Make split_and_orient_path robust to edge cases

lib/glyphs.js

@@ -17,13 +17,24 @@ Glyphs.get_svg_path = function(glyph) {
 
 // Error out if the condition does not hold.
 function assert(condition, message) {
-  if (!condition) throw new Error(message);
+  if (!condition) {
+    console.error(message);
+    throw new Error;
+  }
 }
 
 function clone(point) {
   return [point[0], point[1]];
 }
 
+function equal(point1, point2) {
+  return point1[0] === point2[0] && point1[1] === point2[1];
+}
+
+function valid(point) {
+  return point[0] !== undefined && point[1] !== undefined;
+}
+
 // Takes a non-empty list of SVG commands that may contain multiple contours.
 // Returns a list of lists of path segment objects that each form one contour.
 // Each path segment has three keys: start, end, and control.
@@ -35,6 +46,7 @@ function split_path(path) {
   var result = [[]];
   var start = [path[0].x, path[0].y];
   var current = clone(start);
+  assert(valid(current));
 
   for (var i = 1; i < path.length; i++) {
     var command = path[i];
@@ -45,16 +57,27 @@ function split_path(path) {
         assert(i === path.length - 1, 'Path ended early!');
         return result;
       }
-      var start = {x: command.x, y: command.y};
-      var current = {x: start_point.x, y: start_point.y};
+      var start = [command.x, command.y];
+      var current = clone(start);
+      assert(valid(current));
       continue;
     }
-    assert(command.type === 'Q', 'Got unexpected TTF command: ' + command.type);
+    assert(command.type === 'Q' || command.type === 'L',
+           'Got unexpected TTF command: ' + command.type);
     var segment = {
       'start': clone(current),
       'end': [command.x, command.y],
       'control': [command.x1, command.y1],
     };
+    assert(valid(segment.end));
+    if (equal(segment.start, segment.end)) {
+      continue;
+    }
+    if (!valid(segment.control) ||
+        equal(segment.start, segment.control) ||
+        equal(segment.end, segment.control)) {
+      delete segment.control;
+    }
     result[result.length - 1].push(segment);
     current = clone(segment.end);
   }