@thi.ng/imago/utils.js

JSON & API-based declarative and extensible image processing trees/pipelines

import {
  isArray,
  isArrayLike,
  isNumber,
  isPlainObject,
  isString,
  isTypedArray
} from "@thi.ng/checks";
import { illegalArgs } from "@thi.ng/errors";
import {
  GRAVITY_MAP
} from "./api.js";
const round = Math.round;
const isIntBufferLike = (x) => isNumber(x.width) && isNumber(x.height) && isTypedArray(x.data) && isPlainObject(x.format);
const ensureSize = (meta) => !(isNumber(meta.width) && isNumber(meta.height)) && illegalArgs("can't determine image size");
const coerceColor = (col) => isString(col) ? col : isArrayLike(col) ? { r: col[0], g: col[1], b: col[2], alpha: col[3] ?? 1 } : col;
const positionOrGravity = ([w, h], parentSize, {
  pos,
  gravity,
  origin,
  ref,
  unit = "px"
}) => {
  if (!pos) return gravity ? { gravity: GRAVITY_MAP[gravity] } : void 0;
  const [parentW, parentH] = parentSize;
  let { l, r, t, b } = pos;
  [l, r, t, b] = computeMargins(
    [l || 0, r || 0, t || 0, b || 0],
    parentSize,
    ref,
    unit
  );
  let left, top;
  const [isE, isW, isN, isS] = origin ? gravityFlags(origin) : [];
  const w2 = w >> 1;
  const h2 = h >> 1;
  if (pos.l != null)
    left = round(l) + (origin ? isW ? 0 : isE ? -w : -w2 : 0);
  if (pos.r != null)
    left = round(parentW - r) + (origin ? isW ? 0 : isE ? -w : -w2 : -w);
  if (pos.t != null)
    top = round(t) + (origin ? isN ? 0 : isS ? -h : -h2 : 0);
  if (pos.b != null)
    top = round(parentH - b) + (origin ? isN ? 0 : isS ? -h : -h2 : -h);
  return { left, top };
};
const gravityFlags = (gravity) => ["e", "w", "n", "s"].map((x) => gravity.includes(x));
const gravityPosition = (gravity, [w, h], [parentW, parentH]) => [
  gravity.includes("w") ? 0 : gravity.includes("e") ? parentW - w : parentW - w >> 1,
  gravity.includes("n") ? 0 : gravity.includes("s") ? parentH - h : parentH - h >> 1
];
const refSize = ([w, h], ref) => {
  let v;
  switch (ref) {
    case "w":
      return [w, w];
    case "h":
      return [h, h];
    case "max":
      v = Math.max(w, h);
      return [v, v];
    case "min":
      v = Math.min(w, h);
      return [v, v];
    case "both":
    default:
      return [w, h];
  }
};
const computeSize = (size, curr, ref, unit = "px") => {
  const aspect = curr[0] / curr[1];
  let res;
  if (isNumber(size)) {
    if (unit === "%") {
      res = refSize(curr, ref);
      res = [res[0] * size / 100, res[1] * size / 100];
    } else {
      res = [size, size];
    }
  } else {
    let [w, h] = size;
    if (unit === "%") {
      const [rw, rh] = refSize(curr, ref);
      w *= rw / 100;
      h *= rh / 100;
      size = [w, h];
    }
    res = w >= 0 ? h >= 0 ? size : [w, w / aspect] : h >= 0 ? [h * aspect, h] : illegalArgs(
      `require at least width or height, but got: ${JSON.stringify(
        size
      )}`
    );
  }
  res[0] = round(res[0]);
  res[1] = round(res[1]);
  return res;
};
const computeSizeWithAspect = (size, [w, h], aspect, unit = "px", clamp = true) => {
  const origAspect = w / h;
  const min = Math.min(w, h);
  const max = Math.max(w, h);
  let res;
  if (unit === "%") {
    size = size / 100 * max;
  }
  if (clamp) {
    size = Math.min(size, max);
    if (size / aspect > min) size = min * aspect;
  }
  res = origAspect > 1 ? [size, size / aspect] : [size / aspect, size];
  res[0] = round(res[0]);
  res[1] = round(res[1]);
  return res;
};
const computeMargins = (size, curr, ref, unit = "px") => {
  let res;
  const refSide = refSize(curr, ref);
  const isPC = unit === "%";
  if (isArray(size) && size.length === 4) {
    res = isPC ? size.map((x, i) => round(x * refSide[i >> 1] / 100)) : size.map(round);
  } else if (isNumber(size)) {
    const w = round(isPC ? refSide[0] * size / 100 : size);
    const h = round(isPC ? refSide[1] * size / 100 : size);
    res = [w, w, h, h];
  } else {
    const w = round(isPC ? refSide[0] * size[0] / 100 : size[0]);
    const h = round(isPC ? refSide[1] * size[1] / 100 : size[1]);
    res = [w, w, h, h];
  }
  return res;
};
export {
  coerceColor,
  computeMargins,
  computeSize,
  computeSizeWithAspect,
  ensureSize,
  gravityFlags,
  gravityPosition,
  isIntBufferLike,
  positionOrGravity,
  refSize
};