DPI Awareness, why window client area not scale while dpi changed.

[thegoodtgg]

I am using SDL3 on Windows 11. I don't see why dpi changed, window area not scaled according to dpi. Does I miss anything? It is not same as windows default behaviour.

[slouken]

SDL assumes your application is high DPI aware by default. There's more information on how to handle this situation here:
https://wiki.libsdl.org/SDL3/README-highdpi

[thegoodtgg]

I had read the wiki before the post this issue. It does not help for my confuseness and solve my problem.

When DPI changed, window procedure receive "WM_GETDPISCALEDSIZE" "WM_DPICHANGED" in sequence. When handle "WM_DPICHANGED" event, windows doc suggest to call SetWindowPos, what sdl just did in "src/video/windows/SDL_windowsevents.c“. When SetWindowPos get called, we receive "WM_WINDOWPOSCHANGING" and "WM_WINDOWPOSCHANGED" events in sequence, where client size get actually changed.

Here is the point, when DPI changed or move window from 96 dpi monitor to 144 dpi monitor, SDL would handle "WM_GETDPISCALEDSIZE" "WM_DPICHANGED", it overrided the suggested width and height. For my application, while the window size still was origin size, however all ui element got 1.5 larger. It just looks terriable.

Does SDL intend to override windows default behaviour? I make a commit here to use windows default behaviour.