Determine MATLAB's Monitor in a multiple monitor configuration

Question

I move around from a company site to another a lot. At any given day, I might have just my laptop or as many as four monitors. With multiple monitors, I don't know which monitor I will choose to use for MATLAB main GUI (the main GUI launched when double-clicking matlab.exe). It depends on the resolutions of the available monitors.

I use scripts that utilize programmatically generated GUIs (not by GUIDE) and it seems that MATLAB pops them up always on the first monitor. I've researched a little bit and found to locate the GUIs to a monitor of choice by using p = get(gcf, 'Position'), set(0, 'DefaultFigurePosition', p), and movegui command, but this will only work if I know beforehand which monitor I want to use.

Is there a way to find out on which monitor the main MATLAB GUI is up and have other little GUIs pop up on the same monitor?

Answer 1

We can use some Java tricks to get the current monitor; see code with comments below:

function mon = q37705169
%% Get monitor list:
monitors = get(groot,'MonitorPositions'); % also get(0,'MonitorPositions');
%% Get the position of the main MATLAB screen:
pt = com.mathworks.mlservices.MLEditorServices.getEditorApplication.getActiveEditor.getComponent.getRootPane.getLocationOnScreen;
matlabScreenPos = [pt.x pt.y]+1; % "+1" is to shift origin for "pixel" units.
%% Find the screen in which matlabScreenPos falls:
mon = 0;
nMons = size(monitors,1);
if nMons == 1
  mon = 1;
else
  for ind1 = 1:nMons    
    mon = mon + ind1*(...
      matlabScreenPos(1) >= monitors(ind1,1) && matlabScreenPos(1) < sum(monitors(ind1,[1 3])) && ...
      matlabScreenPos(2) >= monitors(ind1,2) && matlabScreenPos(2) < sum(monitors(ind1,[2 4])) );
  end
end

Few notes:

• Root properties documentation.
• An output value of "0" means that something's wrong.
• There may be an easier way to get the "RootPane"; I've used a method with which I have good experience.
• This will only recognize one of the monitors in case your MATLAB window spans several monitors. If this functionality is required you can use com.mathworks.mlservices.MLEditorServices.getEditorApplication.getActiveEditor.getComponent.getRootPane.getWidth etc. to find the other corners of the MATLAB window and do the same test with them.
• I didn't bother with breaking out of the loop after the first valid monitor was found since it is assumed that: 1) Only one monitor is valid. 2) The overall amount of monitors the loop will have to process is small.
• For the brave, one can perform a check with polygons (i.e. inpolygon).