Hover styling for dataset in 'dataset' mode (chartjs#6527)

* Hover styling for dataset in 'dataset' mode

Author: kurkle

docs/charts/line.md

@@ -52,6 +52,13 @@ The line chart allows a number of properties to be specified for each dataset. T
 | [`borderWidth`](#line-styling) | `number` | Yes | - | `3`
 | [`cubicInterpolationMode`](#cubicinterpolationmode) | `string` | Yes | - | `'default'`
 | [`fill`](#line-styling) | <code>boolean&#124;string</code> | Yes | - | `true`
+| [`hoverBackgroundColor`](#line-styling) | [`Color`](../general/colors.md) | Yes | - | `undefined`
+| [`hoverBorderCapStyle`](#line-styling) | `string` | Yes | - | `undefined`
+| [`hoverBorderColor`](#line-styling) | [`Color`](../general/colors.md) | Yes | - | `undefined`
+| [`hoverBorderDash`](#line-styling) | `number[]` | Yes | - | `undefined`
+| [`hoverBorderDashOffset`](#line-styling) | `number` | Yes | - | `undefined`
+| [`hoverBorderJoinStyle`](#line-styling) | `string` | Yes | - | `undefined`
+| [`hoverBorderWidth`](#line-styling) | `number` | Yes | - | `undefined`
 | [`label`](#general) | `string` | - | - | `''`
 | [`lineTension`](#line-styling) | `number` | - | - | `0.4`
 | [`order`](#general) | `number` | - | - | `0`

docs/charts/radar.md

@@ -74,6 +74,13 @@ The radar chart allows a number of properties to be specified for each dataset.
 | [`borderDashOffset`](#line-styling) | `number` | Yes | - | `0.0`
 | [`borderJoinStyle`](#line-styling) | `string` | Yes | - | `'miter'`
 | [`borderWidth`](#line-styling) | `number` | Yes | - | `3`
+| [`hoverBackgroundColor`](#line-styling) | [`Color`](../general/colors.md) | Yes | - | `undefined`
+| [`hoverBorderCapStyle`](#line-styling) | `string` | Yes | - | `undefined`
+| [`hoverBorderColor`](#line-styling) | [`Color`](../general/colors.md) | Yes | - | `undefined`
+| [`hoverBorderDash`](#line-styling) | `number[]` | Yes | - | `undefined`
+| [`hoverBorderDashOffset`](#line-styling) | `number` | Yes | - | `undefined`
+| [`hoverBorderJoinStyle`](#line-styling) | `string` | Yes | - | `undefined`
+| [`hoverBorderWidth`](#line-styling) | `number` | Yes | - | `undefined`
 | [`fill`](#line-styling) | <code>boolean&#124;string</code> | Yes | - | `true`
 | [`label`](#general) | `string` | - | - | `''`
 | [`order`](#general) | `number` | - | - | `0`

docs/general/options.md

@@ -43,5 +43,6 @@ The context object contains the following properties:
 - `dataIndex`: index of the current data
 - `dataset`: dataset at index `datasetIndex`
 - `datasetIndex`: index of the current dataset
+- `hover`: true if hovered
 
 **Important**: since the context can represent different types of entities (dataset, data, etc.), some properties may be `undefined` so be sure to test any context property before using it.

src/core/core.controller.js

@@ -989,15 +989,19 @@ helpers.extend(Chart.prototype, /** @lends Chart */ {
 	},
 
 	updateHoverStyle: function(elements, mode, enabled) {
-		var method = enabled ? 'setHoverStyle' : 'removeHoverStyle';
+		var prefix = enabled ? 'set' : 'remove';
 		var element, i, ilen;
 
 		for (i = 0, ilen = elements.length; i < ilen; ++i) {
 			element = elements[i];
 			if (element) {
-				this.getDatasetMeta(element._datasetIndex).controller[method](element);
+				this.getDatasetMeta(element._datasetIndex).controller[prefix + 'HoverStyle'](element);
 			}
 		}
+
+		if (mode === 'dataset') {
+			this.getDatasetMeta(elements[0]._datasetIndex).controller['_' + prefix + 'DatasetHoverStyle']();
+		}
 	},
 
