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Perf: use more efficient data representation and significantly reduce…
… virtual function overhead (plus some minor cleanups, e.g. spiderify property to layer). In my tests, this reduces the execution time (i.e. ClusterManager.addLayer) for the "Clustering Many Markers" example experience from ~1s to 700ms, i.e. roughly a 30% reduction.
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -1,108 +1,108 @@ | ||
| import 'dart:collection'; | ||
| import 'dart:math'; | ||
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| class CellEntry<T> { | ||
| final T obj; | ||
| final double x; | ||
| final double y; | ||
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| const CellEntry(this.x, this.y, this.obj); | ||
| } | ||
|
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| class GridKey { | ||
| final int row; | ||
| final int col; | ||
|
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| const GridKey(this.row, this.col); | ||
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| @override | ||
| bool operator ==(Object other) => | ||
| other is GridKey && other.row == row && other.col == col; | ||
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| @override | ||
| int get hashCode => (col << 26) ^ row; | ||
| } | ||
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| class DistanceGrid<T> { | ||
| final num cellSize; | ||
| final int cellSize; | ||
| final double _sqCellSize; | ||
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| final num _sqCellSize; | ||
| final Map<num, Map<num, List<T>>> _grid = {}; | ||
| final Map<T, Point> _objectPoint = {}; | ||
| final _grid = HashMap<GridKey, List<CellEntry<T>>>(); | ||
| final _objectPoint = HashMap<T, GridKey>(); | ||
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| DistanceGrid(this.cellSize) : _sqCellSize = cellSize * cellSize; | ||
| DistanceGrid(int cellSize) | ||
| : cellSize = cellSize > 0 ? cellSize : 1, | ||
| _sqCellSize = (cellSize * cellSize).toDouble(); | ||
|
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| void addObject(T obj, Point point) { | ||
| final x = _getCoord(point.x), y = _getCoord(point.y); | ||
| final row = _grid[y] ??= {}; | ||
| final cell = row[x] ??= []; | ||
| void clear() { | ||
| _grid.clear(); | ||
| _objectPoint.clear(); | ||
| } | ||
|
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| _objectPoint[obj] = point; | ||
| void addObject(T obj, Point<double> point) { | ||
| final key = GridKey(_getCoord(point.y), _getCoord(point.x)); | ||
| final cell = _grid[key] ??= []; | ||
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| cell.add(obj); | ||
| _objectPoint[obj] = key; | ||
| cell.add(CellEntry<T>(point.x, point.y, obj)); | ||
| } | ||
|
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| void updateObject(T obj, Point point) { | ||
| void updateObject(T obj, Point<double> point) { | ||
| removeObject(obj); | ||
| addObject(obj, point); | ||
| } | ||
|
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| //Returns true if the object was found | ||
| bool removeObject(T obj) { | ||
| final point = _objectPoint[obj]; | ||
| if (point == null) return false; | ||
|
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| final x = _getCoord(point.x), y = _getCoord(point.y); | ||
| final row = _grid[y] ??= {}; | ||
| final cell = row[x] ??= []; | ||
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| _objectPoint.remove(obj); | ||
|
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| final len = cell.length; | ||
| for (var i = 0; i < len; i++) { | ||
| if (cell[i] == obj) { | ||
| cell.removeAt(i); | ||
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| if (len == 1) { | ||
| row.remove(x); | ||
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| if (_grid[y]!.isEmpty) { | ||
| _grid.remove(y); | ||
| } | ||
| } | ||
|
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| return true; | ||
| } | ||
| final key = _objectPoint.remove(obj); | ||
| if (key == null) return false; | ||
|
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| // Object existed in the _objectPoint map, thus must exist in the grid. | ||
| final cell = _grid[key]!; | ||
| cell.removeWhere((e) => e.obj == obj); | ||
| if (cell.isEmpty) { | ||
| _grid.remove(key); | ||
| } | ||
| return false; | ||
| return true; | ||
| } | ||
|
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| void eachObject(Function(T) fn) { | ||
| for (final i in _grid.keys) { | ||
| final row = _grid[i]!; | ||
|
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| for (final j in row.keys) { | ||
| final cell = row[j]!; | ||
|
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| for (var k = 0; k < cell.length; k++) { | ||
| fn(cell[k]); | ||
| } | ||
| for (final cell in _grid.values) { | ||
| for (final entry in cell) { | ||
| fn(entry.obj); | ||
| } | ||
| } | ||
| } | ||
|
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| T? getNearObject(Point point) { | ||
| final x = _getCoord(point.x), y = _getCoord(point.y); | ||
| var closestDistSq = _sqCellSize; | ||
| T? getNearObject(Point<double> point) { | ||
| final px = point.x; | ||
| final py = point.y; | ||
|
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| final x = _getCoord(px), y = _getCoord(py); | ||
| double closestDistSq = _sqCellSize; | ||
| T? closest; | ||
|
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| for (var i = y - 1; i <= y + 1; i++) { | ||
| final row = _grid[i]; | ||
| if (row != null) { | ||
| for (var j = x - 1; j <= x + 1; j++) { | ||
| final cell = row[j]; | ||
| if (cell != null) { | ||
| for (var k = 0; k < cell.length; k++) { | ||
| final obj = cell[k]; | ||
| final dist = _sqDist(_objectPoint[obj]!, point); | ||
|
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| if (dist < closestDistSq || | ||
| dist <= closestDistSq && closest == null) { | ||
| closestDistSq = dist; | ||
| closest = obj; | ||
| } | ||
| // Checks rows and columns with index +/- 1. | ||
| for (int i = y - 1; i <= y + 1; i++) { | ||
| for (int j = x - 1; j <= x + 1; j++) { | ||
| final cell = _grid[GridKey(i, j)]; | ||
| if (cell != null) { | ||
| for (final entry in cell) { | ||
| final double dx = px - entry.x; | ||
| final double dy = py - entry.y; | ||
| final double distSq = dx * dx + dy * dy; | ||
|
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| if (distSq <= closestDistSq) { | ||
| closestDistSq = distSq; | ||
| closest = entry.obj; | ||
| } | ||
| } | ||
| } | ||
| } | ||
| } | ||
| return closest; | ||
| } | ||
|
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| num _getCoord(num x) { | ||
| final coord = x / cellSize; | ||
| return coord.isFinite ? coord.floor() : x; | ||
| return closest; | ||
| } | ||
|
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| num _sqDist(Point p1, Point p2) { | ||
| final dx = p2.x - p1.x, dy = p2.y - p1.y; | ||
| return dx * dx + dy * dy; | ||
| } | ||
| int _getCoord(double x) => x ~/ cellSize; | ||
| } |
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