Fix bug when setting axis_x_tick_rotate to 0 didn't turn ticks

c3.js

@@ -4917,7 +4917,15 @@
     };
     c3_chart_internal_fn.rotateTickText = function (axis, transition, rotate) {
         axis.selectAll('.tick text')
-            .style("text-anchor", rotate > 0 ? "start" : "end");
+            .style("text-anchor", function(){
+                if(rotate > 0){
+                    return 'start';
+                } else if(rotate < 0){
+                    return 'end';
+                } else {
+                    return 'middle';
+                }
+            });
         transition.selectAll('.tick text')
             .attr("y", this.yForRotatedTickText(rotate))
             .attr("transform", "rotate(" + rotate + ")")
@@ -4963,6 +4971,7 @@
         // assume padding is pixels if unit is not specified
         return this.convertPixelsToAxisPadding(padding[key], domainLength);
     };
+
     c3_chart_internal_fn.convertPixelsToAxisPadding = function (pixels, domainLength) {
         var length = this.config.axis_rotated ? this.width : this.height;
         return domainLength * (pixels / length);
@@ -5014,7 +5023,7 @@
         transitions.axisY2.call($$.y2Axis);
         transitions.axisSubX.call($$.subXAxis);
         // rotate tick text if needed
-        if (!config.axis_rotated && config.axis_x_tick_rotate) {
+        if (!config.axis_rotated) {
             $$.rotateTickText($$.axes.x, transitions.axisX, config.axis_x_tick_rotate);
             $$.rotateTickText($$.axes.subx, transitions.axisSubX, config.axis_x_tick_rotate);
         }

src/axis.js

@@ -295,7 +295,15 @@ c3_chart_internal_fn.yForRotatedTickText = function (r) {
 };
 c3_chart_internal_fn.rotateTickText = function (axis, transition, rotate) {
     axis.selectAll('.tick text')
-        .style("text-anchor", rotate > 0 ? "start" : "end");
+        .style("text-anchor", function(){
+            if(rotate > 0){
+                return 'start';
+            } else if(rotate < 0){
+                return 'end';
+            } else {
+                return 'middle';
+            }
+        });
     transition.selectAll('.tick text')
         .attr("y", this.yForRotatedTickText(rotate))
         .attr("transform", "rotate(" + rotate + ")")
@@ -341,6 +349,7 @@ c3_chart_internal_fn.getAxisPadding = function (padding, key, defaultValue, doma
     // assume padding is pixels if unit is not specified
     return this.convertPixelsToAxisPadding(padding[key], domainLength);
 };
+
 c3_chart_internal_fn.convertPixelsToAxisPadding = function (pixels, domainLength) {
     var length = this.config.axis_rotated ? this.width : this.height;
     return domainLength * (pixels / length);
@@ -392,7 +401,7 @@ c3_chart_internal_fn.redrawAxis = function (transitions, isHidden) {
     transitions.axisY2.call($$.y2Axis);
     transitions.axisSubX.call($$.subXAxis);
     // rotate tick text if needed
-    if (!config.axis_rotated && config.axis_x_tick_rotate) {
+    if (!config.axis_rotated) {
         $$.rotateTickText($$.axes.x, transitions.axisX, config.axis_x_tick_rotate);
         $$.rotateTickText($$.axes.subx, transitions.axisSubX, config.axis_x_tick_rotate);
     }