Using a function to pass variables to another .m File (GUI)

I wanted to pass a value obtained in my File1.m to File2.m using functions. I tried using global vairables but it started get messy

Example:

% In File1

I = snapshot(cam)

% In File2

rgb2gray(I)

How would use function to transfer this to file2.m.

Thank you for your help

Answer 1

[DGM]

This is the background material:

https://www.mathworks.com/help/matlab/functions.html

Say File1.m is something like you showed, and you're expecting the processed image to be returned by File2:

I=snapshot(camera);
graypict=File2(I);

and then File2.m would look something like this:

function outpict=File2(inpict)
    outpict=rgb2gray(inpict);
end

Though maybe you'd want to choose a better function name than "File2", and maybe you want it to do more than one thing. Let's say it needs to be flipped too:

function outpict=grayimageflipper(inpict)
    outpict=flip(rgb2gray(inpict),2);
end

... which would be called like:

flippedpicture=grayimageflipper(I);

and so on. In both examples, the first non-commented line in File2 is a function definition that describes three basic things:

• The output argument(s)
• The function name
• The input argument(s)

There can be multiple input and output arguments specified, and the number of arguments can be variable. It all depends what you want to do.

[Jesvin Jose]

Thank you for your response Im getting an error, I am using GUI therefore I cannot use "end" to terminate the function. Furthermore, would you mind explaining "inpict" where did that variable come from?

Thank you for your time :)

[DGM]

inpict is just what I chose to call the input argument. Since you're passing I as the argument in the call to File2, and the function definition says the first (and only) input argument is called inpict, then inpict is a copy of I that exists only within the scope of File2.

Similarly, the function definition in File2 describes the output argument as outpict. Outpict is the array that becomes graypict. I'm probably doing a terrible job of describing this.

https://www.mathworks.com/help/matlab/matlab_prog/base-and-function-workspaces.html

Unless you're nesting functions, you usually don't need the end statement. I find it's easier to read with them, so I use them. If you add an end statement to any one function in a file, then all the functions do need an end statement, otherwise the scoping becomes ambiguous.