Blurry fonts/bitmaps Win XP guest & Win 10 host

[loukingjr]

Mark, I think I am starting to understand. The article you linked was how to make a Windows 10 guest look better on a Retina screen. By default VirtualBox enables HDPI scaling for Windows 10 guests and you have to explicitly disable it if you don't want that. For example if you aren't using a HDPI display. Parallels on the other hand did not have Retina scaling enabled by default so you had to enable it. All that setting does as near as I can tell, whether in Parallels Desktop, VirtualBox or VMWare Fusion is let Windows 10 know it's running on a HDPI screen and Windows 10 takes care of the rest because, Windows 10 is DPI aware. Legacy programs or Windows XP are not DPI aware so it doesn't matter whether they know they are running on a HDPI screen. The bottom line is Legacy apps just aren't going to look great on HDPI displays. You just have to manually adjust them to your liking.

I think I am getting a blurry brain.

[loukingjr]

In the display settings for your XP guest, try enabling "Use Unscaled HiDPI Output" and a Scale Factor of 200%. see if that looks better to you.

edit: on second thought, don't. It does weird things on a HDPI display.

[Mark Y]

Mark, I think I am starting to understand. The article you linked was how to make a Windows 10 guest look better on a Retina screen. By default VirtualBox enables HDPI scaling for Windows 10 guests and you have to explicitly disable it if you don't want that. For example if you aren't using a HDPI display. Parallels on the other hand did not have Retina scaling enabled by default so you had to enable it. All that setting does as near as I can tell, whether in Parallels Desktop, VirtualBox or VMWare Fusion is let Windows 10 know it's running on a HDPI screen and Windows 10 takes care of the rest because, Windows 10 is DPI aware. Legacy programs or Windows XP are not DPI aware so it doesn't matter whether they know they are running on a HDPI screen. The bottom line is Legacy apps just aren't going to look great on HDPI displays. You just have to manually adjust them to your liking.

I think I am getting a blurry brain.

Sorry that I missed your post yesterday. I did check the thread and I did not realise that it had gone to a second page (at least on my browser).

Most of my legacy apps look good on the 4K display (when DPI scaling is disabled) and one of them (the 1-2-3 spreadsheet program, a program that I still prefer to any version of Excel despite its age) looks just as good as it does in Win 7. (There is one other XP era program that I still like that causes major system stability problems and I will only be able to run it in the Win 7 VM.)

A few posts back you mentioned that you do not see any display problems with a Win XP VM on your laptop. I have a copy of the Win XP VM on my laptop (1920 x 1080, scale factor of 100%) and there are no display issues. I think that the problems only arise with larger displays and scale factors much greater than 100%.

I can not find any options related to HDPI scaling in the settings for either VM. The only optional display settings that I see are related to 3D and 2D acceleration (which I have enabled for the Win 7 VM, but not for the Win XP VM). Is there something that I am missing, or is this something that appears on a Mac host?

I had an issue with installing an update for my Asus video card, where the install program failed before completing the install. One of the suggested fixes was to run the setup program in Compatibility mode for an earlier Windows version, and this solved the problem. I thought this might help with the XP VM so I set the VirtualBox.exe program (the one that opens the VirtualBox Manager) to run in compatibility mode for Windows 7. This seemed to improve the Win XP VM display a bit, but it did not fix the display completely (and the improvement might actually be my imagination). I tried setting all of the exe files in the VirtualBox program directory to run the Win 7 compatibility mode but it did not help (and actually might have made it worse). I have now reset all of these other files to the default (VirtualBox.exe is the only one still running in Win 7 compatibility mode).

I am running out of things to try. At least some of the issues that I see are related to Microsoft's implementation of DPI scaling in Win 10 (e.g. programs being less clear on the smaller, non-primary display has been noted by others, and seems to be due to Win 10 scaling the primary display first, and then doing a second scaling to implement the lower scale factors on the secondary displays). I think that I am going to put in a bug report for VirtualBox. I have not decided whether I should give up on Win 10 for now and go back to Win 7 until Microsoft and/or VirtualBox issue fixes.

[heidl]

Hello Mark,

I just registered because of you and I hope it was worth it

I had the same issues with VB running on an Win8.1 host. The DPI scaling drove me crazy. I am using a Lenovo notebook and usually work docked in with multiple external displays. VB runs normally, crisp and clear on my external display. But when I boot the notebook without any external display attached to it, my VB guest machine looks blurry as hell.

