openlayers/src/ol/geom/flatgeom.js

goog.provide('ol.geom.flat');

goog.require('goog.asserts');
goog.require('goog.vec.Mat4');


/**
 * @param {Array.<number>} flatCoordinates Flat coordinates.
 * @param {number} offset Offset.
 * @param {Array.<ol.Coordinate>} coordinates Coordinates.
 * @param {number} stride Stride.
 * @return {number} offset Offset.
 */
ol.geom.flat.deflateCoordinates =
    function(flatCoordinates, offset, coordinates, stride) {
  var i, ii;
  for (i = 0, ii = coordinates.length; i < ii; ++i) {
    var coordinate = coordinates[i];
    goog.asserts.assert(coordinate.length == stride);
    var j;
    for (j = 0; j < stride; ++j) {
      flatCoordinates[offset++] = coordinate[j];
    }
  }
  return offset;
};


/**
 * @param {Array.<number>} flatCoordinates Flat coordinates.
 * @param {number} offset Offset.
 * @param {Array.<Array.<ol.Coordinate>>} coordinatess Coordinatess.
 * @param {number} stride Stride.
 * @param {Array.<number>=} opt_ends Ends.
 * @return {Array.<number>} Ends.
 */
ol.geom.flat.deflateCoordinatess =
    function(flatCoordinates, offset, coordinatess, stride, opt_ends) {
  var ends = goog.isDef(opt_ends) ? opt_ends : [];
  var i = 0;
  var j, jj;
  for (j = 0, jj = coordinatess.length; j < jj; ++j) {
    var end = ol.geom.flat.deflateCoordinates(
        flatCoordinates, offset, coordinatess[j], stride);
    ends[i++] = end;
    offset = end;
  }
  ends.length = i;
  return ends;
};


/**
 * @param {Array.<number>} flatCoordinates Flat coordinates.
 * @param {number} offset Offset.
 * @param {Array.<Array.<Array.<ol.Coordinate>>>} coordinatesss Coordinatesss.
 * @param {number} stride Stride.
 * @param {Array.<Array.<number>>=} opt_endss Endss.
 * @return {Array.<Array.<number>>} Endss.
 */
ol.geom.flat.deflateCoordinatesss =
    function(flatCoordinates, offset, coordinatesss, stride, opt_endss) {
  var endss = goog.isDef(opt_endss) ? opt_endss : [];
  var i = 0;
  var j, jj;
  for (j = 0, jj = coordinatesss.length; j < jj; ++j) {
    var ends = ol.geom.flat.deflateCoordinatess(
        flatCoordinates, offset, coordinatesss[j], stride, endss[i]);
    endss[i++] = ends;
    offset = ends[ends.length - 1];
  }
  return endss;
};


/**
 * @param {Array.<number>} flatCoordinates Flat coordinates.
 * @param {number} offset Offset.
 * @param {number} end End.
 * @param {number} stride Stride.
 * @param {Array.<ol.Coordinate>=} opt_coordinates Coordinates.
 * @return {Array.<ol.Coordinate>} Coordinates.
 */
ol.geom.flat.inflateCoordinates =
    function(flatCoordinates, offset, end, stride, opt_coordinates) {
  var coordinates = goog.isDef(opt_coordinates) ? opt_coordinates : [];
  var i = 0;
  var j;
  for (j = offset; j < end; j += stride) {
    coordinates[i++] = flatCoordinates.slice(j, j + stride);
  }
  coordinates.length = i;
  return coordinates;
};


/**
 * @param {Array.<number>} flatCoordinates Flat coordinates.
 * @param {number} offset Offset.
 * @param {Array.<number>} ends Ends.
 * @param {number} stride Stride.
 * @param {Array.<Array.<ol.Coordinate>>=} opt_coordinatess Coordinatess.
 * @return {Array.<Array.<ol.Coordinate>>} Coordinatess.
 */
ol.geom.flat.inflateCoordinatess =
    function(flatCoordinates, offset, ends, stride, opt_coordinatess) {
  var coordinatess = goog.isDef(opt_coordinatess) ? opt_coordinatess : [];
  var i = 0;
  var j, jj;
  for (j = 0, jj = ends.length; j < jj; ++j) {
    var end = ends[j];
    coordinatess[i++] = ol.geom.flat.inflateCoordinates(
        flatCoordinates, offset, end, stride, coordinatess[i]);
    offset = end;
  }
  coordinatess.length = i;
  return coordinatess;
};


