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# targetHDRHeadroom

Target HDR headroom for image rendering.

```
var targetHDRHeadroom: CGFloat { get set }
```

## Discussion

Specifies the target headroom value for HDR image rendering. Headroom represents the ratio between
the maximum display brightness and standard dynamic range (SDR) white level.

- A headroom value of `0.0` means “headroom unknown”. Images with unknown content headroom will be
  excluded from tone mapping, following CGImage documentation behavior.
- Headroom values less than `0.0` or between `0.0` and `1.0` (exclusive) are undefined and will be
  clamped to `0.0` (unknown) rather than throwing an error.
- Headroom is dependent on the current display capabilities. It is the responsibility of the caller
  to re-request the image if the display’s headroom characteristics change. Swift view default behavior
  applies to views that use images outside of the current display headroom supported range.

Defaults to `1.0` (SDR, fully tone mapped).

---

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