Add support for 'inner' border for arc elements (#5841)

docs/charts/doughnut.md

@@ -55,12 +55,21 @@ The doughnut/pie chart allows a number of properties to be specified for each da
 
 | Name | Type | Description
 | ---- | ---- | -----------
-| `backgroundColor` | `Color[]` | The fill color of the arcs in the dataset. See [Colors](../general/colors.md#colors).
+| `backgroundColor` | `Color/Color[]` | The fill color of the arcs in the dataset. See [Colors](../general/colors.md#colors).
-| `borderColor` | `Color[]` | The border color of the arcs in the dataset. See [Colors](../general/colors.md#colors).
+| `borderColor` | `Color/Color[]` | The border color of the arcs in the dataset. See [Colors](../general/colors.md#colors).
-| `borderWidth` | `Number[]` | The border width of the arcs in the dataset.
+| `borderWidth` | `Number/Number[]` | The border width of the arcs in the dataset.
-| `hoverBackgroundColor` | `Color[]` | The fill colour of the arcs when hovered.
+| `borderAlign` | `String/String[]` | The border alignment of the arcs in the dataset. [more...](#border-alignment)
-| `hoverBorderColor` | `Color[]` | The stroke colour of the arcs when hovered.
+| `hoverBackgroundColor` | `Color/Color[]` | The fill colour of the arcs when hovered.
-| `hoverBorderWidth` | `Number[]` | The stroke width of the arcs when hovered.
+| `hoverBorderColor` | `Color/Color[]` | The stroke colour of the arcs when hovered.
+| `hoverBorderWidth` | `Number/Number[]` | The stroke width of the arcs when hovered.
+
+### Border Alignment
+
+The following values are supported for `borderAlign`.
+* `'center'` (default)
+* `'inner'`
+
+When `'center'` is set, the borders of arcs next to each other will overlap. When `'inner'` is set, it is guaranteed that all the borders are not overlap.
 
 ## Config Options
 

docs/charts/polar.md

@@ -46,12 +46,21 @@ The following options can be included in a polar area chart dataset to configure
 
 | Name | Type | Description
 | ---- | ---- | -----------
-| `backgroundColor` | `Color[]` | The fill color of the arcs in the dataset. See [Colors](../general/colors.md#colors).
+| `backgroundColor` | `Color/Color[]` | The fill color of the arcs in the dataset. See [Colors](../general/colors.md#colors).
-| `borderColor` | `Color[]` | The border color of the arcs in the dataset. See [Colors](../general/colors.md#colors).
+| `borderColor` | `Color/Color[]` | The border color of the arcs in the dataset. See [Colors](../general/colors.md#colors).
-| `borderWidth` | `Number[]` | The border width of the arcs in the dataset.
+| `borderWidth` | `Number/Number[]` | The border width of the arcs in the dataset.
-| `hoverBackgroundColor` | `Color[]` | The fill colour of the arcs when hovered.
+| `borderAlign` | `String/String[]` | The border alignment of the arcs in the dataset. [more...](#border-alignment)
-| `hoverBorderColor` | `Color[]` | The stroke colour of the arcs when hovered.
+| `hoverBackgroundColor` | `Color/Color[]` | The fill colour of the arcs when hovered.
-| `hoverBorderWidth` | `Number[]` | The stroke width of the arcs when hovered.
+| `hoverBorderColor` | `Color/Color[]` | The stroke colour of the arcs when hovered.
+| `hoverBorderWidth` | `Number/Number[]` | The stroke width of the arcs when hovered.
+
+### Border Alignment
+
+The following values are supported for `borderAlign`.
+* `'center'` (default)
+* `'inner'`
+
+When `'center'` is set, the borders of arcs next to each other will overlap. When `'inner'` is set, it is guaranteed that all the borders are not overlap.
 
