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Changing system preferences programmatically

Posted By Yair Altman On June 17, 2009 | 16 Comments

My very first post on this blog showed how to change Matlab’s command-window colors [1]. In that post I promised to write another post detailing how system preferences can be changed from the command line.
Last week I wrote about undocumented GUIDE features [2]. After my initial post, I realized that I forgot to mention all the different relevant system preferences that can also be modified. I therefore modified last week’s post with the preferences information. I now wish to finally detail how such preferences can be changed programmatically, from within your Matlab application or from the Matlab desktop command prompt.
Matlab’s user preferences are stored in the matlab.prf text file which is stored in the user’s Matlab preferences folder:


Each preference appears to be on a separate line in the following format: <pref-name>=<pref-type><pref-value>
where <pref-type> appears to be one of these:

  • ‘B’ => boolean/logical flag
  • ‘C’ => color (RGB numeric value)
  • ‘F’ => font (type,size,name)
  • ‘I’ => int16
  • ‘J’ => int64
  • ‘R’ => rectangular area (x,y,h,w)
  • ‘S’ => string/char

You can read the preference names from this matlab.prf file and then use the following (you-guessed-it) java calls to get/set the values:

com.mathworks.services.Prefs.setPref(, newValue);

where <type> is one of: Boolean, Color, RGBColor, Font, Integer, Rectangle, String, Double (I believe Doubles get converted to int64 – possibly a bitwise casting since both use 64 bits)
For example:

com.mathworks.services.Prefs.setIntegerPref('LayoutGridWidth', 25)

adding a second argument to get<type>Pref() appears to indicate a default value that is returned if <pref-name> is not defined:

=> 123

We can programmatically set any preference key we like – we are not limited to Matlab’s built-in set. I used this feature in my CPRINTF utility [3], to set user-defined colors for later use by the desktop’s UI syntax-highlighting engine. The relevant code segment is this:

% Convert a Matlab RGB vector into a known style name (e.g., '[255,37,0]')
function styleName = getColorStyle(rgb)
  % Convert Matlab RGB array into a Java Color object
  intColor = int32(rgb*255);
  javaColor = java.awt.Color(intColor(1), intColor(2), intColor(3));
  % Preference key name format: '[RRR,GGG,BBB]'
  styleName = sprintf('[%d,%d,%d]',intColor);
  % Set/update the preference with this Java Color

…which in turn adds entries such as the following to my matlab.prf file:
Note that -15982013 = 0xFF0C2243, which is the RGB value [12,34,67] with an opaque alpha value. This value can later be retrieved using:

>> com.mathworks.services.Prefs.getColorPref('[12,34,67]')
ans =

Warning: I published much of this information on the CSSM forum [4] back in 2007. Ben Steiner then shared his experience on that thread that:
For anyone else that’s playing with this: I don’t advise trying to edit the matlab.prf via matlab(!). I created a situation that made Matlab unworkable. I did find that deleting the matlab.prf completely (in frustration) solved it.
Take a look at your matlab.prf file – can you spot any interesting preference? If so, please share it in the comments section below.

Categories: Desktop, High risk of breaking in future versions, Java

16 Comments (Open | Close)

16 Comments To "Changing system preferences programmatically"

#1 Pingback By Undocumented feature() function | Undocumented Matlab On May 4, 2010 @ 09:21

[…] feature(’GetPref’,prefName) – returns the system preference value for the requested preference name in the global prefs file ([prefdir,’matlab.prf’]) that is explained here. […]

#2 Comment By Shaul On February 2, 2011 @ 08:07

Hi Yair,

I work on multiple projects at the same time and I like to have multiple matlab instances open on my computer, one for each project (I realize this might not be a particularly smart way to work). However, I would like each of them to save to a different command window history file. Is there a good safe way to do this?

Thanks! All the best,

#3 Comment By Yair Altman On February 2, 2011 @ 09:54

@Shaul – I do not know a way to customize the history file path

#4 Comment By Paul On May 25, 2011 @ 13:33

Is there a way to programmatically update the Simulink preferences, such as the Autosave option?



#5 Comment By Yair Altman On May 25, 2011 @ 13:38

@Paul – I’m sure there is, but I don’t know…

#6 Comment By Chad Gilbert On January 10, 2012 @ 12:13

Hi Yair,

It seems that after doign this, I need to re-start MATLAB before the changes take effect. Do you know of any better way to make my changes “kick in”?

#7 Comment By Yair Altman On January 10, 2012 @ 12:56

@Chad – there is a com.mathworks.services.Prefs.load() method, but I think it will not help you much because I think that most preferences are loaded and used during startup, not dynamically.

#8 Comment By Jonas On November 14, 2012 @ 15:56

I just learned once more that it’s extremely helpful to programmatically check for the correct “MatfileSaveFormat” property to avoid being unable to save (or later: load) your results. Thanks for your helpful post!

