# `Color.Rec2020`

ITU-R BT.2020 / Rec. 2020 color space, using the Rec. 2020 wide-gamut
primaries (D65 reference white) and the BT.2020 SDR opto-electronic
transfer function at 12-bit precision.

Rec. 2020 is the wide-gamut color space standardised for UHDTV and is
the basis for HDR signalling in BT.2100 (with PQ or HLG encoding). Its
primaries enclose a substantially larger portion of the visible
spectral locus than sRGB or P3.

Channels `r`, `g` and `b` are unit floats in the nominal range `[0, 1]`.

# `t`

```elixir
@type t() :: %Color.Rec2020{
  alpha: number() | nil,
  b: number() | nil,
  g: number() | nil,
  r: number() | nil
}
```

# `from_xyz`

```elixir
@spec from_xyz(Color.XYZ.t()) :: {:ok, t()}
```

Converts a CIE `XYZ` color (assumed D65/2°) to Rec. 2020.

### Arguments

* `xyz` is a `Color.XYZ` struct.

### Returns

* A `Color.Rec2020` struct.

### Examples

    iex> xyz = %Color.XYZ{x: 0.95047, y: 1.0, z: 1.08883, illuminant: :D65, observer_angle: 2}
    iex> {:ok, rec} = Color.Rec2020.from_xyz(xyz)
    iex> {Float.round(rec.r, 3), Float.round(rec.g, 3), Float.round(rec.b, 3)}
    {1.0, 1.0, 1.0}

# `to_xyz`

```elixir
@spec to_xyz(t()) :: {:ok, Color.XYZ.t()}
```

Converts a Rec. 2020 color to a CIE `XYZ` color.

### Arguments

* `rec2020` is a `Color.Rec2020` struct with unit-range channels.

### Returns

* A `Color.XYZ` struct tagged with D65/2°, `Y ∈ [0, 1]`.

### Examples

    iex> {:ok, xyz} = Color.Rec2020.to_xyz(%Color.Rec2020{r: 1.0, g: 1.0, b: 1.0})
    iex> {Float.round(xyz.x, 4), Float.round(xyz.y, 4), Float.round(xyz.z, 4)}
    {0.9505, 1.0, 1.0888}

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*Consult [api-reference.md](api-reference.md) for complete listing*