Horizon Client external monitor scaling problem on MacOS

[hmoazed]

I have a 13" M1 MacBook connected to a 38" external display with a resolution of 3840x1600.

I wish to use both displays on the remote Windows 10 (21H2) computer.

When using Horizon 5.0.0 everything displays fine (there is some blurriness due to subpixel rendering not working but it is not so bad).
When using Horizon 5.5 through the lates 8.3.1 the external monitor looks horrendous and is not usable, the text and icons seems to be getting scaled, even though the resolution reported on the remote Windows 10 machine is the same as the native resolution of the monitor (3840x1600). I suspect the DPI matching is causing poor scaling, or something of that sort.

The same issue does *not* appear when using 8.3.1 on Windows, connecting to the remote Windows machine, so this is a MacOS only issue.

I spent over 3 hours trying different Horizon versions and configuration settings (single monitor setting with just the external monitor, specifying the resolution) as well as the settings on the MacBook (different scaling) but nothing worked, no setting results in a usable external display.

Using a smaller external monitor with a lower resolution doesn't seem to exhibit the same issue. Again, this might be due to the DPI matching mechanism.

Has anyone found a workaround or a fix? If it is indeed the DPI matching mechanism, is there any way to disable it? I really don't care if my window sizes don't match when dragged across monitors, I just want to be able to see text clearly on the external monitor,

[YunYiQun]

Hi,

What's your agent version? Is it 7.x or 8.x?

If it's 7.x, it doesn't support DPI sync per monitor.

Suggest upgrading to 8.x agent.

But it's weird that you said 8.3 Windows client doesn't have the same issue.

Could you provide client&agent trace level logs?

[hmoazed]

Hi, sorry for the late reply, I didn't realize anyone had replied to my post until now.

I'm using either 13" or 16" M1 MacBook Pro running Ventura.

I have an external monitor with 3440x1600 resolution (side note: I noticed this resolution is not listed in the Horizon display resolution dropdown menu).

If I use Horizon in windowed mode it works fine, the Windows remote desktop I connect to reports the resolution as 3440x1537, which is correct as the vertical resolution is reduced by the title bar at the top of the window). 

If I then switch to fullscreen mode, the Windows remote desktop I connect to reports the resolution as 3440x1600 which is also correct, but the displayed desktop looks horrible with major scaling artifacts.

I have attached two screenshots that demonstrate the issue, one in windowed mode and one in fullscreen.

I will attach logs in a minute.

[hmoazed]

Where are the log/trace files located please? Do I need to do something to trigger logging or trace?
I'm running version 2212, build 8.8.0 (21070757)