2 files changed, 41 insertions, 0 deletions
diff --git a/lib/extensions/__init__.py b/lib/extensions/__init__.py
index b8951e12..b11ba1a4 100644
--- a/lib/extensions/__init__.py
+++ b/lib/extensions/__init__.py
@@ -6,3 +6,4 @@ from simulate import Simulate
 from input import Input
 from output import Output
 from zip import Zip
+from flip import Flip
diff --git a/lib/extensions/flip.py b/lib/extensions/flip.py
new file mode 100644
index 00000000..d8d78cb5
--- /dev/null
+++ b/lib/extensions/flip.py
@@ -0,0 +1,40 @@
+import sys
+import inkex
+import cubicsuperpath
+from shapely import geometry as shgeo
+
+from .base import InkstitchExtension
+from ..i18n import _
+from ..elements import SatinColumn
+
+class Flip(InkstitchExtension):
+    def subpath_to_linestring(self, subpath):
+        return shgeo.LineString()
+
+    def flip(self, satin):
+        csp = satin.path
+
+        if len(csp) > 1:
+            flattened = satin.flatten(csp)
+
+            # find the rails (the two longest paths) and swap them
+            indices = range(len(csp))
+            indices.sort(key=lambda i: shgeo.LineString(flattened[i]).length, reverse=True)
+
+            first = indices[0]
+            second = indices[1]
+            csp[first], csp[second] = csp[second], csp[first]
+
+            satin.node.set("d", cubicsuperpath.formatPath(csp))
+
+    def effect(self):
+        if not self.get_elements():
+            return
+
+        if not self.selected:
+            inkex.errormsg(_("Please select one or more satin columns to flip."))
+            return
+
+        for element in self.elements:
+            if isinstance(element, SatinColumn):
+                self.flip(element)