high DPI display issue in MATLAB R2021a

Result and one-line proposed solution:

User-specific settings, `settings.matlab.desktop.DisplayScaleFactor`in particular, in MATLAB R2021a are not saved in R2021a. This setting seems to be correctly addressed in other versions, such as R2019b (tested) and R2020a (shown in the url below).

Test platform:

MATLAB R2021a on Ubuntu 20.04 LTS (and MATLAB R2019b on the same OS for comparison)

Details:

I found this issue because I was seeking for the high DPI solution for MATLAB R2021a. I found a related question as listed below. I tried the suggested solution, which seems to work perfectly on MATLAB R2020a. However, it does not work on my side.

s = settings;s.matlab.desktop.DisplayScaleFactor
s.matlab.desktop.DisplayScaleFactor.PersonalValue = 2

At first, I thought it might be the OS, since I am using the relatively new fractional scaling feature of Ubuntu 20.04 to better use 4K monitors. Out of curiosity, I tried R2019b on the same computer and it worked perfectly. Then I realize that the issue might be that R2021a forgot to write the display factor setting to the user directory (instead of global setting which requires sudo in Linux because I do not need sudo to change this setting). Then I compare `~/.matlab/R2021a` and `~/.matlab/R2019b` and eventually found that in `matlab.mlsettings/fsroot/settingstree/matlab/display/settings.json`, new setting `DisplayScaleFactor` was not saved. By comparing it with the value in `~/.matlab/R2019b`, I added

{"attributes":{"readonly":false,"runtimeDefaultFcn":{},"settingValueValidator":{},"validationFcn":{},"visible":true},"hasValue":true,"isUserDefined":false,"isVector":false,"name":"DisplayScaleFactor","value":"2"}

in the settings string and save it, it turned out to be solved perfectly.

Related question:

https://askubuntu.com/questions/1262836/why-are-some-gui-fonts-so-small-in-ubuntu-20-04-how-can-i-fix-them

https://wiki.archlinux.org/title/HiDPI#MATLAB

[Rubem Pacelli]

I am on Linux mint and I haven't found the path

matlab.mlsettings/fsroot/settingstree/matlab/display/settings.json

In the matlabR2021a. The correct path that seems to correct was

matlab.mlsettings/fsroot/settingstree/matlab/editor/displaysettings/

which already had a "DisplayScaleFactor" in the JSON file. Changing this value leads to the desired result. Regardless, the command line

s = settings;s.matlab.desktop.DisplayScaleFactor
s.matlab.desktop.DisplayScaleFactor.PersonalValue = 2

Already solved (partially, at least) the problem after you restart the matlab. Most of the font is corrected, but other windows (such as the "help -> about MATLAB" or the scope window) still very tiny... Do you know how to fix it?

[Emanuele Russomanno]

Hi,

what that path is supposed to be?

Should I find a folder named `matlab.mlsettings` inside `~/.matlab/R2022b`?

[Ahmed Riza]

There is no such folder in R2022b and I also have the same problem. Can't find a way to get hidpi working on a Fedora 36 Linux laptop! Very annoying.

[Johannes Anastasiadis]

Hi.

I had the same problem on Fedora 37 with R2022b.

I found the setting at matlab.mlsettings/fsroot/settingstree/matlab/desktop/settings.json . It was already there with scaling factor 1. Maybe because I tried

s = settings;s.matlab.desktop.DisplayScaleFactor
s.matlab.desktop.DisplayScaleFactor.PersonalValue = 2

before. I just had to change DisplayScaleFactor it to 2 and it worked.

@Emanuele Russomanno it is a zipped folder called matlab.mlsettings inside of ~/.matlab/R2022b. I had to unzip it, make the change, zip it again and rename it. Possible error: when zipping again a root folder named matlab can appear inseide the zip file. Duouble check if the structure of the file is exaclty as before. Backup the original file for that purpose.