I want to display rectangle to every image in the loop but my code shows rectangle only at last image.So please help me

here is my code

if true
  % code
for k = 100 : 108

i=i+1;
I=imread(['C:\Users\shraddha\Documents\MATLAB\Snaps\' num2str(k) '.png']);
imshow(I);
subplot(3,3,i)

 a=rand(4);
rectangle('Position',a(1,:),'linewidth',1,'linestyle','-','EdgeColor','r');

end end

here rectangle function shows rectangle at last plot,but i want it to every frame in the subplot... please help me..

[Shraddha Agnihotri]

Reactangle appear before image and then disappear..Reactangle should appear above image permanently..

Answer 1

[Image Analyst]

Put this before the end of the loop

drawnow;
pause(0.5);

[Image Analyst]

There's so much wrong with it that I just decided to fix everything. The main problem was that the subplot was not before the imshow() and rectangle() - it was between them. Here is the fixed code, which has a number of improvements:

clc;
fontSize = 10;
plotNumber = 0;
folder = 'C:/Users/shraddha/Documents/MATLAB/Snaps';
for k = 100 : 108
  plotNumber=plotNumber+1;
  subplot(3, 3, plotNumber);
  if plotNumber == 1
    % Enlarge figure to full screen.
    set(gcf, 'Units', 'Normalized', 'OuterPosition', [0 0 1 1]);
  end
  baseFileName = sprintf('%d.png', k);
  fullFileName = fullfile(folder, baseFileName);
  if exist(fullFileName, 'file')
    thisImage = imread(fullFileName);
    imshow(thisImage);  
    axis on;
    title(baseFileName, 'FontSize', fontSize, 'Interpreter', 'none');
    recPosition = rand(1, 4);
    hold on;
    rectangle('Position', recPosition,...
      'linewidth',1,...
      'linestyle','-',...
      'EdgeColor','r');
  else
    message = sprintf('Error: the image file does not exist:\n%s', fullFileName);
    title(message, 'FontSize', fontSize, 'Interpreter', 'none');
    uiwait(warndlg(message));
  end
end