Merge pull request #7148 from plotly/refactor-before-fix-zorder

Some refactor before fixing zorder bug

Author: archmoj

src/plots/cartesian/index.js

@@ -244,7 +244,7 @@ function plotOne(gd, plotinfo, cdSubplot, transitionOpts, makeOnCompleteCallback
                 if(cdModule.length) {
                     layerData.push({
                         i: traceLayerClasses.indexOf(classBaseName),
-                        zorder: z,
+                        zindex: z,
                         className: className,
                         plotMethod: plotMethod,
                         cdModule: cdModule
@@ -257,10 +257,10 @@ function plotOne(gd, plotinfo, cdSubplot, transitionOpts, makeOnCompleteCallback
             }
         }
     }
-    // Sort the layers primarily by z, then by i
+    // Sort the layers primarily by zindex, then by i
     layerData.sort(function(a, b) {
         return (
-            (a.zorder || 0) - (b.zorder || 0) ||
+            (a.zindex || 0) - (b.zindex || 0) ||
             (a.i - b.i)
         );
     });

test/image/baselines/zorder-overlayed-subplots-multiple-traces-main-subplot.png

@@ -43,10 +43,7 @@
  "layout": {
   "showlegend": true,
   "title": {
-   "text": "zorder overlayed subplots - multiple on the same subplot",
-   "subtitle": {
-    "text": "Orange trace is displayed on top!"
-   }
+   "text": "zorder overlayed subplots - multiple on the same subplot"
   },
   "width": 600,
   "height": 400,

test/image/baselines/zorder-overlayed-subplots-multiple-traces-main-subplot2.png

@@ -43,10 +43,7 @@
  "layout": {
   "showlegend": true,
   "title": {
-   "text": "zorder overlayed subplots - multiple on the same subplot",
-   "subtitle": {
-    "text": "Orange trace is displayed on top!"
-   }
+   "text": "zorder overlayed subplots - multiple on the same subplot"
   },
   "width": 600,
   "height": 400,