Plotting in GUI from an external function using imagesc()

So I've got an image file loaded in using image = imread(app.ImageName) and I am trying to send it off to an external function to do a fourier transform on it then show it on the gui using imagesc..

How do I use imagesc in a way that might be similar to imshow(img,'parent',app.UIaxes)??

Just to see if I could get something working, I also tried using imshow(img,'parent',app.UIaxes) within this external function to see if I could plot to the gui using that and it is not working either... giving me an error. I need to use imagesc but figured I'd mess around with imshow to see if I could get anything working. Heres whats happening

in GUI:

app.baseImg = imread(app.Input);
imshow(app.baseImg,'Parent',app.UIAxes)
doFourier(app.baseImg,app.RunMode,app.flareAngle,app.stepSize) %calls external function doFourier.m, plugging in the image

in external function, doFourier.m:

imshow(I,'parent',FourierApp.UIAxes2);   %I is a modified image of the input image, app.baseImg

and heres the error it is giving me

The property 'UIAxes2' in class 'FourierApp' must be accessed from a class instance because it is not a Constant property.
Error in doFourier (line 5)
imshow(I,'parent',FourierApp.UIAxes2);

EDIT: If I tyoe

FourierApp()

before the imshow() in doFourier it works because it calls the class or something, but then it opens up another instance of the app... I need to call the class somehow at the beginning of the external function so that I can use it to modify things in the FourierApp class.

[Walter Roberson]

It is not clear where it is getting FourierApp from? You are not passing in the app explicitly ?

[Darren Miller]

FourierApp is the name of the app I am making, and the function doFourier is a function which exists in the same directory.

[Darren Miller]

OK I see what you mean now.. I need to pass in the app into the function correct? How do I do that?

I tried typing

FourierApp(); 

at the beginning of the doFourier external function but then it opens a new instance of the app. It does work though, allowing me to use imshow() to put the image on the axes (UIaxes2) in the GUI!

[Mohammad Sami]

You need to pass it in when you are calling the function. It should not be created inside the external function.

function externalfunc(a,b,c,app)
% UIAxes2 must be a public property in the FourierApp
    imshow(I,'parent',app.UIAxes2); 
end

[Mohammad Sami]

You can also pass in the uiaxes itself, rather then the app

function externalfunc(a,b,c,uiax)
    imshow(I,'parent',uiax); 
end

[Darren Miller]

Ahh thanks Walter and Mohammad.. I totally see now. I moved the external function in the app for convenience and followed your instructions and it is working now.

Now, any idea how to use imagesc to plot on a specific axes?? I need to do something like the imshow(I,'parent',uiaxes2) but with imagesc. Is that possible?

[Mohammad Sami]

You can specify the Parent property when calling imagesc

imagesc(C,'Parent',uiax)

[Walter Roberson]

or for many of the plotting routines you can pass the handle to the container object as the first parameter

imagesc(uiax, C)