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Strange Behaviour using Zoom with app designer

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Jason on 3 Nov 2020
Commented: Adam Danz on 4 Nov 2020
Hello. I have an image on a UIAxes and want to use a checkbox to either zoom in 4X, or retrun to 1x.
I have tried this:
value = app.xZoomCheckBox.Value;
switch value
case 1
zoom(app.UIAxes,'reset') % Sets baselevel zoom
zoom(app.UIAxes,4) % Zoom 4x
case 0
zoom(app.UIAxes,'out') % Return to baselevel zoom
with the checkboxclicked (case 1), the image does zoom in 4x.
However when I unclick the checkbox (case 0), I get the error message
Unrecognized function or variable 'firstinput'.
Error in
I have also tried zooming 1x, but this did nothing.


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Accepted Answer

Adam Danz
Adam Danz on 3 Nov 2020
Edited: Adam Danz on 3 Nov 2020
According to the documentation, the zoom() function can receive a figure handle as input, not an axes handle. Zoom is applied to the current axes within the figure.
If you call zoom(app.UIFigure,'out') with a figure handle, it works.
Note that you can change the current axes programmatically by setting
The weird thing is that the function breaks with axes inputs when the 'out' option is used (and maybe others) but not with 'reset' or factor values. Too bad the section of code that receives the inputs is wrapped in p-code.


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Adam Danz
Adam Danz on 3 Nov 2020
Yes. As my answer states, the zoom is applied to the current axes on the figure and you can control which axes is current either by clicking on the axes or setting it programmatically using the CurrentAxes property of the figure.
So the workflow would look like this,
app.UIFigure.CurrentAxes = app.UIAxes1;
zoom(app.UIFigure, 'out')

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