 ## Config Options
 

src/controllers/controller.doughnut.js

@@ -143,14 +143,15 @@ module.exports = DatasetController.extend({
 		var chart = me.chart;
 		var chartArea = chart.chartArea;
 		var opts = chart.options;
-		var arcOpts = opts.elements.arc;
+		var availableWidth = chartArea.right - chartArea.left;
-		var availableWidth = chartArea.right - chartArea.left - arcOpts.borderWidth;
+		var availableHeight = chartArea.bottom - chartArea.top;
-		var availableHeight = chartArea.bottom - chartArea.top - arcOpts.borderWidth;
 		var minSize = Math.min(availableWidth, availableHeight);
 		var offset = {x: 0, y: 0};
 		var meta = me.getMeta();
+		var arcs = meta.data;
 		var cutoutPercentage = opts.cutoutPercentage;
 		var circumference = opts.circumference;
+		var i, ilen;
 
 		// If the chart's circumference isn't a full circle, calculate minSize as a ratio of the width/height of the arc
 		if (circumference < Math.PI * 2.0) {
@@ -171,7 +172,11 @@ module.exports = DatasetController.extend({
 			offset = {x: (max.x + min.x) * -0.5, y: (max.y + min.y) * -0.5};
 		}
 
-		chart.borderWidth = me.getMaxBorderWidth(meta.data);
+		for (i = 0, ilen = arcs.length; i < ilen; ++i) {
+			arcs[i]._options = me._resolveElementOptions(arcs[i], i, reset);
+		}
+
+		chart.borderWidth = me.getMaxBorderWidth();
 		chart.outerRadius = Math.max((minSize - chart.borderWidth) / 2, 0);
 		chart.innerRadius = Math.max(cutoutPercentage ? (chart.outerRadius / 100) * (cutoutPercentage) : 0, 0);
 		chart.radiusLength = (chart.outerRadius - chart.innerRadius) / chart.getVisibleDatasetCount();
@@ -183,9 +188,9 @@ module.exports = DatasetController.extend({
 		me.outerRadius = chart.outerRadius - (chart.radiusLength * me.getRingIndex(me.index));
 		me.innerRadius = Math.max(me.outerRadius - chart.radiusLength, 0);
 
-		helpers.each(meta.data, function(arc, index) {
+		for (i = 0, ilen = arcs.length; i < ilen; ++i) {
-			me.updateElement(arc, index, reset);
+			me.updateElement(arcs[i], i, reset);
-		});
+		}
 	},
 
 	updateElement: function(arc, index, reset) {
@@ -202,7 +207,7 @@ module.exports = DatasetController.extend({
 		var circumference = reset && animationOpts.animateRotate ? 0 : arc.hidden ? 0 : me.calculateCircumference(dataset.data[index]) * (opts.circumference / (2.0 * Math.PI));
 		var innerRadius = reset && animationOpts.animateScale ? 0 : me.innerRadius;
 		var outerRadius = reset && animationOpts.animateScale ? 0 : me.outerRadius;
-		var valueAtIndexOrDefault = helpers.valueAtIndexOrDefault;
+		var options = arc._options || {};
 
 		helpers.extend(arc, {
 			// Utility
@@ -211,6 +216,10 @@ module.exports = DatasetController.extend({
 
 			// Desired view properties
 			_model: {
+				backgroundColor: options.backgroundColor,
+				borderColor: options.borderColor,
+				borderWidth: options.borderWidth,
+				borderAlign: options.borderAlign,
 				x: centerX + chart.offsetX,
 				y: centerY + chart.offsetY,
 				startAngle: startAngle,
@@ -218,20 +227,12 @@ module.exports = DatasetController.extend({
 				circumference: circumference,
 				outerRadius: outerRadius,
 				innerRadius: innerRadius,
-				label: valueAtIndexOrDefault(dataset.label, index, chart.data.labels[index])
+				label: helpers.valueAtIndexOrDefault(dataset.label, index, chart.data.labels[index])
 			}
 		});
 
 		var model = arc._model;
 
-		// Resets the visual styles
-		var custom = arc.custom || {};
-		var valueOrDefault = helpers.valueAtIndexOrDefault;
-		var elementOpts = this.chart.options.elements.arc;
-		model.backgroundColor = custom.backgroundColor ? custom.backgroundColor : valueOrDefault(dataset.backgroundColor, index, elementOpts.backgroundColor);
-		model.borderColor = custom.borderColor ? custom.borderColor : valueOrDefault(dataset.borderColor, index, elementOpts.borderColor);
-		model.borderWidth = custom.borderWidth ? custom.borderWidth : valueOrDefault(dataset.borderWidth, index, elementOpts.borderWidth);
-
 		// Set correct angles if not resetting
 		if (!reset || !animationOpts.animateRotate) {
 			if (index === 0) {
@@ -276,19 +277,58 @@ module.exports = DatasetController.extend({
 
