Randomly moving circles in a graph

I have created circles by the help of fill command. how can I make them movingly linearly.

fill(xobs(k)+robs(k)*cos(theta),yobs(k)+robs(k)*sin(theta),[1 0 0]);

They can be moving in circular motion.

Answer 1

[Walter Roberson]

You can record the handles returned by fill(), which will be handles of patch objects. The patch objects that are created will have a Vertices property which will be an N x 2 array. You can change the Vertices property to update the locations, such as

rot = makehgtform('zrotate', 15*180/pi);
V = h.Vertices;
temp = [V,zeros(size(V,1),2)] * rot;
h.Vertices = temp(:,1:2);

[passioncoding]

xobs=[1.5 4.0 1.2 7.0 8.0];
    yobs=[4.5 3.0 1.5 5.0 8.0];
    robs=[1.5 1.0 0.8 1.0 1.0];
     theta=linspace(0,2*pi,100);
for k=1:numel(xobs)
        fill(xobs(k)+robs(k)*cos(theta),yobs(k)+robs(k)*sin(theta),[1 1 0]);
      
end

This is code I need these circles to be moving linearly

[Walter Roberson]

xobs=[1.5 4.0 1.2 7.0 8.0];
    yobs=[4.5 3.0 1.5 5.0 8.0];
    robs=[1.5 1.0 0.8 1.0 1.0];
     theta=linspace(0,2*pi,100);
for k=1:numel(xobs)
        fh(k) = fill(xobs(k)+robs(k)*cos(theta),yobs(k)+robs(k)*sin(theta),[1 1 0]);
        xspeed(k) = randn()/2;
        yspeed(k) = randn()/2;
end

for iterations = 1 : 100
    for k = 1 : length(fh)
        fh(k).Vertices = fh(k).Vertices + [xspeed(k), yspeed(k)];
    end
    drawnow();
end

The code assumes R2016b or later.

[passioncoding]

the code does not know what vertices are. and it does make acircle but not moving circles.

[Walter Roberson]

Put a

hold on

before the code here, and

hold off

after the "for k" loop.

[passioncoding]

the code doesnot recognize 'Vertices' it says Invalid or deleted object. Plus there is no motion in circles. only a single circle is plot

[Walter Roberson]

Code enclosed to prove that it does work. Also enclosed is a movie with proof that it works.