Handle runtime change of DPI (text size) on Windows 10

Question

On Windows 10, the system no longer requires restart (logoff/logon) to change DPI (text size).

My application is not ready for such a runtime change.

How does system inform an application that the DPI is changing? What message should I handle?

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I'm using C++ Builder, so I'm looking for a pure WinAPI solution, no WinForms.

Answer 1

Since C++ Builder 10.3 you can use these form events:

• OnAfterMonitorDpiChanged
• OnBeforeMonitorDpiChanged

Of course you also need to set DPI Awareness to PerMonitorV2 in the application manifest in the project settings.