Better number -> string callback for the radial linear scale

src/chart.js

@@ -12,6 +12,7 @@ require('./core/core.datasetController')(Chart);
 require('./core/core.layoutService')(Chart);
 require('./core/core.scaleService')(Chart);
 require('./core/core.plugin.js')(Chart);
+require('./core/core.ticks.js')(Chart);
 require('./core/core.scale')(Chart);
 require('./core/core.title')(Chart);
 require('./core/core.legend')(Chart);

src/core/core.scale.js

@@ -47,7 +47,7 @@ module.exports = function(Chart) {
 			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;
+				return Chart.Ticks.formatters.values(value);
 			}
 		}
 	};

src/core/core.ticks.js

@@ -0,0 +1,73 @@
+'use strict';
+
+module.exports = function(Chart) {
+
+	var helpers = Chart.helpers;
+
+	/**
+	 * Namespace to hold static tick generation functions
+	 * @namespace Chart.Ticks
+	 */
+	Chart.Ticks = {
+		/**
+		 * Namespace to hold formatters for different types of ticks
+		 * @namespace Chart.Ticks.formatters
+		 */
+		formatters: {
+			/**
+			 * Formatter for value labels
+			 * @method Chart.Ticks.formatters.values
+			 * @param value the value to display
+			 * @return {String|Array} the label to display
+			 */
+			values: function(value) {
+				return helpers.isArray(value) ? value : '' + value;
+			},
+
+			/**
+			 * Formatter for linear numeric ticks
+			 * @method Chart.Ticks.formatters.linear
+			 * @param tickValue {Number} the value to be formatted
+			 * @param index {Number} the position of the tickValue parameter in the ticks array
+			 * @param ticks {Array<Number>} the list of ticks being converted
+			 * @return {String} string representation of the tickValue parameter
+			 */
+			linear: function(tickValue, index, ticks) {
+				// If we have lots of ticks, don't use the ones
+				var delta = ticks.length > 3 ? ticks[2] - ticks[1] : ticks[1] - ticks[0];
+
+				// If we have a number like 2.5 as the delta, figure out how many decimal places we need
+				if (Math.abs(delta) > 1) {
+					if (tickValue !== Math.floor(tickValue)) {
+						// not an integer
+						delta = tickValue - Math.floor(tickValue);
+					}
+				}
+
+				var logDelta = helpers.log10(Math.abs(delta));
+				var tickString = '';
+
+				if (tickValue !== 0) {
+					var numDecimal = -1 * Math.floor(logDelta);
+					numDecimal = Math.max(Math.min(numDecimal, 20), 0); // toFixed has a max of 20 decimal places
+					tickString = tickValue.toFixed(numDecimal);
+				} else {
+					tickString = '0'; // never show decimal places for 0
+				}
+
+				return tickString;
+			},
+
+			logarithmic: function(tickValue, index, ticks) {
+				var remain = tickValue / (Math.pow(10, Math.floor(helpers.log10(tickValue))));
+
+				if (tickValue === 0) {
+					return '0';
+				} else if (remain === 1 || remain === 2 || remain === 5 || index === 0 || index === ticks.length - 1) {
+					return tickValue.toExponential();
+				}
+				return '';
+			}
+		}
+	};
+};

src/scales/scale.linear.js

@@ -8,29 +8,7 @@ module.exports = function(Chart) {
 		position: 'left',
 		ticks: {
 			callback: function(tickValue, index, ticks) {
-				// If we have lots of ticks, don't use the ones
-				var delta = ticks.length > 3 ? ticks[2] - ticks[1] : ticks[1] - ticks[0];
-
-				// If we have a number like 2.5 as the delta, figure out how many decimal places we need
-				if (Math.abs(delta) > 1) {
-					if (tickValue !== Math.floor(tickValue)) {
-						// not an integer
-						delta = tickValue - Math.floor(tickValue);
-					}
-				}
-
-				var logDelta = helpers.log10(Math.abs(delta));
-				var tickString = '';
-
-				if (tickValue !== 0) {
-					var numDecimal = -1 * Math.floor(logDelta);
-					numDecimal = Math.max(Math.min(numDecimal, 20), 0); // toFixed has a max of 20 decimal places
-					tickString = tickValue.toFixed(numDecimal);
-				} else {
-					tickString = '0'; // never show decimal places for 0
-				}
-
-				return tickString;
+				return Chart.Ticks.formatters.linear(tickValue, index, ticks);
 			}
 		}
 	};

src/scales/scale.logarithmic.js

@@ -10,14 +10,7 @@ module.exports = function(Chart) {
 		// label settings
 		ticks: {
 			callback: function(value, index, arr) {
-				var remain = value / (Math.pow(10, Math.floor(helpers.log10(value))));
-
-				if (value === 0) {
-					return '0';
-				} else if (remain === 1 || remain === 2 || remain === 5 || index === 0 || index === arr.length - 1) {
-					return value.toExponential();
-				}
-				return '';
+				return Chart.Ticks.formatters.logarithmic(value, index, arr);
 			}
 		}
 	};

src/scales/scale.radialLinear.js

@@ -31,7 +31,11 @@ module.exports = function(Chart) {
 			backdropPaddingY: 2,
 
 			// Number - The backdrop padding to the side of the label in pixels
-			backdropPaddingX: 2
+			backdropPaddingX: 2,
+
+			callback: function(tickValue, index, ticks) {
+				return Chart.Ticks.formatters.linear(tickValue, index, ticks);
+			}
 		},
 
 		pointLabels: {