 	// gets the max border or hover width to properly scale pie charts
 	getMaxBorderWidth: function(arcs) {
+		var me = this;
 		var max = 0;
-		var index = this.index;
+		var chart = me.chart;
-		var length = arcs.length;
+		var i, ilen, meta, arc, controller, options, borderWidth, hoverWidth;
-		var borderWidth;
-		var hoverWidth;
 
-		for (var i = 0; i < length; i++) {
+		if (!arcs) {
-			borderWidth = arcs[i]._model ? arcs[i]._model.borderWidth : 0;
+			// Find the outmost visible dataset
-			hoverWidth = arcs[i]._chart ? arcs[i]._chart.config.data.datasets[index].hoverBorderWidth : 0;
+			for (i = 0, ilen = chart.data.datasets.length; i < ilen; ++i) {
+				if (chart.isDatasetVisible(i)) {
+					meta = chart.getDatasetMeta(i);
+					arcs = meta.data;
+					if (i !== me.index) {
+						controller = meta.controller;
+					}
+					break;
+				}
+			}
+		}
 
-			max = borderWidth > max ? borderWidth : max;
+		if (!arcs) {
-			max = hoverWidth > max ? hoverWidth : max;
+			return 0;
+		}
+
+		for (i = 0, ilen = arcs.length; i < ilen; ++i) {
+			arc = arcs[i];
+			options = controller ? controller._resolveElementOptions(arc, i) : arc._options;
+			if (options.borderAlign !== 'inner') {
+				borderWidth = options.borderWidth;
+				hoverWidth = options.hoverBorderWidth;
+
+				max = borderWidth > max ? borderWidth : max;
+				max = hoverWidth > max ? hoverWidth : max;
+			}
 		}
 		return max;
+	},
+
+	/**
+	 * @private
+	 */
+	_resolveElementOptions: function(arc, index) {
+		var me = this;
+		var dataset = me.getDataset();
+		var custom = arc.custom || {};
+		var options = me.chart.options.elements.arc;
+		var valueAtIndexOrDefault = helpers.valueAtIndexOrDefault;
+
+		return {
+			backgroundColor: custom.backgroundColor ? custom.backgroundColor : valueAtIndexOrDefault(dataset.backgroundColor, index, options.backgroundColor),
+			borderColor: custom.borderColor ? custom.borderColor : valueAtIndexOrDefault(dataset.borderColor, index, options.borderColor),
+			borderWidth: custom.borderWidth ? custom.borderWidth : valueAtIndexOrDefault(dataset.borderWidth, index, options.borderWidth),
+			borderAlign: custom.borderAlign ? custom.borderAlign : valueAtIndexOrDefault(dataset.borderAlign, index, options.borderAlign)
+		};
 	}
 });

src/controllers/controller.polarArea.js

@@ -148,10 +148,9 @@ module.exports = DatasetController.extend({
 		var chart = me.chart;
 		var chartArea = chart.chartArea;
 		var opts = chart.options;
-		var arcOpts = opts.elements.arc;
 		var minSize = Math.min(chartArea.right - chartArea.left, chartArea.bottom - chartArea.top);
 
-		chart.outerRadius = Math.max((minSize - arcOpts.borderWidth / 2) / 2, 0);
+		chart.outerRadius = Math.max(minSize / 2, 0);
 		chart.innerRadius = Math.max(opts.cutoutPercentage ? (chart.outerRadius / 100) * (opts.cutoutPercentage) : 1, 0);
 		chart.radiusLength = (chart.outerRadius - chart.innerRadius) / chart.getVisibleDatasetCount();
 
