sunburst rotation

Bringing in suggestions from @alexcjohnson

Author: thierryVergult

src/traces/sunburst/attributes.js

@@ -204,15 +204,13 @@ module.exports = {
         ].join(' ')
     }),
     rotation: {
-        valType: 'number',
+        valType: 'angle',
         role: 'style',
-        min: -180,
-        max: 180,
         dflt: 0,
         editType: 'plot',
         description: [
-            'Instead of the first slice starting at 3 o\'clock,',
-            'rotate to some other angle.'
+            'Rotates the whole diagram counterclockwise by some angle.',
+            'By default the first slice starts at 3 o\'clock.'
         ].join(' ')
     },
     sort: pieAttrs.sort,

src/traces/sunburst/plot.js

@@ -150,6 +150,14 @@ function plotOne(gd, cd, element, transitionOpts) {
     // filter out slices that won't show up on graph
     sliceData = sliceData.filter(function(pt) { return pt.y1 <= cutoff; });
 
+    if(trace.rotation && trace.rotation !== 'auto') {
+        var extraAngle = trace.rotation * Math.PI / 180;
+        sliceData.forEach(function(pt) {
+            pt.x0 += extraAngle;
+            pt.x1 += extraAngle;
+        });
+    }
+
     // partition span ('y') to sector radial px value
     var maxY = Math.min(maxHeight, maxDepth);
     var y2rpx = function(y) { return (y - yOffset) / maxY * rMax; };
@@ -220,10 +228,6 @@ function plotOne(gd, cd, element, transitionOpts) {
             s.style('pointer-events', 'all');
         });
 
-        var extraAngle = trace.rotation * Math.PI / 180;
-        pt.x0 = pt.x0 + extraAngle;
-        pt.x1 = pt.x1 + extraAngle;
-
         pt.rpx0 = y2rpx(pt.y0);
         pt.rpx1 = y2rpx(pt.y1);
         pt.xmid = (pt.x0 + pt.x1) / 2;