Retain double float resolution of position data

Author: monfera

Diff for: package.json

@@ -68,7 +68,7 @@
     "gl-plot2d": "^1.1.6",
     "gl-plot3d": "^1.5.1",
     "gl-pointcloud2d": "^1.0.0",
-    "gl-scatter2d": "^1.0.5",
+    "gl-scatter2d": "monfera/gl-scatter2d#64-bit",
     "gl-scatter2d-fancy": "^1.1.1",
     "gl-scatter3d": "^1.0.4",
     "gl-select-box": "^1.0.1",

Diff for: src/lib/float32_truncate.js

@@ -8,14 +8,25 @@
 
 'use strict';
 
+function truncateFloat32(arrayIn, len) {
+    var arrayOut = new Float32Array(len);
+    for(var i = 0; i < len; i++) arrayOut[i] = arrayIn[i];
+    return arrayOut;
+}
+
+function truncateFloat64(arrayIn, len) {
+    var arrayOut = new Float64Array(len);
+    for(var i = 0; i < len; i++) arrayOut[i] = arrayIn[i];
+    return arrayOut;
+}
+
 /**
- * Truncate a Float32Array to some length. A wrapper to support environments
- * (e.g. node-webkit) that do not implement Float32Array.prototype.slice
+ * Truncate a typed array to some length.
+ * For some reason, ES2015 Float32Array.prototype.slice takes
+ * 2x as long, therefore we aren't checking for its existence
  */
-module.exports = function truncate(float32ArrayIn, len) {
-    // for some reason, ES2015 Float32Array.prototype.slice takes 2x as long...
-    // therefore we aren't checking for its existence
-    var float32ArrayOut = new Float32Array(len);
-    for(var i = 0; i < len; i++) float32ArrayOut[i] = float32ArrayIn[i];
-    return float32ArrayOut;
+module.exports = function truncate(arrayIn, len) {
+    if(arrayIn instanceof Float32Array) return truncateFloat32(arrayIn, len);
+    if(arrayIn instanceof Float64Array) return truncateFloat64(arrayIn, len);
+    throw new Error("This array type is not yet supported by `truncate`.")
 };

Diff for: src/traces/scattergl/convert.js

@@ -265,7 +265,7 @@ proto.updateFast = function(options) {
 
     var len = x.length,
         idToIndex = new Array(len),
-        positions = new Float32Array(2 * len),
+        positions = new Float64Array(2 * len),
         bounds = this.bounds,
         pId = 0,
         ptr = 0;