Using a loop to add a new point to a figure at each constant rate

Question

I am trying to plot figures that have a point inside it. I want to add a new point to the figure at each 10 steps (or any constant rate).For example, if I have 50 steps then I should have 50 figures. Figures from 1 to 10 will have one point, figures from 11 to 20 will have two points, and figures from 21 to 30 will have three points, and so on. I did that in the below code but, unfortunately, it gave me only one point for all figures.

clc;
clear;
Current_Path=pwd;
cd (Current_Path)
mkdir('Photos','part1')
pridir = 'Photos\part';
R=rand(1,50);
Y=rand(1,50);
for i=1:50
    figure
    for jj = 1:floor((i-1)/10)+1
        if jj<=1
            plot (R(i),Y(i),'*r');
            printto = sprintf('%s%d\\Motion%03d',pridir,1,i);
            print('-djpeg90',printto)
            close(gcf);
            hold on
        else
            R(i)=R(i-((jj-1)*10));
            Y(i)=Y(i-((jj-1)*10));
            plot (R(i),Y(i),'*r');
            printto = sprintf('%s%d\\Motion%03d',pridir,1,i);
            print('-djpeg90',printto)
            close(gcf);
            hold on
        end
    end
    hold off
end

score 1 · Accepted Answer · edited May 23 '17 at 11:58

Your code has two mains problems:

You're closing the figure after each plot. Move the close(clf) to the location your hold off currently is to avoid closing the figure after each plotted point.
You pridir call is missing a 1 in the part1, which causes MATLAB to not save the figure since there is no directory part.

To prettify you could make a couple of additional changes. hold on holds a figure until you call hold off. In your case you can omit the hold off completely, as you close the figure after the loops. Also, consider using ii as a variable (just as your jj) since i is the imaginary unit.

Updated code

Current_Path=pwd;
cd (Current_Path)
mkdir('Photos','part1')
pridir = 'Photos\part1'; % change to 'part1'
R=rand(1,50);
Y=rand(1,50);
for ii=1:50 % change to ii
    figure
    hold on % move hold on here
    for jj = 1:floor((ii-1)/10)+1
        if jj<=1
            plot (R(ii),Y(ii),'*r'); % remove close(gcf) and print calls
        else
            R(ii)=R(ii-((jj-1)*10));
            Y(ii)=Y(ii-((jj-1)*10));
            plot (R(ii),Y(ii),'*r'); % remove close and print 
        end
    end
    printto = sprintf('%s%d\\Motion%03d',pridir,1,ii); 
    print('-djpeg90',printto) % move print outside the inner loop
    close(gcf); % finally close the figure after saving
end

Using a loop to add a new point to a figure at each constant rate

1 Answers1