#9 Comment By Oleg Komarov On October 13, 2014 @ 03:08

To change Parallel Pool settings:

ps = parallel.Settings;
ans = 
  PoolSettings with properties:
                            AutoCreate: 0
                RestartOnClusterChange: 1
    RestartOnPreferredNumWorkersChange: 1
                           IdleTimeout: 30
                   PreferredNumWorkers: 12

#10 Comment By Yair Altman On October 13, 2014 @ 04:24

To complete the picture:

>> ps = parallel.Settings
ps = 
 Parallel Settings Information
       DefaultProfile: local

    Profiles and Components: 

             Profiles: [1x1 parallel.settings.Profile]
  SchedulerComponents: [1x1 parallel.settings.schedulerComponent.Local]
    ProjectComponents: [0x0 parallel.settings.ProjectComponent]

>> getundoc(ps)
ans = 
            ConfigsMcrUserDataKey: 'ParallelConfigurationFile'
    ConfigurationsLastUpgradeTime: '???'
    DefaultProfileChangedListener: [1x1 event.proplistener]
          DefaultProfileListeners: [1x2 event.listener]
             DefaultProfileObject: [1x1 parallel.settings.Profile]
           DummyEnforceInitClient: 'BMPA'
                 ImportNameSuffix: '_Import'
         LastUpgradeSettingsLevel: [1x1 parallel.internal.types.SettingsLevel]
                 LocalProfileName: 'local'
            McrUserDataNameSuffix: '_mcruserdata'
                       NodeFacade: [1x1 parallel.internal.settings.SettingsNodeFacade]
                             Pool: [1x1 parallel.internal.settings.PoolSettings]
               ProfilesCollection: [1x1 parallel.internal.settings.NamedNodesCollection]
           ProfilesMcrUserDataKey: 'ParallelProfile'
      ProjectComponentsCollection: [1x1 parallel.internal.settings.NamedNodesCollection]
    SchedulerComponentsCollection: [1x1 parallel.internal.settings.TypedNodesCollection]
         UsingDeployedCollections: 0

#11 Comment By Scott Lowe On November 8, 2015 @ 21:00

Hi Yair,

Thanks for this article!

I took inspiration from it to create a package to import and export color schemes in MATLAB. This definitely would not have been possible without undocumentedmatlab!

It is available on [11] and [12].

All the best,

#12 Comment By jon On May 13, 2016 @ 20:06

Thank you!

#13 Comment By Parvaneh On September 28, 2016 @ 13:59

Hi Yair,

I was looking for a way to change the setting of the system using matlab when I saw this post.
I wonder if you can help me with it.
I’m connecting two monitors and I want to run a program from one monitor and make it run on the other one.
In the process I need to change setting from ‘screen resolution’ in the control panel.
Could this be done with matlab?

I would appreciate any help.


#14 Comment By Yair Altman On September 28, 2016 @ 14:09

@Parvaneh – you will need to check the web for a utility that has a command-line interface that does what you want, and then you can call that utility from Matlab using the system command.

#15 Comment By Mohit On May 22, 2020 @ 15:11

Hi Yair,
I am trying to change keybindings to certain keys for many systems is there any way that we can change these settings.
i can change in window dialogue like Home>Environment>Preferences>keyboard>Shortcuts > then i select shortcut and change ….can we do it through code like above ? I tried many things but didn’t able get it to work

#16 Comment By Robin On October 30, 2020 @ 14:49

Hi Yair,

This has been a great help.
With the removal of com.mathworks sometime in the future (as announced in R2020b), is there an alternative?
For me, just getting a preference value programmatically would be enough. I am not interested in setting them.


Article printed from Undocumented Matlab: https://undocumentedmatlab.com

URL to article: https://undocumentedmatlab.com/articles/changing-system-preferences-programmatically

URLs in this post:

[1] change Matlab’s command-window colors: http://undocumentedmatlab.com/blog/changing-matlab-command-window-colors/

[2] undocumented GUIDE features: http://undocumentedmatlab.com/blog/guide-customization/

[3] CPRINTF utility: http://undocumentedmatlab.com/blog/cprintf-display-formatted-color-text-in-command-window/

[4] on the CSSM forum: https://www.mathworks.com/matlabcentral/newsreader/view_thread/154608

[5] Setting the Matlab desktop layout programmatically : https://undocumentedmatlab.com/articles/setting-the-matlab-desktop-layout-programmatically

[6] Changing Matlab's Command Window colors : https://undocumentedmatlab.com/articles/changing-matlab-command-window-colors

[7] Changing Matlab's Command Window colors – part 2 : https://undocumentedmatlab.com/articles/changing-matlab-command-window-colors-part2

[8] Removing user preferences from deployed apps : https://undocumentedmatlab.com/articles/removing-user-preferences-from-deployed-apps

[9] R2009b keyboard bindings : https://undocumentedmatlab.com/articles/r2009b-keyboard-bindings

[10] cprintf – display formatted color text in the Command Window : https://undocumentedmatlab.com/articles/cprintf-display-formatted-color-text-in-command-window

[11] : https://github.com/scottclowe/matlab-schemer

[12] : http://www.mathworks.com/matlabcentral/fileexchange/53862-matlab-schemer

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