drawGrid3d

DRAWGRID3D Draw a 3D grid on the current axis.

   drawGrid3d
   draws a 3D square grid, with origin (0,0,0) and spacing 1 in each
   direction, with bounds corresponding to the bounds of current axis.

   drawGrid3d(SPACING)
   where spacing is either a scalar or a [1x3] matrix, specifies the size
   of the unit cell.

   drawGrid3d(ORIGIN, SPACING)
   Also specify origin of grid. ORIGIN is a [1x3] array.

   drawGrid3d(..., EDGE)
   specifies whether function should draw edges touching edges of axis.
   EDGE is a characheter string, which can be :
   - 'OPEN' : each line start from one face of window to the opposite
   face. This results in a 'spiky' grid.
   - 'CLOSED' (default value) : each line stops at the last visible point
   of the grid for this line. The result looks like a box (no free spikes
   around the grid).

   H = drawGrid3d(...);
   return a vector of handles for each LINE object which was crated.


   Example
     figure; hold on; axis equal; axis([-5 65 -5 45 -5 45]); view(3);
     drawGrid3d([0 0 0], [20 20 20]);


   See also
     drawLine3d, drawEdge3d, clipLine3d

0001 function varargout = drawGrid3d(varargin)
0002 %DRAWGRID3D Draw a 3D grid on the current axis.
0003 %
0004 %   drawGrid3d
0005 %   draws a 3D square grid, with origin (0,0,0) and spacing 1 in each
0006 %   direction, with bounds corresponding to the bounds of current axis.
0007 %
0008 %   drawGrid3d(SPACING)
0009 %   where spacing is either a scalar or a [1x3] matrix, specifies the size
0010 %   of the unit cell.
0011 %
0012 %   drawGrid3d(ORIGIN, SPACING)
0013 %   Also specify origin of grid. ORIGIN is a [1x3] array.
0014 %
0015 %   drawGrid3d(..., EDGE)
0016 %   specifies whether function should draw edges touching edges of axis.
0017 %   EDGE is a characheter string, which can be :
0018 %   - 'OPEN' : each line start from one face of window to the opposite
0019 %   face. This results in a 'spiky' grid.
0020 %   - 'CLOSED' (default value) : each line stops at the last visible point
0021 %   of the grid for this line. The result looks like a box (no free spikes
0022 %   around the grid).
0023 %
0024 %   H = drawGrid3d(...);
0025 %   return a vector of handles for each LINE object which was crated.
0026 %
0027 %
0028 %   Example
0029 %     figure; hold on; axis equal; axis([-5 65 -5 45 -5 45]); view(3);
0030 %     drawGrid3d([0 0 0], [20 20 20]);
0031 %
0032 %
0033 %   See also
0034 %     drawLine3d, drawEdge3d, clipLine3d
0035 
0036 % ------
0037 % Author: David Legland
0038 % E-mail: david.legland@inrae.fr
0039 % Created: 2005-11-17
0040 % Copyright 2005-2024 INRA - CEPIA Nantes - MIAJ (Jouy-en-Josas)
0041 
0042 %% initialize variables
0043 
0044 % extract handle of axis to draw on
0045 [hAx, varargin] = parseAxisHandle(varargin{:});
0046 
0047 % default values
0048 closed = true;
0049 origin = [0 0 0];
0050 spacing = [1 1 1];
0051 
0052 % check if grid is open or not
0053 str = '';
0054 if ~isempty(varargin)
0055     str = varargin{end};
0056 end
0057 if ischar(str)
0058     if strncmpi(str, 'open', 4)
0059         closed = false;
0060     end
0061     varargin = varargin(1:end-1);
0062 end
0063 
0064 % check origin and grid spacing
0065 if isscalar(varargin)
0066     spacing = varargin{1};
0067 elseif length(varargin)==2
0068     origin = varargin{1};
0069     spacing = varargin{2};
0070 end
0071 
0072 %% Compute internal data
0073 
0074 % get axis limits
0075 ax = axis(hAx);
0076 x0 = ax(1); x1 = ax(2);
0077 y0 = ax(3); y1 = ax(4);
0078 z0 = ax(5); z1 = ax(6);
0079 
0080 % get first and last coordinates of the grid in each direction
0081 dx = spacing(1); dy = spacing(2); dz = spacing(3);
0082 xe = x0 + mod(origin(1) - x0, dx);
0083 xf = x1 - mod(x1 - origin(1), dx);
0084 ye = y0 + mod(origin(2) - y0, dy);
0085 yf = y1 - mod(y1 - origin(2), dy);
0086 ze = z0 + mod(origin(1) - z0, dz);
0087 zf = z1 - mod(z1 - origin(1), dz);
0088 
0089 % update first and last coordinate if grid is 'closed'
0090 if closed
0091     x0 = xe; x1 = xf;
0092     y0 = ye; y1 = yf;
0093     z0 = ze; z1 = zf;
0094 end
0095 
0096 
0097 %% Draw the grid
0098 
0099 % header array, one header for each line segment
0100 h = [];
0101 
0102 % draw lines parallel to x axis
0103 for y = ye:dy:yf
0104     for z = ze:dz:zf
0105         h = [h; drawEdge3d(hAx, [x0 y z x1 y z])]; %#ok<AGROW>
0106     end
0107 end
0108 
0109 % draw lines parallel to y axis
0110 for x = xe:dx:xf
0111     for z = ze:dz:zf
0112         h = [h; drawEdge3d(hAx, [x y0 z x y1 z])]; %#ok<AGROW>
0113     end
0114 end
0115 
0116 % draw lines parallel to z axis
0117 for x = xe:dx:xf
0118     for y = ye:dy:yf
0119         h = [h; drawEdge3d(hAx, [x y z0 x y z1])]; %#ok<AGROW>
0120     end
0121 end
0122 
0123 
0124 %% Check output arguments
0125 
0126 if nargout > 0
0127     varargout{1} = h;
0128 end