Add zoom API - #610

c3.js

@@ -5533,7 +5533,10 @@
         $$.isTargetToShow(targetId) ? this.hide(targetId) : this.show(targetId);
     };
 
-    c3_chart_fn.zoom = function () {
+    c3_chart_fn.zoom = function (domain) {
+        var $$ = this.internal;
+        $$.brush.extent(domain);
+        $$.redraw({withUpdateXDomain: true});
     };
     c3_chart_fn.zoom.enable = function (enabled) {
         var $$ = this.internal;

spec/api.zoom-spec.js

@@ -0,0 +1,73 @@
+var describe = window.describe,
+    expect = window.expect,
+    it = window.it,
+    beforeEach = window.beforeEach;
+
+describe('c3 api zoom', function () {
+    'use strict';
+
+    var chart, d3;
+
+    var args = {
+        data: {
+            columns: [
+                ['data1', 30, 200, 100, 400, 150, 250],
+                ['data2', 50, 20, 10, 40, 15, 25],
+                ['data3', 150, 120, 110, 140, 115, 125]
+            ]
+        },
+        zoom: {
+            enabled: true
+        }
+    };
+
+    beforeEach(function (done) {
+        if (typeof chart === 'undefined') {
+            window.initDom();
+        }
+        chart = window.c3.generate(args);
+        d3 = chart.internal.d3;
+//        chart.internal.d3.select('.jasmine_html-reporter').style('display', 'none');
+
+        window.setTimeout(function () {
+            done();
+        }, 10);
+    });
+
+    describe('zoom', function () {
+
+        it('should be zoomed properly', function () {
+            chart.zoom([3, 5]);
+            var domain = chart.internal.x.domain();
+            expect(domain[0]).toBe(3);
+            expect(domain[1]).toBe(5);
+        });
+
+        it('should be zoomed properly again', function () {
+            chart.zoom([1, 4]);
+            var domain = chart.internal.x.domain();
+            expect(domain[0]).toBe(1);
+            expect(domain[1]).toBe(4);
+        });
+
+    });
+
+    describe('unzoom', function () {
+
+        it('should be unzoomed properly', function () {
+            var domain;
+
+            chart.zoom([1, 4]);
+            domain = chart.internal.x.domain();
+            expect(domain[0]).toBe(1);
+            expect(domain[1]).toBe(4);
+
+            chart.unzoom();
+            domain = chart.internal.x.domain();
+            expect(domain[0]).toBe(-0.05);
+            expect(domain[1]).toBe(5.05);
+        });
+
+    });
+
+});

src/api.zoom.js

@@ -1,4 +1,7 @@
-c3_chart_fn.zoom = function () {
+c3_chart_fn.zoom = function (domain) {
+    var $$ = this.internal;
+    $$.brush.extent(domain);
+    $$.redraw({withUpdateXDomain: true});
 };
 c3_chart_fn.zoom.enable = function (enabled) {
     var $$ = this.internal;