Continual points on a movie

I have a movie made of a plot with images behind each frame and points that mark certain locations via plots. I want to have the points from previous frames showing on the current frame as if showing a "path" per se. I have made the movie using the imshow, hold on, plot(), and get frame functions in a for loop. What would be the best way to accomplish this? Thank you.

[Geoff Hayes]

Jake - can you show some of your code? Do you have a for loop that - on each iteration - creates a new figure (via imshow) to which you had a plot to? Do you want to all past calls to plot to be carried forward to the next iteration? (If so, then just maintain an array of this historical data to update (with new data) and plot on each iteration.)

[Jake Elliott]

q=1
for i=1:numimgs
    imshow(I{i})
    hold on
    fishplot(i)=plot(x(i,:),y(i,:),'r.')
    hold off
    P(q)=getframe
q=q+1;
end

[Jake Elliott]

Here is my for loop. I would like all past points to be added to the current frame with the new data

[darova]

If you want to write a movie use VideoWriter

Answer 1

[Bjorn Gustavsson]

If you want to plot all the points (x,y) from the first to point i you can do something like this:

q = 1;
for i1 = 1:numimgs % Avoid using i and j as indices, they are also used for (-1)^(1/2)
    imshow(I{i1})
    hold on
    plot(x(1:i1),y(1:i1),'b.')
    fishplot(i1) = plot(x(i1,:),y(i1,:),'r.')
    hold off
    P(q) = getframe;
    q = q+1;
end

Maybe that is what you want to achieve.

HTH