fix errorbar when coord input arrays differ from their calc arrays

- for example, when 'x' array is given (i.e. the x0/dx case)
  or when numeric string are inputted.

Author: etpinard

src/traces/scattergl/convert.js

@@ -360,10 +360,11 @@ function convertLinePositions(gd, trace, positions) {
     };
 }
 
-function convertErrorBarPositions(gd, trace, positions) {
+function convertErrorBarPositions(gd, trace, pos, x, y) {
     var calcFromTrace = Registry.getComponentMethod('errorbars', 'calcFromTrace');
-    var vals = calcFromTrace(trace, gd._fullLayout);
-    var count = positions.length / 2;
+    var _trace = Lib.extendFlat({}, trace, {x: x, y: y});
+    var vals = calcFromTrace(_trace, gd._fullLayout);
+    var count = pos.length / 2;
     var out = {};
 
     function put(axLetter) {
@@ -373,25 +374,24 @@ function convertErrorBarPositions(gd, trace, positions) {
         var eOffset = {x: [0, 1, 2, 3], y: [2, 3, 0, 1]}[axLetter];
 
         for(var i = 0, p = 0; i < count; i++, p += 4) {
-            errors[p + eOffset[0]] = positions[i * 2 + pOffset] - ax.d2l(vals[i][axLetter + 's']) || 0;
-            errors[p + eOffset[1]] = ax.d2l(vals[i][axLetter + 'h']) - positions[i * 2 + pOffset] || 0;
+            errors[p + eOffset[0]] = pos[i * 2 + pOffset] - ax.c2l(vals[i][axLetter + 's']) || 0;
+            errors[p + eOffset[1]] = ax.c2l(vals[i][axLetter + 'h']) - pos[i * 2 + pOffset] || 0;
             errors[p + eOffset[2]] = 0;
             errors[p + eOffset[3]] = 0;
         }
 
         return errors;
     }
 
-
     if(trace.error_x && trace.error_x.visible) {
         out.x = {
-            positions: positions,
+            positions: pos,
             errors: put('x')
         };
     }
     if(trace.error_y && trace.error_y.visible) {
         out.y = {
-            positions: positions,
+            positions: pos,
             errors: put('y')
         };
     }

src/traces/scattergl/index.js

@@ -82,7 +82,7 @@ function calc(gd, trace) {
 
     // create scene options and scene
     calcColorscales(trace);
-    var opts = sceneOptions(gd, subplot, trace, positions);
+    var opts = sceneOptions(gd, subplot, trace, positions, x, y);
     var scene = sceneUpdate(gd, subplot);
 
     // Re-use SVG scatter axis expansion routine except
@@ -133,7 +133,7 @@ function calc(gd, trace) {
 }
 
 // create scene options
-function sceneOptions(gd, subplot, trace, positions) {
+function sceneOptions(gd, subplot, trace, positions, x, y) {
     var opts = convertStyle(gd, trace);
 
     if(opts.marker) {
@@ -148,7 +148,7 @@ function sceneOptions(gd, subplot, trace, positions) {
     }
 
     if(opts.errorX || opts.errorY) {
-        var errors = convertErrorBarPositions(gd, trace, positions);
+        var errors = convertErrorBarPositions(gd, trace, positions, x, y);
 
         if(opts.errorX) {
             Lib.extendFlat(opts.errorX, errors.x);

test/image/baselines/gl2d_error_bars.png

@@ -1,5 +1,15 @@
 {
     "data": [
+        {
+            "x": [6],
+            "y": ["2"],
+            "error_y": {
+                "type": "data",
+                "array": [2],
+                "arrayminus": [4]
+            },
+            "type": "scattergl"
+        },
         {
             "x": [
                 0,
@@ -92,6 +102,19 @@
                 "value": 10
             },
             "type": "scattergl"
+        },
+        {
+            "y": [
+                3,
+                3,
+                6,
+                5
+            ],
+            "error_x": {
+                "type": "constant",
+                "value": 0.1
+            },
+            "type": "scattergl"
         }
     ]
 }