Backend Dispatch

Backend dispatch in ritk is designed to be explicit in the type system and cheap at runtime. ritk-image re-exports Atlas backends such as SequentialBackend and MoiraiBackend, while ritk-io binds readers and writers to a chosen backend through types like PngReader<B>, MetaImageWriter<B>, and VtkReader<B>. Deeper in the stack, many filters expose a native host-core path and then reconstruct the same ritk-image::Image boundary, so callers get one public API while the compiler monomorphizes concrete backend implementations underneath.

That matters for Atlas because Coeus is not just a storage detail: it is the execution substrate that lets the same algorithm run deterministically on the sequential backend or in parallel on Moirai. The chapter therefore covers where dispatch is compile-time, where a host extraction is unavoidable, and how the unified read_image_native and write_image_native helpers keep format inference separate from compute choice.

Example Summary