Roll Observatory packages and add a roll script

charted/lib/charts/behaviors/axis_label_tooltip.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 AxisLabelTooltip implements ChartBehavior {
-  static const _AXIS_SELECTOR = '.measure-axis-group,.dimension-axis-group';
-
-  SubscriptionsDisposer _disposer = new SubscriptionsDisposer();
-  StreamSubscription _axesChangeSubscription;
-  CartesianArea _area;
-  Element _tooltipRoot;
-
-  math.Rectangle _hostAreaRect;
-  math.Rectangle _renderAreaRect;
-
-  void init(ChartArea area, Selection upper, Selection lower) {
-    if (area is! CartesianArea) return;
-    _area = area;
-    _axesChangeSubscription =
-        _area.onChartAxesUpdated.listen((_) => _subscribe());
-
-    // Axis tooltip requires host to be position: relative.
-    area.host.style.position = 'relative';
-  }
-
-  void dispose() {
-    _disposer.dispose();
-    if (_tooltipRoot != null) _tooltipRoot.remove();
-  }
-
-  void _subscribe() {
-    var elements = _area.host.querySelectorAll(_AXIS_SELECTOR);
-    _disposer.dispose();
-    _disposer.addAll(
-        elements.map((x) => x.onMouseOver.listen(_handleMouseOver)));
-    _disposer.addAll(
-        elements.map((x) => x.onMouseOut.listen(_handleMouseOut)));
-  }
-
-  void _handleMouseOver(MouseEvent e) {
-    Element target = e.target;
-    if (!target.dataset.containsKey('detail')) return;
-    ensureTooltipRoot();
-    ensureRenderAreaRect();
-
-    _tooltipRoot.text = target.dataset['detail'];
-    var position = computeTooltipPosition(
-        target.getBoundingClientRect(),
-        _tooltipRoot.getBoundingClientRect(),
-        _renderAreaRect);
-
-    _tooltipRoot.style
-      ..left = '${position.x}px'
-      ..top = '${position.y}px'
-      ..opacity = '1'
-      ..visibility = 'visible';
-  }
-
-  void _handleMouseOut(MouseEvent e) {
-    Element target = e.target;
-    if (!target.dataset.containsKey('detail')) return;
-    if (_tooltipRoot != null) {
-      _tooltipRoot.style
-        ..opacity = '0'
-        ..visibility = 'hidden';
-    }
-  }
-
-  void ensureTooltipRoot() {
-    if (_tooltipRoot == null) {
-      _tooltipRoot = new Element.tag('div')
-        ..style.position = 'absolute'
-        ..attributes['dir'] = _area.config.isRTL ? 'rtl' : ''
-        ..classes.add('chart-axis-label-tooltip');
-      if (_area.config.isRTL) {
-        _tooltipRoot.classes.add('rtl');
-      } else {
-        _tooltipRoot.classes.remove('rtl');
-      }
-      _area.host.append(_tooltipRoot);
-    }
-  }
-
-  void ensureRenderAreaRect() {
-    var layout = _area.layout;
-    _hostAreaRect = _area.host.getBoundingClientRect();
-    _renderAreaRect = new math.Rectangle(
-        _hostAreaRect.left + layout.chartArea.x + layout.renderArea.x,
-        _hostAreaRect.top + layout.chartArea.y + layout.renderArea.y,
-        layout.renderArea.width, layout.renderArea.height);
-  }
-
-  /// Computes the ideal tooltip position based on orientation.
-  math.Point computeTooltipPosition(math.Rectangle label,
-      math.Rectangle tooltip, math.Rectangle renderArea) {
-    var x = label.left + (label.width - tooltip.width) / 2,
-        y = label.top + (label.height - tooltip.height) / 2;
-
-    if (x + tooltip.width > renderArea.right) {
-      x = renderArea.right - tooltip.width;
-    } else if (x < renderArea.left) {
-      x = renderArea.left;
-    }
-
-    if (y + tooltip.height > renderArea.bottom) {
-      y = renderArea.bottom - tooltip.height;
-    } else if (y < renderArea.top) {
-      y = renderArea.top;
-    }
-
-    return new math.Point(x - _hostAreaRect.left, y - _hostAreaRect.top);
-  }
-}