117 lines
2.2 KiB
JavaScript
117 lines
2.2 KiB
JavaScript
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L.DistanceGrid = function (cellSize) {
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this._cellSize = cellSize;
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this._sqCellSize = cellSize * cellSize;
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this._grid = {};
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this._objectPoint = { };
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};
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L.DistanceGrid.prototype = {
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addObject: function (obj, point) {
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var x = this._getCoord(point.x),
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y = this._getCoord(point.y),
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grid = this._grid,
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row = grid[y] = grid[y] || {},
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cell = row[x] = row[x] || [],
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stamp = L.Util.stamp(obj);
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this._objectPoint[stamp] = point;
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cell.push(obj);
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},
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updateObject: function (obj, point) {
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this.removeObject(obj);
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this.addObject(obj, point);
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},
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//Returns true if the object was found
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removeObject: function (obj, point) {
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var x = this._getCoord(point.x),
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y = this._getCoord(point.y),
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grid = this._grid,
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row = grid[y] = grid[y] || {},
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cell = row[x] = row[x] || [],
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i, len;
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delete this._objectPoint[L.Util.stamp(obj)];
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for (i = 0, len = cell.length; i < len; i++) {
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if (cell[i] === obj) {
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cell.splice(i, 1);
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if (len === 1) {
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delete row[x];
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}
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return true;
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}
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}
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},
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eachObject: function (fn, context) {
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var i, j, k, len, row, cell, removed,
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grid = this._grid;
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for (i in grid) {
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row = grid[i];
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for (j in row) {
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cell = row[j];
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for (k = 0, len = cell.length; k < len; k++) {
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removed = fn.call(context, cell[k]);
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if (removed) {
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k--;
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len--;
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}
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}
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}
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}
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},
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getNearObject: function (point) {
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var x = this._getCoord(point.x),
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y = this._getCoord(point.y),
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i, j, k, row, cell, len, obj, dist,
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objectPoint = this._objectPoint,
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closestDistSq = this._sqCellSize,
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closest = null;
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for (i = y - 1; i <= y + 1; i++) {
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row = this._grid[i];
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if (row) {
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for (j = x - 1; j <= x + 1; j++) {
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cell = row[j];
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if (cell) {
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for (k = 0, len = cell.length; k < len; k++) {
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obj = cell[k];
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dist = this._sqDist(objectPoint[L.Util.stamp(obj)], point);
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if (dist < closestDistSq) {
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closestDistSq = dist;
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closest = obj;
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}
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}
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}
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}
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}
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}
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return closest;
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},
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_getCoord: function (x) {
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return Math.floor(x / this._cellSize);
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},
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_sqDist: function (p, p2) {
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var dx = p2.x - p.x,
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dy = p2.y - p.y;
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return dx * dx + dy * dy;
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}
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};
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