Create a figure with slider (before/after)

I want to create a figure or an app that can show before and after image draw by plot(), the slider can be pull to show the before/after (the picture below for example). How can I do that in Matlab?

Answer 1

[Venkat Siddarth Reddy]

Hi Huy Nguyen Minh,

You can achieve this functionality using the MATLAB feature called "uislider".

Firstly, create a horizontrol slider in an "uifigure" using the above feature and associate a callback to the slider such that the value selected in the slider determines the percentage of the image to be shown in the selected "uifigure".

Please refer to the following code snippet for the implementation of the above logic in MATLAB:

% Load the images
beforeImg = imread('peppers.png');
afterImg = imresize(imread('saturn.png'),[384,512]);% Ensure both images are of the same size

% Get the size of the images
[rows, cols, ~] = size(beforeImg);

%Create a uifigure and uiaxes to display the images and the slider
fig = uifigure('Name', 'Before v/s After');
ax = uiaxes('Parent', fig, 'Position', [100 100 600 400]);

% Display the "before" image first
imshow(beforeImg, 'Parent', ax);

% Create the slider and add the operation to be done when the value is
% changed
slider = uislider(fig, ...
    'Position', [100 50 600 3], ...
    'Limits', [1 cols], ...
    'ValueChangedFcn', @(sld, event) updateImage(sld, ax, beforeImg, afterImg, rows));

% Callback function to update the image
function updateImage(slider, ax, beforeImg, afterImg, rows)
    
    colPos = round(slider.Value);
    
    % Create a composite image from the parts of "before" and "after" image
    % needs to be displayed
    compositeImg = beforeImg;
    compositeImg(:, colPos:end, :) = afterImg(:, colPos:end, :);
    
    % Display the composite image
    imshow(compositeImg, 'Parent', ax);
end

To learn more about uislider, please refer to the following documentation:

https://www.mathworks.com/help/matlab/ref/uislider.html

I hope it helps!

Regards

Venkat Siddarth V

Answer 2

[Voss]

This File Exchange submission may be useful:

https://www.mathworks.com/matlabcentral/fileexchange/23073-uisplitpane-split-a-container-figure-frame-uipanel-into-two-resizable-sub-containers