Add getStyle method to provide style properties for dataset or data

src/controllers/controller.doughnut.js

@@ -46,13 +46,13 @@ defaults._set('doughnut', {
 				if (data.labels.length && data.datasets.length) {
 					return data.labels.map(function(label, i) {
 						var meta = chart.getDatasetMeta(0);
-						var model = meta.controller._resolveElementOptions(meta.data[i] || {}, i);
+						var style = meta.controller.getStyle(i);
 
 						return {
 							text: label,
-							fillStyle: model.backgroundColor,
-							strokeStyle: model.borderColor,
-							lineWidth: model.borderWidth,
+							fillStyle: style.backgroundColor,
+							strokeStyle: style.borderColor,
+							lineWidth: style.borderWidth,
 							hidden: isNaN(data.datasets[0].data[i]) || meta.data[i].hidden,
 
 							// Extra data used for toggling the correct item

src/controllers/controller.line.js

@@ -125,6 +125,16 @@ module.exports = DatasetController.extend({
 		};
 	},
 
+	/**
+	 * @private
+	 */
+	_resolveElementOptions: function(element, index) {
+		if (index !== undefined) {
+			return this._resolvePointOptions(element, index);
+		}
+		return this._resolveLineOptions(element);
+	},
+
 	/**
 	 * @private
 	 */

src/controllers/controller.polarArea.js

@@ -59,13 +59,13 @@ defaults._set('polarArea', {
 				if (data.labels.length && data.datasets.length) {
 					return data.labels.map(function(label, i) {
 						var meta = chart.getDatasetMeta(0);
-						var model = meta.controller._resolveElementOptions(meta.data[i] || {}, i);
+						var style = meta.controller.getStyle(i);
 
 						return {
 							text: label,
-							fillStyle: model.backgroundColor,
-							strokeStyle: model.borderColor,
-							lineWidth: model.borderWidth,
+							fillStyle: style.backgroundColor,
+							strokeStyle: style.borderColor,
+							lineWidth: style.borderWidth,
 							hidden: isNaN(data.datasets[0].data[i]) || meta.data[i].hidden,
 
 							// Extra data used for toggling the correct item

src/controllers/controller.radar.js

@@ -102,6 +102,16 @@ module.exports = DatasetController.extend({
 		};
 	},
 
+	/**
+	 * @private
+	 */
+	_resolveElementOptions: function(element, index) {
+		if (index !== undefined) {
+			return this._resolvePointOptions(element, index);
+		}
+		return this._resolveLineOptions(element);
+	},
+
 	/**
 	 * @private
 	 */

src/core/core.datasetController.js

@@ -268,6 +268,49 @@ helpers.extend(DatasetController.prototype, {
 		}
 	},
 
+	/*
+	 * Returns a set of predefined style properties that should be used to represent the dataset
+	 * or the data if the index is specified
+	 * @params {number} index - data index
+	 * @return {IStyleInterface} style object
+	 */
+	getStyle: function(index) {
+		var me = this;
+		var meta = me.getMeta();
+		var element, style;
+
+		if (meta.dataset && index === undefined) {
+			element = meta.dataset;
+		} else {
+			index = index || 0;
+			element = meta.data[index];
+		}
+		style = me._resolveElementOptions(element || {}, index);
+
+		if (style.fill === false || style.fill === null) {
+			style.backgroundColor = 'rgba(0,0,0,0)';
+		}
+
+		return {
+			backgroundColor: style.backgroundColor,
+			borderCapStyle: style.borderCapStyle,
+			borderDash: style.borderDash,
+			borderDashOffset: style.borderDashOffset,
+			borderJoinStyle: style.borderJoinStyle,
+			borderWidth: style.borderWidth,
+			borderColor: style.borderColor,
+			pointStyle: style.pointStyle,
+			rotation: style.rotation
+		};
+	},
+
+	/**
+	 * @private
+	 */
+	_resolveElementOptions: function() {
+		// noop
+	},
+
 	removeHoverStyle: function(element) {
 		helpers.merge(element._model, element.$previousStyle || {});
 		delete element.$previousStyle;

src/plugins/plugin.legend.js

@@ -48,36 +48,25 @@ defaults._set('global', {
 			// lineWidth :
 			generateLabels: function(chart) {
 				var data = chart.data;
+				var options = chart.options.legend || {};
+				var usePointStyle = options.labels && options.labels.usePointStyle;
+
 				return helpers.isArray(data.datasets) ? data.datasets.map(function(dataset, i) {
 					var meta = chart.getDatasetMeta(i);
-					var controller = meta.controller;
-					var legendOpts = chart.options.legend;
-					var usePointStyle = legendOpts && legendOpts.labels && legendOpts.labels.usePointStyle;
-					var model;
-
-					if (controller._resolveLineOptions && !usePointStyle) {
-						model = controller._resolveLineOptions(meta.dataset || {});
-						if (model.fill === false || model.fill === null) {
-							model.backgroundColor = 'rgba(0,0,0,0)';
-						}
-					} else if (controller._resolvePointOptions) {
-						model = controller._resolvePointOptions(meta.data[0] || {}, 0);
-					} else {
-						model = controller._resolveElementOptions(meta.data[0] || {}, 0);
-					}
+					var style = meta.controller.getStyle(usePointStyle ? 0 : undefined);
 
 					return {
 						text: dataset.label,
-						fillStyle: model.backgroundColor,
+						fillStyle: style.backgroundColor,
 						hidden: !chart.isDatasetVisible(i),
-						lineCap: model.borderCapStyle,
-						lineDash: model.borderDash,
-						lineDashOffset: model.borderDashOffset,
-						lineJoin: model.borderJoinStyle,
-						lineWidth: model.borderWidth,
-						strokeStyle: model.borderColor,
-						pointStyle: model.pointStyle,
-						rotation: model.rotation,
+						lineCap: style.borderCapStyle,
+						lineDash: style.borderDash,
+						lineDashOffset: style.borderDashOffset,
+						lineJoin: style.borderJoinStyle,
+						lineWidth: style.borderWidth,
+						strokeStyle: style.borderColor,
+						pointStyle: style.pointStyle,
+						rotation: style.rotation,
 
 						// Below is extra data used for toggling the datasets
 						datasetIndex: i