%% how a DXGI colour space becomes a CAMetalLayer set-up on each present. The layer only changes its tags; no shader converts colour.
flowchart LR
    A["SetColorSpace1<br/>(or the format's default)"] --> B{"colour space"}
    B -- "G22 P709<br/>(sRGB)" --> C["back buffer's format<br/>sRGB colour space<br/>no EDR"]
    B -- "G10 P709<br/>(scRGB, FP16 only)" --> D["RGBA16Float<br/>extended linear sRGB<br/>EDR on"]
    B -- "G2084 P2020<br/>(HDR10, RGB10A2 only)" --> E["RGB10A2<br/>ITU-R 2100 PQ<br/>EDR on"]
    F["SetHDRMetaData(HDR10)"] --> G["CAEDRMetadata HDR10<br/>from H.265 SEI bytes"]
    G --> E
    C --> H["macOS compositor:<br/>colour matching,<br/>tone mapping to the<br/>screen's headroom"]
    D --> H
    E --> H
    I["NSScreen EDR headroom<br/>and P3 gamut"] --> J["GetDesc1: HDR10,<br/>100 nits × headroom"]