Snowland Desktop Renderer

Snowland is a custom desktop background renderer, similar to Wallpaper Engine - but way more primitive. The project developed as a fun idea and interest in drawing on the Windows wallpaper without overriding the icons. At the moment Snowland implements a very basic rendering module system and a GUI written using ImGui-rs.

See the chapters below for instructions on building and usage.

Supported platforms

• Windows
• Linux

Building Snowland

Snowland is written in Rust and thus requires the Rust toolchain in order to build. It is recommended to use Rustup for managing the Rust toolchain. The required toolchain version can be found in the rust-toolchain file, cargo should automatically download the correct toolchain though when first running it inside the project.

After Rust has been installed building and running Snowland is straight forward and not different from any other Rust program:

cargo build # Create a debug build in target/debug
cargo run   # Build and run snowland

To create a release build do the following:

cargo build --release

The resulting binary can be found in target/release, look for a file called snowland-system-host, where system is the name of the operating system you are on.

Project structure

The Snowland project structure is split into multiple parts:

• universal - The snowland core implementation, OS independent
• win-host - Windows specific implementation, responsible for bootstrapping on Windows

The *-host modules contain the main function and are executables, whereas the universal module is a library which then is linked into the *-host modules.

Inner Workings

universal

The universal library provides the core drawing routines and hosts the user interface as well as configuration management. It uses Skia with the help of skia-safe to perform the actual drawing without knowing about the rendering library.

win-host

The win-host executable provides the entry point and shell integration on Windows. The shell integration consists of a simple system tray icon and the code responsible for acquiring a drawing context on the desktop background.

The Windows shell (specifically explorer.exe) provides an undocumented window message for separating the desktop icons and desktop background into separate windows. Snowland uses this message to first perform this split and then acquires a window handle to the freshly created background window. With the help of WGL (the Windows OpenGL implementation) an OpenGL context is created and then passed to a new Skia context. From here on the universal library takes over the Skia context and performs the common drawing routines.

See here (WebArchive version) for more details on drawing behind the desktop icons.