drawrectangle not a defined function?

I've been programming in App Designer and I want to have a ROI over some axes that would return its position. However, for some reason drawrectangle is undefined as a function. When I look up the documentation for it through matlab it cannot find the function either. A lot of answers on different posts say it might be the path but the MATLAB folder is still in my path. Please help.

ax = axes(app.UIFigure); 
drawrectangle(ax); %Undefined function 'drawrectangle' for input arguments of type 'matlab.graphics.axis.Axes'.

Answer 1

[Walter Roberson]

It needs R2018b or later.

[Raymond Mo]

I'm on a demo version of 2019a. Would the trial be causing problems?

[Guillaume]

No, a trial is a full version.

What does

which drawrectangle -all

return?

[Raymond Mo]

It says this:

'drawrectangle' not found.

also the alternative function "imrect" isn't found either

[Guillaume]

Oh, it's part of the image processing toolbox. Of course, if the toolbox is not part of your trial, you won't have access to the function.

[Walter Roberson]

A trial is a full version of the products included in the trial license and installed.

This particular function needs the Image Processing toolbox

However, I have to wonder whether

ax = axes(app.UIFigure); 

is correct. axes() does not apply to uifigure objects: you need uiaxes():

ax = uiaxes(app.UIFigure);

axes() applied to a UIFigure would give you an error about undefined function isvalid for datatype double.

[Raymond Mo]

Oh, can I add it in or would I need to purchase the full version?

[Walter Roberson]

You can request that products be added to the trial.