/**
 * @param {Array.<number>} flatCoordinates Flat coordinates.
 * @param {number} offset Offset.
 * @param {Array.<Array.<number>>} endss Endss.
 * @param {number} stride Stride.
 * @param {Array.<Array.<Array.<ol.Coordinate>>>=} opt_coordinatesss
 *     Coordinatesss.
 * @return {Array.<Array.<Array.<ol.Coordinate>>>} Coordinatesss.
 */
ol.geom.flat.inflateCoordinatesss =
    function(flatCoordinates, offset, endss, stride, opt_coordinatesss) {
  var coordinatesss = goog.isDef(opt_coordinatesss) ? opt_coordinatesss : [];
  var i = 0;
  var j, jj;
  for (j = 0, jj = endss.length; j < jj; ++j) {
    var ends = endss[j];
    coordinatesss[i++] = ol.geom.flat.inflateCoordinatess(
        flatCoordinates, offset, ends, stride, coordinatesss[i]);
    offset = ends[ends.length - 1];
  }
  coordinatesss.length = i;
  return coordinatesss;
};


/**
 * @param {Array.<number>} flatCoordinates Flat coordinates.
 * @param {number} offset Offset.
 * @param {number} end End.
 * @param {number} stride Stride.
 * @param {number} x X.
 * @param {number} y Y.
 * @return {boolean} Contains (x, y).
 */
ol.geom.flat.linearRingContainsXY =
    function(flatCoordinates, offset, end, stride, x, y) {
  // http://www.ecse.rpi.edu/Homepages/wrf/Research/Short_Notes/pnpoly.html
  var contains = false;
  var xi = flatCoordinates[offset];
  var yi = flatCoordinates[offset + 1];
  for (offset += stride; offset < end; offset += stride) {
    var xj = flatCoordinates[offset];
    var yj = flatCoordinates[offset + 1];
    var intersect = ((yi > y) != (yj > y)) &&
        (x < (xj - xi) * (y - yi) / (yj - yi) + xi);
    if (intersect) {
      contains = !contains;
    }
    xi = xj;
    yi = yj;
  }
  return contains;
};


/**
 * @param {Array.<number>} flatCoordinates Flat coordinates.
 * @param {number} offset Offset.
 * @param {number} end End.
 * @param {number} stride Stride.
 * @return {boolean} Is clockwise.
 */
ol.geom.flat.linearRingIsClockwise =
    function(flatCoordinates, offset, end, stride) {
  // http://tinyurl.com/clockwise-method
  // https://github.com/OSGeo/gdal/blob/trunk/gdal/ogr/ogrlinearring.cpp
  var edge = 0;
  var x1 = flatCoordinates[end - stride];
  var y1 = flatCoordinates[end - stride + 1];
  for (; offset < end; offset += stride) {
    var x2 = flatCoordinates[offset];
    var y2 = flatCoordinates[offset + 1];
    edge += (x2 - x1) * (y2 + y1);
    x1 = x2;
    y1 = y2;
  }
  return edge > 0;
};


/**
 * @param {Array.<number>} flatCoordinates Flat coordinates.
 * @param {number} offset Offset.
 * @param {Array.<number>} ends Ends.
 * @param {number} stride Stride.
 * @param {number} x X.
 * @param {number} y Y.
 * @return {boolean} Contains (x, y).
 */
ol.geom.flat.linearRingsContainsXY =
    function(flatCoordinates, offset, ends, stride, x, y) {
  goog.asserts.assert(ends.length > 0);
  if (ends.length === 0) {
    return false;
  }
  if (!ol.geom.flat.linearRingContainsXY(
      flatCoordinates, offset, ends[0], stride, x, y)) {
    return false;
  }
  var i, ii;
  for (i = 1, ii = ends.length; i < ii; ++i) {
    if (ol.geom.flat.linearRingContainsXY(
        flatCoordinates, ends[i - 1], ends[i], stride, x, y)) {
      return false;
    }
  }
  return true;
};


