Function extendBasis

external/.d3.js:13310–13337

(B, p)

}

function extendBasis(B, p) {
  var i, j;

  if (enclosesWeakAll(p, B)) return [p];

  // If we get here then B must have at least one element.
  for (i = 0; i < B.length; ++i) {
    if (enclosesNot(p, B[i])
        && enclosesWeakAll(encloseBasis2(B[i], p), B)) {
      return [B[i], p];
    }
  }

  // If we get here then B must have at least two elements.
  for (i = 0; i < B.length - 1; ++i) {
    for (j = i + 1; j < B.length; ++j) {
      if (enclosesNot(encloseBasis2(B[i], B[j]), p)
          && enclosesNot(encloseBasis2(B[i], p), B[j])
          && enclosesNot(encloseBasis2(B[j], p), B[i])
          && enclosesWeakAll(encloseBasis3(B[i], B[j], p), B)) {
        return [B[i], B[j], p];
      }
    }
  }

  // If we get here then something is very wrong.
  throw new Error;
}

function enclosesNot(a, b) {
  var dr = a.r - b.r, dx = b.x - a.x, dy = b.y - a.y;