scatter3d properly handles error bars with negative lower bounds

Author: antoinerg

Diff for: src/plots/gl3d/scene.js

@@ -523,7 +523,11 @@ proto.plot = function(sceneData, fullLayout, layout) {
                 var objBounds = obj.bounds;
                 var pad = obj._trace.data._pad || 0;
 
-                sceneBounds[0][i] = Math.min(sceneBounds[0][i], objBounds[0][i] / dataScale[i] - pad);
+                if(obj.constructor.name === 'ErrorBars' && axis._lowerLogErrorBound) {
+                    sceneBounds[0][i] = Math.min(sceneBounds[0][i], axis._lowerLogErrorBound);
+                } else {
+                    sceneBounds[0][i] = Math.min(sceneBounds[0][i], objBounds[0][i] / dataScale[i] - pad);
+                }
                 sceneBounds[1][i] = Math.max(sceneBounds[1][i], objBounds[1][i] / dataScale[i] + pad);
             }
 

Diff for: src/traces/scatter3d/calc_errors.js

@@ -21,10 +21,20 @@ function calculateAxisErrors(data, params, scaleFactor, axis) {
 
         if(axis.type === 'log') {
             var point = axis.c2l(data[i]);
+            var min = data[i] - errors[0],
+                max = data[i] + errors[1];
+
             result[i] = [
-                (axis.c2l(data[i] - errors[0]) - point || -point) * scaleFactor,
-                (axis.c2l(data[i] + errors[1]) - point) * scaleFactor
+                (axis.c2l(min, true) - point) * scaleFactor,
+                (axis.c2l(max, true) - point) * scaleFactor
             ];
+
+            // Keep track of the lower error bound which isn't negative!
+            if(min > 0) {
+                var lower = axis.c2l(min);
+                if(!axis._lowerLogErrorBound) axis._lowerLogErrorBound = lower;
+                axis._lowerErrorBound = Math.min(axis._lowerLogErrorBound, lower);
+            }
         } else {
             result[i] = [
                 -errors[0] * scaleFactor,

Diff for: test/image/baselines/gl3d_error_bars_log.png

@@ -2,13 +2,13 @@
     "data": [{
         "x": [0, 1, 2, 3, 4, 5, 6, 7, 8, 9],
         "y": [0, 0, 0, 0, 0, 0, 0, 0, 0, 0],
-        "z": [1e+00, 1e+01, 1e+02, 1e+03, 1e+04,
+        "z": [1e00, 1e+01, 1e+02, 1e+03, 1e+04,
             1e+05, 1e+06, 1e+07, 1e+08, 1e+09
         ],
         "type": "scatter3d",
         "error_z": {
-            "array": [1e-01, 2e+01, 1e+1, 9e+03, 5e+03,
-                0.9e+05, 1e+05, 1e+07, 9e+08, 1e+09
+            "array": [1e-01, 1e+00, 1e+02, 9e+03, 5e+03,
+                0.9e+05, 1e+05, 1e+07, 9e+08, 2e+09
             ],
             "type": "data",
             "visible": true

Diff for: test/image/baselines/gl3d_error_bars_log_2.png

@@ -0,0 +1,22 @@
+{
+    "data": [{
+        "x": [0],
+        "y": [0],
+        "z": [1e-08],
+        "type": "scatter3d",
+        "error_z": {
+            "array": [0.9e-08],
+            "type": "data",
+            "visible": true
+        }
+    }],
+    "layout": {
+        "scene": {
+            "zaxis": {
+                "type": "log"
+            }
+        },
+        "width": 800,
+        "height": 800
+    }
+}