add support for selection of aggregations

- similar to pointNumber and pointNumbers, make the distinction
  between 1-to-1 input to selection/hovered pt and many-to-1 maps
  like for histogram traces and aggregation transforms.

Author: etpinard

src/components/fx/helpers.js

@@ -111,6 +111,17 @@ exports.makeEventData = function makeEventData(pt, trace, cd) {
         pointNumber: pointNumber
     };
 
+    if(trace._indexToPoints) {
+        var pointIndices = trace._indexToPoints[pointNumber];
+
+        if(pointIndices.length === 1) {
+            out.pointIndex = pointIndices[0];
+        } else {
+            out.pointIndices = pointIndices;
+        }
+    } else {
+        out.pointIndex = pointNumber;
+    }
 
     if(trace._module.eventData) {
         out = trace._module.eventData(out, pt, trace, cd, pointNumber);

src/plots/cartesian/select.js

@@ -308,8 +308,13 @@ function updateSelectedState(gd, searchTraces, eventData) {
             var data = pt.data;
             var fullData = pt.fullData;
 
-            data.selectedpoints.push(pt.pointIndex);
-            fullData.selectedpoints.push(pt.pointIndex);
+            if(pt.pointIndices) {
+                data.selectedpoints = data.selectedpoints.concat(pt.pointIndices);
+                fullData.selectedpoints = fullData.selectedpoints.concat(pt.pointIndices);
+            } else {
+                data.selectedpoints.push(pt.pointIndex);
+                fullData.selectedpoints.push(pt.pointIndex);
+            }
         }
     }
     else {

src/traces/histogram/event_data.js

@@ -25,6 +25,19 @@ module.exports = function eventData(out, pt, trace, cd, pointNumber) {
         out.pointNumbers = pts;
         out.binNumber = out.pointNumber;
         delete out.pointNumber;
+        delete out.pointIndex;
+
+        var pointIndices;
+        if(trace._indexToPoints) {
+            pointIndices = [];
+            for(var i = 0; i < pts.length; i++) {
+                pointIndices = pointIndices.concat(trace._indexToPoints[pts[i]]);
+            }
+        } else {
+            pointIndices = pts;
+        }
+
+        out.pointIndices = pointIndices;
     }
 
     return out;