220 lines
7.6 KiB
JavaScript
220 lines
7.6 KiB
JavaScript
// FIXME find better names for these functions
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goog.provide('ol.geom.closest');
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goog.require('goog.asserts');
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goog.require('ol.geom.flat');
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/**
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* Return the squared of the largest distance between any pair of consecutive
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* coordinates.
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* @param {Array.<number>} flatCoordinates Flat coordinates.
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* @param {number} offset Offset.
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* @param {number} end End.
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* @param {number} stride Stride.
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* @param {number} maxSquaredDelta Max squared delta.
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* @return {number} Max squared delta.
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*/
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ol.geom.closest.getMaxSquaredDelta =
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function(flatCoordinates, offset, end, stride, maxSquaredDelta) {
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var x1 = flatCoordinates[offset];
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var y1 = flatCoordinates[offset + 1];
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for (offset += stride; offset < end; offset += stride) {
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var x2 = flatCoordinates[offset];
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var y2 = flatCoordinates[offset + 1];
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var squaredDelta = ol.geom.flat.squaredDistance(x1, y1, x2, y2);
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if (squaredDelta > maxSquaredDelta) {
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maxSquaredDelta = squaredDelta;
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}
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x1 = x2;
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y1 = y2;
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}
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return maxSquaredDelta;
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};
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/**
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* @param {Array.<number>} flatCoordinates Flat coordinates.
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* @param {number} offset Offset.
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* @param {Array.<number>} ends Ends.
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* @param {number} stride Stride.
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* @param {number} maxSquaredDelta Max squared delta.
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* @return {number} Max squared delta.
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*/
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ol.geom.closest.getsMaxSquaredDelta =
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function(flatCoordinates, offset, ends, stride, maxSquaredDelta) {
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var i, ii;
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for (i = 0, ii = ends.length; i < ii; ++i) {
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var end = ends[i];
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maxSquaredDelta = ol.geom.closest.getMaxSquaredDelta(
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flatCoordinates, offset, end, stride, maxSquaredDelta);
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offset = end;
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}
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return maxSquaredDelta;
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};
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/**
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* @param {Array.<number>} flatCoordinates Flat coordinates.
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* @param {number} offset Offset.
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* @param {Array.<Array.<number>>} endss Endss.
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* @param {number} stride Stride.
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* @param {number} maxSquaredDelta Max squared delta.
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* @return {number} Max squared delta.
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*/
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ol.geom.closest.getssMaxSquaredDelta =
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function(flatCoordinates, offset, endss, stride, maxSquaredDelta) {
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var i, ii;
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for (i = 0, ii = endss.length; i < ii; ++i) {
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var ends = endss[i];
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maxSquaredDelta = ol.geom.closest.getsMaxSquaredDelta(
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flatCoordinates, offset, ends, stride, maxSquaredDelta);
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offset = ends[ends.length - 1];
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}
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return maxSquaredDelta;
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};
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/**
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* @param {Array.<number>} flatCoordinates Flat coordinates.
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* @param {number} offset Offset.
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* @param {number} end End.
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* @param {number} stride Stride.
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* @param {number} maxDelta Max delta.
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* @param {boolean} isRing Is ring.
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* @param {number} x X.
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* @param {number} y Y.
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* @param {Array.<number>} closestPoint Closest point.
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* @param {number} minSquaredDistance Minimum squared distance.
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* @param {Array.<number>=} opt_tmpPoint Temporary point object.
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* @return {number} Minimum squared distance.
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*/
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ol.geom.closest.getClosestPoint = function(flatCoordinates, offset, end, stride,
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maxDelta, isRing, x, y, closestPoint, minSquaredDistance, opt_tmpPoint) {
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if (offset == end) {
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return minSquaredDistance;
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}
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var i, squaredDistance;
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if (maxDelta === 0) {
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// All points are identical, so just test the first point.
