Overload get(0, 'MonitorPositions')

I am using someone else's toolbox that calls get(0, 'MonitorPositions') all over the place. The problem is that on my system get(0, 'MonitorPositions') returns nonsense. I understand that dual monitors are not officially supported by MATLAB despite the existence of a property like MonitorPositions.

Is it possible to overload either get(0, 'MonitorPositions') or whatever is called by get(0, 'MonitorPositions')?

The problem is not getting the monitor positions from the OS. I can write a MATLAB function that uses either java or system calls to get the monitor positions. I do not want to edit the code in the toolbox.

[Andrew Newell]

Do you have dual monitors?

[Daniel Shub]

Yes, I have dual monitors.

Answer 1

[Daniel Shub]

While it is not a very satisfying answer, upgrading to r2011a fixed my problem. I am not sure if this is a universal solution or not, but it makes me happy.

[Jan]

I haven't seen this thread before.

You can overload the "get" command by creating a function with this name in the Matlab path:

function Out = get(varargin)

Then you can check if the first two inputs are {0, 'MonitorPositions'} and create an adjusted output. In all other cases you can forward the input to the built-in "get":

Out = builtin('get', varargin{:});

You have to catch missing output and multiple inputs, but it is possible with some effort.

However, if upgrading solves the known bug, this is a far better idea.

[Daniel Shub]

You are right about just overloading get. It seemed like overkill to overwrite a crucial function just to intercept one property of one handle. I was worried about performance and multiple inputs and in general screwing something up. What I really wanted to do was intercept whatever the hell was called to actually get the monitor position.

Answer 2

[Andrew Newell]

Judging by the documentation for Root properties, MATLAB does officially support dual monitors, but this is a documented bug. You could try doing this:

set(0,'MonitorPositions',get(0,'ScreenSize'))

but there's no guarantee you'll get good results.

[Daniel Shub]

>> set(0, 'MonitorPositions', [1,1,1024,1280])

??? Error using ==> set

Attempt to modify a property that is read-only.

Object Name : root

Property Name : 'MonitorPositions'.

As for official support, it really is a mixed message. There is documentation and even reported bugs. My support request asking if there was something I could change in my software or hardware configuration to get the correct values was meet with "MATLAB is not officially tested on multi-monitor setups, and so this is not an officially supported setup." They also tried to be helpful and provided some java code that correctly gets my monitor positions.

[Andrew Newell]

I wonder how you can tell in advance what is "official"?

Answer 3

[Matt Fig]

What does the code you are using do with the value returned by

get(0,'MontorPosition')

Depending on your answer to that question, you could just hardcode some the pixel width and height of one of your monitors in the code. For example, everywhere you see this code, replace it with:

[1 1 1920 1200]

Or with whatever monitor size you have.

[Daniel Shub]

I have edited the question in response to this...

I can do a number of things to accurately get the monitor positions. What I do not want to do is go through the code and change all the get(0,'MontorPositions') to some other function and hence the desire to overload something.

[Matt Fig]

Of course it is easy with Ctrl+f do replace all in about 1 second. My suggestion is more of a do-or-die idea. I do not think you can overload the root. Generally, messing with the root is a no-no.

[Matt Fig]

The other, non code-replacing option would be to simply unplug one of your monitors when using this toolbox.

[Daniel Shub]

Yes, but it is not my code. Ideally, I will get the change accepted into the repo so that I do not have to keep editing the code on every update. I agree that messing with the root is not ideal. I was really hoping that there was an underlying function that was being called that I could change.

Answer 4

[Andrew Newell]

If the code is positioning windows, maybe you can follow the advice of How can I force MATLAB to bring up figure windows on the primary monitor or in a specific position on my dual monitor machine?.

[Daniel Shub]

Yes, the toolbox is using the information to set the position and size of multiple figures. Since the toolbox is using the information to set the position of the figures, the default value will not being used.

[Andrew Newell]

One solution, then, is to not set the position and size of the figures. Just let the figures open wherever Matlab decides to open them.

Answer 5

[Andrew Newell]

The underlying code is Java. You could try looking in the Undocumented Matlab site.