Adding slider to heatmap

I am dealing with a 3D double which I want to visualize slice by slice.

To do that, I tried plotting a heatmap and then adding a slider to select the index for the third dimension.

However, I get the following error:

Error using uislider (line 34) HeatmapChart cannot be a parent.

A minimal example to reproduce my problem:

% Generate dummy 3d array
img = ones(5,4,3);
for ii=1:size(img,3)
    img(:,:,ii)=ii;
end
% Try plotting heatmap with slider
h = heatmap(img(:,:,1));
uislider(h)

Is there actually a way/workaround to use a slider on a heatmap?

Thanks!

Answer 1

[Ines Pereira]

This question was answered here.

Answer 2

[Mario Malic]

Hello,

I modified your code a little bit. Uislider can only be used on uifigure components. Whenever you're using uifigure you need to specify axes handle, because uifigure's handle visibility by default is set to 'off'.

UIFigure = uifigure;

img = ones(5,4,3);
img(:,:,2) = img(:,:,2)*2;
img(:,:,3) = img(:,:,3)*3;

% Try plotting heatmap with slider
h = heatmap(UIFigure, img(:,:,1));
UISlider = uislider(UIFigure);
UISlider.Limits = [1, 3];
UISlider.MajorTicks = 1:3;
UISlider.MinorTicks = 1:3;
UISlider.ValueChangedFcn = {@UISliderValueChangedFcn, img};

function UISliderValueChangedFcn(Source, ~, img)
    sliderValue = round(Source.Value); % We need to round the decimal value we get from UISlider.Value to index into img
    Source.Value = sliderValue; % Change slider to rounded value to show it on UIFigure
    
    UIFigure = Source.Parent;
    h = heatmap(UIFigure, img(:,:,sliderValue));
end

However, this uislider is not nicely position on UIFigure, so you can use Position property for both components to set their size and location.

[Ines Pereira]

Hey Mario, thanks for checking in on this! Ok so your code does display the slider, but it doesn't allow me to view slices of my tensor. I got a workaround from StackOverflow which I'll post here.

[Mario Malic]

I edited the example so it can be used with UISlider component.

[Ines Pereira]

Really cool! Works now, thank you!