react-native-windows
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microsoft
Remove assumptions that XamlRoot::Content() matches Window size
Problem Description
There are at least two callsites that assume that the XamlRoot Size or the ActualSize of the XamlRoot::Content matches the size of the XAML Islands HWND:
- https://github.com/microsoft/react-native-windows/blob/003602b90aeda1b2a43702c6a9307c0f01010e59/vnext/Microsoft.ReactNative/Modules/LogBoxModule.cpp#L48-L54
- https://github.com/microsoft/react-native-windows/blob/cc7095ce487625a9a0a9b99b4b8df4043698eb78/vnext/Microsoft.ReactNative/Modules/AlertModule.cpp#L67-L85
While this is generally a good assumption, this may not always be the case. For example, in our app, we've worked around a XAML Islands bug https://github.com/microsoft/microsoft-ui-xaml/issues/2101 by making the root Grid larger than the HWND by a factor equivalent to the DPI scale factor.
Steps To Reproduce
There's no immediate repro in this repo, but one way to repro is to try and build a drag and drop handler for a XAML Islands react-native-windows app, and see that the full window is not a valid drop target for high DPI scale settings.
Expected Results
React Native Windows may want to assume that the root level content or XamlRoot matches the HWND size by default, but we should allow apps to override this behavior with a "window sizing root" target element that does match the window size.
CLI version
npx react-native --version
Environment
npx react-native info
Target Platform Version
No response
Target Device(s)
No response
Visual Studio Version
No response
Build Configuration
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Snack, code example, screenshot, or link to a repository
No response
Discussed a bit in triage, several possible options/concerns. Alert module should support both Win32 style modal dialog as well as the UWP style (smoke screen). Needs design. @stmoy ?
@rozele I think the PR description has an incomplete sentence:
As such, we need to
