Master Makepad Cross-Platform Development

The skill covers Makepad cross-platform development: understanding supported platforms and backends, and writing platform-specific code via conditional compilation and platform APIs. It documents eight platform targets with their graphics backend and OS module: macOS (Metal, apple/metal_*.rs/apple/cocoa_*.rs), iOS (Metal, apple/metal_*.rs/apple/ios_*.rs), Windows (D3D11, mswindows/d3d11_*.rs/mswindows/win32_*.rs), Linux (OpenGL, linux/opengl_*.rs/linux/x11*.rs/linux/wayland*.rs), Web (WebGL2, web/*.rs/web_browser/*.rs), Android (OpenGL ES, android/*.rs), OpenHarmony (OHOS, open_harmony/*.rs), and OpenXR (VR/AR, open_xr/*.rs).

Runtime platform detection uses an OsType enum, quoted verbatim from the source:

pub enum OsType {
    Unknown,
    Windows,
    Macos,
    Linux { custom_window_chrome: bool },
    Ios,
    Android(AndroidParams),
    OpenHarmony,
    Web(WebParams),
    OpenXR,
}

checked via cx.os_type() inside an event handler's match statement, alongside other Cx methods (gpu_info(), xr_capabilities(), cpu_cores()). Compile-time detection instead uses #[cfg(target_os = "...")] attributes for macOS, Windows, Linux, Android, and iOS, and #[cfg(target_arch = "wasm32")] for web.

Platform-specific feature groups are named explicitly: desktop (macOS/Windows/Linux) gets window management, file dialogs, a system menu, drag and drop, and multiple monitors; mobile (iOS/Android) gets touch input, a virtual keyboard, screen orientation, and app lifecycle (foreground/background) handling; web (WebGL2) gets DOM integration, browser events, local storage, and HTTP requests. The app entry point uses an app_main!(App) macro with the app struct implementing LiveRegister (to register components via live_design(cx)) and AppMain (to route events to the UI's handle_event). Five rules guide platform-code answers: Makepad compiles to native code per platform with no runtime interpreter, shaders are compiled at build time per graphics backend, platform-specific code lives in platform/src/os/, cx.os_type() is for runtime detection, and #[cfg(target_os = "...")] is for compile-time detection. Before answering, the skill must read references/platform-support.md; if that file is missing or empty it tells the user to run /sync-crate-skills makepad --force to update the local docs, then falls back to SKILL.md patterns and built-in knowledge.

Use it when targeting or understanding specific platforms and graphics backends in Makepad, when platform compatibility, conditional compilation, or OS-specific behavior across desktop, mobile, or web needs handling, or when backend differences between Metal, D3D11, OpenGL, and WebGL matter.

Input is a platform-targeting or compatibility question (which backend a platform uses, how to detect the platform at runtime or compile time, which features are available on a given platform). Output is the relevant platform table entry, OsType/cfg code pattern, or feature list, incorporating references/platform-support.md when available.

Makepad developers writing cross-platform UI code who need to know which graphics backend and OS module a target platform uses and how to branch code correctly between them.