d3-array#Adder JavaScript Examples

areaStream = {
  point: noop,
  lineStart: noop,
  lineEnd: noop,
  polygonStart: function() {
    areaRingSum = new Adder();
    areaStream.lineStart = areaRingStart;
    areaStream.lineEnd = areaRingEnd;
  },
  polygonEnd: function() {
    var areaRing = +areaRingSum;
    areaSum.add(areaRing < 0 ? tau + areaRing : areaRing);
    this.lineStart = this.lineEnd = this.point = noop;
  },
  sphere: function() {
    areaSum.add(tau);
  }
}

boundsStream = {
  point: boundsPoint,
  lineStart: boundsLineStart,
  lineEnd: boundsLineEnd,
  polygonStart: function() {
    boundsStream.point = boundsRingPoint;
    boundsStream.lineStart = boundsRingStart;
    boundsStream.lineEnd = boundsRingEnd;
    deltaSum = new Adder();
    areaStream.polygonStart();
  },
  polygonEnd: function() {
    areaStream.polygonEnd();
    boundsStream.point = boundsPoint;
    boundsStream.lineStart = boundsLineStart;
    boundsStream.lineEnd = boundsLineEnd;
    if (areaRingSum < 0) lambda0 = -(lambda1 = 180), phi0 = -(phi1 = 90);
    else if (deltaSum > epsilon) phi1 = 90;
    else if (deltaSum < -epsilon) phi0 = -90;
    range[0] = lambda0, range[1] = lambda1;
  },
  sphere: function() {
    lambda0 = -(lambda1 = 180), phi0 = -(phi1 = 90);
  }
}

export default function(object) {
  W0 = W1 =
  X0 = Y0 = Z0 =
  X1 = Y1 = Z1 = 0;
  X2 = new Adder();
  Y2 = new Adder();
  Z2 = new Adder();
  stream(object, centroidStream);

  var x = +X2,
      y = +Y2,
      z = +Z2,
      m = hypot(x, y, z);

  // If the area-weighted ccentroid is undefined, fall back to length-weighted ccentroid.
  if (m < epsilon2) {
    x = X1, y = Y1, z = Z1;
    // If the feature has zero length, fall back to arithmetic mean of point vectors.
    if (W1 < epsilon) x = X0, y = Y0, z = Z0;
    m = hypot(x, y, z);
    // If the feature still has an undefined ccentroid, then return.
    if (m < epsilon2) return [NaN, NaN];
  }

  return [atan2(y, x) * degrees, asin(z / m) * degrees];
}

areaStream = {
  point: noop,
  lineStart: noop,
  lineEnd: noop,
  polygonStart: function() {
    areaStream.lineStart = areaRingStart;
    areaStream.lineEnd = areaRingEnd;
  },
  polygonEnd: function() {
    areaStream.lineStart = areaStream.lineEnd = areaStream.point = noop;
    areaSum.add(abs(areaRingSum));
    areaRingSum = new Adder();
  },
  result: function() {
    var area = areaSum / 2;
    areaSum = new Adder();
    return area;
  }
}

lengthStream = {
  point: noop,
  lineStart: function() {
    lengthStream.point = lengthPointFirst;
  },
  lineEnd: function() {
    if (lengthRing) lengthPoint(x00, y00);
    lengthStream.point = noop;
  },
  polygonStart: function() {
    lengthRing = true;
  },
  polygonEnd: function() {
    lengthRing = null;
  },
  result: function() {
    var length = +lengthSum;
    lengthSum = new Adder();
    return length;
  }
}

export default function(object) {
  areaSum = new Adder();
  stream(object, areaStream);
  return areaSum * 2;
}

areaRingSum = new Adder()

areaSum = new Adder()

export default function(object) {
  lengthSum = new Adder();
  stream(object, lengthStream);
  return +lengthSum;
}

areaSum = new Adder()

areaRingSum = new Adder()

lengthSum = new Adder()

export default function(polygon, point) {
  var lambda = longitude(point),
      phi = point[1],
      sinPhi = sin(phi),
      normal = [sin(lambda), -cos(lambda), 0],
      angle = 0,
      winding = 0;

  var sum = new Adder();

  if (sinPhi === 1) phi = halfPi + epsilon;
  else if (sinPhi === -1) phi = -halfPi - epsilon;

  for (var i = 0, n = polygon.length; i < n; ++i) {
    if (!(m = (ring = polygon[i]).length)) continue;
    var ring,
        m,
        point0 = ring[m - 1],
        lambda0 = longitude(point0),
        phi0 = point0[1] / 2 + quarterPi,
        sinPhi0 = sin(phi0),
        cosPhi0 = cos(phi0);

    for (var j = 0; j < m; ++j, lambda0 = lambda1, sinPhi0 = sinPhi1, cosPhi0 = cosPhi1, point0 = point1) {
      var point1 = ring[j],
          lambda1 = longitude(point1),
          phi1 = point1[1] / 2 + quarterPi,
          sinPhi1 = sin(phi1),
          cosPhi1 = cos(phi1),
          delta = lambda1 - lambda0,
          sign = delta >= 0 ? 1 : -1,
          absDelta = sign * delta,
          antimeridian = absDelta > pi,
          k = sinPhi0 * sinPhi1;

      sum.add(atan2(k * sign * sin(absDelta), cosPhi0 * cosPhi1 + k * cos(absDelta)));
      angle += antimeridian ? delta + sign * tau : delta;

      // Are the longitudes either side of the point’s meridian (lambda),
      // and are the latitudes smaller than the parallel (phi)?
      if (antimeridian ^ lambda0 >= lambda ^ lambda1 >= lambda) {
        var arc = cartesianCross(cartesian(point0), cartesian(point1));
        cartesianNormalizeInPlace(arc);
        var intersection = cartesianCross(normal, arc);
        cartesianNormalizeInPlace(intersection);
        var phiArc = (antimeridian ^ delta >= 0 ? -1 : 1) * asin(intersection[2]);
        if (phi > phiArc || phi === phiArc && (arc[0] || arc[1])) {
          winding += antimeridian ^ delta >= 0 ? 1 : -1;
        }
      }
    }
  }

  // First, determine whether the South pole is inside or outside:
  //
  // It is inside if:
  // * the polygon winds around it in a clockwise direction.
  // * the polygon does not (cumulatively) wind around it, but has a negative
  //   (counter-clockwise) area.
  //
  // Second, count the (signed) number of times a segment crosses a lambda
  // from the point to the South pole.  If it is zero, then the point is the
  // same side as the South pole.

  return (angle < -epsilon || angle < epsilon && sum < -epsilon2) ^ (winding & 1);
}