Webview2 Not Scaling on High DPI monitor when gdiScaling is true

[veevandyke]

Description
I have a form on which I was using the old webbrowser control. Support is going away, so I am upgrading to the new webview2 control. My entire app is scaling properly (on high DPI monitors) using these settings in the app.manifest:

  <asmv3:application>
    <asmv3:windowsSettings xmlns="http://schemas.microsoft.com/SMI/2017/WindowsSettings">
      <dpiAware xmlns="http://schemas.microsoft.com/SMI/2005/WindowsSettings">true/pm</dpiAware> 
      <!-- legacy -->
      <dpiAwareness xmlns="http://schemas.microsoft.com/SMI/2016/WindowsSettings">permonitorv2,permonitor</dpiAwareness>
      <gdiScaling>true</gdiScaling>
    </asmv3:windowsSettings>
  </asmv3:application>

Here's the problem: My webview2 control is NOT scaling. (Monitor scaled at 200%.) So when I open the form on my high DPI monitor, the webview control takes up about 25 of the total form, even though it's docked to take up the entire form. If I move the form to my non-scaled monitor, it displays properly. I tested the size of the webview control and even though it's taking up 25% of the form, the actual pixel size is the same as the form. (Form is 1200x800, Webview control is 1180x760.)

What do I need to do to make this display properly on a scaled monitor?

Version
SDK: 1.0.902.49
Runtime: 92.0.902.84
Framework: WinForms
OS: Win10

Repro Steps
Create a windows form. Place a webview2 control on the form. Dock or Anchor form. Open form on a scaled monitor. Note that I can repro the images below by simply dragging the form from one window to the other. It doesn't matter which monitor is primary/secondary or even IF there is a secondary monitor. Issue persists when there is only one monitor and it is scaled.

Screenshots
Scaled monitor:

Unscaled Monitor

AB#35684950

[liminzhu]

@veevandyke thanks for opening the bug, I'm adding a tag to track this internally. Do you happen to also have a small repro app that we can debug with?

[xblack0]

hope this could help

[veevandyke]

I do have that setting in my app.config.

After further testing, it's specifically the GDIscaling=true settings in the manifest that's causing the issue with the WebView2. Changing that to false (or removing it) causes the WebView2 to scale appropriately, however, then the rest of the app is NOT scaled.

[veevandyke]

@liminzhu I have a scaled down version of my app that you can use to test. (Vb.net unfortunately, but that's what I inherited.) How would you like me to send it to you? (Can't attach a zip here.)

[leaanthony]

Added a similar question here. One extra thing to add to this is that it seems when I use a manifest, WebView2 doesn't respect the correct client area (though I'm open to the fact it may be an issue on my side):
Without Manifest:

With Manifest:

Manifest used:

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<assembly manifestVersion="1.0" xmlns="urn:schemas-microsoft-com:asm.v1" xmlns:asmv3="urn:schemas-microsoft-com:asm.v3">
    <assemblyIdentity type="win32" name="MyApplication" version="1.0.0.0" processorArchitecture="amd64"/>
    <dependency>
        <dependentAssembly>
            <assemblyIdentity type="win32" name="Microsoft.Windows.Common-Controls" version="6.0.0.0" processorArchitecture="*" publicKeyToken="6595b64144ccf1df" language="*"/>
        </dependentAssembly>
    </dependency>
    <asmv3:application>
        <asmv3:windowsSettings>
            <dpiAware xmlns="http://schemas.microsoft.com/SMI/2005/WindowsSettings">true/pm</dpiAware> <!-- fallback for Windows 7 and 8 -->
            <dpiAwareness xmlns="http://schemas.microsoft.com/SMI/2016/WindowsSettings">permonitorv2,permonitor</dpiAwareness> <!-- falls back to per-monitor if per-monitor v2 is not supported -->
            <gdiScaling xmlns="http://schemas.microsoft.com/SMI/2017/WindowsSettings">true</gdiScaling> <!-- enables GDI DPI scaling -->
        </asmv3:windowsSettings>
    </asmv3:application>
</assembly>

With the gdiScaling line removed, the app doesn't even run.

[xblack0]

can you try my application using your current setup, is it work ok & scaling ok
smart-andromeda.com

[veevandyke]

@leaanthony - mine is the same. If I change the manifest to gdiscaling = false, then the rest of my app doesn't scale correctly, but the webview2 fills the entire form. Interestingly, the sample app seems to work fine, so I'm certain there is something I am missing on my end.

[champnic]

@veevandyke @leaanthony My understanding of the GDI Scaling manifest property is that it enables GDI to scale properly, but disables other DPI scaling By Design:
https://blogs.windows.com/windowsdeveloper/2017/05/19/improving-high-dpi-experience-gdi-based-desktop-apps/

We'll look into whether we can ignore the GDI Scaling setting within the WebView2, so that it would only take effect for the app.

Just want to confirm - If you disable GDI Scaling and try one of the other DPI awareness modes for you app, your app UI still doesn't scale properly, correct? https://docs.microsoft.com/en-us/windows/win32/hidpi/high-dpi-desktop-application-development-on-windows?redirectedfrom=MSDN

[leaanthony]

At least for me, it's hard to tell as all my monitors are hiDPI. I do recall that the label that appears when resizing showing width and height looked blurry but i'd need to investigate more tomorrow. Thanks for your help on this!

[veevandyke]

@champnic - Correct. I need GDI scaling to make the REST of my app scale properly in High DPI situations. But it breaks the scaling on the WebView2. I have a scaled down sample app that I created, but I couldn't attach a zip file to this thread. If you want to use it to test, I'm happy to upload somewhere. Just let me know.

[champnic]

@veevandyke The easiest is probably to upload to the cloud somewhere (like OneDrive, DropBox, etc.) and send me the link at champnic@microsoft.com. Thanks!