Step-back button in GUI

Hello. I have a GUI with an image processing functions. My question is, is it possible to do Back button in this gui? I store and update all events in handles. e.g. handles.inputImage = handles.inputImage_gray, handles.inputImage = handles.inputImage_poisson_noise, handles.inputImage = handles.inputImage_gaussian_filter ... The result is grayscale image with Poisson noise which is filtered by Gaussian Filter... And what if i want to do step back button and remove last event (in this case handles.inputImage = handles.inputImage_gaussian_filter ) and then next and then next last event. Is it possible to store handles in listbox and find last value and then assing to this value inverted state? handles.inputImage_poisson_noise = handles.inputImage. I hope u can understand what i want to do. Thank you very much.

Answer 1

[Jan]

After the colors have been converted to gray, there is no way to get the colors back. But of course you can store the initial value (image) in a list to which you append the new image after each operation. Then an undo is easy to implement.

% After loading the image
handles.imageList = {imageRGB};
handles.operation = {'original'};

...
% At applying any operation:
image = rgb2gray(image);
handles.imageList{end+1} = image;
handles.operation{end+1} = {'RGB to gray'};

Now an "undo" is:

if numel(handles.imageList) > 1
  image = handles.imageList{end-1};
end

and updating the display, maybe removing the last element from the lists, except you want t "redo".

[Walter Roberson]

Note that you must program all of this yourself. None of the gui tools have built-in "undo".

[Michal Bella]

Sir, thank u very much, i understood the syntax, but when i press back button it's working until one state, when i press second press its stopped working. I tried this

   //
      handles.RGB is input image

   // RGB to gray button
      handles.RGB_gray = rgb2gray(handles.RGB); 
      handles.RGB = handles.RGB_gray;
      handles.imageList{end+1} = handles.RGB_gray;
      imshow(handles.RGB_gray);
      guidata(hObject, handles);

// rotate 180 button

      handles.RGB_rotate = imrotate(handles.RGB,180);
      handles.RGB = handles.RGB_rotate;       
      handles.imageList{end+1} = handles.RGB_otocenie;
      handles.operation{end+1} = {'RGB to gray'};
      axes(handles.axes2); 
      imshow(handles.RGB_rotate);

// Step back button

          if numel(handles.imageList) > 1
            handles.RGB = handles.imageList{end-1};    
            imshow( handles.RGB);   
            guidata(hObject, handles);        
          end

[Jan]

If you want to undo multiple steps, handles.imageList{end-1} is not sufficient. Add a cursor for the current state:

% For adding a new step:
handles.imageCursor = handles.imageCursor + 1;
handles.imageList{handles.imageCursor} = newImage
handles.operation{handles.imageCursor} = operation

And the undo:

handles.imageCursor = handles.imageCursor - 1;
image = handles.imageList{handles.imageCursor}

[Walter Roberson]

Using // for comments is not valid MATLAB code. The Octave forum is elsewhere.

Answer 2

[Michal Bella]

Thank u, but i did it like this and its working perfectly

    if numel(handles.imageList) > 1 
                handles.imageList(end)=[];
                handles.RGB = handles.imageList{end};
                handles.imageList
                imshow( handles.RGB);
                guidata(hObject, handles);                   
   end

Big thank for you :)