# `Color.Luv`

CIE 1976 `L*u*v*` color space.

Conversions use the Lindbloom formulas with exact CIE constants
`ε = 216/24389` and `κ = 24389/27`.

# `t`

```elixir
@type t() :: %Color.Luv{
  alpha: number() | nil,
  illuminant: atom(),
  l: number() | nil,
  observer_angle: 2 | 10,
  u: number() | nil,
  v: number() | nil
}
```

# `from_xyz`

Converts a CIE `XYZ` color to an `L*u*v*` color.

### Arguments

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

### Returns

* A `Color.Luv` struct tagged with the same illuminant and observer
  angle as the input `xyz`.

### Examples

    iex> xyz = %Color.XYZ{x: 0.95047, y: 1.0, z: 1.08883, illuminant: :D65, observer_angle: 2}
    iex> {:ok, luv} = Color.Luv.from_xyz(xyz)
    iex> {Float.round(luv.l, 3), Float.round(luv.u, 3), Float.round(luv.v, 3)}
    {100.0, 0.0, 0.0}

# `to_xyz`

Converts an `L*u*v*` color to a CIE `XYZ` color.

### Arguments

* `luv` is a `Color.Luv` struct.

* `options` is a keyword list.

### Options

* `:illuminant` overrides the reference-white illuminant from the
  `luv` struct. Defaults to `luv.illuminant`.

* `:observer_angle` overrides the observer angle. Defaults to
  `luv.observer_angle`.

### Returns

* A `Color.XYZ` struct.

### Examples

    iex> {:ok, xyz} = Color.Luv.to_xyz(%Color.Luv{l: 100.0, u: 0.0, v: 0.0})
    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*