fixup comments

Author: etpinard

src/traces/contour/convert_to_constraints.js

@@ -14,6 +14,8 @@ var Lib = require('../../lib');
 // need weird range loops and flipped contours instead of the usual format. This function
 // does some weird manipulation of the extracted pathinfo data such that it magically
 // draws contours correctly *as* constraints.
+//
+// ** I do not know which "weird range loops" the comment above is referring to.
 module.exports = function(pathinfo, operation) {
     var i, pi0, pi1;
 
@@ -29,9 +31,8 @@ module.exports = function(pathinfo, operation) {
                 Lib.warn('Contour data invalid for the specified inequality operation.');
             }
 
-            // In this case there should be exactly two contour levels in pathinfo. We
-            // simply concatenate the info into one pathinfo and flip all of the data
-            // in one. This will draw the contour as closed.
+            // In this case there should be exactly one contour levels in pathinfo.
+            // We flip all of the data. This will draw the contour as closed.
             pi0 = pathinfo[0];
 
             for(i = 0; i < pi0.edgepaths.length; i++) {
@@ -54,9 +55,10 @@ module.exports = function(pathinfo, operation) {
                 Lib.warn('Contour data invalid for the specified inequality range operation.');
             }
 
-            // In this case there should be exactly two contour levels in pathinfo. We
-            // simply concatenate the info into one pathinfo and flip all of the data
-            // in one. This will draw the contour as closed.
+            // In this case there should be exactly two contour levels in pathinfo.
+            // - We concatenate the info into one pathinfo.
+            // - We must also flip all of the data in the `[]` case.
+            // This will draw the contours as closed.
             pi0 = copyPathinfo(pathinfo[0]);
             pi1 = copyPathinfo(pathinfo[1]);