Color.XyY (Color v0.4.0)

CIE xyY color space — chromaticity coordinates x, y and luminance Y.

Conversions use the Lindbloom formulas. The Y channel carries the luminance on the same scale as CIE XYZ (typically Y ∈ [0, 1]).

Summary

Types

t()

CIE xyY chromaticity (x, y) plus luminance (yY). Useful for reasoning about gamut on a chromaticity diagram.

Functions

from_xyz(xyz)

Converts a CIE XYZ color to xyY.

to_xyz(xyy)

Converts an xyY color to CIE XYZ.

Types

t()

@type t() :: %Color.XyY{
  alpha: Color.Types.alpha(),
  illuminant: Color.Types.illuminant(),
  observer_angle: Color.Types.observer(),
  x: float() | nil,
  y: float() | nil,
  yY: float() | nil
}

CIE xyY chromaticity (x, y) plus luminance (yY). Useful for reasoning about gamut on a chromaticity diagram.

Functions

from_xyz(xyz)

Converts a CIE XYZ color to xyY.

When X + Y + Z = 0 the chromaticity is taken from the xyz's reference white, as prescribed by Lindbloom.

Arguments

xyz is a Color.XYZ struct.

Returns

A Color.XyY struct.

Examples

iex> xyz = %Color.XYZ{x: 0.95047, y: 1.0, z: 1.08883, illuminant: :D65, observer_angle: 2}
iex> {:ok, xyy} = Color.XyY.from_xyz(xyz)
iex> {Float.round(xyy.x, 5), Float.round(xyy.y, 5), Float.round(xyy.yY, 4)}
{0.31273, 0.32902, 1.0}

to_xyz(xyy)

Converts an xyY color to CIE XYZ.

Arguments

xyy is a Color.XyY struct.

Returns

A Color.XYZ struct.

Examples

iex> {:ok, xyz} = Color.XyY.to_xyz(%Color.XyY{x: 0.31271, y: 0.32902, yY: 1.0})
iex> {Float.round(xyz.x, 4), Float.round(xyz.y, 4), Float.round(xyz.z, 4)}
{0.9504, 1.0, 1.0889}