@@ -206,6 +205,7 @@ module.exports = DatasetController.extend({
 		model.backgroundColor = custom.backgroundColor ? custom.backgroundColor : valueOrDefault(dataset.backgroundColor, index, elementOpts.backgroundColor);
 		model.borderColor = custom.borderColor ? custom.borderColor : valueOrDefault(dataset.borderColor, index, elementOpts.borderColor);
 		model.borderWidth = custom.borderWidth ? custom.borderWidth : valueOrDefault(dataset.borderWidth, index, elementOpts.borderWidth);
+		model.borderAlign = custom.borderAlign ? custom.borderAlign : valueOrDefault(dataset.borderAlign, index, elementOpts.borderAlign);
 
 		arc.pivot();
 	},

src/elements/element.arc.js

@@ -9,7 +9,8 @@ defaults._set('global', {
 		arc: {
 			backgroundColor: defaults.global.defaultColor,
 			borderColor: '#fff',
-			borderWidth: 2
+			borderWidth: 2,
+			borderAlign: 'center'
 		}
 	}
 });
@@ -85,23 +86,51 @@ module.exports = Element.extend({
 		var vm = this._view;
 		var sA = vm.startAngle;
 		var eA = vm.endAngle;
+		var pixelMargin = (vm.borderAlign === 'inner') ? 0.33 : 0;
+		var angleMargin;
+
+		ctx.save();
 
 		ctx.beginPath();
-
+		ctx.arc(vm.x, vm.y, vm.outerRadius - pixelMargin, sA, eA);
-		ctx.arc(vm.x, vm.y, vm.outerRadius, sA, eA);
 		ctx.arc(vm.x, vm.y, vm.innerRadius, eA, sA, true);
-
 		ctx.closePath();
-		ctx.strokeStyle = vm.borderColor;
-		ctx.lineWidth = vm.borderWidth;
 
 		ctx.fillStyle = vm.backgroundColor;
-
 		ctx.fill();
-		ctx.lineJoin = 'bevel';
 
 		if (vm.borderWidth) {
+			if (vm.borderAlign === 'inner') {
+				// Draw an inner border by cliping the arc and drawing a double-width border
+				// Enlarge the clipping arc by 0.33 pixels to eliminate glitches between borders
+				ctx.beginPath();
+				angleMargin = pixelMargin / vm.outerRadius;
+				ctx.arc(vm.x, vm.y, vm.outerRadius, sA - angleMargin, eA + angleMargin);
+				if (vm.innerRadius > pixelMargin) {
+					angleMargin = pixelMargin / vm.innerRadius;
+					ctx.arc(vm.x, vm.y, vm.innerRadius - pixelMargin, eA + angleMargin, sA - angleMargin, true);
+				} else {
+					ctx.arc(vm.x, vm.y, pixelMargin, eA + Math.PI / 2, sA - Math.PI / 2);
+				}
+				ctx.closePath();
+				ctx.clip();
+
+				ctx.beginPath();
+				ctx.arc(vm.x, vm.y, vm.outerRadius, sA, eA);
+				ctx.arc(vm.x, vm.y, vm.innerRadius, eA, sA, true);
+				ctx.closePath();
+
+				ctx.lineWidth = vm.borderWidth * 2;
+				ctx.lineJoin = 'round';
+			} else {
+				ctx.lineWidth = vm.borderWidth;
+				ctx.lineJoin = 'bevel';
+			}
+
+			ctx.strokeStyle = vm.borderColor;
 			ctx.stroke();
 		}
+
+		ctx.restore();
 	}
 });

test/context.js

@@ -79,6 +79,7 @@ Context.prototype._initMethods = function() {
 		beginPath: function() {},
 		bezierCurveTo: function() {},
 		clearRect: function() {},
+		clip: function() {},
 		closePath: function() {},
 		fill: function() {},
 		fillRect: function() {},

test/fixtures/controller.doughnut/doughnut-border-align-center.json

@@ -0,0 +1,31 @@
+{
+    "config": {
+        "type": "doughnut",
+        "data": {
+            "labels": ["A", "B", "C", "D", "E"],
+            "datasets": [{
+                "data": [1, 5, 10, 50, 100],
+                "backgroundColor": [
+                    "rgba(255, 99, 132, 0.8)",
+                    "rgba(54, 162, 235, 0.8)",
+                    "rgba(255, 206, 86, 0.8)",
+                    "rgba(75, 192, 192, 0.8)",
+                    "rgba(153, 102, 255, 0.8)"
+                ],
+                "borderWidth": 20,
+                "borderColor": [
+                    "rgb(255, 99, 132)",
+                    "rgb(54, 162, 235)",
+                    "rgb(255, 206, 86)",
+                    "rgb(75, 192, 192)",
+                    "rgb(153, 102, 255)"
+                ]
+            }]
+        },
+        "options": {
+            "responsive": false,
+            "legend": false,
+            "title": false
+        }
+    }
+}

