Blurry fonts/bitmaps Win XP guest & Win 10 host

[Mark Y]

STUB TOPIC AT MODERATORS REQUEST

This is my first post (switched from Windows 10 hosts at the moderator's request). I have Googled extensively and searched the site and not found a solution.

I am using VirtualBox Ver 5.0.12 in a Win 10 host with Win XP x32 and Win 7 x64 guests.

I have been using the Win XP guest for several years with a Win 7 x64 host to be able to run 32 bit programs that would not run in Win 7 x64. I created the Win 7 x64 guest just before I upgraded the Win 7 host to Win 10 a week ago (to be able to run a few older programs that work OK in Win 7 but have issues in Win 8/10). Both guests open properly with the Win 10 host.

I am working with several displays (with different resolutions) and the main reason for upgrading to Win 10 was too be able to use different DPI scaling for text, apps, etc. for each display. However, Win 10 tries to scale every program to the display size and this can produce blurry fonts for legacy programs (see: http://blogs.technet.com/b/askcore/arch ... ws-10.aspx). There are many posts on blurred text in Win 10, and the recommended solution is to go to the Properties for the program exe file, and under Compatibility check the option to Disable display scaling on high DPI settings (e.g.: http://www.addictivetips.com/windows-ti ... indows-10/). This does remove most display problems for older (so called "scaling unaware") programs when there is a specific exe file to adjust.

The problem is that the desktop and programs in the Win XP x32 guest have blurry, hard to read fonts, muddy bitmaps (e.g. cards in the Solitare program) or lines that are fuzzy (e.g. in XY graphs). The display issues seem not to be as bad for the Win 7 x64 guest, but I have not tested it extensively. I also have several legacy programs installed in the Win 10 host that show the same display issues until I start them with "Disable display scaling on high DPI settings" checked.

The problem with the Win XP x32 guest arose when I upgraded to Win 10. The Win XP guest has been running in Win 7 x64 for several years with no display (or other) problems. The degradation in display quality between Win 7 and Win 10 hosts is quite dramatic, and I would have difficulty working with the XP guest for any length of time. With a Win 7 host I can apply different View scale factors to the guest and the text/bitmaps are easily readable. With the Win 10 host the fonts are blurry whatever scale factor I use with the VM (or size of the display that I move the VM to).

Scale mode is not enabled in the Win XP x32 guest (and I get the same display problems with it enabled). MPack asked whether Guest Additions were installed. I am pretty sure that I installed the Guest Additions when I first set up the Win XP x32 guest a few years ago. I just did a (re-)install of the Guest Additions and it does not change anything. The Extension pack is installed.

I have checked the option to "Disable display scaling on high DPI settings" for every exe file in the directory with the VirtualBox program files and it does not solve the display problem for the Win XP guest. None of the files associated with the virtual machines have a Compatibility tab in the Properties and I have not been able to find a way to alter the DPI settings for either VM.

I think that fixing this issue is going to require a new option in the Guest settings in the VirtualBox Manager. However, I hope that someone can suggest a workaround and I would appreciate any suggestions for a fix.

I have attached a copy of the VBox log for the Win XP x32 guest.

Thanks,

Mark

[loukingjr]

Mark, could you attach a section of a screen shot that demonstrates the image issues you are having?

thanks.

[Mark Y]

Mark, could you attach a section of a screen shot that demonstrates the image issues you are having?

thanks.

I have attached a screenshot showing the XP desktop, a peak in a mass chromatogram (a program that I really need and will only run in 32 bit XP) and a Solitaire game (to show bitmaps). I had to make the VM a bit smaller than I normally use to make the screenshot small enough to upload.

Relative to what I was seeing last week with the same virtual machine running in a Win 7 x64 host, the text below the icons on the desktop is blurry and more difficult to read, the line defining the peak in the chromatogram is fuzzy and the text on the y-axis is harder to read, and the face cards in the Solitaire game are muddy and poorly resolved.

If I move the VM from one screen to another, the VM appears best on the primary (largest) screen and is more fuzzy on the two smaller screens (it is worst on the smallest screen). However, even on the primary screen the resolution is far worse than with a Win 7 host.

And now that I have taken a screen shot, I notice that if I put the XP VM side by side with the png file screen shot image of the XP VM in Windows Photo Viewer, the image is clearer (sharper text, chromatogram peak and bitmap) in the Windows Photo Viewer.

