@thi.ng/grid-iterators/clipping.js

2D grid and shape iterators w/ multiple orderings

function* clipped(src, left, top, right, bottom) {
  for (let p of src) {
    if (p[0] >= left && p[0] < right && p[1] >= top && p[1] < bottom)
      yield p;
  }
}
const __axis = (a, b, c) => (a < b ? a - b : a > b + c ? a - b - c : 0) ** 2;
const intersectRectCircle = (x, y, w, h, cx, cy, r) => __axis(cx, x, w) + __axis(cy, y, h) <= r * r;
const liangBarsky = (ax, ay, bx, by, minx, miny, maxx, maxy) => {
  const dx = bx - ax;
  const dy = by - ay;
  let alpha = 0;
  let beta = 1;
  const clip = (p, q) => {
    if (p < 0) {
      const r = q / p;
      if (r > beta) return false;
      r > alpha && (alpha = r);
    } else if (p > 0) {
      const r = q / p;
      if (r < alpha) return false;
      r < beta && (beta = r);
    } else if (q < 0) {
      return false;
    }
    return true;
  };
  return clip(-dx, ax - minx) && clip(dx, maxx - ax) && clip(-dy, ay - miny) && clip(dy, maxy - ay) ? [alpha * dx + ax, alpha * dy + ay, beta * dx + ax, beta * dy + ay] : void 0;
};
export {
  clipped,
  intersectRectCircle,
  liangBarsky
};