all files / ol/geom/flat/ straightchunk.js

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goog.provide('ol.geom.flat.straightchunk');
 
 
/**
 * @param {number} angleDelta Maximum acceptable angle delta between segments.
 * @param {number} length Required length of the resulting chung.
 * @param {Array.<number>} flatCoordinates Flat coordinates.
 * @param {number} offset Offset.
 * @param {number} end End.
 * @param {number} stride Stride.
 * @return {Array.<number>} Offset and end of the longest suitable chunk of the
 * given `flatCoordinates`, or `null` if there is none.
 */
ol.geom.flat.straightchunk.lineString = function(angleDelta, length, flatCoordinates, offset, end, stride) {
  var x1 = flatCoordinates[offset];
  var y1 = flatCoordinates[offset + 1];
  var chunkOffset = offset;
  var chunkLength = 0;
  var chunk = [];
  var m = 0;
  var acos, i, m12, x21, y21;
  for (i = offset + stride; i < end; i += stride) {
    var x2 = flatCoordinates[i];
    var y2 = flatCoordinates[i + 1];
    var x32 = x2 - x1;
    var y32 = y2 - y1;
    var m23 = Math.sqrt(x32 * x32 + y32 * y32);
    if (m12 !== undefined) {
      m += m23;
      acos = Math.acos((x21 * x32 + y21 * y32) / (m12 * m23));
      if (acos > angleDelta) {
        Iif (m >= chunkLength && m >= length) {
          chunk[0] = chunkOffset;
          chunk[1] = i + stride;
          chunkLength = m;
        }
        m = 0;
        chunkOffset = i;
      }
    }
    x21 = x32;
    y21 = y32;
    m12 = m23;
  }
  return chunk.length == 2 ? chunk : null;
};