Problem with screen scale factor > 100%

Hello Pierre-Jean,

The observed behavior is caused by the application which suddenly becomes DPI-aware because of the increased Windows scaling. Creating PDF files will result in initiating a type from our Document Processing Libraries. These libraries internally reference WPF types. WPF in contrast to WinForms is DPI-aware technology by design and accessing such types at run-time will make you WinForms application DPI-aware which will cause scaling as the one observed by some of your users. We have a blog post discussing this in details: https://www.telerik.com/blogs/winforms-scaling-at-large-dpi-settings-is-it-even-possible.

In order to resolve this you have two options: 

1. Develop your WinForms application to be DPI-aware. This way it will scale properly when it is run on systems having high DPI. Using the PdfViewer control will not cause additional scaling as the application would have been scaled on startup. We have introduced HDPI support in the suite and you can enable it by following the instructions in this documentation article: https://docs.telerik.com/devtools/winforms/telerik-presentation-framework/dpi-support.
2. Do not create a DPI-aware application and avoid the observed scaling. The only way to prevent this is to use the approach suggested in the blog post. Please refer to the DPI Awareness and Document Processing Libraries section.

I hope this will help. Let me know if you have other questions.

Regards,
Hristo
Progress Telerik

Hello Hristo

thank you for your reply.

I have tried to follow the instructions of:

https://docs.telerik.com/devtools/winforms/telerik-presentation-framework/dpi-support 

and I still have the same problem.

Here are the extracts of my app.config and my app.manifest file, as far as I can see they match the referenced link

All my forms have the property autoscalemode set to None

I may be missing something but I fail to see what ...

Thanks in advance for your advice

Best regards

Pierre-Jean

--------------------------------------------APP.CONFIG -------------------------------------------------------

  <startup>
    <supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.8" />
  </startup>
  <System.Windows.Forms.ApplicationConfigurationSection>
    <add key="DpiAwareness" value="PerMonitorV2" />
    <add key="DisableDpiChangedMessageHandling" value="True" />
  </System.Windows.Forms.ApplicationConfigurationSection>

-----------------------------------------------------APP:MANIFEST--------------------------------------------------------

<?xml version="1.0" encoding="utf-8"?>
<assembly manifestVersion="1.0" xmlns="urn:schemas-microsoft-com:asm.v1">
  <assemblyIdentity version="1.0.0.0" name="MyApplication.app"/>
  <compatibility xmlns="urn:schemas-microsoft-com:compatibility.v1">
    <application>
      <supportedOS Id="{8e0f7a12-bfb3-4fe8-b9a5-48fd50a15a9a}" />
    </application>
  </compatibility>
</assembly>

--------------------------------------------------------------------------------------------------------

Hi Pierre-Jean,

It looks like that you have declared the application as dpi-aware. In that case, the app should scale once upon startup or when you move a window to a screen with different DPI. Opening a document in the PdfViewer should not cause any additional scaling.

From your last post, I understand that you are still having the issue. It may be caused if the DPI awareness is not declared properly. Please note however, that the app.config and manifest files you shared are suitable for .NET 4.7 and Windows 10 Creators update. In case it is not working on you end, you can also try setting the DPI awareness using only the manifest file as per the documentation article: https://docs.telerik.com/devtools/winforms/telerik-presentation-framework/dpi-support#how-to-enable-hdpi-support-in-your-application.

In case you don`t to want to make the application DPI aware, you can use the approach with the native dlls as per the DPI Awareness and Document Processing Libraries in the article here: https://www.telerik.com/blogs/winforms-scaling-at-large-dpi-settings-is-it-even-possible-. 

I hope this will help.

Regards,
Hristo
Progress Telerik