cut out duplicate setPositions calls (and loops)

Author: alexcjohnson

src/plot_api/plot_api.js

@@ -237,21 +237,32 @@ Plotly.plot = function(gd, data, layout, config) {
             return;
         }
 
-        var subplots = Plots.getSubplotIds(fullLayout, 'cartesian'),
-            modules = fullLayout._modules;
+        var subplots = Plots.getSubplotIds(fullLayout, 'cartesian');
+        var modules = fullLayout._modules;
+        var setPositionsArray = [];
+        var hasSetPositions = false;
 
         // position and range calculations for traces that
         // depend on each other ie bars (stacked or grouped)
         // and boxes (grouped) push each other out of the way
 
-        var subplotInfo, _module;
+        var subplotInfo, setPositionsFunc, i, j;
 
-        for(var i = 0; i < subplots.length; i++) {
-            subplotInfo = fullLayout._plots[subplots[i]];
+        for(j = 0; j < modules.length; j++) {
+            setPositionsFunc = modules[j].setPositions;
+            if(setPositionsFunc && setPositionsArray.indexOf(setPositionsFunc) === -1) {
+                setPositionsArray.push(setPositionsFunc);
+                hasSetPositions = true;
+            }
+        }
 
-            for(var j = 0; j < modules.length; j++) {
-                _module = modules[j];
-                if(_module.setPositions) _module.setPositions(gd, subplotInfo);
+        if(hasSetPositions) {
+            for(i = 0; i < subplots.length; i++) {
+                subplotInfo = fullLayout._plots[subplots[i]];
+
+                for(j = 0; j < setPositionsArray.length; j++) {
+                    setPositionsArray[j](gd, subplotInfo);
+                }
             }
         }