So the fact that there are noticeable differences in the appearance of the XP VM between different size display screens and that Windows Photo Viewer (presumably a "scale aware" program, since it comes with Win 10) is able to make a screen shot look better than the actual VM, suggests the the problem is Win 10 trying to adjust the DPI scaling for the Win XP VM.

This is why I suggested that the fix was a way to tell Win 10 to "Disable display scaling" for the virtual machine. (And why I posted in the Windows 10 hosts forum initially.)

Thanks,

Mark

[Mark Y]

And now that I view my last post in a Firefox browser (where I am running the program with Display scaling disabled), the png file screen shot looks much clearer than the same image in the Photo Viewer or in the Win XP VM.

I think that this confirms that the problem is due to Win 10 scaling a legacy program that was never designed for it.

Mark

[loukingjr]

Thanks for posting the screen shot. It does look clear here as well and I'm not using a Windows host. My XP guest running on an iMac 5K Retina screen looks much the same as your screen shot. I think part of the problem is Windows XP is not DPI aware. i could be wrong of course. I sometimes am.

[mpack]

I think that this confirms that the problem is due to Win 10 scaling a legacy program that was never designed for it.

I don't believe that logic works, at least not with the information given. A screenshot captured by the guest is never scaled, so obviously won't be affected by scaling.

Was this screenshot captured by the guest or the host? If a screenshot captured by the host shows the guest window in sharp detail, then you can be sure that you have a host display problem.

p.s. I'm confused: I asked you to create a stub topic (so that it would have you as the author), then I'd move the off topic posts to it. Did you mark this as a stub topic and then provide the text as well?

[Mark Y]

I think that this confirms that the problem is due to Win 10 scaling a legacy program that was never designed for it.

I don't believe that logic works, at least not with the information given. A screenshot captured by the guest is never scaled, so obviously won't be affected by scaling.

Was this screenshot captured by the guest or the host? If a screenshot captured by the host shows the guest window in sharp detail, then you can be sure that you have a host display problem.

p.s. I'm confused: I asked you to create a stub topic (so that it would have you as the author), then I'd move the off topic posts to it. Did you mark this as a stub topic and then provide the text as well?

mpack,

I have no experience on this site (and almost no experience with online forums). The phrase "stub topic" means nothing to me. I understood that you wanted me to post to another forum on the site, so I re-posted the original query with edits to make things clearer (particularly in response to your comments) and to add the urls that bounced the message the first time because I had been a member for less than one day. My apologies if this is not what you wanted.

The screenshot was captured by the guest. I have only one week experience with Windows 10, but there are a lot of posts related to blurry fonts/display due to DPI scaling of a legacy program by Win 10. If I remember correctly, some of these posts mentioned that text printed OK but it was hard to read on the screen. So this does not rule out a host display problem.

In the Windows 10 registry at HKEY_USERS\S-1-5-21-866679635-3297970986-4144722677-1000\SOFTWARE\Microsoft\Windows NT\CurrentVersion\AppCompatFlags\Layers
there is a list of the full path for all of the program files where I have disabled DPI scaling. (The Data value for these entries is ~ HIGHDPIAWARE.)

If I can find out the name (and path) that Windows uses for the Win XP x32 guest, I should be able to create a new key for the program with this data value. If this fixes the problem then we know that the VirtualBox Manager needs an option to enable this registry setting for Win 10 host VMs.

Thanks,

Mark

[mpack]

If I can find out the name (and path) that Windows uses for the Win XP x32 guest

You presumably need the software path, not the path to the VM data.

The software path is common to all VMs and on Windows hosts is "C:\Program Files\Oracle\VirtualBox".

[loukingjr]

FWIW, I have an ASUS Zenbook with a 13.3"- 1920x1080 non-HDPI screen running Windows 10. I cannot seem to make a Windows XP guest look blurry. As I mentioned before, XP is not DPI aware. In other words, it is always at 96 DPI no matter what the DPI of the monitor is. I think the issue is when XP is used on a HDPI screen and various scaling artifacts that can only be minimized.

[mpack]

I can't see how the DPI issue is relevant - XP has a virtual monitor and can't see the display size or resolution of the host.