test/fixtures/controller.doughnut/doughnut-border-align-inner.json

@@ -0,0 +1,32 @@
+{
+    "config": {
+        "type": "doughnut",
+        "data": {
+            "labels": ["A", "B", "C", "D", "E"],
+            "datasets": [{
+                "data": [1, 5, 10, 50, 100],
+                "backgroundColor": [
+                    "rgba(255, 99, 132, 0.8)",
+                    "rgba(54, 162, 235, 0.8)",
+                    "rgba(255, 206, 86, 0.8)",
+                    "rgba(75, 192, 192, 0.8)",
+                    "rgba(153, 102, 255, 0.8)"
+                ],
+                "borderWidth": 20,
+                "borderColor": [
+                    "rgb(255, 99, 132)",
+                    "rgb(54, 162, 235)",
+                    "rgb(255, 206, 86)",
+                    "rgb(75, 192, 192)",
+                    "rgb(153, 102, 255)"
+                ],
+                "borderAlign": "inner"
+            }]
+        },
+        "options": {
+            "responsive": false,
+            "legend": false,
+            "title": false
+        }
+    }
+}

test/fixtures/controller.doughnut/pie-border-align-center.json

@@ -0,0 +1,31 @@
+{
+    "config": {
+        "type": "pie",
+        "data": {
+            "labels": ["A", "B", "C", "D", "E"],
+            "datasets": [{
+                "data": [1, 5, 10, 50, 100],
+                "backgroundColor": [
+                    "rgba(255, 99, 132, 0.8)",
+                    "rgba(54, 162, 235, 0.8)",
+                    "rgba(255, 206, 86, 0.8)",
+                    "rgba(75, 192, 192, 0.8)",
+                    "rgba(153, 102, 255, 0.8)"
+                ],
+                "borderWidth": 20,
+                "borderColor": [
+                    "rgb(255, 99, 132)",
+                    "rgb(54, 162, 235)",
+                    "rgb(255, 206, 86)",
+                    "rgb(75, 192, 192)",
+                    "rgb(153, 102, 255)"
+                ]
+            }]
+        },
+        "options": {
+            "responsive": false,
+            "legend": false,
+            "title": false
+        }
+    }
+}

test/fixtures/controller.doughnut/pie-border-align-inner.json

@@ -0,0 +1,32 @@
+{
+    "config": {
+        "type": "pie",
+        "data": {
+            "labels": ["A", "B", "C", "D", "E"],
+            "datasets": [{
+                "data": [1, 5, 10, 50, 100],
+                "backgroundColor": [
+                    "rgba(255, 99, 132, 0.8)",
+                    "rgba(54, 162, 235, 0.8)",
+                    "rgba(255, 206, 86, 0.8)",
+                    "rgba(75, 192, 192, 0.8)",
+                    "rgba(153, 102, 255, 0.8)"
+                ],
+                "borderWidth": 20,
+                "borderColor": [
+                    "rgb(255, 99, 132)",
+                    "rgb(54, 162, 235)",
+                    "rgb(255, 206, 86)",
+                    "rgb(75, 192, 192)",
+                    "rgb(153, 102, 255)"
+                ],
+                "borderAlign": "inner"
+            }]
+        },
+        "options": {
+            "responsive": false,
+            "legend": false,
+            "title": false
+        }
+    }
+}

