copy Freehand object from a figure and pate into another figure

Hi there,

I have used the drawfreehand function in matlab using the command below to draw an roi in my figure and save it:

z = drawfreehand();
save('roi.mat', 'z');
so now when i type z in the command window I will get the following Freehand object :
z = 

  Freehand with properties:

      Position: [298×2 double]
        Closed: 1
         Label: ''
    Multiclick: 0
         Color: [0 0.4470 0.7410]
        Parent: [1×1 Axes]
       Visible: 'on'
      Selected: 0

Now I would like to copy this freehand object and display it on another figure in the excat same position.

It would be noice if i can move it around as well on the new figure

could you please kindly help me with this issue?

Best,

Nikan

Answer 1

[Image Analyst]

In your other program, use load() to load it in and then use plot() to display it

figure(1);
rgbImage = imread('peppers.png');
imshow(rgbImage);
uiwait(msgbox('Draw a freehand roi'));
roi = drawfreehand('Color', 'yellow');
% Save it
save('roi.mat', 'roi');

% Make new figure
figure(2);
rgbImage = imread('peppers.png');
imshow(rgbImage);

% Recall ROI
s = load('roi.mat')
freehandROI = s.roi.Position;
% % Plot it over the second image.
% x = freehandROI(:, 1);
% y = freehandROI(:, 2);
% hold on;
% plot(x, y, 'y.-', 'LineWidth', 2, 'MarkerSize', 20);
% hold off;
uiwait(msgbox('Adjust the freehand roi'));
roi = drawfreehand('Position', freehandROI, 'Color', 'yellow');

[Adam Danz]

Since drawfreehand() automatically connects the first and last cursor location by default you'd need to wrap the first and last coordinates explicitly to copy the ROI unless the user set the Closed property to false.

x = freehandROI([1:end,1], 1);
y = freehandROI([1:end,1], 2);

This method also ignores all of the ROI formatting such as color, transparency, markersize, etc. Why not just use copyobj?

[Image Analyst]

@Adam Danz, with my code, the second ROI is closed if you use drawfreehand(), at least for me. It plots a closed curve with spots at the vertices, which you can grab and drag. Then

However if you wanted to plot it with plot(), and not have it be adjustable, like the code I had commented out, you would need to tack on the first point to close it.

x = [x; x(1)];
y = [y; y(1)];

The main problem is the code goes forging ahead with the rest of your code though, not waiting for you to adjust and accept it before continuing. I tried putting in uiwait() but that just left it hanging with no way to tell it to continue. It should be easier than this. It should just automatically wait and then when you type Enter or right click, tell it to accept the shape and move on. Well after a few minutes of playing around with it, I didn't figure it out. Maybe I would need to add a listener, but what a pain. It should be simpler.

[Nikan Fakhari]

Thank you @Image Analyst, that helped a lot

[Adam Danz]

@Image Analyst, the solution in your original answer (currently commented out) is what I was referring to. Your updated version doesn't have this problem. I think your new approach is better than using a listener or uiwait, although I'd still prefer using copyobj and then editing the copied obj as needed.

f1 = figure();
ax1 = axes(); 
grid(ax1,'on')

f2 = figure();
ax2 = axes(); 

linkaxes([ax1,ax2])

roi = drawfreehand(ax1); 

plot(ax2, roi.Position(:,1), roi.Position(:,2), '-o')
grid(ax2,'on')

[Image Analyst]

Adam, I knew about that but intentionally left it off so that if someone ran it, they would see it wasn't connected and realize they had to do it. I guess I could have closed it but I think knowing that is what happens is a good thing?

So anyway, how to keep the code from blasting onwards? One way I'm going it is to have my script or GUI open a new, separate figure and then put a button on it that says "Accept" whereupon it will close the new figure and return to the original GUI or script. Then I think there's some calls to wait(), uiwait(), or uiresume() or something very confusing and non-intuitive that I don't remember off the top of my head. Kind of clunky but it works and I don't know of any more elegant, single window way of doing it. Do you?

I did find this code for GUIDE where I could popup a new figure and draw an ellipse on the same GUI:

%=====================================================================
% Get a elliptical mask.
function mask = GetManualMask(handles, rgbImage)
try
	[rows, columns, numberOfColorChannels] = size(rgbImage);
	mask = true(rows, columns); % Initialize so we'll have something in case an error is thrown.
	hFig = figure;
	imshow(rgbImage);
	hFig.WindowState = 'maximized';
 
	h = uicontrol('Position',[20 620 200 40],'String','Accept', 'FontSize', 12, 'FontWeight', 'bold', ...
        'Callback','uiresume(gcbf)');
 
	userPrompt = sprintf('Please draw out an ellipse.\nClick the Accept button to the left when done.');
	msgboxw(userPrompt);
	caption = sprintf('Please draw out an ellipse.  Close the window when done.');
	title(caption, 'FontSize', 14);
	
	% Have the user interactively drag out the ellipse and adjust its size and position.
	roi = drawellipse();
	xy = roi.Vertices;
	% Quirky other stuff needed to let the user adjust the ellipse and get back the xy coordinates.
	% The listener updates xy in the base workspace when the user changes the ellipse.
	addlistener(roi, 'ROIMoved', @(src,evt) assignin('base','xy',src.Vertices)); 
	uiwait(hFig);
	xy = evalin('base', 'xy'); % Get the xy coordinates from the base workspace.
	
	mask = poly2mask(xy(:, 1), xy(:, 2), rows, columns);
	imshow(mask);
 	drawnow;
 	close(hFig);
catch ME
	% Some error happened if you get here.
	errorMessage = GetErrorMessage(ME); % Get error message with call traceback and file's date.
	WarnUser(errorMessage); % Pop up error message to show user what it is.  Also prints to command window or console window (if program is an executable).
end
return;  % GetManualMask

Answer 2

[Adam Danz]

You could use copyobj(z,ax) where z is an existing freehand object or a freehand object saved to a mat file and ax is the handle to the new axes.

[Nikan Fakhari]

Thank you very much