HDR colormap — gain-map (Ultra HDR) · adaptive headroom

Same field, same lift — but baked as an Ultra-HDR JPEG (SDR base + gain map) via ocdkit's apply_hdr_cmap → uhdr_data_url. This is a plain <img>: Safari/Chrome apply the gain map up to whatever headroom your display has right now, rolling off smoothly — so it never hard-clips, even authored brighter than your panel.

colormap try it at 100% screen brightness — no clipping

viridis · gain-map max boost ≈ 7.1× SDR white

vs the WebGPU prototype: there you set an absolute headroom and it hard-clips if your display can't reach it. Here the gain map is relative (HDR÷SDR) with a max-boost capacity, and the OS applies min(gain, available headroom) with a smooth rolloff — the adaptive behaviour you wanted. Downside: it's a baked raster (re-encode on colormap/data change, not per-frame), so it fits the image layer; live overlays still want the GL path.