XP doesn't run on the host, VirtualBox does. So it is VirtualBox which has to be compatible with a high DPI host... and I'm still not convinced that it isn't. After all, VBox has had to cope with high DPI displays on some OS X hosts for some time now.

[loukingjr]

Perhaps the scaling used by VirtualBox for Windows 10 isn't as good as it is for OSX? Beats me. But XP looks fine on my OSX Retina displays.

[Mark Y]

If I can find out the name (and path) that Windows uses for the Win XP x32 guest

You presumably need the software path, not the path to the VM data.

The software path is common to all VMs and on Windows hosts is "C:\Program Files\Oracle\VirtualBox".

Disabling display scaling for the VirtualBox.exe file was the first thing that I tried. It makes the text and icons in the VirtualBox Manager easier to read, but it does not affect the display of the XP Virtual Machine. As I mentioned in my initial post, I have also disabled scaling for every exe file in the C:\Program Files\Oracle\VirtualBox directory.

I just searched the registry again and I did not find a reference to the name of either VM.

[Mark Y]

FWIW, I have an ASUS Zenbook with a 13.3"- 1920x1080 non-HDPI screen running Windows 10. I cannot seem to make a Windows XP guest look blurry. As I mentioned before, XP is not DPI aware. In other words, it is always at 96 DPI no matter what the DPI of the monitor is. I think the issue is when XP is used on a HDPI screen and various scaling artifacts that can only be minimized.

I am running 3 displays in Win 10 with different scale factors: 3840 x 2160 (4K) with a scale factor of 150%, 2560 x 1440 with a factor of 125% and 1920 x 1200 with a factor of 100%. All scale factors are the ones recommended by Windows for the display. They are all NEC wide gammut displays and are colour calibrated. Both the Win XP x32 and and Win 7 x64 VMs look clearest on the 4K display, a little less clear on the middle display, and are fuzziest on the smallest display. The differences between displays for each VM are noticeable but not really dramatic (you have to look close to see them). The biggest difference is between the quality/clarity of the the XP VM relative to the Win 7 VM.

Before I upgraded to Win 10 I was running the Win 7 x64 host at a scale factor of 125% (Win 7 scales every display the same). I usually run the Win XP VM on the 2560 x 1440 display (where the scale factor is 125% in Win 10), so I expected everything to look the same when I upgraded.

A couple of days ago I rebooted the computer into Win 7 again (I copied the latest Win 7 backup to a spare hard drive). The Win XP x32 looked clear and readable on the 2560 x 1440 display with scale factors of 100% and 125% in the VM (View-Scale Factor), so it is not my imagination.

Most of the posts on blurry fonts in Win 10 are by people running displays at scale factors substantially larger than 100%. Win 10 handles scaling very differently than in previous versions, by adding an expectation that every app (program) should be able to be scaled from the size of a smartphone to a 5K display, and then applying its idea of the optimum scaling based on the display size and scale factor. This is a definite challenge for a legacy program (see the first url in my initial post), which is why the option to disable all of this is needed.

Should I be posting this as an issue that needs to be looked at by the programmers?

Thank you all for your comments and suggestions.

Mark

[loukingjr]

Mark, it sounds like you're suggesting VirtualBox includes a setting to "hack" how Windows 10 behaves. I doubt that will ever happen.

[Mark Y]

Mark, it sounds like you're suggesting VirtualBox includes a setting to "hack" how Windows 10 behaves. I doubt that will ever happen.

Loukingjr, thanks for your continued input.

Searching for DPI scaling/blurry fonts and Windows 10 turned up a lot of posts about a program called Parallels (which seems to be a VirtualBox type program for the Mac). The Parallels program appears to have additional settings for the video/display settings to accommodate high resolution displays and the display scaling behavior of Windows 10 (e.g. see: http://www.nextofwindows.com/how-to-fix ... retina-mac or Google "parallels blurry fonts").

I have several legacy programs that initially looked terrible (blurry hard to read text, etc) when I first opened them in Windows 10. All of these problems disappeared when I checked the Compatibility setting "Disable display scaling on high DPI settings" and the programs are all now usable without eye strain. I am asking for a way to enable this setting in the registry for Guests running in a Win 10 host (so Win 10 does not try to "improve" the displayed image) and I think that this could be enabled as an additional option in the Display section of the Settings.