fix issue with tozeroy/tozerox by only enable new fill behavior for toself/tonext

Author: ruijin

package-lock.json

@@ -110,7 +110,7 @@
     "polybooljs": "^1.2.0",
     "regl": "^1.6.1",
     "regl-error2d": "^2.0.11",
-    "regl-line2d": "git://github.com/ruijin/regl-line2d.git#e9d0198ece05e135557e786d8815c23ed3fb0e9f",
+    "regl-line2d": "git://github.com/ruijin/regl-line2d.git#75188f75010ed77e5f376e7f7dc153cd89813c88",
     "regl-scatter2d": "^3.2.1",
     "regl-splom": "^1.0.12",
     "right-now": "^1.0.0",

package.json

@@ -182,6 +182,9 @@ module.exports = function plot(gd, subplot, cdata) {
                 } else if(trace.fill === 'toself' || trace.fill === 'tonext') {
                     pos = [];
                     last = 0;
+
+                    fillOptions.splitNull = true
+                    
                     for(j = 0; j < srcPos.length; j += 2) {
                         if(isNaN(srcPos[j]) || isNaN(srcPos[j + 1])) {
                             pos = pos.concat(srcPos.slice(last, j));