 0122 line = [varargin{1} varargin{2} varargin{3} varargin{4}]; 0123 else 0124 error('Wrong number of arguments in ''createLine'' '); 0125 end