test/fixtures/controller.polarArea/border-align-center.json

@@ -0,0 +1,41 @@
+{
+    "config": {
+        "type": "polarArea",
+        "data": {
+            "labels": ["A", "B", "C", "D", "E"],
+            "datasets": [{
+                "data": [11, 16, 21, 1, 10],
+                "backgroundColor": [
+                    "rgba(255, 99, 132, 0.8)",
+                    "rgba(54, 162, 235, 0.8)",
+                    "rgba(255, 206, 86, 0.8)",
+                    "rgba(75, 192, 192, 0.8)",
+                    "rgba(153, 102, 255, 0.8)"
+                ],
+                "borderWidth": 20,
+                "borderColor": [
+                    "rgb(255, 99, 132)",
+                    "rgb(54, 162, 235)",
+                    "rgb(255, 206, 86)",
+                    "rgb(75, 192, 192)",
+                    "rgb(153, 102, 255)"
+                ]
+            }]
+        },
+        "options": {
+            "elements": {
+                "arc": {
+                    "angle": [
+                        0.0378, 0.1892, 0.3786, 1.8925, 3.7849
+                    ]
+                }
+            },
+            "responsive": false,
+            "legend": false,
+            "title": false,
+            "scale": {
+                "display": false
+            }
+        }
+    }
+}

test/fixtures/controller.polarArea/border-align-inner.json

@@ -0,0 +1,42 @@
+{
+    "config": {
+        "type": "polarArea",
+        "data": {
+            "labels": ["A", "B", "C", "D", "E"],
+            "datasets": [{
+                "data": [11, 16, 21, 1, 10],
+                "backgroundColor": [
+                    "rgba(255, 99, 132, 0.8)",
+                    "rgba(54, 162, 235, 0.8)",
+                    "rgba(255, 206, 86, 0.8)",
+                    "rgba(75, 192, 192, 0.8)",
+                    "rgba(153, 102, 255, 0.8)"
+                ],
+                "borderWidth": 20,
+                "borderColor": [
+                    "rgb(255, 99, 132)",
+                    "rgb(54, 162, 235)",
+                    "rgb(255, 206, 86)",
+                    "rgb(75, 192, 192)",
+                    "rgb(153, 102, 255)"
+                ],
+                "borderAlign": "inner"
+            }]
+        },
+        "options": {
+            "elements": {
+                "arc": {
+                    "angle": [
+                        0.0378, 0.1892, 0.3786, 1.8925, 3.7849
+                    ]
+                }
+            },
+            "responsive": false,
+            "legend": false,
+            "title": false,
+            "scale": {
+                "display": false
+            }
+        }
+    }
+}