Here's what I did to solve the issue for me:

1. Create a shortcut of your VB client on your desktop
2. Deactivate the DPI-scaling in the compatibility tab of that shortcut
3. Activate the Win7-compatibility mode as well

And now, here's the key thing I found out just a few minutes ago:

4. Once you've booted up without any external displays, you need to shutdown again AND boot one more time. Only then Windows recognizes the DPI settings and deactivates DPI scaling for the VB guest properly (even though the compatibility setting is always active).

Let me know if I could help.

[Mark Y]

Hello Heidl,

Thank you for registering and telling me about this work-around.

I have been busy with other things and I have not checked this thread for a few weeks. (I have now checked the "Notify me when a reply is posted box".)

I had to search for a method to create a shortcut of the VB client on the desktop (there is a method at https://www.virtualbox.org/ticket/2322 if anyone else is looking), checked the Deactivate DPI scaling and Win 7 compatibility boxes and rebooted once.

The Win XP x32 and Win 7 x64 VMs showed a tremendous improvement in sharpness, even at larger scale factors than I could use without the DPI scaling fixed (150% for Win XP and 110% for Win 7, although both are clearer at 125% and 100%, respectively). (I think that the Win 7 VM in particular is being limited by the 256 MB display memory limit.) The text was still a bit rasterized so I rebooted a second time but there was no further improvement.

A few weeks ago I set the DPI scaling for all three displays to 100% as a test. The readability in both VMs was much improved (proving that the DPI scaling is the cause of the blurry fonts/bitmaps), but it was still not as good as for applications running in Win 10. I have not checked thoroughly, but I think that the readability of the VMs with the DPI scaling for all displays at 100% is comparable to what I am now getting with DPI scaling deactivated in the shortcuts. There are a few possible causes for this. Win 10 could still be doing some adjustment to the image (despite telling it to go away) or the image rendering may not be as good for legacy applications as it was for, say, Win 7. Alternatively, the legacy program that I am trying to run is an older version of CorelDraw (a vector graphics program) which, despite being written in the Win XP era, still may need more display memory resources than the VM can provide.

In any case, your post has given me a method to make both VMs usable with a Win 10 host. My next step was going to be to revert from Win 10 back to Win 7 on my laptop (so I could run the legacy programs using one of my displays as an external display). Before I take this step I will work with the VMs with DPI scaling disabled for a while to see if I really need to do this. There is a good chance that the small amount of remaining fuzziness will not be a major issue.

Thanks again,

Mark

[Jonas H]

Hi,

I have two VM's with Windows Server 2008 R2 and Windows Server 2012 R2 respectively which I run in Virtual Box 5.0.20. Recently I got a new host computer with a internal screen with HiDPI 3840 x 2160 which I connect to an external screen with 2560 x 1600. When I start my VM's they get the non existing resolution of 4480 x 2520.

I tried the tips in this thread as follows:

1. Created shortcuts to the VM's and set the Windows 7 compatibility and disabled the scaling on high DPI.
2. Rebooted my *host* without the external screen connected.
3. Started each VM without any scaling in Virtual Box using the internal screen, stopped them and repeated this once more.
4. Shutdown my *host*, connected the external screen and started up again.
5. Started my VM's and they still get the non existing resolution.

Did I miss something in your solution?

Please advise, thanks!

Jonas

[Mark Y]

Hi Jonas,

Executing step 1 of your method (creating shortcuts to the VMs and setting the Windows 7 compatibility and disabling the scaling on high DPI) is about the limit of my knowledge with configuring/customizing the behaviour of VMs.

I am running 3 displays (2560 x 1440, 3840 x 2160 and 1900 x 1200) as one extended desktop. I run the two VMs at a size convenient for the applications that I am running, which is currently 2050 x 1180 for Win XP x32 and 2350 x 1850 for Win 7 x64. If I make the Win 7 VM screen substantially larger I run into memory limitations that slow the display refresh down substantially (I currently have the Aero display enabled as a test, which is a stretch for the video memory maximum of 256 MB).

I do not see the large screen resolution for the VMs that you are seeing and I have no idea what is causing it.

Mark