Moving Vertices in a Voronoi diagram and updating

Is it possible to move vertices using a basic update method while updating the diagram as an animation. I've seen the center points be manipulated, but not the vertices.

Thanks

Answer 1

[Jordan Ross]

Hello,

In order to animate moving the vertices in a Voronoi diagram you can return the vertices from the "voronoi" function as follows:

x = gallery('uniformdata',[1 10],0);
y = gallery('uniformdata',[1 10],1);
[vx,vy] = voronoi(x,y);

Note that by returning the vertices, the "voronoi" function does not produce a plot. You can plot the vertices and center points using the "plot" function as follows:

plot(x,y,'r+',vx,vy,'b-')
xlim([min(x) max(x)])
ylim([min(y) max(y)])

This example is available in the documentation given here: https://www.mathworks.com/help/matlab/ref/voronoi.html

In order to animate the diagram you can plot again using the updated vertices. However, to give the delay to produce the animation you need to make use of the "pause" function. http://www.mathworks.com/help/matlab/ref/pause.html

Furthermore, the "drawnow" function may be required to see the next plot immediately. http://www.mathworks.com/help/matlab/ref/drawnow.html

Consider the following example in which I animate through multiple Voronoi diagrams:

for i = 1:10
    x = gallery('uniformdata',[1 10*i],0);
    y = gallery('uniformdata',[1 10*i],1);
    [vx,vy] = voronoi(x,y);
    plot(x,y,'r+',vx,vy,'b-');
    ylim([min(x) max(x)]);
    xlim([min(y) max(y)]);
    drawnow;
    pause(0.5);
end

An alternative to plotting each time is to get a handle to original plot and to update the "XData" and "YData" parameters of the line objects. Note however that you will need to manipulate the matrices "vx" and "vy" for input to "XData" and "YData" parameters.