Roll Observatory packages and add a roll script

charted/lib/charts/behaviors/line_marker.dart

-//
-// Copyright 2014 Google Inc. All rights reserved.
-//
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file or at
-// https://developers.google.com/open-source/licenses/bsd
-//
-
-part of charted.charts;
-
-/// A behavior that draws marking lines on the chart.
-class LineMarker implements ChartBehavior {
-  /// Position of the line markers.
-  final Map<int,dynamic> positions;
-
-  /// If true, the markers are drawn above the series
-  final bool drawAboveSeries;
-
-  /// If true, animates (grows from the axis into the chart)
-  final bool animate;
-
-  CartesianArea _area;
-  bool _isLeftAxisPrimary = false;
-  Rect _rect;
-
-  bool _showing;
-  Selection _parent;
-  DataSelection _markers;
-
-  StreamSubscription _axesChangeSubscription;
-
-  LineMarker(this.positions,
-      {this.drawAboveSeries: false, this.animate: false});
-
-  void init(ChartArea area, Selection upper, Selection lower) {
-    if (area is! CartesianArea) return;
-    _area = area;
-    _parent = drawAboveSeries ? upper : lower;
-    _isLeftAxisPrimary = _area.config.isLeftAxisPrimary;
-    _axesChangeSubscription =
-        _area.onChartAxesUpdated.listen((_) => _update());
-    _update();
-  }
-
-  void dispose() {
-    if (_axesChangeSubscription != null) _axesChangeSubscription.cancel();
-    if (_markers != null) _markers.remove();
-  }
-
-  bool _isDimension(int column) => _area.config.dimensions.contains(column);
-
-  String _pathForDimension(int column, bool initial) {
-    assert(_isDimension(column));
-
-    int index;
-    for(index = 0;
-        _area.config.dimensions.elementAt(index) != column; ++index);
-
-    assert(index == 0 || index == 1 && _area.useTwoDimensionAxes);
-
-    var dimensionAtBottom =
-            index == 1 && _isLeftAxisPrimary ||
-            index == 0 && !_isLeftAxisPrimary,
-        scale = _area.dimensionScales.elementAt(index),
-        scaled = scale.scale(positions[column]),
-        theme = _area.theme.getDimensionAxisTheme(),
-        renderAreaRect = _area.layout.renderArea,
-        left = renderAreaRect.x,
-        right = initial ? left : (left + renderAreaRect.width),
-        bottom = renderAreaRect.y + renderAreaRect.height,
-        top = initial ? bottom : renderAreaRect.y;
-
-    if (scale is OrdinalScale) {
-      var band = scale.rangeBand,
-          bandPadding = theme.axisBandInnerPadding;
-      scaled = scaled - band * bandPadding + _area.theme.defaultStrokeWidth;
-      band = band + 2 * (band * bandPadding - _area.theme.defaultStrokeWidth);
-      return dimensionAtBottom
-          ? 'M ${left + scaled} ${bottom} V ${top} H ${left + scaled + band} V ${bottom} Z'
-          : 'M ${left} ${scaled + band} H ${right} V ${scaled - band} H ${left} Z';
-    } else {
-      return dimensionAtBottom
-          ? 'M ${left + scaled} ${bottom} V ${top}'
-          : 'M ${left} ${scaled} H ${right}';
-    }
-  }
-
-  String _pathForMeasure(int column, bool initial) {
-    throw new UnimplementedError('Measure axis markers');
-  }
-
-  String _getMarkerPath(int column, bool initial) =>
-      _isDimension(column)
-          ? _pathForDimension(column, initial)
-          : _pathForMeasure(column, initial);
-
-  void _update() {
-    if (!_area.isReady) return;
-    _markers = _parent.selectAll('.line-marker').data(positions.keys);
-
-    _markers.enter.append('path').each((d, i, e) {
-      e.classes.add('line-marker');
-      e.attributes['d'] = _getMarkerPath(d, animate);
-    });
-
-    if (animate) {
-      _markers.transition()
-          .attrWithCallback('d', (d, i, e) => _getMarkerPath(d, false));
-    }
-
-    _markers.exit.remove();
-  }
-}
-