add ternary axis layer mock

Author: etpinard

test/image/baselines/ternary_axis_layers.png

@@ -0,0 +1,59 @@
+{
+    "data": [
+        {
+            "type": "scatterternary",
+            "mode": "markers",
+            "a": [70, 75, 5, 10],
+            "b": [10, 20, 60, 80],
+            "c": [20, 5, 35, 10],
+            "name": "not clipped",
+            "marker": {
+                "symbol": "square",
+                "size": 40,
+                "line": { "width": 4 }
+            },
+            "cliponaxis": false
+        },
+        {
+            "type": "scatterternary",
+            "mode": "markers",
+            "name": "clipped",
+            "a": [10, 20, 10, 15, 10, 20],
+            "b": [90, 70, 20, 5, 10, 10],
+            "c": [0, 10, 70, 80, 80, 70],
+            "marker": {
+                "symbol": "diamond",
+                "size": 30,
+                "line": { "width": 4 }
+            },
+            "cliponaxis": true
+        }
+    ],
+    "layout": {
+        "ternary": {
+            "sum": 100,
+            "aaxis": {
+                "title": "",
+                "layer": "below traces",
+                "linewidth": 4,
+                "min": 4.5
+            },
+            "baxis": {
+                "title": "",
+                "layer": "below traces",
+                "linewidth": 4,
+                "min": 7.5
+            },
+            "caxis": {
+                "title": "",
+                "layer": "below traces",
+                "linewidth": 4,
+                "min": 7.5
+            }
+        },
+        "title": "ternary axes below traces",
+        "showlegend": false,
+        "height": 450,
+        "width": 500
+    }
+}