@thi.ng/pixel/format/float-hsva.js

Typedarray integer & float pixel buffers w/ customizable formats, blitting, drawing, convolution

import { EPS } from "@thi.ng/math/api";
import { clamp01 } from "@thi.ng/math/interval";
import { Lane } from "../api.js";
import { defFloatFormat } from "./float-format.js";
const abs = Math.abs;
const min = Math.min;
const FLOAT_HSVA = defFloatFormat({
  alpha: true,
  channels: [Lane.RED, Lane.GREEN, Lane.BLUE, Lane.ALPHA],
  convert: {
    fromABGR: (x, out = []) => {
      const a = (x >>> 24 & 255) / 255;
      const b = (x >>> 16 & 255) / 255;
      const g = (x >>> 8 & 255) / 255;
      const r = (x & 255) / 255;
      let p0, p1, p2, p3;
      let q0, q1, q2, q3;
      if (g < b) {
        p0 = b;
        p1 = g;
        p2 = -1;
        p3 = 2 / 3;
      } else {
        p0 = g;
        p1 = b;
        p2 = 0;
        p3 = -1 / 3;
      }
      if (r < p0) {
        q0 = p0;
        q1 = p1;
        q2 = p3;
        q3 = r;
      } else {
        q0 = r;
        q1 = p1;
        q2 = p2;
        q3 = p0;
      }
      const c = q0 - min(q1, q3);
      q0 = clamp01(q0);
      out[0] = clamp01(abs((q3 - q1) / (6 * c + EPS) + q2));
      out[1] = clamp01(c / (q0 + EPS));
      out[2] = q0;
      out[3] = a;
      return out;
    },
    toABGR: (x) => {
      const h = x[0] * 6;
      const s = x[1];
      const v = x[2] * 255;
      const a = x[3] * 255;
      const r = ((clamp01(abs(h - 3) - 1) - 1) * s + 1) * v;
      const g = ((clamp01(2 - abs(h - 2)) - 1) * s + 1) * v;
      const b = ((clamp01(2 - abs(h - 4)) - 1) * s + 1) * v;
      return (a << 24 | b << 16 | g << 8 | r) >>> 0;
    }
  }
});
export {
  FLOAT_HSVA
};