Do not bridge actual segments (#3669)

lib/extensions/fill_to_satin.py

@@ -164,7 +164,6 @@ class FillElementToSatin:
         self.rung_sections = defaultdict(list)  # rung_index: section indices
         self.section_rungs = defaultdict(list)  # section index: rung indices
         self.bridged_rungs = defaultdict(list)  # bridge index: rung indices
-        self.rung_bridges = defaultdict(list)  # rung index: bridge indices
 
     def convert_to_satin(self):
         intersection_points, bridges = self._validate_rungs()
@@ -281,7 +280,9 @@ class FillElementToSatin:
                                     continue
                                 rung1 = rung_list[0]
                                 rung2 = rung_list[1]
-                                segment = self._get_segment(rung1, rung2, intersection_points, line_section_multi)
+                                segment = self._get_bridged_segment(rung1, rung2, intersection_points, line_section_multi)
+                                if not segment:
+                                    continue
                                 satin_segments.append(segment)
                                 rung_segments[rung_list[0]].append(segment_index)
                                 rung_segments[rung_list[1]].append(segment_index)
@@ -295,13 +296,16 @@ class FillElementToSatin:
                 pass
         return rung_segments, satin_segments
 
-    def _get_segment(self, rung1, rung2, intersection_points, line_section_multi):
+    def _get_bridged_segment(self, rung1, rung2, intersection_points, line_section_multi):
         rung_sections1 = self.rung_sections[rung1]
         rung_sections2 = self.rung_sections[rung2]
         points1 = self._get_rung_points(rung1, intersection_points)
         points2 = self._get_rung_points(rung2, intersection_points)
 
         connected_section = list(set(rung_sections1) & set(rung_sections2))
+        if len(connected_section) > 1:
+            # this is an unnecessarily bridged section, we can savely skip it
+            return
         if len(connected_section) == 1:
             # do not bridge a segment side if there is an actual section we could use
             segment1 = self.line_sections[connected_section[0]]
@@ -450,11 +454,20 @@ class FillElementToSatin:
                 if section.distance(rung) < 0.01:
                     self.section_rungs[i].append(j)
                     self.rung_sections[j].append(i)
+
+        bridged_rungs = defaultdict(list)
         for i, bridge in enumerate(bridges):
             for j, rung in enumerate(self.rungs):
                 if bridge.intersects(rung):
-                    self.bridged_rungs[i].append(j)
-                    self.rung_bridges[j].append(i)
+                    bridged_rungs[i].append(j)
+
+        # for the case that they - for whatever reason -
+        # drew a bridge over the same rungs twice, clean up duplicated bridges
+        seen_bridged_rungs = []
+        for bridge, rungs in bridged_rungs.items():
+            if rungs not in seen_bridged_rungs:
+                self.bridged_rungs[bridge] = rungs
+            seen_bridged_rungs.append(rungs)
 
     def _validate_rungs(self):
         ''' Returns only valid rungs and bridge section markers'''