events: plotly_click, plotly_hover, plotly_unhover

* Include the mouse event in the event data returned by `plotly_click`,
  `plotly_hover` and `plotly_unhover`.

* Keep compatibility with IE9:
  - try `new MouseEvent(type, evt)`,
  - and revert to `initMouseEvent` in case of failure.

Author: n-riesco

src/components/dragelement/index.js

@@ -140,8 +140,22 @@ dragElement.init = function init(options) {
         if(options.doneFn) options.doneFn(gd._dragged, numClicks, e);
 
         if(!gd._dragged) {
-            var e2 = document.createEvent('MouseEvents');
-            e2.initEvent('click', true, true);
+            var e2;
+
+            try {
+                e2 = new MouseEvent('click', e);
+            }
+            catch(err) {
+                e2 = document.createEvent('MouseEvents');
+                e2.initMouseEvent('click',
+                    e.bubbles, e.cancelable,
+                    e.view, e.detail,
+                    e.screenX, e.screenY,
+                    e.clientX, e.clientY,
+                    e.ctrlKey, e.altKey, e.shiftKey, e.metaKey,
+                    e.button, e.relatedTarget);
+            }
+
             initialTarget.dispatchEvent(e2);
         }
 

src/components/dragelement/unhover.js

@@ -44,6 +44,9 @@ unhover.raw = function unhoverRaw(gd, evt) {
     gd._hoverdata = undefined;
 
     if(evt.target && oldhoverdata) {
-        gd.emit('plotly_unhover', {points: oldhoverdata});
+        gd.emit('plotly_unhover', {
+            event: evt,
+            points: oldhoverdata
+        });
     }
 };

src/plots/cartesian/graph_interact.js

@@ -305,6 +305,7 @@ fx.hover = function(gd, evt, subplot) {
 function hover(gd, evt, subplot) {
     if(subplot === 'pie') {
         gd.emit('plotly_hover', {
+            event: evt,
             points: [evt]
         });
         return;
@@ -624,10 +625,14 @@ function hover(gd, evt, subplot) {
     if(!hoverChanged(gd, evt, oldhoverdata)) return;
 
     if(oldhoverdata) {
-        gd.emit('plotly_unhover', { points: oldhoverdata });
+        gd.emit('plotly_unhover', {
+            event: evt,
+            points: oldhoverdata
+        });
     }
 
     gd.emit('plotly_hover', {
+        event: evt,
         points: gd._hoverdata,
         xaxes: xaArray,
         yaxes: yaArray,
@@ -1350,7 +1355,7 @@ function hoverChanged(gd, evt, oldhoverdata) {
 fx.click = function(gd, evt) {
     var annotationsDone = Registry.getComponentMethod('annotations', 'onClick')(gd, gd._hoverdata);
 
-    function emitClick() { gd.emit('plotly_click', {points: gd._hoverdata}); }
+    function emitClick() { gd.emit('plotly_click', {points: gd._hoverdata, event: evt}); }
 
     if(gd._hoverdata && evt && evt.target) {
         if(annotationsDone && annotationsDone.then) {

src/traces/pie/plot.js

@@ -85,7 +85,9 @@ module.exports = function plot(gd, cdpie) {
                     slicePath = sliceTop.selectAll('path.surface').data([pt]),
                     hasHoverData = false;
 
-                function handleMouseOver(evt) {
+                function handleMouseOver() {
+                    var evt = d3.event;
+
                     // in case fullLayout or fullData has changed without a replot
                     var fullLayout2 = gd._fullLayout,
                         trace2 = gd._fullData[trace.index],
@@ -131,8 +133,11 @@ module.exports = function plot(gd, cdpie) {
                     hasHoverData = true;
                 }
 
-                function handleMouseOut(evt) {
+                function handleMouseOut() {
+                    var evt = d3.event;
+
                     gd.emit('plotly_unhover', {
+                        event: evt,
                         points: [evt]
                     });
 
@@ -145,7 +150,7 @@ module.exports = function plot(gd, cdpie) {
                 function handleClick() {
                     gd._hoverdata = [pt];
                     gd._hoverdata.trace = cd.trace;
-                    Fx.click(gd, { target: true });
+                    Fx.click(gd, d3.event);
                 }
 
                 slicePath.enter().append('path')