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squaredDistance = ol.geom.flat.squaredDistance(
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x, y, flatCoordinates[offset], flatCoordinates[offset + 1]);
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if (squaredDistance < minSquaredDistance) {
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for (i = 0; i < stride; ++i) {
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closestPoint[i] = flatCoordinates[offset + i];
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}
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closestPoint.length = stride;
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return squaredDistance;
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} else {
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return minSquaredDistance;
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}
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}
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goog.asserts.assert(maxDelta > 0);
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var tmpPoint = goog.isDef(opt_tmpPoint) ? opt_tmpPoint : [NaN, NaN];
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var index = offset + stride;
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while (index < end) {
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ol.geom.flat.closestPoint(
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flatCoordinates, index - stride, index, stride, x, y, tmpPoint);
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squaredDistance = ol.geom.flat.squaredDistance(
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x, y, tmpPoint[0], tmpPoint[1]);
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if (squaredDistance < minSquaredDistance) {
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minSquaredDistance = squaredDistance;
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for (i = 0; i < stride; ++i) {
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closestPoint[i] = tmpPoint[i];
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}
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closestPoint.length = stride;
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index += stride;
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} else {
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// Skip ahead multiple points, because we know that all the skipped
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// points cannot be any closer than the closest point we have found so
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// far. We know this because we know how close the current point is, how
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// close the closest point we have found so far is, and the maximum
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// distance between consecutive points. For example, if we're currently
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// at distance 10, the best we've found so far is 3, and that the maximum
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// distance between consecutive points is 2, then we'll need to skip at
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// least (10 - 3) / 2 == 3 (rounded down) points to have any chance of
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// finding a closer point. We use Math.max(..., 1) to ensure that we
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// always advance at least one point, to avoid an infinite loop.
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index += stride * Math.max(
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((Math.sqrt(squaredDistance) -
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Math.sqrt(minSquaredDistance)) / maxDelta) | 0, 1);
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}
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}
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if (isRing) {
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// Check the closing segment.
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ol.geom.flat.closestPoint(
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flatCoordinates, end - stride, offset, stride, x, y, tmpPoint);
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squaredDistance = ol.geom.flat.squaredDistance(
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x, y, tmpPoint[0], tmpPoint[1]);
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if (squaredDistance < minSquaredDistance) {
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minSquaredDistance = squaredDistance;
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for (i = 0; i < stride; ++i) {
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closestPoint[i] = tmpPoint[i];
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}
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closestPoint.length = stride;
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}
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}
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return minSquaredDistance;
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};
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/**
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* @param {Array.<number>} flatCoordinates Flat coordinates.
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* @param {number} offset Offset.
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* @param {Array.<number>} ends Ends.
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* @param {number} stride Stride.
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* @param {number} maxDelta Max delta.
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* @param {boolean} isRing Is ring.
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* @param {number} x X.
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* @param {number} y Y.
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* @param {Array.<number>} closestPoint Closest point.
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* @param {number} minSquaredDistance Minimum squared distance.
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* @param {Array.<number>=} opt_tmpPoint Temporary point object.
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* @return {number} Minimum squared distance.
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*/
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ol.geom.closest.getsClosestPoint = function(flatCoordinates, offset, ends,
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stride, maxDelta, isRing, x, y, closestPoint, minSquaredDistance,
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opt_tmpPoint) {
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var tmpPoint = goog.isDef(opt_tmpPoint) ? opt_tmpPoint : [NaN, NaN];
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var i, ii;
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for (i = 0, ii = ends.length; i < ii; ++i) {
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var end = ends[i];
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minSquaredDistance = ol.geom.closest.getClosestPoint(
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flatCoordinates, offset, end, stride,
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maxDelta, isRing, x, y, closestPoint, minSquaredDistance, tmpPoint);
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offset = end;
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}
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return minSquaredDistance;
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};
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/**
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* @param {Array.<number>} flatCoordinates Flat coordinates.
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* @param {number} offset Offset.
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* @param {Array.<Array.<number>>} endss Endss.
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* @param {number} stride Stride.
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* @param {number} maxDelta Max delta.
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* @param {boolean} isRing Is ring.
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* @param {number} x X.
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* @param {number} y Y.
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* @param {Array.<number>} closestPoint Closest point.
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* @param {number} minSquaredDistance Minimum squared distance.
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* @param {Array.<number>=} opt_tmpPoint Temporary point object.
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* @return {number} Minimum squared distance.
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*/
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ol.geom.closest.getssClosestPoint = function(flatCoordinates, offset, endss,
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stride, maxDelta, isRing, x, y, closestPoint, minSquaredDistance,
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opt_tmpPoint) {
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var tmpPoint = goog.isDef(opt_tmpPoint) ? opt_tmpPoint : [NaN, NaN];
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var i, ii;
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for (i = 0, ii = endss.length; i < ii; ++i) {
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var ends = endss[i];
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minSquaredDistance = ol.geom.closest.getsClosestPoint(
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flatCoordinates, offset, ends, stride,
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maxDelta, isRing, x, y, closestPoint, minSquaredDistance, tmpPoint);
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offset = ends[ends.length - 1];
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}
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return minSquaredDistance;
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};
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