Fix bar.zerobased and add sample

c3.js

@@ -1259,6 +1259,7 @@
                 domainLength, padding, padding_top, padding_bottom,
                 center = axisId === 'y2' ? __axis_y2_center : __axis_y_center,
                 yDomainAbs, lengths, diff, ratio, isAllPositive, isAllNegative,
+                isZeroBased = (hasBarType(yTargets) && __bar_zerobased) || hasAreaType(yTargets),
                 showHorizontalDataLabel = hasDataLabel() && __axis_rotated,
                 showVerticalDataLabel = hasDataLabel() && !__axis_rotated;
             if (yTargets.length === 0) { // use current domain if target of axisId is none
@@ -1271,7 +1272,7 @@
             isAllNegative = yDomainMin <= 0 && yDomainMax <= 0;
 
             // Bar/Area chart should be 0-based if all positive|negative
-            if ((hasBarType(yTargets) && isBarZerobased()) || hasAreaType(yTargets)) {
+            if (isZeroBased) {
                 if (isAllPositive) { yDomainMin = 0; }
                 if (isAllNegative) { yDomainMax = 0; }
             }
@@ -1305,7 +1306,7 @@
                 padding_bottom = getAxisPadding(__axis_y2_padding, 'bottom', padding, domainLength);
             }
             // Bar/Area chart should be 0-based if all positive|negative
-            if ((hasBarType(yTargets) && isBarZerobased()) || hasAreaType(yTargets)) {
+            if (isZeroBased) {
                 if (isAllPositive) { padding_bottom = yDomainMin; }
                 if (isAllNegative) { padding_top = -yDomainMax; }
             }
@@ -2237,10 +2238,6 @@
             var id = (typeof d === 'string') ? d : d.id;
             return __data_types[id] === 'bar';
         }
-        function isBarZerobased()
-        {
-            return __bar_zerobased;
-        }
         function isScatterType(d) {
             var id = (typeof d === 'string') ? d : d.id;
             return __data_types[id] === 'scatter';

htdocs/index.html

@@ -313,6 +313,12 @@
                 Change radius of data point
               </a>
             </div>
+            <div class="col-md-4">
+              <h3>Bar</h3>
+              <a href="./samples/bar_zerobased.html">
+                Disable zero-based y domain
+              </a>
+            </div>
           </div>
         </div>
       </div>

htdocs/samples/chart_bar.html

@@ -11,8 +11,10 @@
       var chart = c3.generate({
         data: {
           columns: [
-            ['data1', 30, 200, 100, 400, 150, 250],
-            ['data2', 130, 100, 140, 200, 150, 50]
+            ['data1', 1030, 1200, 1100, 1400, 1150, 1250],
+            ['data2', 2130, 2100, 2140, 2200, 2150, 1850]
+//           ['data1', 30, 200, 100, 400, 150, 250],
+//           ['data2', 130, 100, 140, 200, 150, 50]
           ],
           type: 'bar',
           onclick: function (d, element) { console.log("onclick", d, element); },
@@ -27,7 +29,8 @@
         bar: {
           width: {
             ratio: 0.3
-          }
+          },
+          zerobased: false
         }
       });
     </script>