Gradient color: fix cache key error (#4007)

* use first stop color for non linear gradient fill objects
* fix bug in get_cache_key for gradient objects

2 files changed, 10 insertions, 2 deletions

diff --git a/lib/elements/element.py b/lib/elements/element.py
index 6b1ca47c..f1e6eb36 100644
--- a/lib/elements/element.py
+++ b/lib/elements/element.py
@@ -12,7 +12,7 @@ from typing import List, Optional
 
 import inkex
 import numpy as np
-from inkex import BaseElement, bezier
+from inkex import BaseElement, Color, bezier
 from shapely import Point as ShapelyPoint
 from shapely.ops import nearest_points
 
@@ -599,6 +599,10 @@ class EmbroideryElement(object):
         stitch_plan_cache = get_stitch_plan_cache()
         cache_key = self.get_cache_key(previous_stitch, next_element)
         if cache_key not in stitch_plan_cache:
+            # fix up colors for cache
+            for stitch_group in stitch_groups:
+                if not isinstance(stitch_group.color, Color):
+                    stitch_group.color = "black"
             stitch_plan_cache[cache_key] = stitch_groups
 
         if previous_stitch is not None:
diff --git a/lib/elements/fill_stitch.py b/lib/elements/fill_stitch.py
index 7ce3188a..3c871b8e 100644
--- a/lib/elements/fill_stitch.py
+++ b/lib/elements/fill_stitch.py
@@ -632,7 +632,11 @@ class FillStitch(EmbroideryElement):
 
     @property
     def color(self):
-        return self.fill_color
+        color = self.fill_color
+        # if color is a gradient, pick the first color
+        if isinstance(color, LinearGradient):
+            color = self._get_color(color.stops[0], "stop-color", "black")
+        return color
 
     @property
     def gradient(self):