# `Color.RGB.WorkingSpace`

# `from_css_name`

```elixir
@spec from_css_name(String.t()) :: {:ok, atom()} | {:error, Exception.t()}
```

Looks up an RGB working space by its CSS Color 4 name.

### Arguments

* `name` is a string.

### Returns

* `{:ok, atom}` — the internal working-space atom.

* `{:error, reason}` if the name is unknown.

### Examples

    iex> Color.RGB.WorkingSpace.from_css_name("display-p3")
    {:ok, :P3_D65}

    iex> Color.RGB.WorkingSpace.from_css_name("srgb")
    {:ok, :SRGB}

# `primaries`

```elixir
@spec primaries(atom()) :: %{
  red: {float(), float()},
  green: {float(), float()},
  blue: {float(), float()},
  illuminant: atom()
}
```

Returns the `(x, y)` chromaticities of a working space's three
primaries plus its illuminant atom.

### Arguments

* `working_space` is an atom identifying the working space,
  for example `:SRGB`, `:P3_D65`, `:Rec2020`.

### Returns

* `%{red: {x, y}, green: {x, y}, blue: {x, y}, illuminant: atom}`.

### Examples

    iex> p = Color.RGB.WorkingSpace.primaries(:SRGB)
    iex> p.red
    {0.64, 0.33}

    iex> Color.RGB.WorkingSpace.primaries(:P3_D65).illuminant
    :D65

# `rgb_conversion_matrix`

```elixir
@spec rgb_conversion_matrix(atom()) ::
  {:ok,
   %{
     to_xyz: list(),
     from_xyz: list(),
     illuminant: atom(),
     observer_angle: 2 | 10,
     gamma: term()
   }}
  | {:error, Exception.t()}
```

Returns the RGB→XYZ and XYZ→RGB conversion matrices for a named RGB
working space, computed from its primaries and reference white using
the Lindbloom formulas.

### Arguments

* `rgb_space` is the working-space atom (for example `:sRGB`, `:Adobe`,
  `:ProPhoto`).

### Returns

* An `{:ok, %{to_xyz: m, from_xyz: mi, illuminant: atom, observer_angle: 2}}`
  tuple where `m` and `mi` are 3x3 matrices represented as lists of rows.

* `{:error, reason}` when the working space is unknown.

### Examples

    iex> {:ok, %{to_xyz: [[a, _, _] | _]}} = Color.RGB.WorkingSpace.rgb_conversion_matrix(:SRGB)
    iex> Float.round(a, 4)
    0.4125

# `rgb_working_spaces`

# `to_css_name`

```elixir
@spec to_css_name(atom()) :: String.t() | nil
```

Returns the CSS Color 4 name for an internal working-space atom,
or `nil` if there isn't one.

### Arguments

* `atom` is a working-space atom.

### Returns

* A string or `nil`.

### Examples

    iex> Color.RGB.WorkingSpace.to_css_name(:P3_D65)
    "display-p3"

    iex> Color.RGB.WorkingSpace.to_css_name(:SRGB)
    "srgb"

    iex> Color.RGB.WorkingSpace.to_css_name(:Bruce)
    nil

---

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