 	/**

src/core/core.datasetController.js

@@ -356,29 +356,31 @@ helpers.extend(DatasetController.prototype, {
 	/**
 	 * @private
 	 */
-	_resolveDatasetElementOptions: function(element) {
+	_resolveDatasetElementOptions: function(element, hover) {
 		var me = this;
 		var chart = me.chart;
 		var datasetOpts = me._config;
 		var custom = element.custom || {};
 		var options = chart.options.elements[me.datasetElementType.prototype._type] || {};
 		var elementOptions = me._datasetElementOptions;
 		var values = {};
-		var i, ilen, key;
+		var i, ilen, key, readKey;
 
 		// Scriptable options
 		var context = {
 			chart: chart,
 			dataset: me.getDataset(),
-			datasetIndex: me.index
+			datasetIndex: me.index,
+			hover: hover
 		};
 
 		for (i = 0, ilen = elementOptions.length; i < ilen; ++i) {
 			key = elementOptions[i];
+			readKey = hover ? 'hover' + key.charAt(0).toUpperCase() + key.slice(1) : key;
 			values[key] = resolve([
-				custom[key],
-				datasetOpts[key],
-				options[key]
+				custom[readKey],
+				datasetOpts[readKey],
+				options[readKey]
 			], context);
 		}
 
@@ -468,6 +470,42 @@ helpers.extend(DatasetController.prototype, {
 		model.borderWidth = resolve([custom.hoverBorderWidth, dataset.hoverBorderWidth, model.borderWidth], undefined, index);
 	},
 
+	/**
+	 * @private
+	 */
+	_removeDatasetHoverStyle: function() {
+		var element = this.getMeta().dataset;
+
+		if (element) {
+			this.removeHoverStyle(element);
+		}
+	},
+
+	/**
+	 * @private
+	 */
+	_setDatasetHoverStyle: function() {
+		var element = this.getMeta().dataset;
+		var prev = {};
+		var i, ilen, key, keys, hoverOptions, model;
+
+		if (!element) {
+			return;
+		}
+
+		model = element._model;
+		hoverOptions = this._resolveDatasetElementOptions(element, true);
+
+		keys = Object.keys(hoverOptions);
+		for (i = 0, ilen = keys.length; i < ilen; ++i) {
+			key = keys[i];
+			prev[key] = model[key];
+			model[key] = hoverOptions[key];
+		}
+
+		element.$previousStyle = prev;
+	},
+
 	/**
 	 * @private
 	 */

test/specs/controller.line.tests.js

@@ -895,6 +895,34 @@ describe('Chart.controllers.line', function() {
 			expect(point._model.borderWidth).toBe(2);
 			expect(point._model.radius).toBe(3);
 		});
+
+		it ('should handle dataset hover styles defined via dataset properties', function() {
+			var chart = this.chart;
+			var point = chart.getDatasetMeta(0).data[0];
+			var dataset = chart.getDatasetMeta(0).dataset;
+
+			Chart.helpers.merge(chart.data.datasets[0], {
+				backgroundColor: '#AAA',
+				borderColor: '#BBB',
+				borderWidth: 6,
+				hoverBackgroundColor: '#000',
+				hoverBorderColor: '#111',
+				hoverBorderWidth: 12
+			});
+
+			chart.options.hover = {mode: 'dataset'};
+			chart.update();
+
+			jasmine.triggerMouseEvent(chart, 'mousemove', point);
+			expect(dataset._model.backgroundColor).toBe('#000');
+			expect(dataset._model.borderColor).toBe('#111');
+			expect(dataset._model.borderWidth).toBe(12);
+
+			jasmine.triggerMouseEvent(chart, 'mouseout', point);
+			expect(dataset._model.backgroundColor).toBe('#AAA');
+			expect(dataset._model.borderColor).toBe('#BBB');
+			expect(dataset._model.borderWidth).toBe(6);
+		});
 	});
 
 	it('should allow 0 as a point border width', function() {