/**
 * @param {Array.<number>} flatCoordinates Flat coordinates.
 * @param {number} offset Offset.
 * @param {Array.<Array.<number>>} endss Endss.
 * @param {number} stride Stride.
 * @param {number} x X.
 * @param {number} y Y.
 * @return {boolean} Contains (x, y).
 */
ol.geom.flat.linearRingssContainsXY =
    function(flatCoordinates, offset, endss, stride, x, y) {
  goog.asserts.assert(endss.length > 0);
  if (endss.length === 0) {
    return false;
  }
  var i, ii;
  for (i = 0, ii = endss.length; i < ii; ++i) {
    var ends = endss[i];
    if (ol.geom.flat.linearRingsContainsXY(
        flatCoordinates, offset, ends, stride, x, y)) {
      return true;
    }
    offset = ends[ends.length - 1];
  }
  return false;
};


/**
 * @param {Array.<number>} flatCoordinates Flat coordinates.
 * @param {number} offset Offset.
 * @param {Array.<number>} ends Ends.
 * @param {number} stride Stride.
 * @return {number} End.
 */
ol.geom.flat.orientLinearRings =
    function(flatCoordinates, offset, ends, stride) {
  var i, ii;
  for (i = 0, ii = ends.length; i < ii; ++i) {
    var end = ends[i];
    var isClockwise = ol.geom.flat.linearRingIsClockwise(
        flatCoordinates, offset, end, stride);
    var reverse = i === 0 ? !isClockwise : isClockwise;
    if (reverse) {
      ol.geom.flat.reverseCoordinates(flatCoordinates, offset, end, stride);
    }
    offset = end;
  }
  return offset;
};


/**
 * @param {Array.<number>} flatCoordinates Flat coordinates.
 * @param {number} offset Offset.
 * @param {Array.<Array.<number>>} endss Endss.
 * @param {number} stride Stride.
 * @return {number} End.
 */
ol.geom.flat.orientLinearRingss =
    function(flatCoordinates, offset, endss, stride) {
  var i, ii;
  for (i = 0, ii = endss.length; i < ii; ++i) {
    offset = ol.geom.flat.orientLinearRings(
        flatCoordinates, offset, endss[i], stride);
  }
  return offset;
};


/**
 * @param {Array.<number>} flatCoordinates Flat coordinates.
 * @param {number} offset Offset.
 * @param {number} end End.
 * @param {number} stride Stride.
 */
ol.geom.flat.reverseCoordinates =
    function(flatCoordinates, offset, end, stride) {
  while (offset < end - stride) {
    var i;
    for (i = 0; i < stride; ++i) {
      var tmp = flatCoordinates[offset + i];
      flatCoordinates[offset + i] = flatCoordinates[end - stride + i];
      flatCoordinates[end - stride + i] = tmp;
    }
    offset += stride;
    end -= stride;
  }
};


/**
 * @param {Array.<number>} flatCoordinates Flat coordinates.
 * @param {number} stride Stride.
 * @param {goog.vec.Mat4.AnyType} transform Transform.
 * @param {Array.<number>=} opt_dest Destination.
 * @return {Array.<number>} Transformed coordinates.
 */
ol.geom.flat.transform2D =
    function(flatCoordinates, stride, transform, opt_dest) {
  var m00 = goog.vec.Mat4.getElement(transform, 0, 0);
  var m10 = goog.vec.Mat4.getElement(transform, 1, 0);
  var m01 = goog.vec.Mat4.getElement(transform, 0, 1);
  var m11 = goog.vec.Mat4.getElement(transform, 1, 1);
  var m03 = goog.vec.Mat4.getElement(transform, 0, 3);
  var m13 = goog.vec.Mat4.getElement(transform, 1, 3);
  var dest = goog.isDef(opt_dest) ? opt_dest : [];
  var i = 0;
  var j, jj;
  for (j = 0, jj = flatCoordinates.length; j < jj; j += stride) {
    var x = flatCoordinates[j];
    var y = flatCoordinates[j + 1];
    dest[i++] = m00 * x + m01 * y + m03;
    dest[i++] = m10 * x + m11 * y + m13;
  }
  if (goog.isDef(opt_dest) && dest.length != i) {
    dest.length = i;
  }
  return dest;
};