Add colorPattern updater

c3.js

@@ -6058,7 +6058,6 @@
             else {
                 if (ids.indexOf(id) < 0) { ids.push(id); }
                 color = pattern[ids.indexOf(id) % pattern.length];
-                colors[id] = color;
             }
             return callback instanceof Function ? callback(color, d) : color;
         };
@@ -7646,6 +7645,18 @@
         return $$.color(id); // more patterns
     };
 
+    c3_chart_fn.colorPattern = function(pattern){
+        var $$ = this.internal;
+
+        if(!pattern){
+            return $$.config.color_pattern;
+        }
+
+        $$.config.color_pattern = pattern;
+        $$.color = $$.generateColor();
+
+    };
+
     c3_chart_fn.x = function (x) {
         var $$ = this.internal;
         if (arguments.length) {

spec/api.color-spec.js

+describe("c3 chart", function(){
+    'use strict';
+    var chart;
+    var args = {
+        data: {
+            columns: [
+                ['data1', 30, 200, 100, 400, 150, 250],
+                ['data2', 5000, 2000, 1000, 4000, 1500, 2500]
+            ]
+        }
+    };
+ 
+
+    beforeEach(function (done) {
+        chart = window.initChart(chart, args, done);
+    });
+
+    describe("colorPattern", function(){
+        it("should update pattern", function(){
+            chart.colorPattern(['#fff', '#000', '#fff', '#fff']);
+
+            expect(chart.color("data1")).toBe("#fff");
+            expect(chart.color("data2")).toBe("#000");
+        });
+    });
+});

src/api.color.js

@@ -3,3 +3,15 @@ c3_chart_fn.color = function (id) {
     var $$ = this.internal;
     return $$.color(id); // more patterns
 };
+
+c3_chart_fn.colorPattern = function(pattern){
+    var $$ = this.internal;
+
+    if(!pattern){
+        return $$.config.color_pattern;
+    }
+
+    $$.config.color_pattern = pattern;
+    $$.color = $$.generateColor();
+
+};

src/color.js

@@ -20,7 +20,6 @@ c3_chart_internal_fn.generateColor = function () {
         else {
             if (ids.indexOf(id) < 0) { ids.push(id); }
             color = pattern[ids.indexOf(id) % pattern.length];
-            colors[id] = color;
         }
         return callback instanceof Function ? callback(color, d) : color;
     };