etui/color

gradient

pub fn gradient(
  stops: List(style.Color),
  pos: Int,
  max: Int,
) -> style.Color

Color at integer position pos within [0, max] across a list of color stops. Stops are distributed evenly. Lerps between adjacent stops. Requires Rgb stops for smooth blending; non-Rgb stops snap.

hue_to_rgb

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pub fn hue_to_rgb(hue: Int) -> style.Color

Convert a hue angle (0–359) to a fully-saturated Rgb color. Implements the HSV→RGB formula with S=1, V=1, integer arithmetic.

lerp_rgb

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pub fn lerp_rgb(
  a: style.Color,
  b: style.Color,
  t: Int,
  max: Int,
) -> style.Color

Linear interpolation between two Rgb colors. For non-Rgb inputs, returns whichever endpoint is closer to t.

pulse

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pub fn pulse(
  c: style.Color,
  frame: Int,
  period: Int,
) -> style.Color

Oscillate an Rgb color between half and full brightness. Use frame + x * phase_step for a per-cell wave effect. Non-Rgb colors are returned unchanged.

rainbow

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pub fn rainbow(frame: Int, period: Int) -> style.Color

Returns an Rgb color that cycles through the full hue spectrum with the given period in frames.

scale

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pub fn scale(c: style.Color, factor: Int) -> style.Color

Scale all RGB channels by factor / 255. factor=255 → unchanged, factor=128 → half brightness.