@thi.ng/imago/ops/crop.js

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

import { isNumber } from "@thi.ng/checks";
import { illegalArgs } from "@thi.ng/errors";
import {
  computeMargins,
  computeSize,
  computeSizeWithAspect,
  gravityPosition,
  positionOrGravity
} from "../utils.js";
const cropProc = async (spec, input, ctx) => {
  const { aspect, border, gravity, pos, size, ref, unit } = spec;
  if (border == null && size == null)
    illegalArgs("require `border` or `size` option");
  if (border != null) {
    const sides = computeMargins(border, ctx.size, ref, unit);
    const [left2, right, top2, bottom] = sides;
    return [
      input.extract({
        left: left2,
        top: top2,
        width: ctx.size[0] - left2 - right,
        height: ctx.size[1] - top2 - bottom
      }),
      true
    ];
  }
  let $size;
  if (aspect != void 0) {
    if (!isNumber(size))
      illegalArgs("size must be numeric if aspect is used");
    $size = computeSizeWithAspect(size, ctx.size, aspect, unit);
  } else {
    $size = computeSize(size, ctx.size, ref, unit);
  }
  let left = 0, top = 0;
  if (pos) {
    ({ left = 0, top = 0 } = positionOrGravity($size, ctx.size, spec) || {});
  } else {
    [left, top] = gravityPosition(gravity || "c", $size, ctx.size);
  }
  return [
    input.extract({
      left,
      top,
      width: $size[0],
      height: $size[1]
    }),
    true
  ];
};
export {
  cropProc
};