Matlab App Designer - Image Editing

Hi, I have a project I need some help with. I need to make a matlab app in app designer that can upload an image, change the brightness, contrast, and saturation using sliders, and save the image. I made a button, a UIAxis, and 3 sliders. Here is the code for the button and contrast slider.

        function UploadImageButtonPushed(app, event)
           [filename,filepath] = uigetfile({'*.*;*.jpg;*.png;*.bmp;*.oct'}, 'Select File to Open');
           fullname = [filepath, filename];
           ImageFile = imread(fullname);
           imshow(ImageFile, 'Parent', app.UIAxes);  
        end

        % Value changed function: ContrastSlider
        function ContrastSliderValueChanged(app, event)
            contrastVal = app.ContrastSlider.Value;
            newImage = uint8(double(ImageFile*contrastVal))
            imshow(newImage,'Parent',app.UIAxes)

the upload image works, but the contrast doesn't, ImageFile is not recognized. I would also appreciate help in how to implement brightness and saturation changes. Thanks.

[Bilal Mudasar]

hey i have the same project rn , can you tell me if you were able to finish your code ?

thanks a lot mate

[black]

same here

could u make one

Answer 1

[Cris LaPierre]

Have you considered variable scope? Each callback is a function. Once you leave a function, the variables created inside it no longer exist. The normal way around this is to return the variables you want to keep as outputs of the function.

App designer has implemented a way of doing this - using properties. This page will show you how to share data within App Designer apps.