test/specs/controller.doughnut.tests.js

@@ -1,4 +1,6 @@
 describe('Chart.controllers.doughnut', function() {
+	describe('auto', jasmine.fixture.specs('controller.doughnut'));
+
 	it('should be registered as dataset controller', function() {
 		expect(typeof Chart.controllers.doughnut).toBe('function');
 		expect(Chart.controllers.doughnut).toBe(Chart.controllers.pie);
@@ -106,8 +108,8 @@ describe('Chart.controllers.doughnut', function() {
 		].forEach(function(expected, i) {
 			expect(meta.data[i]._model.x).toBeCloseToPixel(256);
 			expect(meta.data[i]._model.y).toBeCloseToPixel(256);
-			expect(meta.data[i]._model.outerRadius).toBeCloseToPixel(254);
+			expect(meta.data[i]._model.outerRadius).toBeCloseToPixel(256);
-			expect(meta.data[i]._model.innerRadius).toBeCloseToPixel(190);
+			expect(meta.data[i]._model.innerRadius).toBeCloseToPixel(192);
 			expect(meta.data[i]._model.circumference).toBeCloseTo(expected.c, 8);
 			expect(meta.data[i]._model).toEqual(jasmine.objectContaining({
 				startAngle: Math.PI * -0.5,
@@ -129,8 +131,8 @@ describe('Chart.controllers.doughnut', function() {
 		].forEach(function(expected, i) {
 			expect(meta.data[i]._model.x).toBeCloseToPixel(256);
 			expect(meta.data[i]._model.y).toBeCloseToPixel(256);
-			expect(meta.data[i]._model.outerRadius).toBeCloseToPixel(254);
+			expect(meta.data[i]._model.outerRadius).toBeCloseToPixel(256);
-			expect(meta.data[i]._model.innerRadius).toBeCloseToPixel(190);
+			expect(meta.data[i]._model.innerRadius).toBeCloseToPixel(192);
 			expect(meta.data[i]._model.circumference).toBeCloseTo(expected.c, 8);
 			expect(meta.data[i]._model.startAngle).toBeCloseTo(expected.s, 8);
 			expect(meta.data[i]._model.endAngle).toBeCloseTo(expected.e, 8);
@@ -200,10 +202,10 @@ describe('Chart.controllers.doughnut', function() {
 			{c: Math.PI / 8, s: Math.PI, e: Math.PI + Math.PI / 8},
 			{c: 3 * Math.PI / 8, s: Math.PI + Math.PI / 8, e: Math.PI + Math.PI / 2}
 		].forEach(function(expected, i) {
-			expect(meta.data[i]._model.x).toBeCloseToPixel(511);
+			expect(meta.data[i]._model.x).toBeCloseToPixel(512);
-			expect(meta.data[i]._model.y).toBeCloseToPixel(511);
+			expect(meta.data[i]._model.y).toBeCloseToPixel(512);
-			expect(meta.data[i]._model.outerRadius).toBeCloseToPixel(510);
+			expect(meta.data[i]._model.outerRadius).toBeCloseToPixel(512);
-			expect(meta.data[i]._model.innerRadius).toBeCloseToPixel(382);
+			expect(meta.data[i]._model.innerRadius).toBeCloseToPixel(384);
 			expect(meta.data[i]._model.circumference).toBeCloseTo(expected.c, 8);
 			expect(meta.data[i]._model.startAngle).toBeCloseTo(expected.s, 8);
 			expect(meta.data[i]._model.endAngle).toBeCloseTo(expected.e, 8);
@@ -405,4 +407,52 @@ describe('Chart.controllers.doughnut', function() {
 		expect(arc._model.borderColor).toBe('rgb(17, 17, 17)');
 		expect(arc._model.borderWidth).toBe(3.14159);
 	});
+
+	it ('should calculate radiuses based on the border widths of the visible outermost dataset', function() {
+		var chart = window.acquireChart({
+			type: 'doughnut',
+			data: {
+				datasets: [{
+					data: [2, 4],
+					borderWidth: 4,
+					hidden: true
+				}, {
+					data: [1, 3],
+					borderWidth: 8
+				}, {
+					data: [1, 0],
+					borderWidth: 12
+				}],
+				labels: ['label0', 'label1']
+			},
+			options: {
+				legend: false,
+				title: false
+			}
+		});
+
+		chart.update();
+
+		expect(chart.chartArea.bottom - chart.chartArea.top).toBe(512);
+		expect(chart.borderWidth).toBe(8);
+		expect(chart.outerRadius).toBe(252);
+		expect(chart.innerRadius).toBe(126);
+		expect(chart.radiusLength).toBe(63);
+
+		var controller = chart.getDatasetMeta(0).controller;
+		expect(controller.getMaxBorderWidth()).toBe(8);
+		expect(controller.outerRadius).toBe(252);
+		expect(controller.innerRadius).toBe(189);
+
+		controller = chart.getDatasetMeta(1).controller;
+		expect(controller.getMaxBorderWidth()).toBe(8);
+		expect(controller.outerRadius).toBe(252);
+		expect(controller.innerRadius).toBe(189);
+
+		controller = chart.getDatasetMeta(2).controller;
+		expect(controller.getMaxBorderWidth()).toBe(8);
+		expect(controller.outerRadius).toBe(189);
+		expect(controller.innerRadius).toBe(126);
+	});
+
 });

test/specs/core.tooltip.tests.js

@@ -943,7 +943,7 @@ describe('Core.Tooltip', function() {
 				if (model.width <= chart.width) {
 					expect(model.x + model.width).toBeLessThanOrEqual(chart.width);
 				}
-				expect(model.caretX).toBe(tooltipPosition.x);
+				expect(model.caretX).toBeCloseToPixel(tooltipPosition.x);
 				// if tooltip is longer than chart area then all tests done
 				if (model.width > chart.width) {
 					break;

test/specs/element.arc.tests.js

@@ -126,6 +126,9 @@ describe('Arc element tests', function() {
 		arc.draw();
 
 		expect(mockContext.getCalls()).toEqual([{
+			name: 'save',
+			args: []
+		}, {
 			name: 'beginPath',
 			args: []
 		}, {
@@ -137,12 +140,6 @@ describe('Arc element tests', function() {
 		}, {
 			name: 'closePath',
 			args: []
-		}, {
-			name: 'setStrokeStyle',
-			args: ['rgb(255, 0, 0)']
-		}, {
-			name: 'setLineWidth',
-			args: [undefined]
 		}, {
 			name: 'setFillStyle',
 			args: ['rgb(0, 0, 255)']
@@ -150,8 +147,8 @@ describe('Arc element tests', function() {
 			name: 'fill',
 			args: []
 		}, {
-			name: 'setLineJoin',
+			name: 'restore',
-			args: ['bevel']
+			args: []
 		}]);
 	});
 
