Merge pull request #2418 from inkstitch/lexelby/convert-to-satin-join

produce only one satin from convert to satin

1 files changed, 40 insertions, 0 deletions

diff --git a/lib/elements/satin_column.py b/lib/elements/satin_column.py
index 86c6d05a..4ea26575 100644
--- a/lib/elements/satin_column.py
+++ b/lib/elements/satin_column.py
@@ -713,6 +713,9 @@ class SatinColumn(EmbroideryElement):
         Returns two new SatinColumn instances: the part before and the part
         after the split point.  All parameters are copied over to the new
         SatinColumn instances.
+
+        The returned SatinColumns will not be in the SVG document and will have
+        their transforms applied.
         """
 
         cut_points = self._find_cut_points(split_point)
@@ -825,6 +828,43 @@ class SatinColumn(EmbroideryElement):
 
         return SatinColumn(node)
 
+    def merge(self, satin):
+        """Merge this satin with another satin
+
+        This method expects that the provided satin continues on directly after
+        this one, as would be the case, for example, if the two satins were the
+        result of the split() method.
+
+        Returns a new SatinColumn instance that combines the rails and rungs of
+        this satin and the provided satin.  A rung is added at the end of this
+        satin.
+
+        The returned SatinColumn will not be in the SVG document and will have
+        its transforms applied.
+        """
+        rails = [self.flatten_subpath(rail) for rail in self.rails]
+        other_rails = [satin.flatten_subpath(rail) for rail in satin.rails]
+
+        if len(rails) != 2 or len(other_rails) != 2:
+            # weird non-satin things, give up and don't merge
+            return self
+
+        # remove first node of each other rail before merging (avoid duplicated nodes)
+        rails[0].extend(other_rails[0][1:])
+        rails[1].extend(other_rails[1][1:])
+
+        rungs = [self.flatten_subpath(rung) for rung in self.rungs]
+        other_rungs = [satin.flatten_subpath(rung) for rung in satin.rungs]
+
+        # add a rung in between the two satins and extend it just a litte to ensure it is crossing the rails
+        new_rung = shgeo.LineString([other_rails[0][0], other_rails[1][0]])
+        rungs.append(list(shaffinity.scale(new_rung, 1.2, 1.2).coords))
+
+        # add on the other satin's rungs
+        rungs.extend(other_rungs)
+
+        return self._csp_to_satin(point_lists_to_csp(rails + rungs))
+
     @property
     @cache
     def center_line(self):