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lab2xyz: CIELAB to CIE XYZ Color Space Conversion

Intermediate Color Space Transformation​

The lab2xyz function converts colors from the CIELAB color space to CIE XYZ, serving as the essential intermediate step for color space transformations. This conversion applies the inverse CIE LAB formula with proper gamma correction and white point normalization.

Mathematical Implementation​

The transformation uses the inverse LAB formula with threshold-based calculations:

fy=L+16116,fx=a500+fy,fz=fy−b200f_y = \frac{L + 16}{116}, \quad f_x = \frac{a}{500} + f_y, \quad f_z = f_y - \frac{b}{200}

For each component, the conversion applies:

Component={f3if f>0.206897f−16/1167.787otherwise\text{Component} = \begin{cases} f^3 & \text{if } f > 0.206897 \\ \frac{f - 16/116}{7.787} & \text{otherwise} \end{cases}

The final XYZ values are scaled by the CIE D65 white point and normalized to 0-100 range.

XYZ Color Space Visualization​

Live Editor
const fragment = () => {
      const center = vec2(0.5)
      const p = uv.sub(center).mul(50)

      const L = uv.y
      const A = p.x
      const B = p.y

      const labColor = vec3(L, A, B)
      const rgbColor = lab2xyz(labColor)

      return vec4(rgbColor.max(0).min(1), 1)

}