Suggested changes from PR review

Changes to be committed:
	modified:   docs/02-Scales.md
	modified:   src/core/core.helpers.js
	modified:   src/core/core.scale.js
	modified:   test/core.helpers.tests.js

docs/02-Scales.md

@@ -74,7 +74,7 @@ The grid line configuration is nested under the scale configuration in the `tick
 Name | Type | Default | Description
 --- | --- | --- | ---
 autoSkip | Boolean | true | If true, automatically calculates how many labels that can be shown and hides labels accordingly. Turn it off to show all labels no matter what
-callback | Function | `function(value) { return '' + value; } ` | Returns the string representation of the tick value as it should be displayed on the chart. See [callback](#scales-creating-custom-tick-formats) section below.
+callback | Function | `function(value) { return helpers.isArray(value) ? value : '' + value; }` | Returns the string representation of the tick value as it should be displayed on the chart. See [callback](#scales-creating-custom-tick-formats) section below.
 display | Boolean | true | If true, show the ticks.
 fontColor | Color | "#666" | Font color for the tick labels.
 fontFamily | String | "'Helvetica Neue', 'Helvetica', 'Arial', sans-serif" | Font family for the tick labels, follows CSS font-family options.
@@ -359,8 +359,8 @@ The default configuration for a scale can be easily changed using the scale serv
 For example, to set the minimum value of 0 for all linear scales, you would do the following. Any linear scales created after this time would now have a minimum of 0.
 ```
 Chart.scaleService.updateScaleDefaults('linear', {
-	ticks: {
-		min: 0
-	}
+    ticks: {
+        min: 0
+    }
 })
 ```

src/core/core.helpers.js

@@ -839,7 +839,7 @@ module.exports = function(Chart) {
 				// to do maybe simplify this function a bit so we can do this more recursively?
 				helpers.each(thing, function(nestedThing) {
 					// Undefined strings and arrays should not be measured
-					if (nestedThing !== undefined && nestedThing !== null && helpers.isArray(nestedThing)) {
+					if (nestedThing !== undefined && nestedThing !== null && !helpers.isArray(nestedThing)) {
 						longest = helpers.measureText(ctx, data, gc, longest, nestedThing);
 					}
 				});

src/core/core.scale.js

@@ -43,6 +43,7 @@ module.exports = function(Chart) {
 			autoSkip: true,
 			autoSkipPadding: 0,
 			labelOffset: 0,
+			// We pass through arrays to be rendered as multiline labels, we convert Others to strings here.
 			callback: function(value) {
 				return helpers.isArray(value) ? value : '' + value;
 			}
@@ -548,7 +549,6 @@ module.exports = function(Chart) {
 				helpers.each(this.ticks, function (label, index) {
 					// Blank optionTicks
 					var isLastTick = this.ticks.length === index + 1;
-					var lineHeight;
 
 					// Since we always show the last tick,we need may need to hide the last shown one before
 					var shouldSkip = (skipRatio > 1 && index % skipRatio > 0) || (index % skipRatio === 0 && index + skipRatio >= this.ticks.length);
@@ -597,13 +597,13 @@ module.exports = function(Chart) {
 						context.font = tickLabelFont;
 						context.textAlign = (isRotated) ? "right" : "center";
 						context.textBaseline = (isRotated) ? "middle" : options.position === "top" ? "bottom" : "top";
-						
-						lineHeight = context.measureText("M").width * 1.2;
-
+					
 						if (helpers.isArray(label)) {
 							for (var i = 0, y = 0; i < label.length; ++i) {
-								context.fillText(label[i], 0, y);
-								y += lineHeight;
+								// We just make sure the multiline element is a string here..
+								context.fillText('' + label[i], 0, y);
+								// apply same lineSpacing as calculated @ L#320
+								y += (tickFontSize * 1.5);
 							}
 						} else {
 							context.fillText(label, 0, 0);

test/core.helpers.tests.js

@@ -454,6 +454,68 @@ describe('Core helper tests', function() {
 		}]);
 	});
 
+	it('should return the width of the longest text in an Array and 2D Array', function() {
+		var context = window.createMockContext();
+		var font = "normal 12px 'Helvetica Neue', 'Helvetica', 'Arial', sans-serif";
+		var arrayOfThings_1D = ['FooBar','Bar'];
+		var arrayOfThings_2D = [['FooBar_1','Bar_2'],'Foo_1'];
+		
+
+		// Regardless 'FooBar' is the longest label it should return (charcters * 10)
+		expect(helpers.longestText(context, font, arrayOfThings_1D, {})).toEqual(60);
+		expect(helpers.longestText(context, font, arrayOfThings_2D, {})).toEqual(80);
+		// We check to make sure we made the right calls to the canvas.
+		expect(context.getCalls()).toEqual([{
+			name: 'measureText',
+			args: ['FooBar']
+		}, {
+			name: 'measureText',
+			args: ['Bar']
+		}, {
+			name: 'measureText',
+			args: ['FooBar_1']
+		}, {
+			name: 'measureText',
+			args: ['Bar_2']
+		}, {
+			name: 'measureText',
+			args: ['Foo_1']
+		}]);
+	});
+
+	it('compare text with current longest and update', function() {
+		var context = window.createMockContext();
+		var data = {};
+		var gc = [];
+		var longest = 70;
+
+		expect(helpers.measureText(context, data, gc, longest, 'foobar')).toEqual(70);
+		expect(helpers.measureText(context, data, gc, longest, 'foobar_')).toEqual(70);
+		expect(helpers.measureText(context, data, gc, longest, 'foobar_1')).toEqual(80);
+		// We check to make sure we made the right calls to the canvas.
+		expect(context.getCalls()).toEqual([{
+			name: 'measureText',
+			args: ['foobar']
+		}, {
+			name: 'measureText',
+			args: ['foobar_']
+		}, {
+			name: 'measureText',
+			args: ['foobar_1']
+		}]);
+	});
+
+	it('count look at all the labels and return maximum number of lines', function() {
+		var context = window.createMockContext();
+		var arrayOfThings_1 = ['Foo','Bar'];
+		var arrayOfThings_2 = [['Foo','Bar'],'Foo'];
+		var arrayOfThings_3 = [['Foo','Bar','Boo'],['Foo','Bar'],'Foo'];
+
+		expect(helpers.numberOfLabelLines(arrayOfThings_1)).toEqual(1);
+		expect(helpers.numberOfLabelLines(arrayOfThings_2)).toEqual(2);
+		expect(helpers.numberOfLabelLines(arrayOfThings_3)).toEqual(3);
+	});
+
 	it('should draw a rounded rectangle', function() {
 		var context = window.createMockContext();
 		helpers.drawRoundedRectangle(context, 10, 20, 30, 40, 5);