Windows Icon for Rust+CxxQt QML Applications (Taskbar + Window + QML + Tray)

This skill documents the layered approach used by ds-viewer-gui to reliably show the correct icon on Windows across all surfaces (taskbar, Alt+Tab, title bar, in-QML display). The canonical reference implementation is ds-render/ds-viewer-gui.

The Three Icon Layers

Layer 1 — Compile-time Win32 PE resource (reliable, required)

The Icon is compiled directly into the .exe binary using the winresource crate. This is the only mechanism that reliably sets the taskbar button, Alt+Tab entry, and title-bar icon without any runtime file system dependency.

Cargo.toml (build-dependency):

[build-dependencies]
winresource = "0.1"