check for keyboard press in while loop

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raheem mian
raheem mian on 10 Mar 2020
I'd like to check for a keyboard press and increment a number if the right arrow key is pressed and decrement if the left array key is pressed.
  2 Comments
Geoff Hayes
Geoff Hayes on 11 Mar 2020
raheem - please provide some context. Do you have a figure or GUI that you can use to listen for key press events? Or are you doing something else?
raheem mian
raheem mian on 11 Mar 2020
Yeah I have a volume of images that I want to iterate through. I would be using imagesc(vol(:, :, i)) where i is the iterator

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Answers (2)

Geoff Hayes
Geoff Hayes on 12 Mar 2020
raheem - since you have a figure, you could use the WindowKeyPressFcn to listen for a key press event (assuming that the figure has focus). You could then change the contents of the axes given the left or right arrow. Just save the below to a file named MyKeyPressListener.m.
function MyKeyPressListener
hFig = figure;
hAxes = gca;
set(hFig,'WindowKeyPressFcn',@keyPressCallback);
function keyPressCallback(source,eventdata)
% determine the key that was pressed
keyPressed = eventdata.Key;
if strcmpi(keyPressed,'rightarrow')
C = [0 2 4; 8 10 12; 16 18 20];
imagesc(C, 'Parent', hAxes);
elseif strcmpi(keyPressed,'leftarrow')
C = [0 2 4 6; 8 10 12 14; 16 18 20 22];
imagesc(C, 'Parent', hAxes);
end
end
end

Amir Azadeh Ranjbar
Amir Azadeh Ranjbar on 19 Oct 2023

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