polypen: can knife selected edge (issue #1368)

retopoflow/common/bmesh.py

@@ -446,7 +446,7 @@ def is_valid(self):
             all(bme.is_valid for bme in self.loose_bmes),
         ))
 
-    def update(self, context, co, *, distance=1.84467e19, distance2d=10):
+    def update(self, context, co, *, distance=1.84467e19, distance2d=10, ignore_selected=True):
         # NOTE: distance here is local to object!!!  target object could be scaled!
         # even stranger is if target is non-uniformly scaled
 
@@ -459,7 +459,8 @@ def update(self, context, co, *, distance=1.84467e19, distance2d=10):
         bmes = []
         if bme_idx is not None: bmes += [self.loose_bmes[bme_idx]]
         if bmf_idx is not None: bmes += self.bm.faces[bmf_idx].edges
-        bmes = [bme for bme in bmes if not any(bmv.select for bmv in bme.verts)]
+        if ignore_selected:
+            bmes = [bme for bme in bmes if not any(bmv.select for bmv in bme.verts)]
         if not bmes: return
 
         inf = float('inf')

retopoflow/rftool_polypen/polypen_logic.py

@@ -172,7 +172,7 @@ def update(self, context, event, insert_mode, parallel_stable):
         if self.nearest.bmv:
             self.hit = Vector(self.nearest.bmv.co)
 
-        self.nearest_bme.update(context, self.hit)
+        self.nearest_bme.update(context, self.hit, ignore_selected=False)
 
 
         ###########################################################################################
@@ -190,6 +190,11 @@ def update(self, context, event, insert_mode, parallel_stable):
                 self.state = PP_Action.VERT
             return
 
+        if self.nearest_bme.bme:
+            if self.nearest_bme.bme.select and not self.nearest_bme.bme.hide:
+                self.state = PP_Action.EDGE_VERT
+                return
+
         if len(self.selected[BMEdge]) == 0 or insert_mode == 'EDGE-ONLY':
             if not self.nearest.bmv and self.nearest_bme.bme:
                 self.state = PP_Action.VERT_EDGE_EDGE