@@ -182,6 +179,9 @@ describe('Arc element tests', function() {
 		arc.draw();
 
 		expect(mockContext.getCalls()).toEqual([{
+			name: 'save',
+			args: []
+		}, {
 			name: 'beginPath',
 			args: []
 		}, {
@@ -194,23 +194,119 @@ describe('Arc element tests', function() {
 			name: 'closePath',
 			args: []
 		}, {
-			name: 'setStrokeStyle',
+			name: 'setFillStyle',
-			args: ['rgb(255, 0, 0)']
+			args: ['rgb(0, 0, 255)']
+		}, {
+			name: 'fill',
+			args: []
 		}, {
 			name: 'setLineWidth',
 			args: [5]
+		}, {
+			name: 'setLineJoin',
+			args: ['bevel']
+		}, {
+			name: 'setStrokeStyle',
+			args: ['rgb(255, 0, 0)']
+		}, {
+			name: 'stroke',
+			args: []
+		}, {
+			name: 'restore',
+			args: []
+		}]);
+	});
+
+	it ('should draw correctly with an inner border', function() {
+		var mockContext = window.createMockContext();
+		var arc = new Chart.elements.Arc({
+			_datasetIndex: 2,
+			_index: 1,
+			_chart: {
+				ctx: mockContext,
+			}
+		});
+
+		// Mock out the view as if the controller put it there
+		arc._view = {
+			startAngle: 0,
+			endAngle: Math.PI / 2,
+			x: 10,
+			y: 5,
+			innerRadius: 1,
+			outerRadius: 3,
+
+			backgroundColor: 'rgb(0, 0, 255)',
+			borderColor: 'rgb(255, 0, 0)',
+			borderWidth: 5,
+			borderAlign: 'inner'
+		};
+
+		arc.draw();
+
+		expect(mockContext.getCalls()).toEqual([{
+			name: 'save',
+			args: []
+		}, {
+			name: 'beginPath',
+			args: []
+		}, {
+			name: 'arc',
+			args: [10, 5, 2.67, 0, Math.PI / 2]
+		}, {
+			name: 'arc',
+			args: [10, 5, 1, Math.PI / 2, 0, true]
+		}, {
+			name: 'closePath',
+			args: []
 		}, {
 			name: 'setFillStyle',
 			args: ['rgb(0, 0, 255)']
 		}, {
 			name: 'fill',
 			args: []
+		}, {
+			name: 'beginPath',
+			args: []
+		}, {
+			name: 'arc',
+			args: [10, 5, 3, -0.11, Math.PI / 2 + 0.11]
+		}, {
+			name: 'arc',
+			args: [10, 5, 1 - 0.33, Math.PI / 2 + 0.33, -0.33, true]
+		}, {
+			name: 'closePath',
+			args: []
+		}, {
+			name: 'clip',
+			args: []
+		}, {
+			name: 'beginPath',
+			args: []
+		}, {
+			name: 'arc',
+			args: [10, 5, 3, 0, Math.PI / 2]
+		}, {
+			name: 'arc',
+			args: [10, 5, 1, Math.PI / 2, 0, true]
+		}, {
+			name: 'closePath',
+			args: []
+		}, {
+			name: 'setLineWidth',
+			args: [10]
 		}, {
 			name: 'setLineJoin',
-			args: ['bevel']
+			args: ['round']
+		}, {
+			name: 'setStrokeStyle',
+			args: ['rgb(255, 0, 0)']
 		}, {
 			name: 'stroke',
 			args: []
+		}, {
+			name: 'restore',
+			args: []
 		}]);
 	});
 });