paintFacet

 paints facets of a polytope

 Syntax: paintFacet(patchHandleVector, facetNormalMatrix, colorMatrix,)

 A typical call could be:
     paintFacet(get(gca, 'Children), cdef.A, [1 0 0])
   to paint all facets of the crystal definition in red for a polytope
   that is just viewed in a new figure.
 The rows of colorMatrix define the colors of facets in the order
 specified in facetNormalMatrix

 See also: viewPolytope

0001 function paintFacet(patchHandleVector, facetNormalMatrix, colorMatrix, varargin)
0002 % paints facets of a polytope
0003 %
0004 % Syntax: paintFacet(patchHandleVector, facetNormalMatrix, colorMatrix,)
0005 %
0006 % A typical call could be:
0007 %     paintFacet(get(gca, 'Children), cdef.A, [1 0 0])
0008 %   to paint all facets of the crystal definition in red for a polytope
0009 %   that is just viewed in a new figure.
0010 % The rows of colorMatrix define the colors of facets in the order
0011 % specified in facetNormalMatrix
0012 %
0013 % See also: viewPolytope
0014 
0015 % The elk-library: convex geometry applied to crystallization modeling.
0016 %   Copyright (C) 2012 Alexander Reinhold
0017 %
0018 % This program is free software: you can redistribute it and/or modify it
0019 %   under the terms of the GNU General Public License as published by the
0020 %   Free Software Foundation, either version 3 of the License, or (at your
0021 %   option) any later version.
0022 %
0023 % This program is distributed in the hope that it will be useful, but
0024 %   WITHOUT ANY WARRANTY; without even the implied warranty of
0025 %   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
0026 %   General Public License for more details.
0027 %
0028 % You should have received a copy of the GNU General Public License along
0029 %   with this program.  If not, see <http://www.gnu.org/licenses/>.
0030 
0031 
0032 %% make color matrix if only a single color is specified
0033 if numel(colorMatrix) == 1
0034     colorMatrix(size(facetNormalMatrix, 1), :) = colorMatrix;
0035 elseif (size(colorMatrix, 1) == 3 && size(colorMatrix, 2) == 1) || ...
0036        (size(colorMatrix, 1) == 1 && size(colorMatrix, 2) == 3)
0037     tmp = colorMatrix;
0038     colorMatrix(1:size(facetNormalMatrix, 1), 1) = tmp(1);
0039     colorMatrix(1:size(facetNormalMatrix, 1), 2) = tmp(2);
0040     colorMatrix(1:size(facetNormalMatrix, 1), 3) = tmp(3);
0041 elseif size(colorMatrix, 1) == size(facetNormalMatrix, 1) && ...
0042        size(colorMatrix, 2) == 3
0043     %everything OK
0044 else
0045     error('elk:polytope:wrongInput', ...
0046         'the color matrix is wrong, try "help paintFacet"');
0047 end
0048 
0049 % ensure only patches are in the handles
0050 patchHandleVector(~strcmp(get(patchHandleVector, 'type'), 'patch')) = [];
0051 
0052 patchX = [];
0053 patchY = [];
0054 patchZ = [];
0055 for iPatch = 1:length(patchHandleVector)
0056     patchX = [patchX; get(patchHandleVector(iPatch), 'XData')];
0057     patchY = [patchY; get(patchHandleVector(iPatch), 'YData')];
0058     patchZ = [patchZ; get(patchHandleVector(iPatch), 'ZData')];
0059 end
0060 
0061 origin = [(max(patchX) + min(patchX))/2; ...
0062           (max(patchY) + min(patchY))/2; ...
0063           (max(patchZ) + min(patchZ))/2];
0064       
0065 %% cycle through facets and move the patches coordinates so that
0066 % origin is in the middle of the polytope
0067 for iPatch = 1:length(patchHandleVector)     
0068     patchX = get(patchHandleVector(iPatch), 'XData'); 
0069     patchX = patchX - origin(1) * ones(size(patchX));
0070     patchY = get(patchHandleVector(iPatch), 'YData');
0071     patchY = patchY - origin(2) * ones(size(patchY));
0072     patchZ = get(patchHandleVector(iPatch), 'ZData');
0073     patchZ = patchZ - origin(3) * ones(size(patchZ));
0074     
0075     % distances of each point from each facet
0076     idx = facetNormalMatrix*[patchX';patchY';patchZ'];
0077     
0078     % This checks if all distances for one facet have the same positive
0079     % value, meaning they are on that facet.
0080     % The value should be positive as the origin is in the middle of
0081     % the polytope. Therefore, if the values are the same and positive,
0082     % idx will be zero everywhere for that facet, if all values are same
0083     % and negative, they will have twice the original value
0084     idx = idx - abs(idx(:,1)) * ones([1, size(idx,2)]);
0085     
0086     % find the rows with all values equal to zero
0087     idx = abs(idx) < 1e-6;
0088     idx = prod(double(idx), 2);
0089     
0090     % take first valid facet
0091     idx = find(idx, 1, 'first');
0092     
0093     % color patch
0094     if isempty(idx),continue;end
0095     set(patchHandleVector(iPatch), 'FaceColor', colorMatrix(idx, :), varargin{:});
0096 end