Windows (XAML)

windows-xaml hosts Windows’ own XAML controls in a plain Win32 window through XAML Islands. There is no framework runtime for your users to install.

HomeControlsDate & timeGrid

Which XAML. This backend uses system XAML — the Windows.UI.Xaml stack that ships inside Windows 10 and 11 — not WinUI 3 / the Windows App SDK. That is why the target is named windows-xaml rather than after a XAML release: many control names exist in both namespaces with different behavior (this ProgressRing is the UWP dotted ring, not WinUI 3’s arc; Pivot doesn’t exist in WinUI 3 at all). The links below point at the UWP Windows.UI.Xaml API reference accordingly.

Getting started

You need the Visual Studio C++ Build Tools (for MSVC and the Windows SDK) and the MSVC Rust toolchain. The C++/WinRT shim is compiled by build.rs against the plain Windows SDK.

rustup default stable-msvc
cargo install day-cli
day new app my-app --toolkit windows-xaml
cd my-app
day launch -p windows-xaml

day doctor --toolkit xaml checks the SDK and toolchain.

day pack -p windows-xaml     # .msix plus an NSIS -setup.exe

The NSIS installer is per-user: no elevation, a normal Add/Remove Programs entry, and a silent /S mode for managed deployment.

Caveats and special considerations

• Less real-application use than the Apple, Linux, and Android targets. It builds and runs the full UI walkthrough in CI on every push, but no large app ships on it yet.
• The web view needs the WebView2 Runtime. Day hosts a WebView2 composition visual — not the legacy EdgeHTML WebView. The runtime ships with Windows 11 and current Windows 10; if it is absent, the piece shows its URL-label fallback instead of failing.
• No native segmented control exists in system XAML, so picker().segmented() is a horizontal row of radio buttons.
• The inline time picker falls back to a flyout — system XAML has no inline clock.
• Text-area read-only, selectable and spell-check patches are accepted but do nothing; those capabilities report unsupported.
• No Lottie, no map on this backend — each renders its placeholder. cover() presents as a topmost window-sized child (no transition, programmatic dismissal only).
• Radial gradients in a canvas are synthesized into a bitmap brush, because system XAML has LinearGradientBrush but no RadialGradientBrush (that type is XAML-only).

What each piece becomes

Text measurement is XAML’s own measure pass (Measure → DesiredSize), with a re-measure after forcing layout when a templated control reports zero before the island’s first async pass.