voronoiDiagramEven2D

Below is a basic demonstration of the features of the voronoiDiagramEven2D function.

Contents

Syntax

[Vv,Fv]=voronoiDiagramEven2D(DT,numPointsVoronoi);

Description

Samples the cells of a Voronoi tesselation using the same amount of points

Examples

clear; close all; clc;

% PLOT SETTINGS
markerSize=15;
lineWidth=2;
fontSize=15;
fAlpha1=0.25;
fAlpha2=0.8;
lineWidth1=1;
lineWidth2=3;

Example: Sampling Voronoi cells with the same amount of points

EXAMPLE DELAUNAY TRIANGULATION

%Boundary and mesh parameters
ns=50; %Number of points on outer boundary (defines how well the circle is sampled)
rOut=1; %Outer radius of circular boundary
pointSpacing=rOut/5; %Approximate initial point spacing for point seeding
stdP=pointSpacing/2*ones(1,2); %Standard deviations for random point offset after point seeding

%Creating boundary curve
tt=linspace(0,2*pi,ns);
tt=tt(1:end-1);
r=rOut.*ones(size(tt));
[x,y] = pol2cart(tt,r);
Vb=[x(:) y(:)];

%Create Delaunay derived mesh
regionCell={Vb};
[Ft,Vt,~,DT]=regionTriMeshRand2D(regionCell,pointSpacing,stdP,1,0);

COMPUTE NORMAL VORONOI TESSELATION REQUIRING LOOP FOR PLOTTING

[Vv,Fv_cell] =voronoiDiagram(DT);
Vv(isinf(Vv))=NaN;

hf1=cFigure;
title('Normal Voronoi tesselation','FontSize',fontSize);
xlabel('X','FontSize',fontSize);ylabel('Y','FontSize',fontSize);zlabel('Z','FontSize',fontSize);
hold on;
patch('faces',Ft,'vertices',Vt,'FaceColor','r','FaceAlpha',fAlpha1,'LineWidth',lineWidth1);

HP=cellPatch(Vv,Fv_cell,'g');
set(HP,'LineWidth',lineWidth,'faceAlpha',fAlpha2,'LineWidth',lineWidth2);

% for q=1:1:numel(Fv_cell)
%     fv=Fv_cell{q};
%     vv=Vv(fv,:);
%     if all(~isnan(vv))
%         patch('faces',fv,'vertices',Vv,'FaceColor','g','faceAlpha',fAlpha2,'LineWidth',lineWidth2);
%     end
% end

axis equal; view(2); axis tight;  set(gca,'FontSize',fontSize); grid on;
drawnow;

Use voronoiDiagramEven2D to sample all cells with same amount of points

numPointsVoronoi1=3;
numPointsVoronoi2=5;
numPointsVoronoi3=11;
numPointsVoronoi4=25;

[Vv1,Fv1]=voronoiDiagramEven2D(DT,numPointsVoronoi1);
[Vv2,Fv2]=voronoiDiagramEven2D(DT,numPointsVoronoi2);
[Vv3,Fv3]=voronoiDiagramEven2D(DT,numPointsVoronoi3);
[Vv4,Fv4]=voronoiDiagramEven2D(DT,numPointsVoronoi4);

Now for loops can be avoided for plotting

hf1=cFigure;
subplot(2,2,1);
title(['Sampled using ',num2str(numPointsVoronoi1),' points'],'FontSize',fontSize);
xlabel('X','FontSize',fontSize);ylabel('Y','FontSize',fontSize);
hold on;
patch('faces',Ft,'vertices',Vt,'FaceColor','r','FaceAlpha',fAlpha1,'LineWidth',lineWidth1);
patch('faces',Fv1,'vertices',Vv1,'FaceColor','g','FaceAlpha',fAlpha2,'LineWidth',lineWidth2);
axis equal; view(2); axis tight;  set(gca,'FontSize',fontSize); grid on;

subplot(2,2,2);
title(['Sampled using ',num2str(numPointsVoronoi2),' points'],'FontSize',fontSize);
xlabel('X','FontSize',fontSize);ylabel('Y','FontSize',fontSize);
hold on;
patch('faces',Ft,'vertices',Vt,'FaceColor','r','FaceAlpha',fAlpha1,'LineWidth',lineWidth1);
patch('faces',Fv2,'vertices',Vv2,'FaceColor','g','FaceAlpha',fAlpha2,'LineWidth',lineWidth2);
axis equal; view(2); axis tight;  set(gca,'FontSize',fontSize); grid on;

subplot(2,2,3);
title(['Sampled using ',num2str(numPointsVoronoi3),' points'],'FontSize',fontSize);
xlabel('X','FontSize',fontSize);ylabel('Y','FontSize',fontSize);
hold on;
patch('faces',Ft,'vertices',Vt,'FaceColor','r','FaceAlpha',fAlpha1,'LineWidth',lineWidth1);
patch('faces',Fv3,'vertices',Vv3,'FaceColor','g','FaceAlpha',fAlpha2,'LineWidth',lineWidth2);
axis equal; view(2); axis tight;  set(gca,'FontSize',fontSize); grid on;

subplot(2,2,4);
title(['Sampled using ',num2str(numPointsVoronoi4),' points'],'FontSize',fontSize);
xlabel('X','FontSize',fontSize);ylabel('Y','FontSize',fontSize);
hold on;
patch('faces',Ft,'vertices',Vt,'FaceColor','r','FaceAlpha',fAlpha1,'LineWidth',lineWidth1);
patch('faces',Fv4,'vertices',Vv4,'FaceColor','g','FaceAlpha',fAlpha2,'LineWidth',lineWidth2);
axis equal; view(2); axis tight;  set(gca,'FontSize',fontSize); grid on;
drawnow;

GIBBON www.gibboncode.org

Kevin Mattheus Moerman, [email protected]

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License: https://github.com/gibbonCode/GIBBON/blob/master/LICENSE

GIBBON: The Geometry and Image-based Bioengineering add-On. A toolbox for image segmentation, image-based modeling, meshing, and finite element analysis.

Copyright (C) 2019 Kevin Mattheus Moerman

This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with this program. If not, see http://www.gnu.org/licenses/.

Published with MATLAB® R2019a